EVN observations of the radio galaxy M87 following a TeV flare
ATel #2437; M. Giroletti (INAF/IRA), G. Giovannini (Univ. of Bologna), M. Beilicke (Washington Univ.), A. Cesarini (NUI), H. Krawczynski (Washington Univ.)
on 13 Feb 2010; 10:16 UT
Credential Certification: Marcello Giroletti (giroletti@ira.inaf.it)
Subjects: Radio, >GeV, AGN, Black Hole
We report on EVN observations of the radio galaxy M87, taken at 5 GHz on 2010
Feb 10. Data were acquired by 7 radio telescopes from 21:40 UT on Feb 10 to 8:30
UT on Feb 11, directly streamed to the central data processor at JIVE, and
correlated in real-time (eVLBI). This permits us to promptly report on the
status of the radio jet of the source, following the increase in gamma ray
emission above 100GeV reported by MAGIC (ATel #2431)
The observations have an angular resolution of about 7 mas x 3 mas and rms
noise of 0.12 mJy/beam. Preliminary analysis reveals a compact 1.73 Jy/beam
core, and a more than 200 mas long collimated jet. We also detect resolved
emission further downstream, in the position of the jet knot known as HST-1. In
this region, the total flux density is 17.9 mJy and the peak brightness is 2.7
mJy/beam, with the brightest component trailing the downstream emission.
The observations are part of an ongoing monitoring with eVLBI and previous
epochs were carried out on 2009 Nov 19 and 2010 Jan 27. The total flux density
and peak brightness of the main jet and of HST-1 do not seem to have undergone
substantial changes so far. Follow up observations are planned, with a fourth
observation epoch already granted.
e-VLBI developments in Europe were supported by the EC DG-INFSO funded
Communication Network Developments project 'EXPReS'
(http://www.expres-eu.org/). The European VLBI Network (http://www.evlbi.org/)
is a joint facility of European, Chinese, South African and other radio
astronomy institutes funded by their national research councils.
