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Fermi LAT detection of a GeV flare from blazar NRAO 190 (PKS 0440-00)

ATEL # 2049; S. Ciprini (Univ./INFN Perugia) on behalf of the Fermi Large Area Telescope Collaboration
on 17 May 2009; 23:43 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Stefano Ciprini (

Subjects: Gamma Ray, >GeV, 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), observed a gamma-ray outburst from a source positionally consistent with the flat spectrum radio quasar NRAO 190 (also known as PKS 0440-00, DA 145, OF -067, 3EG J0442-0033; RA: 04h 42m 38.661s, Dec: -00d 17m 43.42s, J2000.0) with redshift 0.844 (Hewitt & Burbidge 1987, 63, 1). This source is highly polarized, showed strong radio-optical variability, and ejection of superluminal components (Yurchenko et al. 2000, A&A, 358, 428).

Preliminary analysis indicates that on May 16, 2009, NRAO 190 appeared in a high state with a daily gamma-ray flux (E>100MeV) of 1.77+/-0.43 x 10^-6 photons cm^-2 s^-1 (statistical only), about fifteen times the average flux estimated over the first six months of the Fermi LAT survey, and about twice the flux level observed by EGRET during the flare of August 1994 (McGlynn et al. 1997, ApJ, 481, 625).

The beginning of this rapid flaring activity was observed by the LAT on May 15, with a daily flux exceeding already the 1x10^-6 photons cm^-2 s^-1 level. Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing gamma-ray outburst, we strongly encourage multiwavelength observations of this object. For this source the Fermi LAT contact persons are S. Ciprini ( and F. Longo (

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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