ASAS-SN Discovery of an Unusual Outburst from USNO-B1.0 0421-0026203
ATel #6340; J. L. Prieto (Universidad Diego Portales), K. Z. Stanek, C. S. Kochanek, T. W.-S. Holoien, B. J. Shappee, A. B. Davis, J. Jencson, U. Basu, J. F. Beacom (Ohio State), D. Bersier (LJMU), J. Brimacombe (Coral Towers Observatory), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 24 Jul 2014; 19:20 UT
Credential Certification: Jose L. Prieto (jose.prietok@mail.udp.cl)
Subjects: Optical, Transient, Variables
Referred to by ATel #: 6475
During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered an unusual outburst of USNO-B1.0 0421-0026203:
Object RA (J2000) DEC (J2000) Disc. UT Date Disc. V mag
ASASSN-14ei 02:55:33.39 -47:50:42.0 2014-07-21.36 15.8
ASASSN-14ei was discovered in images obtained 2014 UT July 21.36 at V~15.8 mag. We also detect the outburst in images obtained 2014 UT July 09.36 (V~16.8), July 10.38 (V~11.9), and July 24.35 (V~12.1), but we do not detect it (V > 17) in images obtained on 2014 UT July 17.36, July 18.37, July 19.36, and before 2014 UT July 07.39. This figure shows the ASAS-SN light curve beginning on 2014 UT July 05.5 and spanning 20 days.
A cross-check of the transient's ASAS-SN position in Vizier reveals that the source of the outburst is USNO-B1.0 0421-0026203, which has an unusual optical color (B2=17.59, R2=18.33, B2-R2=-0.79). There is also a source detected at the position of the transient in WISE, which has a red mid-IR color (W1=17.62 +/- 0.15, W2=16.76 +/- 0.25, W1-W2~0.9). We also note that the ROSAT X-ray source 1RXS J025533.1-475020, located at 22 +/- 14 arcsec from ASASSN-14ei, might be associated with the transient.
We thank LCOGT and its staff for their continued support of ASAS-SN. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.
