[vsnet-alert 16183] iPTF13cjz in NGC 772 (LBV outburst?) (ATEL)

[Taichi Kato]

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ATEL #5272							     ATEL #5272

Title:	Discovery of an intermediate luminosity transient iPTF13cjz
		in NGC 772
Author:	O. Yaron (Weizmann), M. M. Kasliwal (Carnegie/Princeton),
		S. B. Cenko (NASA/GSFC), Y. Cao, A. Waszczak (Caltech), I. Arcavi,
		D. Tal (Weizmann),  K. Clubb, P. L. Kelly, O. Fox, A. V. Filippenko
		(UC Berkeley), report on behalf of the iPTF collaboration
Queries:	mansi at obs.carnegiescience.edu
Posted:	13 Aug 2013; 17:01 UT
Subjects:Infra-Red, Optical, Supernovae, Transient

The intermediate Palomar Transient Factory (ATel#4807) reports the discovery
of an optical transient, iPTF13cjz, in the spiral arm of NGC772 (~30.3
Mpc; NED). iPTF13cjz was discovered on 2013 August 02.36 UT at RA(J2000)
= 01:59:14.47, DEC(J2000) = +19:01:33.6, at 18.9 mag in the PTF R-band
(calibrated wrt SDSS), which corresponds to absolute magnitude of -13.5.
A follow-up spectrum was promptly obtained on Aug 02.54 (~2.5 hours from
event confirmation) with Keck2-DEIMOS and shows low-velocity P-Cygni profiles,
absorption and emission lines of H, HeI, NII and various intermediate-mass
and Fe-group elements (OI, NaI, MgI, CaII, FeII). The emission lines resemble
those of luminous blue variables(e.g. UGC 2773 OT2009-1; Smith et al. 2010)
but the underlying red continuum is more reminiscent of intermediate luminosity
red transients (e.g. PTF10fqs; Kasliwal et al. 2011). Moreover, follow-up
near-infrared photometry with Reionization and Transients Infrared Camera
(RATIR; www.ratir.org) on Aug 10 confirms the red color of R-H = 2.0 mag.
We note that this transient was independently discovered by LOSS/KAIT and
reported as a <a href="http://www.cbat.eps.harvard.edu/unconf/tocp.html">
TOCP </a> on Aug 12.