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Discovery and classification of four novae in M31

ATel #4193; Y. Cao (Caltech), M. M. Kasliwal (Carnegie/Princeton), M. L. Graham (UCSB/LCOGT), D. Levitan (Caltech), K. Mooley (Caltech), J. M. Silverman (Berkeley), A. A. Miller (Berkeley), J. M. Silverman (Berkeley), K. I. Clubb (Berkeley) and O. D. Fox (Goddard)
on 20 Jun 2012; 15:13 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Mansi Manoj Kasliwal (mansi@astro.caltech.edu)

Subjects: Optical, Nova, Transient

Referred to by ATel #: 4196

 

We report four novae in M31 that are discovered and classified by the Palomar Transient Factory collaboration.

PTF12fdn was discovered on 2012 June 06.46 UT with R=19.8 mag at RA(J2000)=00:40:23.22, Dec(J2000)=+40:36:10.3, about 26'.51 west and 39'.98 south of the center of M31. Nothing was there in an image taken on 2012 June 03.46 with a limiting magnitude of R=19.9 mag. Spectroscopic follow-up was done on 2012 June 16 UT with the Low Resolution Imaging Spectrometer (LRIS) mounted on the Keck-I telescope. The spectrum shows a blue continuum component superposed by strong emission lines, such as Balmer lines, O I 7773, O I 8226, O I 8447, O I 9264, near IR Ca II triplet and Fe II lines in the wavelength range between 5000 and 6500 Angstrom. Balmer series except Halpha, all oxygen lines and iron lines show P-Cygni profiles. The Halpha has a FWHM of about 1,700 km/s. This spectrum illustrates that PTF12fdn is a M31 nova of Fe II type.

PTF12fdo was discovered on 2012 June 07.41 UT with R=17.7 mag at RA(J2000)=00:45:09.79, Dec(J2000)=+41:40:50.6, about 27'.34 east and 24'.69 north of the center of M31. Nothing was there in an image taken on 2012 June 06.46 with a limiting magnitude of R=20.3 mag. Its spectrum was obtained on 2012 June 18 UT with the Double Spectrograph (DBSP) mounted on the 200-inch Hale telescope at Palomar Observatory. The spectrum shows strong Balmer series, O I 7773, O I 8226, O I 8447, O I 9264 and Fe II lines together with very weak continuum. All lines show double-peaked structures. The Halpha has two peaks at 6535 and 6583 Angstrom. Given that the M31 has a systematical velocity of 300 km/s towards us, the two peaks correspond to velocities of -1000 km/s and 1200 km/s. The full width of Halpha at zero intensity is about 4,000 km/s. This spectrum confirms that PTF12fdo is a Fe II type nova in M31.

PTF12fdt was discovered on 2012 June 08.40 UT with R=19.4 mag at RA(J2000)=00:38:56.60, Dec(J2000)=+40:29:49.8, about 42'.79 west and 46'.32 south of the center of M31. Nothing was there in an image taken on 2012 June 07.47 with a limiting magnitude of R=20.5 mag. We got its spectrum on 2012 June 14 UT with the Kast Double Spectrograph mounted on the Shane 3-m telescope at Lick Observatory. The spectrum shows blue continuum with emission lines of Balmer series, O I 7773, O I 8226, O I 8447, O I 9264 and Fe II lines. All lines have P-Cygni profiles. The absorption component of Halpha is centered at about -600 km/s; the emission component is centered at 100 km/s. The full width at zero intensity is about 2,500 km/s. This spectrum confirms PTF12fdt as a Fe II type nova in M31.

PTF12flx was discovered on 2012 June 14.39 UT with R=19.1 mag at RA(J2000)=00:42:05.09, Dec(J2000)=+41:15:48.1, about 7'.37 west and 0'.35 south of the center of M31. Nothing was there in an image taken on 2012 June 13.46 with a limiting magnitude of R=19.4 mag. The spectroscopic follow-up was done on 2012 June 18 UT with DBSP. The spectrum shows very weak continuum with emission lines such as Balmer series, Na I D, O I 7773, O I 8227, O I 8446, O I 9264, Mg II 7890, near IR Ca II triplet and Fe lines. The Halpha has a FWHM of about 2,700 km/s. This spectrum confirms that PTF12flx is a M31 nova of Fe II type.

All photometric measurements are calibrated to the USNO-B1.0 catalog.