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ASAS-SN Discovery of Two Probable Luminous Supernovae in Mrk 0283a and 2MASX J14021617+3339415

ATel #7790; G. Masi (Virtual Telescope Project, Ceccano, Italy), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, A. B. Danilet, G. Simonian, U. Basu, J. F. Beacom, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong (KIAA-PKU), J. Brimacombe (Coral Towers Observatory), E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), J. M. Fernandez (Observatory Inmaculada del Molino), S. Kiyota (Variable Star Observers League in Japan), B. Nicholls (Mt. Vernon Obs., New Zealand), J. Nicolas (Groupe SNAUDE, France)
on 12 Jul 2015; 21:31 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 7796, 7821

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 luminous new transient sources, most likely supernovae, in the galaxies Mrk 0283a and 2MASX J14021617+3339415.

ASASSN-15mi was discovered in images obtained on UT 2015-07-06.32 at V~17.2 mag. We also detect the object in images obtained on UT 2015-07-12.30 (V~16.9). We do not detect (V>17.3) the object in images taken on UT 2015-07-03.26 and before. An image obtained by G. Masi on UT 2015-07-12.83 using the Virtual Telescope Project 17-inch Planewave telescope at Ceccano, Italy 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 3" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-15mi is approximately 0.8" North and 1.6" West from the center of the galaxy Mrk 0283a (z=0.034446, d=148 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.7 (m-M=35.85, A_V=0.058).

ASASSN-15mj was discovered in images obtained on UT 2015-07-12.28 at V~16.4 mag. We do not detect (V>17.3) the object in images taken on UT 2015-07-06.31 and before. An image obtained by G . Masi on UT 2015-07-12.82 using the Virtual Telescope Project 17-inch Planewave telescope at Ceccano, Italy confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the G. Masi confirmation image (right). The red circle has a radius of 4" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-15mj is approximately 0.9" South and 6.7" West from the center of the galaxy 2MASX J14021617+3339415 (z=0.034371, d=148 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.5 (m-M=35.85, A_V=0.04). Properties and photometry of the new sources are summarized in the tables below:

 
Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag  Approx. Abs. Mag   Offset from Host (") 
ASASSN-15mi  14:03:15.75   +41:36:14.36      2015-07-06.32      17.2          -18.7               1.79 
ASASSN-15mj  14:02:15.64   +33:39:40.29      2015-07-12.28      16.4          -19.5               6.76 
ASASSN-15mi photometry:
 
Obs. UT Date         V mag 
2015-07-03.26        >17.3 
2015-07-06.32         17.2 
2015-07-12.30         16.9 
ASASSN-15mj photometry:
 
Obs. UT Date         V mag 
2015-07-06.31        >17.3 
2015-07-12.28         16.4 

Follow-up observations are encouraged.

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported in part by 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.