Discovery of a Luminous Supernova, PTF11rks

ATel #3841; R. M. Quimby (IPMU), A. Gal-Yam, I. Arcavi, O. Yaron (Weizmann), A. Horesh, K. Mooley (Caltech)
on 31 Dec 2011; 09:47 UT
Credential Certification: Robert Quimby (quimby@astro.as.utexas.edu)

Tweet

The Palomar Transient Factory (Law et al., 2009; Rau et al., 2009) reports the discovery of an optical transient, PTF11rks. The source is located at RA = 01:39:45.51, Dec. = +29:55:27.0 (J2000), which is offset from a faint (r~20.9 mag) galaxy detected by the SDSS. PTF11rks was first detected by the Palomar 1.2m telescope with an R-band magnitude of about 19.9 on 2011 Dec 21 (UT). The transient brightened to about 19.1 mag on Dec 27. PTF did not detect the source prior to 2011 Dec 11.

Spectroscopic follow-up was performed with the Palomar 5.1m (+DBSP) on 2011 Dec 27, and Keck (+LRIS) on 2011 Dec 31. The spectra show a blue continuum with broad absorption bands. The spectra are similar to PTF09cnd near maximum light (Quimby et al. 2011). Narrow absorption features consistent with the MgII doublet and emission lines from the host set the redshift at z=0.19.

We requested Swift observations, which were carried out on Dec 30. Including possible contamination from the host galaxy, we measure the following preliminary UVOT magnitudes for the transient:

 
   MJD     Filter   Mag   Mag_err 
55925.2422     U   18.57   0.12 
55925.2461  UVW1   18.94   0.12 
55925.2617  UVM2   19.50   0.14 
55925.2500  UVW2   19.26   0.11 

The source was not detected in the simultaneous XRT observation.

PTF discoveries are made by autonomous PTF software (Bloom et al. 2011, http://adsabs.harvard.edu/abs/2011arXiv1106.5491B ), as well as by the Galaxy Zoo Supernova Project (Smith et al. 2011, MNRAS, 412, 1309; http://supernova.galaxyzoo.org ).

We thank the Swift team for promptly scheduling the ToO observations.