Electronic Telegram No. 4026
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2014dv IN NGC 2501 = PSN J07583010-14211501
     Further to CBET 3967, W. Zheng and A. V. Filippenko, University of
California at Berkeley, report the LOSS discovery of an apparent supernova in
NGC 2501 in unfiltered KAIT images:

 SN       2014 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2014dv   Nov. 17.490  7 58 30.10  -14 21 15.0   16.0    0".9 E, 0".5 N

The variable was designated PSN J07583010-14211501 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2014dv based on the
spectroscopic confirmation reported below.  The new object was first detected
on Nov. 4.49 UT at 16.0 mag, and it was detected again in the following two
weeks with a similar magnitude but with large uncertainty because the object's
position is only about 1" away from the host-galaxy nucleus.  The previous
KAIT image of NGC 2501 was obtained in April.  A finder chart is posted at
URL http://astro.berkeley.edu/~zwk/findingchart/PSN_J07583010-14211501.jpg.

     G. Hosseinzadeh, I. Arcavi, S. Valenti, C. McCully, and D. A. Howell, Las
Cumbres Observatory Global Telescope Network and University of California,
Santa Barbara, report that a spectrogram of PSN J07583010-14211501 = SN
2014dv, obtained on Nov. 18.54 UT with the FLOYDS robotic spectrograph (range
320-1000 nm, resolution 2 nm) mounted on the 2-m "Faulkes Telescope North" at
Haleakala, Hawaii, shows it to be a type-Ia supernova.  Using Superfit (Howell
et al. 2005, Ap.J. 634, 1190), they find a good fit to the type-Ia supernova
1999aa at 51 days after maximum light at the redshift of the host galaxy (z =
0.007; Koribalski et al. 2004, A.J. 128, 16l; via NED).

     M. L. Graham, W. Zheng, B. E. Tucker, K. I. Clubb, and A. V. Filippenko,
University of California at Berkeley, report that a CCD spectrogram (range
380-960 nm) of PSN J07583010-14211501 = SN 2014dv was obtained with the 10-m
Keck I telescope (+ LRIS) on Nov. 20 UT, and classification was performed
using Superfit (Howell et al. 2005, Ap.J. 634, 1190).  SN 2014dv is a
post-maximum type-Ia supernova, with a best fit to SN 1999aa at +51 days.
Note that SN 1999aa was peculiar, resembling SN 1991T at earlier times (e.g.,
Garavini et al. 2004, A.J. 128, 387), but transitioning to a normal type-Ia
supernova a few weeks past maximum brightness; without earlier-phase spectra
for 2014dv, it may have been a normal type-Ia supernova.  The spectrum
exhibits two strong components of Na I D absorption, at redshift z = 0.007
(equivalent width = 0.35 nm) and at z = 0 (EW = 0.11 nm).  Based on Poznanski
et al. (2012, MNRAS 426, 1465), EW = 0.11 nm suggests that E(B-V) = 0.27 mag,
but this is significantly stronger than expected from the line-of-sight
Galactic extinction:  A_V = 0.34 mag, or E(B-V) = 0.11 mag with R_V = 3.1
(Schlegel et al. 1998, Ap.J. 500, 525).  Thus, the z = 0 component of Na I
D might actually be blueshifted in the rest frame of NGC 2501, in which case
its velocity is approximately -2000 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 November 26                 (CBET 4026)              Daniel W. E. Green