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ASASSN-16po and ASASSN-16pp: Discovery of Probable Supernovae in AM 0204-600 and GALEXASC J234236.73-454123.7

ATel #9927; J. Brimacombe (Coral Towers Observatory), S. Kiyota (Variable Star Observers League in Japan), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, 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), P. Marples (Leyburn Observatory, Australia), G. Masi (Virtual Telescope Project, Ceccano, Italy), R. S. Post (Post Astronomy)
on 3 Jan 2017; 04:48 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 9932, 9940

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 galaxies AM 0204-600 and GALEXASC J234236.73-454123.7.

ASASSN-16po (AT 2016jga) was discovered in images obtained on UT 2016-12-21.17 at V~17.2 mag. We also detect the object in images obtained on UT 2016-12-24.14 (V~17.1), UT 2016-12-28.14 (V~17.1), and UT 2017-01-01.12 (V~17.6). We do not detect (V>17.4) the object in images taken on UT 2016-12-18.15 and before. An image obtained on UT 2016-12-25 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 3" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-16po is approximately 0.03" South and 0.45" East from the center of the galaxy AM 0204-600 (z=0.024300, d=100 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.0 (m-M=35.01, A_V=0.078).

ASASSN-16pp (AT 2016jgr) was discovered in images obtained on UT 2016-12-31.08 at V~17.3 mag. We also detect the object in images obtained on UT 2016-12-27.09 (V~17.7) and UT 2017-01-02.04 (V~17.6). We do not detect (V>18.0) the object in images taken on UT 2016-12-23.09 and before. An image obtained on UT 2017-01-02 by S. Kiyota confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-16pp is approximately 1.0" North and 1.5" East from the center of the galaxy GALEXASC J234236.73-454123.7, which has no redshift available in 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-16po  02:05:38.33   -59:47:58.23     2016-12-24.14      17.1          -18.0               0.45 
ASASSN-16pp  23:42:37.01   -45:41:22.79     2016-12-31.08      17.3          N/A                 1.80 
 
ASASSN-16po: 
Obs. UT Date         V mag 
2016-12-18.15        >17.4 
2016-12-21.17         17.2 
2016-12-24.14         17.1 
2016-12-28.14         17.1 
2017-01-01.12         17.2 
 
ASASSN-16pp: 
Obs. UT Date         V mag 
2016-12-23.09        >18.0 
2016-12-27.09         17.7 
2016-12-31.08         17.3 
2017-01-02.04         17.6 

Follow-up observations are encouraged.

While we are participating in the TNS system to minimize potential confusion, ASAS-SN will continue using ASASSN-16xx 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-16xx (AT2016xyz) 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 supported by 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.