INTEGRAL source IGR J16562-3301 --- a new BL Lac object
ATel #1270; R. Burenin, M. Revnivtsev, A. Mescheryakov, I. Bikmaev, M. Pavlinsky, R. Sunyaev (IKI, Moscow, Russia; MPA, Garching, Germany; KSU, Kazan, Russia)
on 11 Nov 2007; 13:47 UT
Credential Certification: Rodion Burenin (rodion@hea.iki.rssi.ru)
Subjects: Radio, Infra-Red, Optical, X-ray, Gamma Ray, AGN, Black Hole, Quasar
The accurate position of the hard X-ray source IGR J16562-3301/SWIFT
J1656.3-3302 (Okajima et al. 2006, ATel #799, Krivonos et al. 2007,
astro-ph/0701836) was determined earlier by Tueller et al. (2006, ATEL #835)
using SWIFT/XRT observation of this field. We found that more accurate
position of this source can be derived from the same data when the
systematics of SWIFT/XRT astrometry is corrected using the other two bright
X-ray sources identified with relatively bright optical stars. From these
data we found the following RA,Dec for IGR J16562-3301/SWIFT J1656.3-3302:
16:56:16.82 -33:02:12.5 (J2000),
with ~1.5'' uncertainty, which now should be almost purely statistical
(astrometry is based on UCAC2 catalog).
Near this improved error circle we found a very bright (~0.4Jy at 1.4GHz)
radio source NVSS J165616-330211.
This field was also observed with Russian-Turkish 1.5-m telescope (RTT-150,
Bakirlitepe, TUBITAK National Observatory, Turkey). The centroid of the only
optical source consistent with both improved SWIFT/XRT position and NVSS
J165616-330211 coordinates is at RA,Dec:
16:56:16.77 -33:02:12.8 (J2000),
which is also coincide with IR source 2MASS 16561677-3302127.
In the optical spectrum of this source we identified no obvious spectral
lines. All these data strongly suggests that the hard X-ray source IGR
J16562-3301/SWIFT J1656.3-3302 is a BL Lac object. In order to determine its
redshift the optical spectrum with significantly higher signal to noise
ratio is needed.
