Spectroscopic classification of Gaia14aat: Hydrogen-rich Dwarf Nova
ATel #6581; A. Piascik, I. A. Steele, C. M. Copperwheat, C. J. Davis (LJMU)
on 15 Oct 2014; 15:37 UT
Credential Certification: Chris Copperwheat (c.m.copperwheat@ljmu.ac.uk)
Subjects: Optical, Cataclysmic Variable
Referred to by ATel #: 6593
The transient Gaia14aat was detected by the Gaia Photometric Science Alerts programme with a magnitude of 15.66 at UT 2014 Oct 10.59. We measured the object position as RA / DEC = 03:31:4.44 17:25:40.22 (J2000). There is an object present at this position in the SDSS survey with an r-band magnitude of 18.93 -/+ 0.15.
Using the SPRAT spectrograph installed on the 2.0m Liverpool Telescope, we obtained a 10 minute low resolution (R=350) spectrum of this object at UT 2014 Oct 15.08, covering the wavelength range 400-790nm. We detect a bright H-alpha emission line and fainter H-beta and H-gamma emission lines in the spectrum.
From our white light acquisition image we estimate the r-band magnitude of the target to be ~18.5 at the time of our observation, implying the object has returned to quiescence in the 5 days since the Gaia detection. Based on the duration and brightness of the transient and the emission features in the quiescent spectrum, we believe this transient was a dwarf nova outburst in a hydrogen-rich cataclysmic variable.
We acknowledge ESA Gaia (cosmos.esa.int/gaia), and the DPAC Photometric Science Alerts Team (http://gaia.ac.uk/selected-gaia-science-alerts).