The Optical Counterpart to XTE J1817-330.
ATel #733; M. A. P. Torres (CfA), D. Steeghs (CfA), P. G. Jonker (SRON/CfA), K. Luhman (Pennsylvania State Univ.), J. E. McClintock (CfA), M. R. Garcia (CfA)
on 11 Feb 2006; 01:57 UT
Credential Certification: Manuel Torres (mtorres@cfa.harvard.edu)
Subjects: Request for Observations, Binary, Black Hole, Transient
We report the counterpart to the X-ray transient and black hole
candidate XTE J1817-330 (ATEL #714).
Our observations consist of a series of 5s and 10s g'-band images
obtained with the 6.5m Magellan Clay telescope during 2006 Feb 10
09:23-09:42 UT using the multi-object imaging spectrograph LDSS-3. The
frames were acquired with an image quality of 1.2 arcsec and a
projected pixel scale of 0.188 arcsec/pixel. The images were
calibrated using the Landolt and u'g'i'r' standard star G 162-62 that
was observed at similar airmass as XTE J1817-330.
Comparison of our images with the Digitized Sky Survey and 2MASS shows
a new single point-like source consistent with the position reported
for the radio and near-infrared counterparts (ATEL #721, #724). We
measure a mean magnitude for the optical counterpart of g'= 14.93 +/-
0.05 from preliminary photometry.
The optical apparent magnitude is comparable to the K-band
magnitude reported in ATEL #724 and supports a low reddening towards
the source. The large outburst amplitude in the optical band (the
source is not detected in POSS plates) suggests a short orbital period
system (see e.g. Shahbaz & Kuulkers,1998,MNRAS,295,L1).
Follow-up observations at all wavelengths, in particular UV, are
encouraged. A finding chart for the candidate may be found at:
http:/hea-www.cfa.harvard.edu/~mtorres/XTEJ1817m330/
Finding chart.
