Brightening of the Magnetar SGR J1745-29 near Sgr A* at 44 GHz
ATel #6041; F. Yusef-Zadeh, D. Roberts (Northwestern/CIERA), C. Heinke (U. Alberta), W. Cotton (NRAO), D. Haggard (Northwestern/CIERA), M. Wardle (U. Macquarie) and M. Royster (Northwestern/CIERA)
on 3 Apr 2014; 15:48 UT
Credential Certification: Craig Heinke (cheinke@virginia.edu)
Subjects: Radio, AGN, Black Hole
Referred to by ATel #: 6064
We carried out observations of the Galactic center at 44 GHz
on 2014, February 21 using the VLA in its A-array configuration.
We detected a compact radio source at
(J2000) α, δ =
17h 45m 40s.1680±0.0002,
-29° 00' 29''.7490±0.0005
with peak flux density 1.62×10-3±2.46×10-5 Jy/beam,
using a spatial resolution of 81×39 milliarcsecond (PA≈10°).
This source coincides (within 2σ) with
the position of the magnetar SGR J1745-29 at
(J2000) α, δ =
17h 45m 40s.164±0.002, -29° 00' 29''.82±0.09
(Shannon and Johnston 2013).
The comparison of the continuum emission from this source
with earlier VLA observations
taken on 2011, August 31 with similar resolution and sensitivity
indicates that the source has brightened by a factor of ≈20. This source was not
detected above 1σ≈81 microJy level at 42 GHz on 2011, August 31.
The magnetar was reported to have a flux density of 0.3 mJy at 18 GHz with a
decreasing flux at higher frequencies on 2013, May 1 (Shannon and Johnston 2013).
Our simultaneous Chandra observation did not detect an increase in the X-ray flux (Rea et
al. 2014, ATEL #5922). We encourage further monitoring of the radio flux from this source.
References:
R. M. Shannon & S. Johnston 2013, MNRAS, 435, L29
