agn monitoring workshop mpifr 14/15 march 2011

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AGN Monitoring WorkshopMPIFR 14/15 March 2011

Reduction and first results of F-GAMMA data

I. Nestoras on behalf of the F-GAMMA team

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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

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• 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.)

Effelsberg

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

• Accuracy ~ < 5% at high frequencies (Angelakis et.al 2008)

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Effelsberg - Calibration

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Some results

Spectra of 0235+164(BL LAC)

Light Curve of 0235+164 (BL LAC)

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Some results

Spectra of 2251+158 (3C 454.3)(FSRQ)

Light Curve of 2251+158 (3C 454.3)(FSRQ)

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• 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)

IRAM - PVObserving Wavelengths : 3, 2,

1mm

• Accuracy ~ < 10%

New receiver (EMIR) since May 2009

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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

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IRAM – PV Error estimation

• Propagated error with every operation

• In every average operation also the scatter of the elements is added

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IRAM – PV Error estimationIn more detail :

• Scatter of measurements in each direction• Fit error in every scan and direction (Azi/Elv) Initial error per direction

Final error :

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

The propagated error after the sensitivity correction

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IRAM – PV Calibration

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IRAM – PV Calibration

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Effelsberg/IRAM Cross Calibration

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Some results

40.781.580.891.194.298.393.593.596.893.5%

2mm3mm7mm9mm13mm20mm28mm36mm60mm110mm-

Percentage of variable sources per

frequency