1FGL AGNs at parsec scales (north)


We propose to observe with VLBA+GBT all counterparts from the 1FGL catalogue of γ-ray sources discovered by Fermi which were not studied before at parsec scales. Their total flux density at 8 GHz is found by Abdo et al. (2010b) and our analysis to be in the range of about 1 to 100 mJy. Despite the previous view that -ray detected AGN are identified with extragalactic objects showing flat radio spectra — an indicator of a compact boosted relativistic jet — some of these objects show peaked or even steep radio spectra.

We will observe 155 1FGL counterparts with declination > -30°. We will extend analysis of AGNs detected by the Fermi LAT and correlate properties of AGN γ-ray emission with properties of parsec-scale radio emission. We assume that the AGN -ray emission is generated in the regions close to the central super-massive black hole, therefore are interested to compare it with the radio emission from nearby regions. We eliminate the current VLBI sample bias towards strong radio jets in order to draw meaningful conclusions from our analysis.

Scientific goal

On the basis of our previous analysis (e.g., Kovalev et al. 2009), we do expect to detect significant parsec-scale emission for most of the targets. In the same time, the cases of non-detections will provide a very important basis to test SED models of emission. This project will deliver the following observational results:

This will allow:


Team members (in alphabetic order):

Source list


Current status

Preliminary results

catalogue of positions of 169 detected sources.

Slides of a conference presentation.


Raw cross-correlation data.
s3111a 2010_12_05_s3111a.fits 148 Gb
s3111b 2010_12_26_s3111b_01.fits 157 Gb
s3111c 2011_01_09_s3111c_01.fits 130 Gb

NB: The total dataset is about 0.5 Tb. Do not attempt to download the data unless you know very well what are you doing!

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This web page was prepared by Leonid Petrov ()
Last update: 2014.08.02_16:33:08