H-alpha Confirmation of Seven Nova Candidates in M31
ATel #4181; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), O. Vaduvescu (ING, La Palma & IAC, Tenerife, Spain), C. Zurita (IAC, Tenerife, Spain)
on 16 Jun 2012; 18:44 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 4511
Recently, the discoveries of several nova candidates in M31 have been reported
(ATEL #3735, #3976, and #3987), but there have been no spectroscopic confirmations.
To classify these objects, we obtained narrow-band H-alpha, Sloan r', and
Sloan i'-band CCD images of the central region of M31 using the 2.5-m Isaac
Newton Telescope (INT) + WFC at La Palma under ~1.2" seeing on May 22.198 - 22.216 UT.
The photometry obtained from the INT + WFC images is summarized in the following table:
TOCP designation CBAT designation H-alpha mag Sloan r' mag Sloan i' mag
PNV J00413185+4108320 M31N 2012-05d? 16.74 +/- 0.05 19.53 +/- 0.08 20.8 +/- 0.15
PNV J00423149+4126138 M31N 2012-05c? 16.67 +/- 0.04 19.16 +/- 0.07 19.49 +/- 0.09
PNV J00423272+4115373 M31N 2012-05b? 16.76 +/- 0.05 19.38 +/- 0.08 20.2 +/- 0.1
PNV J00425927+4118146 M31N 2012-05a? 14.76 +/- 0.04 16.98 +/- 0.04 17.07 +/- 0.08
PNV J00422292+4104165 M31N 2012-03c? 17.58 +/- 0.06 19.59 +/- 0.09 20.6 +/- 0.15
PNV J00422773+4108136 M31N 2012-03b? 17.92 +/- 0.07 19.80 +/- 0.10 20.3 +/- 0.1
PNV J00433417+4125078 M31N 2012-03a? 20.4 +/- 0.15 > 22.2 > 20.9
PNV J00415824+4124011 M31N 2011-11c? 20.8 +/- 0.2 > 22.2 > 20.9
PNV J00421003+4105141 M31N 2011-11a? 18.99 +/- 0.10 21.4 +/- 0.1 > 20.8
PNV J00424359+4116378 M31N 2011-05a? 18.35 +/- 0.09 20.9 +/- 0.3 > 20.8
Strong excess H-alpha emission is present in all seven nova candidates discovered
during 2012 March and May, as well as in PNV J00421003+4105141 and PNV J00415824+4124011,
which were confirmed spectroscopically as FeII-class novae in M31 (ATEL #
3769 and
#
3778). A very similar H-alpha excess is also observed in PNV J00424359+4116378, which was
originally classified as probable nova due to its strong excess H-alpha emission on 2011 July 14
(ATEL #
3486). Relative faintness in the Sloan i' with respect to the Sloan r' band excludes
the possibility that some of the seven spectroscopically unconfirmed objects could be
Mira-like stars observed during a maximum. Instead, there is a strong support for
the classification of the seven objects as novae.
This work is based on observations made with the Isaac Newton Telescope operated
on the island of La Palma by the ING in the Spanish Observatorio del Roque de los
Muchachos.