A candidate near-infrared counterpart to IGRJ 17511-3057
ATel #2216; M. A.P. Torres (CfA), P. G. Jonker (SRON/CfA), D. Steeghs (Warwick/CfA), J. D. Simon (OCIW), G. Gutowski (Haverford College)
on 25 Sep 2009; 16:30 UT
Credential Certification: P.G. Jonker (email@example.com)
Subjects: Infra-Red, Neutron Star, Transient, Pulsar
We report on near-infrared follow-up observations of the field
containing the currently active accreting millisecond pulsar IGR
J17511-3057 (ATels #2196, #2197, #2198, #2199).
Our observations consist of a series of 15s Ks-band images totaling
225s on source. They were acquired on 2009 Sep 22 23:46 - 23:52 UT with the
PANIC camera mounted on the 6.5m Baade telescope at Las Campanas
Observatory. Sky conditions were good with a seeing of
0.5". Additional 3s exposures were obtained to obtain the astrometric
and absolute flux calibration of the data using 2MASS objects in the
field of view. This delivered a positional rms < 0.1' and a zero-point
accuracy < 0.15 mag.
Our mosaic image shows a faint point-like source at R.A
(J2000)=17:51:08.64, Dec (J2000)=-30:57:40.70 consistent with the 0.6"
Chandra position reported by Nowak et al. (2009, ATel #2215).
Preliminary PSF-fitting photometry of the PANIC images yields
Ks=18.0 +/- 0.1.
This source does not appear to be present in UKIDSS GPS frames
obtained in 2007, although the image quality and depth is
significantly worse than our PANIC epoch. The positional match and
apparent variability does point towards a viable counterpart for the
We would like to thank Mike Nowak, Ada Paizis and Joern Wilms for
sharing the Chandra X-ray position prior to publication.