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Status of Point Source Searches. Markus Ackermann for Elisa Bernardini, Elisa Resconi, Tonio Hauschildt and Markus Ackermann. Overview. Status of (time variable) point source searches A Multi-wavelength comparison B Sliding window flare search C 1ES1959+650 D Future prospects

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Status of point source searches

Status of Point Source Searches

Markus Ackermann for

Elisa Bernardini, Elisa Resconi, Tonio Hauschildt and Markus Ackermann


Status of (time variable) point source searches

A Multi-wavelength comparison

B Sliding window flare search

C 1ES1959+650

D Future prospects

(E Online filtering changes 2005 )

Multi wavelength comparison
Multi-wavelength comparison

  • Use information from observations of the electromagnetic spectrum to define states of high activity for a source.

  • If EM & neutrino emission correlated  better S/N ratio

  • Defined high state by:

TeV photons & neutrinos are produced

simultaneously in pp and pg interactions

Double peak structure in AGNs:

high TeV emission  high x-ray emission

Multi wavelength comparison1
Multi-wavelength comparison

  • very limited TeV-g measurements

  • x-ray all-sky monitor provides continuous data

  • high state: x-ray luminosity > L

  • L defined by optimizing S/sqrt(N) ratio

    (S=integr. luminosity, N=duty cycle)

arbitrary relative scaling

Orphan flares
Orphan flares

  • Only one orphan flare known (1ES 1959+650, MJD 52429)

  • very short duration

  • NOT included in high state period defined by x-ray luminosity

  • independent test was taken into consideration

  • rejected for low detection probability (short flare duration)

Results of multi wavelength comparison
Results of Multi-wavelength comparison

  • No significant excess found in high state periods

  • Limit on x-ray/neutrino-ratio can be calculated for the selected AGN’s

  • Full results of this analysis can be found on a dedicated web page:

  • Will be reported in dedicated paper

Search for neutrino flares

sliding window



Search for Neutrino flares

  • Method presented in Uppsala & unblinding proposal

  • event times for 12 sources unblinded

  • 2000-2003 point source data sample used

  • Window size defined via detection probability investigation

  • Calculation of significance for cluster with highest multiplicity in sliding window.

Search for neutrino flares1
Search for neutrino flares

Brown Error bars

expected background for

40 days

Blue lines

Time of AMANDA events

Yellow Box

Sliding Window containing event cluster with highest multiplicity

Results of neutrino flare search
Results of neutrino flare search

Highest multiplicity found in any search window: 2 events

Results of neutrino flare search1
Results of neutrino flare search

  • No significant event cluster found in sliding windows for the selected sources

  • Easy test for event clusters with relatively low trial factor

  • Full results of this analysis can be found on a dedicated web page:

  • Included in 2000-2003 point source paper draft

But afterwards
but afterwards…

  • comparison of the event times of 1ES1959+650 with reports on TeV gamma ray flares of the source reveals that 3 of 5 events are close to its only reported period of strong TeV flare activity in 2000-2003

  • detailed investigation of these events & TeV light curves

The multi wavelength campaign may 2002 aug 2002
The multi-wavelength campaign May 2002-Aug 2002


X-ray (RXTE/PCA)


  • Triggered by WHIPPLE observation

  • TeV flux up to several Crab

  • (average flux ~ 0.05 Crab)


The amanda events
The AMANDA events

AMANDA – 1ES1959+650


Eg > 2TeV

Eg > 600GeV

Looking in a larger bin
Looking in a larger bin

  • 4.5 deg (95% limit of MC point spread function)

  • 8 events in a window of 90 days

  • expected from background : ~ 1.3 events (in 90 days)

Period of multi-wavelength campaign

Interpretation outlooks
Interpretation & Outlooks

  • No way to state a significance for this “unblind” analysis.

    Chance probability: P(bg) = 3 103

  • Even the most “unblind” chance probabilities one could calculate are far from 5s

  • Nevertheless, even though we cannot claim any discovery it is very encouraging for future analyses

  • Could we trigger Gamma Ray Telescope “target of opportunity” observations with neutrinos in the future ?

Future plans for 1es 1959 650
Future plans for 1ES 1959+650

A Statistically independent sample for 1ES 1959+650

  • remove events which passed our quality cuts

  • generate & optimize new sample with new cuts

  • another ‘blind’ search may be possible with a quantitative statistical statement

    B Correlation analysis for neutrino & gamma light curves

  • interesting method in literature (Edelson et al., ApJ 333,646-659)

  • needs adaptations for our case

  • still discussing technical issues

Other promising flares
Other promising flares

  • Promising events happened in 2004 which can be investigated when the data is processed:

  • Markarian 421 possible “orphan” flare

    • preliminary results reported on


    • will be investigated further

  • huge SGR 1806-20 flare

    • 104 times more luminous than largest

      gamma ray bursts

    • Neutrinos could be visible in

      AMANDA (Ioka et al., astro-ph/0503279)

    • 20 deg below horizon, but tflare ~ 0.1s

Hurley et al., astro-ph/0502393

Task for future analyses
Task for future analyses

  • Refine the multi-wavelength approach

    • is it possible to include (x-ray) spectral information in period selection criteria ?

    • define standards (significance thresholds) for a detection/indication

  • Refine the flare search approach

    • work around the arbitrary fixed window size

    • different type of optimization for flare search data sample?

A neutrino alarm using online filtering
A Neutrino alarm using online filtering

Goal: Trigger g-ray-telescope observation of a promising source with AMANDA neutrinos

(possibly increased detection chance for orphan flares)

  • Online filtering chain completed this year at pole

    (details at the end of talk)

  • Neutrino events can be filtered out in (nearly) real time

    (events filtered ~1h after detection)

  • background for standard PS cuts: ~ 1-2 ev/year

  • Telescopes could be notified with very short time lag

    (if SN Iridium modem is used)

A neutrino alarm current status
A Neutrino alarm / Current status

  • Small PERL script can do a “standard” analysis of data files:

    • Zeuthen PS cuts are applied to online L3 filtered data.

    • RA is scrambled for passing events

    • e-mail message containing the event data is sent (to me)


YEAR 2005 GPSDAY 8 MJD 53442 GPSTIME 56439.420513000

ZENITH_PANDEL 121.85 AZIMUTH_PANDEL 74.6655344017576

DEC_PANDEL 31.85 RA_PANDEL 4.12448774588978



DISTANCE FROM Makarian-421 54.0452288086954

DISTANCE FROM 1ES1959+650 84.0200808312958


A neutrino alarm current status1
A Neutrino alarm / Current status

  • integration into online filtering chain at pole trivial

  • should be tested at pole to investigate:

    • false alarm rate

    • quality of passing events

    • time between event & e-mail

Online filtering changes 2004 2005
Online filtering changes 2004/2005

  • NEW data stream: high quality up-going muon events.

    • similar to L4 from offline filtering

    • Additional Smoothness cut: abs(S_Phit)<0.4

    • ~500ev per day

    • contains all fits used in our PS analysis

      (Pandel, Bayesian, Paraboloid, Topf)

    • can be easily used to get the “daily neutrinos”

  • TWR merging now done by Sieglinde

The sad part
The sad part….

Do not use online filtered data from 2005

  • No final T0-calibration for 2005 available (muon-T0 missing)

  • Running on 2004 T0 constants, update to 2005 preliminary constants after the meeting

  • Not reliable because many gains/thresholds were changed

    Will be updated as soon as final calibration is available


  • Flare & Multi-wavelength searches unblinded, no detection of a neutrino source

  • neutrinos for 1ES1959+650 show very interesting correlation to WHIPPLE TeV light curves.

  • Still many things to complete on the time variability analyses

  • 2004 data is very promising with new interesting flares