Fermi LAT detection of a GeV flare from a possible new extragalactic gamma-ray source Fermi J0052+1110
Subjects: Gamma Ray, >GeV, Quasar, Transient
The Large Area Telescope (LAT), on board the Fermi Gamma-ray Space
Telescope, has observed a gamma-ray flare from a new gamma-ray source on
January 29, 2012. The preliminary best-fit location of the gamma-ray
source using the 1-day interval map (R.A.=13.09 deg, Dec:11.16 deg,
J2000) has a 68% containment radius of 37 arcmin (statistical errors
only).
Preliminary analysis indicates that the source brightened in gamma-rays
with a daily integrated flux (E>100MeV) of (1.0+/-0.3) x 10^-6 ph
cm^-2 s^-1 (errors are statistical only) and a soft spectrum. The source
is not present in any existing gamma-ray source catalogs (EGRET, AGILE,
Fermi LAT).
Although the error region is large, it contains no members of known
gamma-ray-producing object classes. Examples of objects in the region
are some optically bright and likely passive galaxies, optically blue
and UV (PHL and GALEX catalogs) unclassified sources, few X-ray ROSAT
and faint radio-band sources, one strong sub-mm Planck ERSC source
(lying at about 6 arcmin from the LAT centroid), and the blue quasar PHL
881 (QSO B0050+106, z=0.321, Schmidt 1974, ApJ, 193, 509), lying at
about 21 arcmin from the LAT centroid. The moon crossed the error box
around 3 UT of the same day. We do not consider any of these objects to
be a plausible counterpart to the new Fermi J0052+1110 source.
Because Fermi operates in all-sky survey mode, gamma-ray monitoring of
this source will continue. In consideration of the activity of this new
gamma-ray source, and the absence of reasonable counterparts we strongly
encourage multiwavelength observations. The Fermi LAT contact person
for this source is S. Ciprini (stefano.ciprini@asdc.asi.it).
The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
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