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ASAS-SN Discovery and Spectroscopic Confirmation of A Supernova in NGC 2771

ATel #6571; J. Thorstensen, E. Alper (Dartmouth), J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Davis, G. Simonian, U. Basu, J. F. Beacom (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 13 Oct 2014; 17:30 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new supernova in the galaxy NGC 2771:

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-14iu  09:10:39.53   +50:22:48.26      2014-10-12.61    15.8 

ASASSN-14iu was discovered in images obtained on UT 2014-10-12.61 at V~15.9 mag. We also detect the object in images obtained with multiple ASAS-SN cameras on UT 2014-10-13.60 (V~15.6) and UT 2014-10-08.61 (V~15.8). We do not detect (V>17.4) the object in images taken on UT 2014-10-05.63 and before. An image obtained by J. Brimacombe on UT 2014-10-13.34 with the RCOS 51-cm telescope in New Mexico confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-14iu is approximately 0.8" North and 1.3" West from the center of the galaxy NGC 2771 (z=0.016855, d=72.5 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.5 (m-M=34.3, A_V=0.054).

We obtained optical spectra of ASASSN-14iu with the MDM 2.4m + Modspec (range 5100-7200 Angs.) on UT 2014 Oct. 13.5. The spectrum shows characteristics of a normal Type Ia SN around maximum light with a fairly red continuum and strong Na I absorption from the host galaxy (EW ~2 Angstroms), consistent with host reddening. After correcting for the redshift of the host galaxy, we measure the blueshifted velocity of the Si II 6355 Angs. line at v~ -13000 km/s.

We thank LCOGT and its staff for their continued support of ASAS-SN. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.