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ASASSN-17fk: Discovery of A Probable Supernova in NGC 2076

ATel #10320; Subo Dong (KIAA-PKU), K. Z. Stanek, C. S. Kochanek, J. S. Brown, T. W.-S. Holoien, J. Shields, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), S. Bose, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory)
on 25 Apr 2017; 01:10 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Subo Dong (dongsubo@pku.edu.cn)

Subjects: Optical, Supernovae

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii and the 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient sources, most likely supernovae, in the galaxy NGC 2076.

ASASSN-17fk (AT 2017dhr) was discovered in images obtained on UT 2017-04-20.98 at V~16.4 mag. We also detected the object in images taken on 2017-04-14.99 at V~17.0 mag, and we do not detect (V>17.0) the object in images taken on UT 2017-04-12.01 and before. An image obtained on 2017-04-24.73 by Las Cumbres Observatory (LCO) 1m telescope at SAAO confirms the discovery of the transient. This figure shows the archival Pan-STARRS (Chambers et al. 2016, arXiv:1612.05560) r-band image of the host (left) and the LCO confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the LCO image.

The position of ASASSN-17fk is close to the center (within ~10") of the galaxy NGC 2076 (z=0.007145, d=30Mpc, via NED), giving an absolute V-band magnitude of approximately -16.2 (m-M=32.4, A_V=0.23) without taking host extinction into account, while host extinction might be important since its apparent position is near a dust lane.

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag  Approx. Abs. Mag   Offset from Host (") 
ASASSN-17fk  05:46:47.27    -16:47:00.30     2017-04-20.98      16.4          -16.2               10 

ASASSN-17fk photometry:

Obs. UT Date         V mag 
2017-04-12.01        >17.0 
2017-04-14.99         17.0 
2017-04-20.98         16.4 

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.