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ASAS-SN Discovery of Two Probable Supernovae

ATel #8473; J. Brimacombe (Coral Towers Observatory), L. A.G. Monard (Klein Karoo Observatory), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, 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), S. Kiyota (Variable Star Observers League in Japan), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 30 Dec 2015; 00:31 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

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 galaxy GALEXASC J042539.92-494621.0 and an uncatalogued galaxy.

ASASSN-15up was discovered in images obtained on UT 2015-12-29.20 at V~16.4 mag. We also detect the object in images obtained on UT 2015-12-27.14 (V~16.7). We do not detect (V>17.2) the object in images taken on UT 2015-12-24.30 and before. Images obtained on 2015-12-29 by J. Brimacombe and B. Monard confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the B. Monard confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the B. Mondard image.

The position of ASASSN-15up is approximately 2.1" North and 7.6" West from the center of the galaxy GALEXASC J042539.92-494621.0 (no redshift information available from NED).

ASASSN-15uq was discovered in images obtained on UT 2015-12-29.21 at V~16.2 mag. We also detect the object in images obtained on UT 2015-12-27.31 (V~16.3). We do not detect (V>17.4) the object in images taken on UT 2015-12-22.14 and before. Images obtained on 2015-12-29 by J. Brimacombe and B. Monard confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the B. Monard confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the B. Monard image.

The position of ASASSN-15uq is approximately 0.2" South and 5.3" East from the center of an uncatalogued galaxy (no redshift information available from NED). Properties of the new source 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-15up  04:25:39.258  -49:46:19.48      2015-12-29.20      16.4            N/A                7.9 
ASASSN-15uq  07:09:58.685  -65:07:56.95      2015-12-29.21      16.2            N/A                5.3 
ASASSN-15up photometry:
 
Obs. UT Date         V mag 
2015-12-24.30        >17.2 
2015-12-27.14         16.7 
2015-12-29.20         16.4 
ASASSN-15uq photometry:
 
Obs. UT Date         V mag 
2015-12-22.14        >17.4 
2015-12-27.31         16.3 
2015-12-29.21         16.2 

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.