ASASSN-17bo and ASASSN-14br: Discovery of Two Probable Supernovae

ATel #10022; G. Krannich (Roof Observatory Kaufering), I. Cruz (Cruz Observatory), J. Brimacombe (Coral Towers Observatory), G. Stone (Sierra Remote Observatories), R. S. Post (Post Astronomy), G. Masi (Virtual Telescope Project, Ceccano, Italy), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, J. Shields, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, S. Bose, Ping Chen (KIAA-PKU), S. Kiyota (Variable Star Observers League in Japan), R. A. Koff (Antelope Hills Observatory)
on 30 Jan 2017; 00:39 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 "Brutus" telescope in Haleakala, Hawaii, we discovered two new transient sources, most likely supernovae, in the galaxies 2MASX J11011991+7039548 and GALEXASC J155200.16+661851.6.

ASASSN-17bo (AT 2017wb) was discovered in images obtained on UT 2017-01-28.59 at V~16.9 mag. We also detect the object in images obtained on UT 2017-01-27.45 (V~17.4). We do not detect (V>18.0) the object in images taken on UT 2017-01-24.53 and before. An image obtained on 2016-01-28 by G. Krannich confirms the discovery of the transient. This figure shows the archival Pan-STARRS g-band image of the host (left) and the G. Krannich confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the G. Krannich image.

The position of ASASSN-17bo is approximately 0.2" South and 1.9" West from the center of the galaxy 2MASX J11011991+7039548 (no redshift information available from NED).

ASASSN-17br (AT 2017xy) was discovered in images obtained on UT 2017-01-29.63 at V~17.1 mag. We also detect the object in images obtained on UT 2017-01-04.25 (V~16.7). We do not detect (V>17.5) the object in images taken on UT 2017-09-10.25 and before. An image obtained on 2017-01-29 by G. Krannich confirms the discovery of the transient. This figure shows the archival Pan-STARRS g-band image of the host (left) and the G. Krannich confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the G. Krannich image.

The position of ASASSN-17br is approximately 3.6" North and 0.9" East from the center of the galaxy GALEXASC J155200.16+661851.6 (no 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-17bo  11:01:19.534   +70:39:54.76     2017-01-28.59      16.9            N/A               1.91 
ASASSN-17br  15:52:00.306   +66:18:55.27     2017-01-29.63      17.1            N/A               3.71 

ASASSN-17bo photometry:

 
Obs. UT Date         V mag 
2017-01-24.53        >18.0 
2017-01-27.45         17.4 
2017-01-28.59         16.9 

ASASSN-17br photometry:

 
Obs. UT Date         V mag 
2016-09-10.25        >17.6 
2017-01-04.75         16.7 
2017-01-29.63         17.1 

Follow-up observations are encouraged.

While we are participating in the TNS system to minimize potential confusion, ASAS-SN will continue using ASASSN-17xx transient names as our primary nomenclature (including supernovae, but also other classes of transients), and we encourage others to do the same. We prefer merging the names as ASASSN-17xx (AT 2017xyz) to preserve, rather than anonymize, the origin of the transient.

We thank Las Cumbres Observatory and its staff for their continued support of ASAS-SN. ASAS-SN is funded in part by the Gordon and Betty Moore Foundation through grant GBMF5490 to the Ohio State University, NSF grant AST-1515927, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of Sciences South America Center for Astronomy (CASSACA), and the 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.