[ Previous | Next | ADS ]

ASASSN-16bl and ASASSN-16bm: ASAS-SN Discovery of Two Probable Supernovae

ATel #8652; J. Brimacombe (Coral Towers Observatory), S. Kiyota (Variable Star Observers League in Japan), 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), J. M. Fernandez (Observatory Inmaculada del Molino)
on 8 Feb 2016; 18:35 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 8679

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two new transient sources, most likely supernovae, in the galaxies 2MASX J11422674-3654256 and GALEXASC J115155.68-132459.3.

ASASSN-16bl (AT 2016adk) was discovered in images obtained on UT 2016-02-08.22 at V~17.3 mag. We also detect the object in images obtained on UT 2016-02-06.31 (V~17.5), UT 2016-02-04.30 (V~17.4), and UT 2016-02-02.21 (V~17.7). We do not detect (V>17.6) the object in images taken on UT 2016-02-01.27 and before. Images obtained on 2016-02-08 by J. Brimacombe and S. Kiyota confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-16bl is approximately 2.1" North and 0.9" West from the center of the galaxy 2MASX J11422674-3654256 (z=0.029547, d=129 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.6 (m-M=35.55, A_V=0.318).

ASASSN-16bm (AT 2016adl) was discovered in images obtained on UT 2016-02-08.210 at V~17.0 mag. We do not detect (V>17.6) the object in images taken on UT 2016-02-06.43 and before. Images obtained on 2016-02-08 by J. Brimacombe and S. Kiyota confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-16bm is approximately 3.4" North and 8.3" East from the center of the galaxy GALEXASC J115155.68-132459.3 (no redshift information available from NED). We note that the host of ASASSN-16bm has a relatively small angular separation from the galaxy GALEXASC J115153.52-132447.1 (z=0.006863, d=33.4 Mpc, m-M=32.62, via NED).

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-16bl  11:42:26.680  -36:54:23.41      2016-02-08.22      17.3          -18.6               2.28 
ASASSN-16bm  11:51:56.238  -13:25:03.07      2016-02-08.21      17.0           N/A                8.97 

ASASSN-16bl photometry:

 
Obs. UT Date         V mag 
2016-02-01.27        >17.6 
2016-02-02.21         17.7 
2016-02-04.30         17.4 
2016-02-06.31         17.5 
2016-02-08.22         17.3 

ASASSN-16bm photometry:

 
Obs. UT Date         V mag 
2016-02-06.43        >17.6 
2016-02-08.21         17.0 

Follow-up observations are encouraged.

As a reminder to the community, the proper, IAU registered name of any ASAS-SN transient is the "ASASSN-16??" name. We are presently participating in the TNS system, and recommend the format ASASSN-16?? (AT 2016??) to indicate the secondary TNS name.

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.