Spectroscopic and photometric observations of the M31 nova candidate PTF12ahb
ATel #3912; A. W. Shafter (SDSU), M. J. Darnley, M. F. Bode (Liverpool JMU, UK), R. Ciardullo (PSU), K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), Y. Cao (Caltech), M. M. Kasliwal (Carnegie Institute for Science and Princeton University)
on 6 Feb 2012; 04:28 UT
Credential Certification: Allen W. Shafter (firstname.lastname@example.org)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 3920
We report spectroscopic and photometric observations of the M31 nova candidate PTF12ahb (tentatively designated M31N 2012-02a) discovered by Cao et al. (ATel #3905) on 2012 Feb 01.117 UT at R = 19.1. At our request, a spectrum (410–900 nm) was obtained by J. Caldwell on 2012 Feb. 03.08 UT with the 9.2m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph). The spectrum reveals narrow (marginally resolved) Balmer and Fe II emission lines (FWHM Hα ~ 600 km/s; EW Hα ~ -9.0 nm) superimposed on a slightly blue continuum. These observations are consistent with the identification of PTF12ahb as a relatively faint (possibly extinguished) Fe II nova in the outskirts of M31. Photometry with the 0.65-m telescope at Ondrejov on the nights of 2012 Feb. 2.710 and Feb. 3.754 UT give R = 19.4 +/- 0.15 and R = 19.9 +/- 0.25, respectively, indicating that the nova was fading rapidly at the time of our spectroscopic observations. If it continues to fade at this rate, PTF12ahb would appear to be a faint and fast outlier of the MMRD relation. A.W.S. thanks the NSF for support through AST-1009566.