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ASAS-SN Discovery of Two Probable Supernovae

ATel #8436; G. Masi (Virtual Telescope Project, Ceccano, Italy), 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), S. Kiyota (Variable Star Observers League in Japan)
on 18 Dec 2015; 18:58 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 #: 8439, 8543

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 transient sources, most likely supernovae, in an uncatalogued galaxy and the galaxy KUG 0925+693.

ASASSN-15ug was discovered in images obtained on UT 2015-12-18.34 at V~16.4 mag. We also detect the object in images obtained on UT 2015-12-12.35 (V~17.1). We do not detect (V>17.5) the object in images taken on UT 2015-12-09.36 and before. An image obtained on 2015-12-18 by G. Masi 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 5" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-15ug is approximately 1.15" North and 1.43" West from the center of an uncatalogued galaxy (no redshift information available from NED).

ASASSN-15uh was discovered in images obtained on UT 2015-12-18.50 at V~16.5 mag. We do not detect (V>17.8) the object in images taken on UT 2015-12-14.44 and before. An image obtained on 2015-12-18 by G. Masi 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 5" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-15uh is approximately 4.82" South and 8.07" West from the center of the galaxy KUG 0925+693 (no redshift information available from NED). 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-15ug  06:45:01.682  +63:14:59.89      2015-12-18.34      16.4          N/A                 1.8 
ASASSN-15uh  09:30:13.694  +69:07:02.54      2015-12-18.50      16.5          N/A                 9.4 
ASASSN-15ug photometry
 
Obs. UT Date         V mag 
2015-12-09.36        >17.5 
2015-12-12.35         17.1 
2015-12-18.34         16.4 
ASASSN-15uh photometry:
 
Obs. UT Date         V mag 
2015-12-14.44        >17.8 
2015-12-18.50         16.5 

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.