Discovery of a Bright Optical Transient from the Catalina Sky Survey
ATel #1411; S. G. Djorgovski, A. J. Drake, R. Williams, A. Mahabal, M. Graham, E. Glikman, C. Donalek (Caltech); J. Hennawi (UCB/LBL); E. C. Beshore, S. M. Larson (UAz/LPL); E. Christensen (Gemini Obs.)
on 4 Mar 2008; 23:58 UT
Credential Certification: Andrew J. Drake (ajd@cacr.caltech.edu)
Subjects: Optical, Request for Observations, Cataclysmic Variable, Nova, Transient
Referred to by ATel #: 1418
We have detected a bright (V ~ 16 mag) optical transient in Catalina Sky Survey
(CSS) images obtained at the Mt. Bigelow 0.7m Catalina Schmidt Telescope on 04 March 2008 UT.
The transient is coincident within the astrometric uncertainties with a
marginally detected SDSS source (ID = 587732578836087360), which has listed
magnitudes:
u = 23.76 +- 0.60
g = 23.17 +- 0.18
r = 23.10 +- 0.22
i = 23.00 +- 0.30
z = 22.19 +- 0.37
Thus, the source has brightened by about 7 magnitudes relative to the SDSS detection.
The discovery data and the finding charts are posted at this webpage: http://voeventnet.caltech.edu/feeds/ATEL/CSS
The source was posted in the real time at VOEvent pages, http://voeventnet.caltech.edu/feeds/Catalina.shtml
A spectrum of the transient has been obtained with the ESI spectrograph at the
WMKO Keck-II 10m telescope on the same night, 04 March 2008 UT, approximately 5
hours after the initial detection. It shows a blue continuum, with emission
lines of H-alpha 6563, H-beta 4861, He I 5015, He I 7065, He II 4687, and He II
6683, with an approximate observed redshift of 150 km/s. The lines are
bimodal, with a velocity splitting of about 500 km/s.
We tentatively interpret this as a nova-like phenomenon. Further analysis of
the spectra is in progress.