ASASSN-17ka: Discovery of A Probable Supernova in ESO 244-G 019
ATel #10607; L. A.G. Monard (Klein Karoo Observatory), J. Brimacombe (Coral Towers Observatory), 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), G. Bock (Runaway Bay Observatory, Australia), J. M. Fernandez (Observatory Inmaculada del Molino), S. Kiyota (Variable Star Observers League in Japan), G. Masi (Virtual Telescope Project, Ceccano, Italy), R. S. Post (Post Astronomy)
on 31 Jul 2017; 23:54 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (email@example.com)
Subjects: Optical, Supernovae, Transient
During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 244-G 019.
ASASSN-17ka (AT 2017frr) was discovered in images obtained on UT 2017-07-27.23 at V~16.5 mag. We also detect the object in images obtained on UT 2017-07-24.24 (V~16.6), UT 2017-07-29.23 (V~16.0), and UT 2017-07-30.23 (V~16.5). We do not detect (V>17.5) the object in images taken on UT 2017-07-17.35 and before. An image obtained on 2017-07-28 by L.A.G. Monard confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the L.A.G. Monard confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the L.A.G. Monard image.
The position of ASASSN-17ka is approximately 1.8" North and 7.3" East from the center of the galaxy ESO 244-G 019 (no redshift information available from NED). Follow-up spectroscopy (ATEL #10605) shows the object to be a Type Ia supernova approximately 1 day after max, at a redshift of 0.027. 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-17ka 01:20:55.501 -43:08:53.53 2017-07-27.23 16.5 -18.7 7.52
Obs. UT Date V mag
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 Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, and the Chinese Academy of Sciences South America Center for Astronomy (CASSACA). For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.