The NIR counterpart to IGR J17497-2821
ATel #1002; M. A. P. Torres, D. Steeghs (CfA), P. G. Jonker (SRON/CfA), N. Morrell, M. Roth (LCO), W. L. Freedman (Carnegie)
on 14 Feb 2007; 05:46 UT
Credential Certification: Manuel Torres (mtorres@cfa.harvard.edu)
Subjects: Infra-Red, X-ray, Binary, Black Hole, Neutron Star, Transient
We report follow-up observations confirming the near-infrared (NIR)
counterpart to the X-ray transient and suggested black hole candidate
IGR J17497-2821 (Soldi et al., ATel #885). A Ks=15.9 mag candidate was
suggested in Torres et al. (ATel #909) on the basis of its coincidence
with the Chandra localization for the X-ray source (Paizis et al. ATel
#907; astro-ph/0611344). The candidate appeared blended with a
brighter nearby NIR source to the east which partially overlaps the 0.6
arscec Chandra error circle.
Our observations consist of a series of Ks-band images obtained with
the 6.5m Magellan Baade telescope between 2007 Feb 10 08:45-08:58 UT
using the PANIC camera and totaling 450s on source. The frames were
acquired with a seeing of 0.6 arcsec and the projected pixel size was
0.127 arcsec. Photometric and astrometric scales were defined with the
same 2MASS references used in ATel #909.
Our images show that the proposed counterpart candidate has faded
significantly and is no longer detected with a 3-sigma upper limit magnitude
of Ks > 17.8. This limit is consistent with a late-type companion at a typical
distance of the Galactic center.
This large decrease in brightness relative to the observations
reported when the transient was in outburst confirms the candidate
reported in ATEL #909 as the NIR counterpart to IGR J17497-2821.
Updated finding chart:
