ASASSN-16az and ASASSN-16ba: Discovery of Two Probable Supernovae in 2MASX J11303364-4233359 and MCG -03-25-015

ATel #8614; T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, 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), J. Brimacombe (Coral Towers Observatory)
on 30 Jan 2016; 17:02 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

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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 J11303364-4233359 and MCG -03-25-015.

ASASSN-16az (AT 2016za) was discovered in images obtained on UT 2016-01-29.38 at V~16.9 mag. We also detect the object in images obtained on UT 2016-01-23.25 (V~17.1), UT 2016-01-21.25 (V~17.1), UT 2016-01-20.35 (V~17.0), and UT 2016-01-19.110 (V~17.2). We do not detect (V>17.8) the object in images taken on UT 2016-01-13.27 and before. An image obtained on UT 2016-01-30.35 with the LCOGT 1-m robotic telescope in Sutherland, South Africa confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the LCOGT image.

The position of ASASSN-16az is approximately 4.6" North and 0.9" East from the center of the galaxy 2MASX J11303364-4233359 (z=0.034067, d=148 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.2 (m-M=35.85, A_V=0.235).

ASASSN-16ba (AT 2016zb) was discovered in images obtained on UT 2016-01-29.34 at V~16.8 mag. We do not detect (V>17.2) the object in images taken on UT 2016-01-28.29 and before. An image obtained on UT 2016-01-30.33 with the LCOGT 1-m robotic telescope in Sutherland, South Africa confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the LCOGT image.

The position of ASASSN-16ba is approximately 9.5" North and 3.3" East from the center of the galaxy MCG -03-25-015 (z=0.013922, d=62.6 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.4 (m-M=33.98, A_V=0.180). 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-16az  11:30:33.73    -42:33:31.44      2016-01-29.38      16.9          -19.2               4.69 
ASASSN-16ba  09:42:29.22    -16:58:26.88      2016-01-29.34      16.8          -17.4               10.06 

ASASSN-16az:

 
Obs. UT Date         V mag 
2016-01-13.27        >17.8 
2016-01-19.11         17.2 
2016-01-20.35         17.0 
2016-01-21.25         17.1 
2016-01-23.25         17.1 
2016-01-29.38         16.9 

ASASSN-16ba:

 
Obs. UT Date         V mag 
2016-01-28.29        >17.2 
2016-01-29.34         16.8 

Follow-up observations are encouraged.

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.