Probable Foreground SN at z=0.39 SN in MACS0744.9+392 galaxy cluster field
ATel #6499; P. Kelly (UCB), K. B. Schmidt (UCSB), S. Rodney (JHU), T. Treu (UCLA), L. Strolger (STScI/WKU), O. Graur (NYU) and the GLASS and FrontierSN Teams
on 25 Sep 2014; 19:28 UT
Credential Certification: Patrick Kelly (pkelly@astro.berkeley.edu)
We report the discovery of a likely supernova in WFC3-IR F105W and
F140W images of the MACS0744.9+392 (z=0.698) galaxy cluster field. The
HST images were acquired on 20 September 2014 as part of the Grism
Lens Amplified Survey from Space (GLASS) to align and calibrate the
G102 grism spectra. We measure magnitudes for the transient of
25.94+-0.06 AB (F105W) and 25.57+-0.05 AB (F140W), and coordinates
RA=07:44:54.1548, Dec=+39:27:30.8189. A finding chart is available at http://astro.berkeley.edu/~pkelly/0744/index.html. The G102 grism spectrum of the spiral host galaxy exhibits a feature at
9100 Angstroms consistent with Halpha emission at z=0.388, in approximate
agreement with the CLASH BPZ and EAZY photometric redshifts. An additional
GLASS visit is scheduled for 4 October 2014.