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Fermi LAT detection of a GeV flare from a possible new extragalactic gamma-ray source Fermi J0052+1110

ATel #3904; Stefano Ciprini (ASI Science Data Center and INAF Observatory of Rome, Italy), on behalf of the Fermi Large Area Telescope Collaboration
on 1 Feb 2012; 21:47 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@pg.infn.it)

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.