ASASSN-16pk and ASASSN-16pl: Discovery of Two Probable Supernovae

ATel #9918; G. Masi (Virtual Telescope Project, Ceccano, Italy), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, J. Shields, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, S. Bose, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory), G. Bock (Runaway Bay Observatory, Australia), J. M. Fernandez (Observatory Inmaculada del Molino), P. Marples (Leyburn Observatory, Australia), R. S. Post (Post Astronomy), G. Stone (Sierra Remote Observatories)
on 30 Dec 2016; 17:06 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@astronomy.ohio-state.edu)

Tweet

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 two new transient sources, most likely supernovae, in the galaxies SDSS J122739.96+403651.3 and IC 0988.

ASASSN-16pk (AT 2016jdl) was discovered in images obtained on UT 2016-12-29.55 at V~16.8 mag. We do not detect (V>18.2) the object in images taken on UT 2016-12-23.64 and before. An image obtained on 2016-12-30 by G. Masi confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the G. Masi confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-16pk is approximately 2.0" North and 0.6" West from the center of the galaxy SDSS J122739.96+403651.3 (no redshift information available from NED).

ASASSN-16pl (AT 2016jdv) was discovered in images obtained on UT 2016-12-29.61 at V~16.6 mag. We do not detect (V>17.2) the object in images taken on UT 2016-07-31.24 and before. An image obtained on 2016-12-30 by G. Masi confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the G. Masi confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-16pl is approximately 4.6" South and 6.4" West from the center of the galaxy IC 0988 (z=0.026934, d=117 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.8 (m-M=35.27, A_V=0.087). Properties of the new sources and photometry are summarized in the tables below:

 
Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag  Approx. Abs. Mag   Offset from Host (") 
ASASSN-16pk  12:27:39.911   +40:36:53.36     2016-12-29.55      16.8           N/A                 2.09 
ASASSN-16pl  14:14:31.630   +03:11:20.33     2016-12-29.61      16.6           -18.8               7.88 

ASASSN-16pk photometry:

 
Obs. UT Date         V mag 
2016-12-23.64        >18.2 
2016-12-29.55         16.8 

ASASSN-16pl photometry:

 
Obs. UT Date         V mag 
2016-07-31.24        >17.2 
2016-12-29.61         16.6 

Follow-up observations are encouraged.

While we are participating in the TNS system to minimize potential confusion, ASAS-SN will continue using ASASSN-16xx transient names as our primary nomenclature (including supernovae, but also other classes of transients), and we encourage others to do the same. We prefer merging the names as ASASSN-16xx (AT2016xyz) to preserve, rather than anonymize, the origin of the transient.

We thank Las Cumbres Observatory and its staff for their continued support of ASAS-SN. ASAS-SN is supported by NSF grant AST-1515927, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of Sciences South America Center for Astronomy (CASSACA), and the Mt. Cuba Astronomical Foundation. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.