ASAS-SN Discovery of a Type Ia SN at maximum light
ATel #5110; J. L. Prieto (Princeton), S. Villanueva Jr., M. Fausnaugh, B. J. Shappee, K. Z. Stanek, C. S. Kochanek, J. Jencson, A. Talabere, J. F. Beacom (Ohio State), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), M. Dubberley, M. Elphick, S. Foale, E. Hawkins, D. Mullens, W. Rosing, R. Ross, Z. Walker (Las Cumbres Observatory)
on 6 Jun 2013; 13:43 UT
Credential Certification: Jose L. Prieto (jose@obs.carnegiescience.edu)
Subjects: Optical, Supernovae, Transient
uring the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or
"Assassin"; ATel #4987, #4999, #5010, #5082, #5102), using data from
the double 14-cm "Brutus" telescope in Haleakala, Hawaii, we
discovered a new transient close to the detection threshold of the
survey:
Object RA (J2000) DEC (J2000) Disc. UT Date Approx. Disc. V mag
ASASSN-13an 13:45:36.21 -07:19:32.62 2013 June 5.34 16.5
ASASSN-13an was discovered in images obtained 2013 UT June 5.34, but
it was also detected in images obtained on 2013 UT May 27. It was
undetected (V > 17) in images obtained 2013 April 20 and earlier.
Images obtained by S. Villanueva Jr. with the MDM 2.4m telescope (+OSMOS)
on 2013 June 6.3 confirmed the detection of the new transient at ~3.3"
W and 1.2" N from its host galaxy 2MASX J13453653-0719350. The
confirmation image can be found here. A low-resolution spectrum
obtained with OSMOS (range 3900-6900 Angstroms, FWHM res. = 7 Angs)
shows that ASASSN-13an is a Type Ia SN around maximum light. After
correcting for the recession velocity of the host galaxy (z=0.0216,
measured from H-alpha emission line detected in the spectrum), we
measure the velocity of the minimum of the Si II 6355 absorption
feature at v(SiII minimum) = -10000 km/s. The Si II 6355 and 5972
features show a clear asymmetry. If the blue side of the features is interpreted
as a second component it has v ~ -15000 km/s. The spectrum is shown here.
