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Example Analysis of a MAGIC GRB Observation at CALP. Markus Gaug (IAC Tenerife). Introduction. Gamma Ray Burst observations can happen at any time during the night (incl. during twilight) and at any zenith angle up to 60 deg.

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introduction
Introduction

Gamma Ray Burst observations can happen at any time during the night (incl. during twilight) and at any zenith angle up to 60 deg.

Observation conditions can cover everything from dark night to clouds and/or moon light and/or twilight.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction3
Introduction

Expected signals can be fast (up to variations <1 s) and/or slow (emission during >1 h).

VHE gamma-ray emission can be correlated with -ray, X-ray or optical emission peaks or not!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction4
Introduction

The earlier the telescope observes, the higher the chance to catch a signal. For this reason, MAGIC observes fully automatically in GRB observation mode, even if the quality of the observation could improve by adjusting the telescope to the conditions found at the new sky position.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction5
Introduction

Multi-wavelength observations are triggered by GCN circulars to which also MAGIC sends reports.

The reports by MAGIC should arrive as soon as possible, at best within days.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction6
Introduction

For this reason, an automatic analysis has been set up at CALP (Centro Astrofisica en La Palma) - to which all members of the GRB WG have access.

The analysis consists of the MARS analysis software, with the inclusion of the mtemp/mgrb directory and a couple of perl-scripts found in the mtemp/mcalp directory of MARS. This documentation was obtained with Mars_V1-7-13.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction7
Introduction
  • The GRB data is usually calibrated at the

Roque on the muxana machine.

The data are transferred to CALP

automatically via a permanent link to:

/datm1/magic/INCOMING/YYYY_MM_DD/

  • The automatic analysis takes these data

and copies them to:

/datm1/magic/GRB/GRBYYMMDD/Calibrated

  • From there, star files, melibea files,

celestina output and upper limits are

created.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction8
Introduction
  • An OFF database has been created at

CALP:

/datm1/magic/OFFData/PSF_XXmm

  • A MC database can be found at:

/datm1/magic/MonteCarlo/M1/PSF_XX.Xmm

  • All RF and DISP matrices have been

produced for all zenith angle ranges:

/datm1/magic/OFFData/PSF_XXmm/Theta_XX_YY/NoMoon/RandomForest/

  • Two standard image cleanings are used so

far: ”Abs” and “Diego”

(at PIC the corresping names are:“notime” and “time”)

introduction9
Introduction

This presentation should be used as a manual to run and understand the automatic analysis.

As exemplary data the especially difficult to analyze data of GRB071112C was used.

The analysis was launched (automatically) via:

$MARSSYS/mtemp/mcalp/analyze <GRB> <author>

e.g.:

$MARSSYS/mtemp/mcalp/analyze GRB071112C Gaug

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction10
Introduction

The automatic analysis will do everything including a draft for an analysis report and a GCN circular.

However you have to check every step for correctness and complete the analysis report.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction11
Introduction

PLEASE DO NOT RUN THE ANALYSIS ON ALREADY ANALYZED GRB DATA!

IT MIGHT OVERWRITE EXISTING DATA….

INSTEAD APPOINT YOURSELF AS A BURST ADVOCATE AND TRY OUT A NEW BURST

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

introduction12
Introduction

For further information about the (general) analysis framework MARS, see:

http://magic.pic.es/wiki

In case of problems with anything related to the GRB analysis, do not hesitate to contact Markus Gaug ([email protected])

At the beginning, this will be the normal case…

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the data
The Data

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the data14
The Data
  • We start our example analysis with the output

of the star-files of GRB01112C,

runs 299332-299437

  • Additionally the star file from

run 299331 (last file from previous run taken

before this burst occurred) has been used to

calculate the reaction times

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide15
STAR

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the output of star
The output of STAR

The STAR program can be run with the following script:

$MARSSYS/mtemp/mcalp/runstar.pl <GRBname> <cleaning>

(this script is launched automatically by the analyze program, with the cleanings “Abs” and “Diego”)

STAR removes spurious noise from the night sky (image cleaning) and calculates suitable parameters of the remaining camera images.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file
The star.root file

We check first the output of star:

showplot/datm1/magic/GRB/GRB071112C/Star/Star_Diego/star.root

or

showplot/datm1/magic/GRB/GRB071112C/Star/Star_Abs/star.root

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file18
The star.root file

Increase in event rate after 10 min. of data. A GRB?

Short period with

no events

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file19
The star.root file

A closer look reveals 3 peak in event rate…

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file20
The star.root file

[2007-11-12 19:44:06]

We have a GRB alert. We follow the established procedure and contact Daniel Kranich in order to modify the schedule. Nicola Galante contacts us also to inform about the nature of this GRB.

[2007-11-12 20:20:33]

Car flashes in runs number 299343, 299344 and 299345.

We have a look in that nights runbook

available at:http://magic.pic.es/datacenter/CCdata/2007_11/2007_11_13/CC_2007_11_12_18_07_50.rbk

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file21
The star.root file

The gap in obs. time occurs during 4.5 minutes

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file22
The star.root file

[2007-11-12 21:46:13]

We stop GRB datataking in order to restart it and take pedestal and calibration files, as suggented by Markus Garcz. We also set extragalactic DT. We continue observing.

We have again a look in that nights runbook

available at:http://magic.pic.es/datacenter/CCdata/2007_11/2007_11_13/CC_2007_11_12_18_07_50.rbk

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file23
The star.root file

Several drops in rate

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file24
The star.root file

Generally, rate increases with time showing two more peaks right after observation gap

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file25
The star.root file

Before the observation gap: Moon Discriminator thresholds

After the observation gap: NoMoon Discriminator thresholds

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file26
The star.root file

--------------------------------------------------------------------

Source Kind Time Evts Rate Zd HD-spc

(min) (Hz) (deg) (GB)

--------------------------------------------------------------------

0851+202-W0.40+000 59 772k 218 10->30 43.1

0851+202-W0.40+180 72 972k 224 8->33 54.3

Crab-SUM 81 3983k 822 7->22 222.5

GRB071112-18 158 1557k 165 22->57 87.0

GRB071112-18 Moon 12 100k 137 57->59 5.6

We have again a look in that nights runbook

available at:http://magic.pic.es/datacenter/CCdata/2007_11/2007_11_13/CC_2007_11_12_18_07_50.rbk

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file27
The star.root file

Mean event rate >100 Hz: OK

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide28

Conclusions from the rate plots

  • At the beginning the moon was still shining and therefore the

operators had “moon” discriminator thresholds (DTs) set. These

DTs are too high for normal data taking resulting in a low rate.

--> take into account for efficiency correction of the upper limits

  • After two hours, the shifters stopped the observation to take

a pedestal and calibration run, and reset the DTs to correct

(lower) values.

--> From that time on the efficiency correction becomes smaller

  • 3 car flashes and 3 (not understood) smaller increases in rate

--> At these times, be careful with patterns in the light curve

  • 3 drops in event rate are found

--> have to check if clouds are responsible

the star root file29
The star.root file

Number of correctly focused mirrors must always be on thereference line (otherwise this analysis is not valid!)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file30
The star.root file

There are also clusters with NO signal :

If these were inner pixels, we could not analyze these data without special MonteCarlo!!!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file31
The star.root file

We see clusters with much higher signal than other pixels

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file32
The star.root file

In the plot with “Used pixels”, the clusters of excess signal have disappeared.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide33

Conclusions from the camera plots

  • Two clusters of not working outer pixels are found.

Fortunately, only outer pixels are affected…

--> take into account for efficiency correction of the upper limits

  • Three clusters of pixels with high average signal are found,

however the pixels are not part of an image more frequently

--> From experience we know that these are pixels sparking at a

rate of ~1 Hz. A dedicated spark-cut is used later in the

analysis, however this cut is not 100% efficient.

--> If at the end of the analysis, more events in these regions

are found, be careful

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file34
The star.root file

Correlated with the decrease of discriminator thresholds the inhomogeneity of the camera response becomes better.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file35
The star.root file

Correlated with the car flashes, the image reconstruction efficiency becomes worse (car flash events are above all very small events).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file36
The star.root file

Number of photo-electrons plot should follow a power-law with low- and high-energy cutoffs.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file37
The star.root file

Distance of shower center from center of camera should rise linearly until end of trigger region

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file38
The star.root file

Distribution of center of gravity should be uniform in azimuth (--> strong inhomogeneity here!)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file39
The star.root file

Distribution of Alpha parameter should be flat

(--> strong inhomogeneity here!)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file40
The star.root file

Distribution of number of core pixels should show a power law with cut-off

(--> tail of events with many core pixels found!)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide41

Conclusions from the Hillas parameters

  • Strong inhomogeneity of the camera has been found, above all

in the first part of the observation with high DT values

--> take into account for efficiency correction of the upper limits

  • The distribution of core pixels show a not expected tail at high

numbers of core pixels

--> We will investigate this now

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide42

Test of the strange distribution of variable MImagePar.fNumSinglePixels:

  • We go to the Star directory of GRB071112C:

> cd /datb/magic/GRB/GRB071112C/Star

  • We start ROOT:

> root

  • We load the MARS library:

> .x $MARSSYS/macros/rootlogon.C

  • We create a TChain object:

> TChain *c = new TChain(“Events”);

  • We load the GRB data:

> c->Add(“2007*.root”);

  • We check if files have been loaded:

> c->GetEntries();

> (const Long64_t)1098087

  • We draw the variable over time:

> c->Draw("MImagePar.fNumSinglePixels:MTime.fTime.fMilliSec/1000.","MImagePar.fNumSinglePixels>5",”colz”)

The output ---->

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

checking variable mimagepar fnumsinglepixels
Checking variable MImagePar.fNumSinglePixels

High values coincide with the car flashes, for the moment nothing to worry about the rest of data…

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file44
The star.root file

The cloudiness parameter (blue line) is generally very high and sometimes > 50%

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the star root file45
The star.root file

Very clear anti-correlations of cloudiness with event rate are visible.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide46

Conclusions from the Pyrometer plots

It seems that the sky was cloudy over some periods

We cannot produce a reasonable upper limit in the cases

when the cloudiness was >50%.

We simply do not know at which height the clouds were

and therefore do not know anything about the absorption

of gamma-ray showers!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

melibea
MELIBEA

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the output of melibea
The output of MELIBEA

The MELIBEA program can be run with the following script:

$MARSSYS/mtemp/mcalp/runmelibea.pl <GRBname> <cleaning> <PSF> 0

(this script is launched automatically by the analyze program, with the cleanings “Diego” and “Abs” and a corresponding simulated point-spread-function (PSF) for MC images (typically “10.6mm”). The “0” stands for ON/OFF observation)

MELIBEA performs an energy reconstruction, makes an estimate of the arrival direction (the DISP) and calculates a hadronness parameter for each event.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the output of melibea49
The output of MELIBEA

MELIBEA stores also the distribution of pointing offsets, obtained from the starguider.

The runmelibea.pl scripts will use this distribution to apply the same pointing offsets to OFF data in a second melibea loop.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files
The melibea.root files

If the zenith angle range is large, the automatic

analysis will:

  • remove runs with average cloudiness > 50%.
  • split the data into parts which match

reasonable zenith angles ranges with MC

zbins.

  • select MC azimuth angles which minimize

the differences of the effects of geomagnetic

field between MC and ON data.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files51
The melibea.root files

In our case, the following files have survived the cloudiness cut:

the melibea root files52
The melibea.root files

We check the output of each melibea file:

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299332_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299342_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299352_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299362_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299373_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299392_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299406_M1.root

showplot /datm1/magic/GRB/GRB071112C/Melibea/melibea00299432_M1.root

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files53
The melibea.root files

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files54
The melibea.root files

Observations span a wide zenith angle range

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files55
The melibea.root files

At the beginning, not yet correct pointing

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files56
The melibea.root files

Huge punctual mispointing, not yet understood..

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files57
The melibea.root files

Quality of starguider OK during whole period!

(Number of identified stars always > 20)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files58
The melibea.root files

Sky brightness slowly decreasing, although

rather high ( > 50) --> maybe because of clouds???

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files59
The melibea.root files

Huge mispointing at beginning of run, several smaller (big) mispointing corrections…

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide60

Conclusions from the starguider plots:

  • At the beginning the telescope was still slewing until reaching

the correct pointing

--> have to take into account for time ranges of the limits

  • Four starguider reports show big mispointing, for unknown

reasons (number of identified stars is always OK)

  • Sky brightness rather high, but constant
  • Zenith angle range is huge

--> maybe clouds?

the analysis will (automatically) split the data in smaller zenith

angle bins from now on

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files61
The melibea.root files

Data is described better using AZ=90

deg MC files w.r.t. orientation towards magn. field

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files62
The melibea.root files

A cut in the number of photo-electrons has been applied now

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files63
The melibea.root files

A cut in the nr. of residual image islands after cleaning has been applied now

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files64
The melibea.root files

Distribution in number of single core pixels still problematic (in first sequence)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files65
The melibea.root files

A cut on the image leakage has been applied now

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files66

ON data (runs 299343 - 299352)

OFF data ( = 50-56 deg.)

The melibea.root files

Distribution of pointing offsets (from starguider)

show considerable offsets (10mm ~1 pixel) in both x and y.

The same offset is applied to OFF data

(in OffMelibea/Theta_XX_YY/melibea.root).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files67
The melibea.root files

Increasing shower energy

The camera inhomogeneity decreases with increasing shower energy (distribution of center-of-gravity of showers becomes more uniform).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files68
The melibea.root files

Skip-non-shower cuts have removed quite some car flash images above 100 ph.e.

the melibea root files69
The melibea.root files

Also filter cuts have removed car flash images (at all sizes)

the melibea root files70
The melibea.root files

Hadronness distribution dominated by hadron-like events for all sizes (this is normal)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the melibea root files71
The melibea.root files

Decreasing zenith angle

The lower the zenith angle, less energetic showers are captured in a given image size

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide72

Conclusions from the melibea plots:

  • A considerable pointing offset (> 1 inner pixel) is detected which

is corrected and applied in the same way to OFF data.

  • The skip-non-showers and filter-cuts have removed (not all)

images from the car flashes

  • The distribution in number of core pixels is still not OK

--> have to check in the end with all cuts applied!

  • The hadronness parameter separates worse at lower zenith

angles for a given (small) size. This is normal since at low zenith

angles, small sizes correspond to very small gamma-ray energies

where the telescope is largely dominated by background.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

getting more information
Getting more information

We retrieve times, PSF and atm. extinction:

> cd /datb/magic/GRB

> $MARSSYS/mtemp/mgrb/grbinfo GRB071112C <password>

(this is done automatically by the “analyze” script, use the usual MAGIC password)

No extinction coefficient available for night starting on 071112

Burst related times:

T0: 2007/11/12 18:32:58

GCN report time: 2007/11/12 18:50:05 GMT

GSPOT alert time: 2007/11/12 18:33:53

Scheduled obs. start: 2007/11/12 19:44:29

Scheduled obs. end: 2007/11/12 22:32:56

Detector related information:

Corresp. PSF: 10.52 mm

  • Now we know that:
  • No atm. extinction coeff.

are available for that night

  • GRB T0 is: 18:32:58
  • The alert was received

53 seconds later

  • The PSF was 10.5 mm

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

getting more information74
Getting more information

We retrieve drive times:

> cd GRB071112C

> $MARSSYS/mtemp/mgrb/grbdrive GRB071112C 18:32:58 18:33:53

(this is done automatically by the “analyze” script)

T0 GRB: 12.11.2007 18:32:57.000

Received alert: 12.11.2007 18:33:53.000

End previous run: 12.11.2007 19:44:45.000

Start first run: 12.11.2007 19:44:48.000

Reaction time shifters: 4252 seconds

Time difference between runs: 3 seconds

Overall time lost before first run: 4311 seconds

zenith GRB report nr.0: 43.5272 at: 12.11.2007 19:44:48.386

zenith GRB report nr.1: 52.495 at: 12.11.2007 19:44:54.583

zenith GRB report nr.2: 59.9444 at: 12.11.2007 19:45:04.695

zenith GRB report nr.3: 59.9244 at: 12.11.2007 19:45:14.983

azimuth GRB report nr.0: 23.2917 at: 12.11.2007 19:44:48.386

azimuth GRB report nr.1: 40.555 at: 12.11.2007 19:44:54.583

azimuth GRB report nr.2: 71.7544 at: 12.11.2007 19:45:04.695

azimuth GRB report nr.3: 71.9508 at: 12.11.2007 19:45:14.983

Now we know that from

19:45:05on, the

telescope was pointing

correctly to GRB071112C

upper limits
UPPER LIMITS

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the output of analyzegrb
The output of ANALYZEGRB

The ANALYZEGRB program can be run with the following script:

$MARSSYS/mtemp/mcalp/runupperlimits.pl <GRBname> <cleaning> <PSF> 0

(this script is launched automatically by the analyze program, with the cleanings “Diego” and “Abs” and a corresponding simulated point-spread-function (PSF) for MC images (typically “10.6mm”). The “0” stands for ON/OFF observation)

ANALYZEGRB performs alpha plots for various energy bins, calculates upper limits, makes light curves and performs a peak emission search.

It is steered by a configuration file (“grb.rc”) which allows to modify important configuration settings.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files
The UL.root files

If the zenith angle range is large, the automatic

analysis will:

  • split the data into parts which match reason-

able zenith angles ranges with MC zbins

(the ranges are bigger than in the case of melibea here).

  • select the corresponding OFF data files

(prepared by melibea and found in the OffMelibea directory)

  • select the corresponding MC files

(with azimuth angles which minimize the differences of the effects

of the geomagnetic field between MC and ON data).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files78
The UL.root files

The following files have been used to calculate ULs:

the ul root files79
The UL.root files

We check the output of each UL file:

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299332_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299343_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299353_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299373_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299392_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299406_M1.root

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299432_M1.root

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files80
The UL.root files

Constant discriminators and energy threshold of 537 GeV.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files81
The UL.root files

At the beginning, nominal and current pointing discrepe. The black error indicates the start of correct pointing.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files82
The UL.root files

Cloudiness is now, by construction, always smaller than 50%.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files83
The UL.root files

No prominent feature in the rate of events ALPHA< 20 deg

This is the only plot shown without hadronness cut!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files84
The UL.root files

Here an excess of events ALPHA< 20 deg correlates with

the background events (blue, ALPHA>20 deg)!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files85
The UL.root files

Event rate per energy bin shows no prominent features.

First bin left out due to high energy thres. at high zenith angle).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide86

Conclusions from the RATES plots

No apparent feature is seen in any of the rates plots,

at any energy range, except for once when also the

background shows the same feature.

This rise coincides in time with the car flashes reported by

the shifters.

For these two reasons (same feature in background and car

flash report by shifters), we do not care any further about this

rise in event rates. Especially we do NOT attribute it to

gamma-ray emission of GRB071112C!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files87
The UL.root files

Calculation of the upper limit of one energy bin.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files88
The UL.root files

After all cuts, w/o Erec cut

After all cuts, 125<Erec<175 GeV

Collection area reaches > 105 m2.

Once cuts in rec. energy are applied, the collection area decreases and shows an approx. Gaussian distribution around the energy bin.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files89
The UL.root files

The energy threshold rises with increasing zenith angle

The collection area at high energies rises with zenith angle.

Increa-sing

zenith

angle

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files90
The UL.root files

Energy reconstruction works correctly, except for events below the threshold.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files91
The UL.root files

The energy threshold rises with increasing zenith angle

The acceptance at high energies rises with zenith angle.

Increa-sing

zenith

angle

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files92
The UL.root files

The mean energy of an energy bin is calculated.

(The mean of a Gauss fit to the distribution gives the “threshold”).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files93
The UL.root files

The mean image size decreases with increasing zenith angle for a same

energy bin.

Increa-sing

zenith

angle

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide94

Conclusions from the EFFECTIVE AREAS

Our observations span a wide range in zenith angle.

During these observations, the effective area and size

of the shower images changesconsiderably at all

energies, but most at low and medium energies!

This is the reason to split up the upper limits into bins of

zenith angle (equiv. to bins in observation time).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files95
The UL.root files

300 - 1000 GeV

ALPHA PLOTS

for each energy bin are calculated.

(The cut in ALPHA is shown by the black lines).

A possible excess is seen below the ALPHA cut

(in red vs. to the blue background)

175 - 300 GeV

125 - 175 GeV

80 - 125 GeV

slide96

300 - 1000 GeV

175 - 300 GeV

125 - 175 GeV

80 - 125 GeV

ALPHA PLOTS

results for each energy bin are shown.

(The cut in ALPHA is shown by the black lines).

slide97

300 - 1000 GeV

175 - 300 GeV

125 - 175 GeV

80 - 125 GeV

Frequentistupper limits

(method by Feldman&Cousins) for each energy bin are shown.

Should agree more or less with Helene!

Sometimes, this method does not work in ROOT.

slide98

300 - 1000 GeV

175 - 300 GeV

125 - 175 GeV

80 - 125 GeV

Frequentistupper limits

including syst. uncertainties

(method by Rolke et al.)

for each energy bin are shown:

0% syst. error

30%syst. error

with and w/o eff. correction due to higher DT thresholds

slide99

300 - 1000 GeV

175 - 300 GeV

125 - 175 GeV

80 - 125 GeV

Frequentist upper limits

including syst. uncertainties

(method by Rolke et al.):

Finally used are the values with eff. correction and a 30% syst. Uncertainty.

the ul root files100
The UL.root files

Table with upper limits for the respective time interval,

converted to fluxes and fluences.

(Values well below the energy threshold are marked in grey).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files101
The UL.root files

Interval and mean energy to which the differential limits apply.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files102
The UL.root files

The applied hadronness cut of the energy bin.

(defined in the grb.rc configuration file).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files103
The UL.root files

The applied ALPHA cut of the energy bin.

(defined in the grb.rc configuration file).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files104
The UL.root files

The differential flux limits of each energy bin.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files105
The UL.root files

The differential fluence limits of each energy bin

(multiplied with <E>2).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files106
The UL.root files

The differential flux limits in units of Crab Nebula flux

(with Fcrab = 0.0015* (E/GeV) -2.58 (ph/cm2/s/TeV)).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files107
The UL.root files

The joint alpha plots of the different zenith ranges can be found in

/datm1/magic/GRB/GRB071112C/UpperLimits/AlphaPlot_0080-0125GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/AlphaPlot_0125-0175GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/AlphaPlot_0175-0300GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/AlphaPlot_0300-1000GeV.root

All are visible with the “showplot” command

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide108

Conclusions from the ALPHA PLOTS

Our observations span a wide range in zenith angle.

Therefore, many ALPHA PLOTS have been produced

for different zenith angle bins and energy ranges.

No significant excess has been observed and upper limits

calculated using different statistical methods.

The introduction of the correction factors and the systematic

uncertainty greatly worsens the limits!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

light curves
LIGHT CURVES

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the light curves
The light curves
  • The light curves are calculated from alpha

plots, in time intervals of 10 minutes.

  • The same OFF data is used as for the overall

ALPHA plots.

  • Apart from the evolution of the number of

excess events, also the evolution of the

estimated background in the signal region

(from ALPHA = 0 to the alpha cut) is shown.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files111
The UL.root files

The light curve of an energy bin is calculated.

(In blue the estimated number of background events).

The x-axis shows the time passed since T0 of GRB071112C

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files112
The UL.root files

The light curve of the different zenith ranges have different

y-axis scales .

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files113
The UL.root files

The joint light curve of the different zenith ranges can be found in

/datm1/magic/GRB/GRB071112C/UpperLimits/LightCurve_0080-0125GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/LightCurve_0125-0175GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/LightCurve_0175-0300GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/LightCurve_0300-1000GeV.root

All are visible with the “showplot” command

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide114

EXCESS EVENTS

fluctuate around zero in each energy bin.

BACK-GROUND

shows the same evolution as the collection area (in energy bins)

with decreasing zenith angle

300 - 1000 GeV

175 - 300 GeV

Increasing zenith angle

125 - 175 GeV

80 - 125 GeV

the ul root files115
The UL.root files

In the first energy bin, the light curve shows an excess.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files116
The UL.root files

We investigate the corresponding ALPHA PLOT:

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/ULs00299392_M1.root

and find a significance of 3.56 sigma…

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files117
The UL.root files

What is the probability to obtain by chance a point with 3.56 sigma out of 32 light curve points?

  • root -b
  • .x $MARSSYS/macros/rootlogon.C
  • MMath::ProbSigma(3.56)
  • (Double_t)3.70854825731958826e-04
  • MMath::ProbOneOutOfMany(3.7E-4, 32)
  • (Double_t)1.17993902112053517e-02
  • MMath::GaussSigma(1.18E-2)
  • (Double_t)2.51806958446816243e+00

The overall probability for such a point by background fluctuations

is thus 2.5 sigma, smaller than the required 3 sigma.

the ul root files118
The UL.root files

We investigate again the ALPHA PLOT:

and find that the excess does not peak at ALPHA = 0

! WE CONCLUDE THAT THE EXCESS IS NOT SIGNIFICANT !

slide119

Conclusions from the LIGHT CURVES

Our observations span a wide range in zenith angle.

Therefore, the hadronic background in one given

energy bin varies considerably. This is visible in the

size of the error of each point of the light curve.

One significant excess of 3.5  significance has been observed.

After correction with the trial factor, a 2.5effect is left.

As the excess does not peak towards ALPHA=0, we conclude

that a statistical fluctuation was observed!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

peak emission search
PEAK EMISSION SEARCH

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the peak emission search
The peak emission search
  • A search for small flares in time intervals of

100 seconds is performed

(with and w/o phase shift of 50 seconds).

  • OFF data is the same ON data, except for the

searched time interval.

  • Apart from the evolution of the number of

excess events, also the evolution of the

significances and upper limits is shown.

  • The upper limits are corrected for the

momentaneous values of mean DT.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files122
The UL.root files

For each time slice, the corresponding average DT value is calculated

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files123
The UL.root files

Based on the DT values, an efficiency correction is calculated

for each energy bin and each time slice

(see right y-axis).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files124
The UL.root files

Table with upper limits for the worst case 100 s time interval,

converted to fluxes and fluences.

(Values well below the energy threshold are marked in grey).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files125
The UL.root files

ALPHA plots for each of the 100 s intervals, one tab per energy bin

(Black points show the values from a corresponding 100 s time bin, blue areas from other time intervals of the same zenith angle range).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files126
The UL.root files

Excess events and upper limits (in different units)

for each of the 100 s intervals, one tab per energy bin.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the ul root files127
The UL.root files

The joint evolution of excess events of the different zenith ranges can be found in

/datm1/magic/GRB/GRB071112C/UpperLimits/TimeLine_0080-0125GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/TimeLine_0125-0175GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/TimeLine_0175-0300GeV.root

/datm1/magic/GRB/GRB071112C/UpperLimits/TimeLine_0300-1000GeV.root

All are visible with the “showplot” command

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide128

300 - 1000 GeV

175 - 300 GeV

without phase shift

with phase shift

125 - 175 GeV

slide129

300 - 1000 GeV

At high zenith angles, the limits for the lower energy bins are not yet available.

For each time slice, the corresponding average DT value is calculated

175 - 300 GeV

125 - 175 GeV

Decreasing zenith angle

slide130

300 - 1000 GeV

The worst limit is taken and used for the list seen previously.

175 - 300 GeV

125 - 175 GeV

Decreasing zenith angle

slide131

The distribution of significances (from all 100 s time intervals and all zenith angle ranges) must show a Gaussian with mean=0, sigma=1.

In our case, small biases are visible because of the choice of OFF (being taken from ON data) and sometimes too small statistics.

300 - 1000 GeV

175 - 300 GeV

Qq

125 - 175 GeV

slide132

Conclusions from the

PEAK EMISSION SEARCH

Our observations span a wide range in zenith angle.

Therefore, many ALPHA PLOTS have been produced

for different zenith angle bins and energy ranges.

No significant excess has been observed and upper limits

calculated.

The distribution of significances shows small biases,

due to residual systematic effects from the choice of the background.

The evolution of excess events of lower energy bins has been

calculated only in smaller zenith angle ranges.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

sky plots
SKY PLOTS

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the output of celestina
The output of CELESTINA

The CELESTINA program can be run with the following script:

$MARSSYS/mtemp/mcalp/runcelestina.pl <GRBname> <cleaning> <PSF> 0

(this script is launched automatically by the analyze program, with the cleanings “Diego” and “Abs” and a corresponding simulated point-spread-function (PSF) for MC images (typically “10.6mm”). The “0” stands for ON/OFF observation)

CELESTINA uses two methods to estimate camera acceptance:

  • a smoothed camera from OFF data (method “OnOff”)
  • a smoothed camera from ON data using a wavelet filter with a Gaussian

kernel of the size of half the PSF for gamma-ray sources (method “model”).

CELESTINA uses a harder cloudiness cut of 40%

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files
The celestina output files

We check the output of celestina:

showplot /datm1/magic/GRB/GRB071112C/UpperLimits/GRB071112C_modelOnOff00299334.root

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files136
The celestina output files

Method “OnOff”

Method “Model”

Camera acceptance is not exactly centered at (0,0)

(due to inhomogeneities).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files137
The celestina output files

Method “OnOff”

Method “Model”

Camera acceptance from ON data (method “Model”) is not exactly the same as the one from OFF data

(due to inhomogeneities changing with time).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files138
The celestina output files

Method “OnOff”

Method “Model”

Fits to radial distribution of camera acceptance (before/after filtering) has to be checked by eye. Sometimes, features are not fitted correctly, especially at the camera center (not the case here).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files139
The celestina output files

Rates (after filter cuts) behave like expected and drop slowly with increasing zenith angle. No outliers are found which otherwise should be removed before running celestina.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files140
The celestina output files

Distribution of de-rotation angles covers only a small range of values. For this reason, the “model” method might show biases, especially filter out possible sources!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files141
The celestina output files

Distribution of effective ON times shows no outliers (anymore, after run selection!). The total effective ON time should be more or less the same as the sum of ON times obtained for each period in which the upper limit was calculated.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide142

We do this check now:

The total summed time amounts to 6801 s.

Means that the about

112 s (1.6%) were lost due to dead time

the celestina output files143
The celestina output files

Distribution of ON data events (unsmoothed) does not show any obvious excess, but the mean numer of entries per bin is small (maybe 1.5?). This means that significance distributions may show Poissonian features!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the celestina output files144
The celestina output files

Method “OnOff”

Method “Model”

Gamma Background from ON data (method “Model”) is rather similar to the one from OFF data

(except for a normalization constant).

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide145

Method “OnOff”

Method “Model”

Excess event density

Significance map

Distr. significances

The skymap from both methods seems to show an excess around RA=2:35 DEC=28.2

slide146

Method “OnOff”

lin. scale

log-scale

Method “Model”

The distribution of significances may show Poissonian features (bumps) at =-1,0,1,2,3,4

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide147

Test the true significance of the excess (1)

  • We go to the Celestina directory of GRB071112C:

> cd /datb/magic/GRB/GRB071112C/Celestina

  • We start ROOT:

> root GRB071112C_modelOnOff00299332.root

  • We draw the sky plot with the “trials” option:

> gFile->Get("SkyPlot")->Draw("model search trials");

> gFile->Get("SkyPlot")->Draw(”offdata search trials");

Method “Model”

Method “OnOff”

The significance of the excess, corrected for the trial factor, is 3.6 and 3.0  for the two methods, respectively.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide148

Test the true significance of the excess (2)

  • We draw the sky plot with the “test” option:

> gFile->Get("SkyPlot")->Draw("model test");

> gFile->Get("SkyPlot")->Draw(”offdata test");

Method “Model”

Method “OnOff”

From the background skymap, a series of random ON skymaps are created using Poissonian statistics and the significances calculated (blue points). One can see that the expected (blue) distribution is close to, but not exactly Gaussian.

Then, the differences between true significance and test distribution is calculated and the cumulative significances counted.

The significance of the excess, corrected for the trial factor, is 2.8 and 2.0  for the two methods, respectively.

slide149

Test the position of the excess

  • We draw the sky plot with the “fit” option:

> gFile->Get("SkyPlot")->Draw("model search fit");

> gFile->Get("SkyPlot")->Draw(”offdata search fit");

Method “Model”

Method “OnOff”

The position is compatible between both methods at

RA=2.585 DEC=28.23

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide150

80 - 125 GeV

125 - 175 GeV

175 - 300 GeV

300 - 1000 GeV

Test the alpha analysis of the excess

  • We launch runmelibea and runupperlimits for a source at the excess position:

> $MARSSYS/mtemp/mcalp/runmelibea.pl GRB071112C -r 2.585 -d 28.23

> $MARSSYS/mtemp/mcalp/runupperlimits.pl GRB071112C -r 2.585 -d 28.23

  • Look at the light curves (and other files) in:

> /datm1/magic/GRB/GRB071112C/UpperLimits_RA=2.585_DEC=28.23/

NO EXCESS or FEATURE IS SEEN in the light curves.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide151

80 - 125 GeV

125 - 175 GeV

175 - 300 GeV

300 - 1000 GeV

Test the alpha analysis of the excess

  • Look at the overall alpha plots in:

> /datm1/magic/GRB/GRB071112C/UpperLimits_RA=2.585_DEC=28.23/

NO significant EXCESS IS SEEN in the ALPHA plots

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide152

Conclusions from the SKY PLOTS

  • There is no excess visible at the position of the GRB
  • At low statistics (which is always the case with GRB

observations), Poissonian features may appear in the

distribution of significances.

  • A ~3 was observed at the position RA=2.585 DEC=28.23,

but was cross-checked with an alpha analysis, where

the excess could not be confirmed.

A possible excess at a different position in the sky has to be

cross-checked always with an ALPHA analysis!

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the report
THE REPORT

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

writing a sample report
Writing a sample report

The sample report can be obtained with the following script:

$MARSSYS/mtemp/mcalp/writereport.pl <GRBname> <cleaning> <author> <satellite>

(this script is launched automatically by the analyze program, with the cleanings “Diego” and “Abs”, as author your second name must be given)

writereport.pl produces two pdf’s (and the corresponding tex files):

  • a suggestion for an analysis report
  • a suggestion for a GCN circular

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report
The analysis report

We make a new directory:

mkdir /datm1/magic/GRB/GRB071112C/Report/Official/

And copy there the contents of

cp -r /datm1/magic/GRB/GRB071112C/Report/Star_Diego/ /datm1/magic/GRB/GRB071112C/Report/Official/

We edit the official analysis report:

acroread /datm1/magic/GRB/GRB071112C/Report/Official/Report.GRB071112C.pdf

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Report.GRB071112C.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Description.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Data.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Delays.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Conditions.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Analysis.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Celestina.tex

emacs /datm1/magic/GRB/GRB071112C/Report/Official/Circular.tex

the analysis report156
The analysis report

Your name should appear here. If not, run writereports.pl again with your family name as <author>.

Abstract is fine, add the redshift (see later), maybe add the fact that excesses were seen in the light curve and the sky plot which were checked afterwards.

Example Analysis of a MAGIC GRB Observation

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MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report157
The analysis report

Here, the webpage of BAT or the analysis report sent to GCN have to be read and the corresponding numbers introduced.

Example Analysis of a MAGIC GRB Observation

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MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report158
The analysis report

cat /datm1/magic/GRB/GRB071112C/Info/grbinfo.out

Date of GRB: 2007_11_12

No extinction coefficient available for night starting on 071112

Burst related times:

T0: 2007/11/12 18:32:58

GCN report time: 2007/11/12 18:50:05 GMT

GSPOT alert time: 2007/11/12 18:33:53

Scheduled obs. start: 2007/11/12 19:44:29

Scheduled obs. end: 2007/11/12 22:32:56

Burst related coordinates:

Zenith at GSPOT alert: 74.450 (deg.)

Azimuth at GSPOT alert: 65.769 (deg.)

Scheduled zenith range: 60.0 --> 23.8

Detector related information:

Corresp. PSF: 10.5232 mm

CMT extinction by dust: 0 +- 0 (mag.)

Messages with further information:

Original alert: /datb/magic/GRB/GRB071112C/GCN/7059.gcn3

Found redshift information in: /datb/magic/GRB/GRB071112C/GCN/7070.gcn3

Found redshift information in: /datb/magic/GRB/GRB071112C/GCN/7076.gcn3

Found redshift information in: /datb/magic/GRB/GRB071112C/GCN/7086.gcn3

Found redshift information in: /datb/magic/GRB/GRB071112C/GCN/7088.gcn3

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report159
The analysis report

We look at the following places:

/datm1/magic/GRB/GRB071112C/Info/grbinfo.out

/datm1/magic/GRB/GRB071112C/GCN/7059.gcn3

/datm1/magic/GRB/GRB071112C/GCN/7070.gcn3

/datm1/magic/GRB/GRB071112C/GCN/7076.gcn3

/datm1/magic/GRB/GRB071112C/GCN/7086.gcn3

/datm1/magic/GRB/GRB071112C/GCN/7088.gcn3

or directly at:

http://gcn.gsfc.nasa.gov/

http://www.swift.ac.uk/results.shtml

http://www.swift.ac.uk/access/obs.php --> go to GRB071112C:

http://www.swift.ac.uk/xrt_positions/ --> go to GRB071112C:

--> go to “LightCurve”

--> go to “Spectrum”

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report160
The analysis report

We look at the Swift homepage:

http://www.swift.ac.uk/results.shtml

  • go to “2007 GRBs”
  • go to “GRB071112C”
  • go to “Report of GRB071112C”

We look at the Fermi homepage:

http://fermi.gsfc.nasa.gov/ssc/

http://fermi.gsfc.nasa.gov/fermi_grbs.html

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report161
The analysis report

Could copied almost identically into the report.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report162
The analysis report

Could copied almost identically into the report.

the analysis report163
The analysis report

Could copied almost identically into the report.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report164
The analysis report

Could copied almost identically into the report.

Or get a better one at:

http://www.swift.ac.uk/xrt_positions/ --> go toGRB071112C:

--> go to “LightCurve”

the analysis report165
The analysis report

We extract the trigger number of BAT:

cat /datm1/magic/GRB/GRB071112C/GCN/7059.gcn3

At 18:32:57 UT, the Swift Burst Alert Telescope (BAT) triggered and

located GRB 071112C (trigger=296504). Swift slewed immediately to this burst. The BAT on-board calculated location is

RA, Dec 39.220, +28.381 which is

RA(J2000) = 02h 36m 53s

Dec(J2000) = +28d 22\' 50"

and have a look at:

http://gcn.gsfc.nasa.gov/notices_s/296504/BA/

--> scroll down to light curves

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report166
The analysis report

We look at the other circulars in

/datm1/magic/GRB/GRB071112C/GCN:

7059.gcn3 7063.gcn3 7067.gcn3 7076.gcn3 7080.gcn3 7083.gcn3 7087.gcn3 7090.gcn3 7094.gcn3

7061.gcn3 7065.gcn3 7069.gcn3 7078.gcn3 7081.gcn3 7084.gcn3 7088.gcn3 7091.gcn3 7096.gcn3

7062.gcn3 7066.gcn3 7070.gcn3 7079.gcn3 7082.gcn3 7086.gcn3 7089.gcn3 7092.gcn3 7135.gcn3

Redshift information is found in:

7070.gcn3, 7076.gcn3, 7086.gcn3 and 7088.gcn3

---> redshift is 0.823 !!

XRT analysis found in: 7079.gcn3

UVOT analysis found in: 7080.gcn3

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report167

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Here, check the 17s delay for the movement:

the analysis report168

We look at:

less -R /datm1/magic/GRB/GRB071112C/Info/grbdrive.out

Last zenith prev. source: 42.5844

Last azimuth prev. source: 23.0564

zenith GRB report nr.0: 43.5272 at: 12.11.2007 19:44:48.386

zenith GRB report nr.1: 52.495 at: 12.11.2007 19:44:54.583

zenith GRB report nr.2: 59.9444 at: 12.11.2007 19:45:04.695

zenith GRB report nr.3: 59.9244 at: 12.11.2007 19:45:14.983

zenith GRB report nr.4: 59.8994 at: 12.11.2007 19:45:25.272

zenith GRB report nr.5: 59.855 at: 12.11.2007 19:45:35.270

zenith GRB report nr.6: 59.8503 at: 12.11.2007 19:45:44.478

zenith GRB report nr.7: 59.7892 at: 12.11.2007 19:45:54.659

zenith GRB report nr.8: 59.7542 at: 12.11.2007 19:46:04.850

zenith GRB report nr.9: 59.7183 at: 12.11.2007 19:46:15.005

zenith GRB report nr.10: 59.6831 at: 12.11.2007 19:46:25.206

zenith GRB report nr.11: 59.6517 at: 12.11.2007 19:46:33.830

zenith GRB report nr.12: 59.615 at: 12.11.2007 19:46:43.791

azimuth GRB report nr.0: 23.2917 at: 12.11.2007 19:44:48.386

azimuth GRB report nr.1: 40.555 at: 12.11.2007 19:44:54.583

azimuth GRB report nr.2: 71.7544 at: 12.11.2007 19:45:04.695

azimuth GRB report nr.3: 71.9508 at: 12.11.2007 19:45:14.983

azimuth GRB report nr.4: 71.9742 at: 12.11.2007 19:45:25.272

azimuth GRB report nr.5: 71.9886 at: 12.11.2007 19:45:35.270

azimuth GRB report nr.6: 72.0017 at: 12.11.2007 19:45:44.478

azimuth GRB report nr.7: 72.0147 at: 12.11.2007 19:45:54.659

azimuth GRB report nr.8: 72.0286 at: 12.11.2007 19:46:04.850

azimuth GRB report nr.9: 72.0414 at: 12.11.2007 19:46:15.005

azimuth GRB report nr.10: 72.0556 at: 12.11.2007 19:46:25.206

azimuth GRB report nr.11: 72.0686 at: 12.11.2007 19:46:33.830

azimuth GRB report nr.12: 72.0817 at: 12.11.2007 19:46:43.791

The analysis report

The correct times would be:

Shifters accept alert at: 19:44:48

Telescope ready at: 19:45:15

Time delays for slewing: 27 s

the analysis report169

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

We have a look in the runbook:

less -R /datm1/magic/GRB/GRB071112C/Runbook/

[2007-11-12 19:44:06]

We have a GRB alert. We follow the stablished procedure and contact Daniel Kranich

in order to modify the schedule. Nicola Galante contacts us also to inform about

the nature of this GRB.

Nothing special about the delays before data taking…

the analysis report170

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Here the three car flashes could be mentioned together with the times when they occurred.

the analysis report172
The analysis report

Nothing to add here….

the analysis report173

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Nothing to add here….

slide174

Here, the very visible two car flashes in figure 1 have to be mentioned.

Also the fact that the rates slowly rise due to the lower zenith angle which is reached with time.

slide175

Here, the reason for the initial moon discriminator thresholds must be mentioned (e.g. with a reference to the runbook and the prev. source observed). The reason why they went down (because shifters took a pedestal and calibration run and the DTs were reset by the shifters.

slide176

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The initial mis-pointing could be mentioned.

slide177

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Maybe the behavior of the cloudiness described in more detail since it was the major limitation for this analysis.

slide178

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Maybe the behavior of the cloudiness described in more detail since it was the major limitation for this analysis.

the analysis report179
The analysis report

Here could come a short hint that the redshift of the burst (z=0.82) would make a signal possible only below at most 150 GeV (because of the EBL). This already discards the possibilities to observe the burst, except only at the very end of the observation (which was however dominated by clouds).

the analysis report180

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Nothing to add here…

the analysis report181

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Nothing to add here, all these cuts are standard ones.

the analysis report182

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Nothing to add here, all these cuts are standard ones. The discussion about the zenith angle range is a rather technical one and applies to all automatic GRB analyses. It should not be removed from the report.

slide183

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Maybe one could mention here that the first alpha plot in the lowest energy bin comes from the very last part of the observation where the cloudiness was high (and therefore not understood systematic effects can influence the results).

slide184

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Now come all the individual ALPHA plots (which are many in our case due to the frequent split of the data set. This is NOT the normal situation!)

slide186

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide187

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

the analysis report188

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Here, please start to CHECK all the limits if they are consistent with our official MAGIC sensitivity (see TDAS0703):

1.6% of Crab for E > 270 GeV (i.e. roughly the energy bin [300-1000 GeV])

5.6% of Crab for 200<Nphe<400 (i.e. roughly the energy bin [175-300 GeV])

17% of Crab for 50<Nphe<200 (i.e. roughly the energy bins [80-175 GeV])

These values have to be corrected for the observation time (multiplied with sqrt(50*3600/Tobs)), the 2 sigma limit (instead of 5 sigma used in TDAS0703) and the 30% systematic uncertainty. Further corrections can be applied for the DT settings and the observation zenith angle.

In table 2, a sensitivity estimate is given automatically to facilitate the check.

slide189

The upper limits in Crab Units should coincide more or less (apart from statistical fluctuations) with the sensitivity estimates.

the analysis report190
The analysis report

Here, all the discussion about the excess seen in one bin has to be explained, together with the calculations done in the section “Light curves”

the analysis report191
The analysis report

Also the (apparently strange) evolution of the background can be explained here shortly.

the analysis report192

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

The analysis report

Here, nothing strange was found during the checks, so nothing special to add...

slide195

The upper limits in Crab Units should coincide more or less (apart from statistical fluctuations) with the sensitivity estimates.

However, THIS ESTIMATE IS STILL RATHER POOR AND HAS TO BE REVISED!

slide196

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

HERE all the discussion about the excess at RA=2:35 DEC=28.2

slide197

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Discuss this point in order to prepare a possible publication (fast)!

slide198

Your name should appear here as first author. If not, run writereports.pl again with your family name as <author>.

slide199

A draft for a GCN circular is the last chapter of the report. If a publication is proposed, please check this part most thoroughly!!

slide200

These should be the same upper limits like in the previous chapter, only expressed in erg/cm2/s (instead of erg/cm2)

slide201

These should be the same upper limits like in the previous chapter (time line), only expressed in erg/cm2/s (instead of erg/cm2)

writing the circular

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

Writing the circular

Finally, please edit the sample circular:

/datm1/magic/GRB/<GRBname>/Reports/Official/Circular.txt

(this file contains the same as the Circular seen in the previous section, but you need to edit your changes also there).

This file will be sent to GCN afterwards (if the decision is taken to send a circular).

slide203

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

!!!! THANK YOU !!!!

slide204

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

BACKUP

finding off data
Finding OFF data

With the previously obtained information, we look for suitable OFF data. It MUST agree in:

  • The PSF
  • The zenith angle range
  • Observed with more or less same DTs

(ambient light conditions, e.g. moon or not)

  • No source should be present in the center of the

camera (i.e. in case of weak sources, wobble data

can be used)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding off data206
Finding OFF data

In case of GRB071112C, we need:

  • PSF ~ 10.5 mm
  • Zenith = 35-60 deg. Moon data (high DT)
  • Zenith = 22-34 deg. NoMoon data (moderate DT)

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding off data207
Finding OFF data

The first place look at, is directly at CALP:

  • > cd /datm1/magic/OFFData/PSF_10mm/
  • > ls
  • Theta_00_25/ Theta_26_36/ Theta_37_45/ Theta_46_53/ Theta_54_60/
  • Theta_19_31/ Theta_32_41/ Theta_42_49/ Theta_50_56/
  • > ls Theta_37_45/Moon/Calibrated/ | wc -l

9 files

  • > ls Theta_46_53/Moon/Calibrated/ | wc -l

13 files

  • > ls Theta_54_60/Moon/Calibrated/ | wc -l

0 files

  • > ls Theta_26_36/NoMoon/Calibrated/ | wc

147 files

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding off data208
Finding OFF data

The second place look at, is the database at PIC:

http://magic.pic.es/interface/

  • --> InfoRun
  • --> Zenith Distance
  • --> e.g.: 55 to 60
  • --> MoonFlag = “Moon”
  • --> RunNumber
  • --> RunStart
  • --> RunStop
  • --> RunType = “Data”
  • --> Source = “All”

Apart from GRB071112C, only data earlier than August 2008 is found

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide209

Conclusions from searching for OFF data:

  • We found suitable OFF data at the CALP, except for

the very beginning of observation

(zenith 55 to 60 deg, moon)

--> have to contact the PI if dedicated OFF data should be taken

  • For the moment, we will make a preliminary analysis,

using NoMoon data from zenith 54 to 60 as OFF

(instead of Moon data).

  • This is done automatically by the “analyze” script.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding mc data
Finding MC data

With the previously obtained information, we look for suitable MC data. It MUST agree in:

  • The PSF
  • The zenith angle range

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding mc data211
Finding MC data

In case of GRB071112C, we need:

  • PSF = 10.5 mm
  • Zenith = 22-60 deg.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

finding mc data212
Finding MC data

The first place look at, is directly at CALP:

  • > cd /datm1/magic/MonteCarlo/M1/PSF_10.6mm/w0/Misp_0.0
  • > ls
  • Camera/ Lvl1/ SumT/
  • > ls Lvl1/

Calibrated/ Camera/ Disp/ EnergyEst/ Melibea/ RandomForest/ Star/

  • > ls SumT/

<empty>

  • > ls Lvl1/Melibea/Star_Diego/00

all/ zbin05_15/ zbin13_17/ zbin18_22/ zbin25_35/ zbin33_37/ zbin38_42/ zbin48_50/

  • zbin03_07/ zbin08_12/ zbin15_25/ zbin23_27/ zbin28_32/ zbin35_45/ zbin43_47/
  • zbin48_52/

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

slide213

Conclusions from searching for MC data:

  • We found suitable MC data at the CALP for Lvl1

triggers (in the case of GRB071112C, only Lvl1

triggers were used, since the SumTrigger was not

yet installed.

  • If SumTrigger would have been used during the observation, we would need to create SumTrigger MC or discard events

Without the Lvl1 trigger flag from the further analysis.

(this is done automatically by the “analyze” scripts.

  • In order to convert “zbin” into “Theta”, use the

$MARSSYS/mtemp/mgrb/theta2zbin.C macro.

Example Analysis of a MAGIC GRB Observation

Markus Gaug

MAGIC GRB meeting, La Palma, 6. December 2007

ad