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AGN Monitoring Workshop MPIFR 14/15 March 2011

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AGN Monitoring Workshop MPIFR 14/15 March 2011. Reduction and first results of F-GAMMA data. I. Nestoras on behalf of the F-GAMMA team. General information . Coordinated observations at Effelsberg and PV Typical 48h per session for Effelsberg / 12h for PV

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slide1

AGN Monitoring Workshop

MPIFR 14/15 March 2011

Reduction and first results of F-GAMMA data

I. Nestoras

on behalf of the F-GAMMA team

slide2

General information

  • Coordinated observations at Effelsberg and PV
  • Typical 48h per session for Effelsberg / 12h for PV
  • Cross scans in Azi/Elv for Effelsberg
  • Wobbling / calibrated cross scans for PV
  • New system in Effelsberg (July 2010)
  • Change to EMIR receivers at IRAM (April 2009)
  • Observing at Horizontal / Vertical polarizations
slide3

Effelsberg

Observing Wavelengths : 11cm to 7mm (8 frequencies)‏

  • Standard reduction procedures

now semi-automatic

(Code by E. Angelakis , A. Kraus)‏

  • Gain Curve Correction
  • Opacity Correction
  • Pointing Corrections
  • Absolute calibration
  • (Calibrators: 3C 286,etc.)‏
  • Accuracy ~ < 5% at high frequencies
  • (Angelakiset.al 2008)‏
slide5

Some results

Light Curve of 0235+164

(BL LAC)

Spectra of 0235+164

(BL LAC)

slide6

Some results

Spectra of 2251+158 (3C 454.3)

(FSRQ)

Light Curve of 2251+158 (3C 454.3)

(FSRQ)

slide7

IRAM - PV

Observing Wavelengths : 3, 2, 1mm‏

  • Reduction with Mira and IDL software
  • Averaging of sub-scans in Azi/Elv
  • Gain Curve Correction
  • Opacity Correction
  • Pointing Corrections
  • Absolute calibration
  • (Main calibrators Mars, Uranus)‏
  • Average polarizations for EMIR
  • (Horizontal / Vertical)

New receiver (EMIR) since May 2009

  • Accuracy ~ < 10%
slide8

IRAM – PV Flagging

First/basic filter on the data :

  • changes of data format
  • remove data that had an ambiguous fit
  • negative values
  • remove first scan before focus for calibrators

Second pass filter :

  • pointing offset
  • Remove all data for which
  • the pointing offset is larger than 0.35*HPBW‏
  • fitting width
  • Remove all data for which
  • the width is larger than HPBW +- 0.45*HPBW
  • Third pass filter :
  • After averaging of sub-scans
  • apply again first and second filters
slide9

IRAM – PV

Error estimation

  • Propagated error with every operation
  • In every average operation also the scatter of the elements is added
slide10

IRAM – PV

Error estimation

In more detail :

  • Fit error in every scan and direction (Azi/Elv)

Initial error per direction

  • Scatter of measurements in each direction

Propagated error per direction

after pointing, opacity

and gain curve correction

Calibration error :

The error in each calibration factor is the propagated error

of each calibration measurement and the corresponding

error in the assumed model. The final calibration factor

is the average of all the available factors

Final error :

The propagated error after

the sensitivity correction

slide13

Effelsberg/IRAM

Cross Calibration

slide14

-

110mm

60mm

36mm

28mm

20mm

13mm

9mm

7mm

3mm

2mm

%

93.5

96.8

93.5

93.5

98.3

94.2

91.1

80.8

81.5

40.7

Some results

Percentage of variable sources per frequency

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