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Fermi LAT detection of a possible new gamma-ray blazar 4C 31.03

ATEL # 2054; Elisabetta Cavazzuti (ASI Science Data Center) on behalf of the Fermi Large Area Telescope Collaboration
on 22 May 2009; 23:50 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Paolo Giommi (

Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Quasars

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope (formerly GLAST, launched June 11, 2008), has observed an increasing gamma-ray flux from a source positionally consistent with 4C 31.03 (RA: 01h12m50.3330s, Dec: +32d08m17.433s , J2000, Beasley, A. J et al., 2002 ApJS, 141) since May 20, 2009.

This object is a Flat Spectrum Radio Source (z= 0.603 +/- 0.005, Wills, D., Wills, B. J., Ap. J. Suppl. 1976 vol. 31 p. 143) reported in the CRATES catalog as CRATES J011250+320832 (Healey, S. et al., 2007 ApJS, 171).

Preliminary analysis indicates that on May. 20, 2009 the source was in a high state with a gamma-ray flux (E>100MeV) of 1.33+/-0.32 x 10^-6 ph cm^-2 s^-1 (statistical only) on a daily time scale, and reaching a value of 1.65+/-0.68 x 10^-6 ph cm^-2 s^-1 (statistical only) on a six-hour time scale starting from 06:00:00 (UT) of the same day. The source was not detected previously by the LAT and there is no previously reported EGRET gamma-ray detection at this location.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source we encourage multiwavelength observations. For this source the Fermi LAT contact person is Elisabetta Cavazzuti (

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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R. E. Rutledge , Editor
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