[vsnet-grb-info 14444] Fermi412093190: iPTF optical counterpart search

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15758
SUBJECT: Fermi412093190: iPTF optical counterpart search
DATE:    14/01/23 10:04:44 GMT
FROM:    Leo Singer at CIT/PTF  <lsinger at caltech.edu>

L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton),
S. B. Cenko (NASA/GSFC), and Y. Cao (Caltech) report on behalf of the
intermediate Palomar Transient Factory (iPTF) collaboration:

We have searched for optical counterparts of Fermi GBM trigger
412093190 (2014-01-22 14:19:47.78) using the Palomar 48-inch Oschin
telescope (P48). Starting at 11.97 hours after the Fermi trigger, we
imaged an area of 75 deg^2 within the GBM 1-sigma
statistical+systematic region, with a 34% chance of containing the
true, unknown location of the source.

We sifted through 14,681 candidate variable sources using standard
iPTF vetting procedures. After obtaining spectra with the Palomar 200
inch (P200) for the most promising sources, no compelling optical
afterglow candidates survived. We note the following unrelated
optical transients:

iPTF14ig, at R=19.9 +/- 0.1 mag, classified as a SN Ia based on P200
observations, at the coordinates:
 RA(J2000)  =  03h 32m 23.94s ( 53.099768 deg)
 Dec(J2000) = +10d 07' 06.2"  (+10.118386 deg)

iPTF14ih, at R=20.2 +/- 0.2 mag, classified as a SN II based on P200
observations, on the outskirts of the galaxy 2MASX J03394459+1548035
a.k.a. PGC 1493639, at the coordinates:
 RA(J2000)  =  03h 39m 43.88s ( 54.932815 deg)
 Dec(J2000) = +15d 47' 43.4"  (+15.795391 deg)

iPTF14ip, at R = 19.6 +/- 0.1 mag, on the edge of the galaxy SDSS
J034353.55+094512.9, at the coordinates:
 RA(J2000)  =  03h 43m 53.69s ( 55.973710 deg)
 Dec(J2000) = +09d 45' 13.1"  (+09.753634 deg)
Given the nearby galaxy and lack of recent limits, we consider it
likely iPTF14ip is also an unrelated foreground supernova. We will
attempt future observations to confirm its origin.

A diagram of the locations of these candidates, the Fermi-GBM
localization, and the ten P48 fields that we imaged can be found at
<http://www.its.caltech.edu/~lsinger/iptf/Fermi412093190.pdf>.

We thank Andrew Drake for promptly obtaining the P200 spectra.