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ASASSN-16bq and ASASSN-16br: Discovery of Two Probable Supernovae

ATel #8685; J. Brimacombe (Coral Towers Observatory), J. S. Brown, T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, D. Godoy-Rivera, U. Basu (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), G. Bock (Runaway Bay Observatory, Australia), I. Cruz (Cruz Observatory), S. Kiyota (Variable Star Observers League in Japan), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 12 Feb 2016; 18:23 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@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 two new transient sources, most likely supernovae, in the galaxies IC 0986 and 2MASX J15453055-1309057.

ASASSN-16bq (AT 2016aew) was discovered in images obtained on UT 2016-02-12.52 at V~17.3 mag. We also detect the object in images obtained on UT 2016-02-11.53 (V~17.6). We do not detect (V>17.8) the object in images taken on UT 2016-02-09.64 and before. An image obtained on 2016-02-12 by J. Brimacombe 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-16bq is approximately 2.0" South and 3.9" East from the center of the galaxy IC 0986 (z=0.025001, d=108 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.9 (m-M=35.12, A_V=0.105).

ASASSN-16br (AT 2016aex) was discovered in images obtained on UT 2016-02-12.56 at V~16.8 mag. We also detect the object in images obtained on UT 2016-02-11.56 (V~17.2). We do not detect (V>18.2) the object in images taken on UT 2016-02-09.38 and before. An image obtained on 2016-02-12 by J. Brimacombe confirms the discovery of the transient. This figure shows the archival DSS 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-16br is approximately 3.4" South and 2.8" West from the center of the galaxy 2MASX J15453055-1309057 (z=0.028520, d=122 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.0 (m-M=35.37, A_V=0.440). 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-16bq  14:11:26.491  +01:17:09.47      2016-02-12.52      17.3          -17.9                4.4 
ASASSN-16br  15:45:30.314  -13:09:10.03      2016-02-12.56      16.8          -19.0                4.4 

ASASSN-16bq photometry:

 
Obs. UT Date         V mag 
2016-02-09.64        >17.8 
2016-02-11.53         17.6 
2016-02-12.52         17.3 

ASASSN-16br photometry:

 
Obs. UT Date         V mag 
2016-02-09.38        >18.2 
2016-02-11.56         17.2 
2016-02-12.56         16.8 

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 (AT2016yy) to preserve, rather than anonymize, the origin of the transient.

We thank LCOGT 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 Mt. Cuba Astronomical Foundation, George Skestos, and the Robert Martin Ayers Sciences Fund. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.