ASAS-SN Discovery of Two Probable Supernovae

ATel #8153; J. Brimacombe (Coral Towers Observatory), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, D. Godoy Rivera, B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), S. Kiyota (Variable Star Observers League in Japan), R. A. Koff (Antelope Hills Observatory), G. Krannich (Roof Observatory Kaufering), G. Masi (Virtual Telescope Project, Ceccano, Italy), B. Nicholls (Mt. Vernon Obs., New Zealand), J. Nicolas (Groupe SNAUDE, France)
on 11 Oct 2015; 22:13 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@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 transient sources, most likely supernovae, in the galaxies 2MASX J00011837-3321048 and ESO 296-G027.

ASASSN-15qy was discovered in images obtained on UT 2015-10-11.31 at V~16.9 mag. We do not detect (V>17.0) the object in images taken on UT 2015-10-09.25 and before. An image obtained on 2015-10-11 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 3" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15qy is approximately 1.49" North and 1.28" West from the center of the galaxy 2MASX J00011837-3321048 (no redshift information available from NED).

ASASSN-15qz was discovered in images obtained on UT 2015-10-11.110 at V~17.1 mag. We do not detect (V>17.6) the object in images taken on UT 2015-10-09.36 and before. An image obtained on 2015-10-11 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 3" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15qz is approximately 0.14" South and 4.37" East from the center of the galaxy ESO 296-G027 (z=0.021638, d=87.5 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.7 (m-M=34.71, A_V=0.048).

Properties of the two 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-15qy  00:01:18.26    -33:21:02.71      2015-10-11.31      16.9         N/A               1.96 
ASASSN-15qz  01:25:36.09    -41:27:55.84      2015-10-11.11      17.1        -17.7              4.37 

ASASSN-15qy photometry:

 
Obs. UT Date         V mag 
2015-10-09.25        >17.0 
2015-10-11.31         16.9 

ASASSN-15qz photometry:

 
Obs. UT Date         V mag 
2015-10-09.36        >17.6 
2015-10-11.11         17.1 

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 Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, 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.