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Gamma-ray detection of the flat-spectrum radio quasar NRAO 150

ATEL # 2517; Luigi Foschini (INAF Osservatorio Astronomico di Brera)
on 27 Mar 2010; 16:15 UT
Password Certification: Luigi Foschini (luigi.foschini@brera.inaf.it)

Subjects: Gamma Ray, >GeV, AGN, Quasars

Following the recent preprint by J.A. Acosta-Pulido et al. (arXiv:1003.3542), who indicated the flat-spectrum radio quasar NRAO 150 (RA=59.87 deg, Dec=50.96 deg, J2000; z=1.517) as a candidate gamma-ray emitter, I have analyzed data from Fermi/LAT and found one gamma-ray source consistent with the blazar.

I have downloaded all the publicly available LAT data starting from 2008-08-04 00:00 UTC and 2010-03-25 00:00 UTC (almost 20 months of elapsed time) and analyzed them with the standard LAT Science Tools 9.15.2 and the corresponding calibration data base (publicly available from HEASARC). I have found one gamma-ray source with flux (E>100 MeV) equal to (3.21.1)x10-8 ph cm-2 s-1 and photon index (2.60.2), which seems to be consistent with the spectral energy distribution reported by Acosta-Pulido et al. The test statistic (Mattox et al. 1996) is 18, equivalent to about 4.2 sigma. Therefore, it is not reported in the LAT 11 months catalog, which in turn has a threshold of TS > 25. The best fit position of the gamma-ray source is RA=60.03 deg and Dec=50.89 deg, with a 95% error radius of 0.24 deg, positionally consistent with the radio position of NRAO 150 (distance 0.12 deg).

Obviously, multiwavelength observations are required to confirm the association of this gamma-ray source with NRAO 150.


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