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ASASSN-17ho and ASASSN-17hq: Discovery of Two Probable Supernovae

ATel #10509; B. Nicholls (Mt. Vernon Obs., New Zealand), J. Brimacombe (Coral Towers Observatory), P. Cacella (DogsHeaven 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), J. M. Fernandez (Observatory Inmaculada del Molino)
on 19 Jun 2017; 20:47 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 #: 10517

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 two new transient sources, most likely supernovae, in the galaxies AM 1904-844 and GALEXASC J184352.21-562927.7.

ASASSN-17ho (AT 2017erv) was discovered in images obtained on UT 2017-06-13.38 at V~16.1 mag. An image obtained on 2017-06-13 by B. Nicholls confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the B. Nicholls confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the B. Nicholls image.

The position of ASASSN-17ho is approximately 3.7" North and 0.5" East from the center of the galaxy AM 1904-844 (z=0.017035, d=71.3 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.5 (m-M=34.23, A_V=0.372).

ASASSN-17hq (AT 2017eve) was discovered in images obtained on UT 2017-06-19.14 at V~16.5 mag. An image obtained on 2017-06-19 by J. Brimacombe confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-17hq is approximately 1.3" South and 10.8" East from the center of the galaxy GALEXASC J184352.21-562927.7 (no redshift information available from NED). Properties of the new 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-17ho  19:18:47.103   -84:41:50.05     2017-06-13.38      16.1          -18.5               3.73 
ASASSN-17hq  18:43:53.509   -56:29:29.07     2017-06-19.14      16.5           N/A               10.88 

ASASSN-17ho photometry:

 
Obs. UT Date         V mag 
2017-06-09.32        >16.5 
2017-06-11.23         16.6 
2017-06-13.31         16.2 
2017-06-19.25         15.8 

ASASSN-17hq photometry:

 
Obs. UT Date         V mag 
2017-06-09.23        >16.9 
2017-06-11.18         16.6 
2017-06-13.26         16.9 
2017-06-19.14         16.5 

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.