Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 15524

Fermi407254341: iPTF optical afterglow candidates
2013-11-28T07:49:40Z (11 years ago)
Leo Singer at CIT/PTF <>
L. P. Singer (Caltech) and M. M. Kasliwal (Carnegie Observatories/Princeton)
report on behalf of the intermediate Palomar Transient Factory (iPTF)

We imaged about 60 deg^2 in the vicinity of the localization of the Fermi-GBM
trigger Fermi407254341 with the Palomar 48-inch Oschin telescope (P48),
starting at 2013-11-28 03:40 UT (13.5 hours after the Fermi trigger). Sifting
through 17,353 candidate variable sources in the GBM error circle using standard
iPTF vetting procedures, we find the following optical afterglow candidates:

iPTF13ecv, possibly fading, at R=18.6mag and with no coincident source visible
in SDSS or in our reference images, at the coordinates:
  RA(J2000)  =  20h 31m 47.76s
  Dec(J2000) = +00d 59' 23.4"

iPTF13ect, at R=17.9 and near the core of a z=0.025 galaxy, at the coordinates:
  RA(J2000)  =  20h 46m 44.63s
  Dec(J2000) = -01d 22' 07.8"

iPTF13ecu, at R=19.1 and near the core of a z=0.030 galaxy, at the coordinates:
  RA(J2000)  =  20h 40m 11.04s
  Dec(J2000) = -01d 37' 09.2"

A diagram of the locations of these candidates and the nine P48 fields that we
imaged in relation to the Fermi-GBM statistical+systematic error contours can be
found at <>.

We have submitted a Swift ToO request to follow up iPTF13ecv.

We caution that many transient or variable sources are found in any such wide-area
targeted search, and that at this burst's galactic latitude of -20 deg many
foreground sources are likely.

Further observations are encouraged to determine the nature of these sources,
and whether one of them is related to the Fermi trigger.
Looking for U.S. government information and services? Visit