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A Swift Observation of PKS 0250-225

ATEL # 2039; J. L. Blum, J. M. Miller (University of Michigan)
on 29 Apr 2009; 17:41 UT
Password Certification: Jon Miller (

Subjects: X-ray, Gamma Ray, AGN, Black Holes

The gamma-ray blazar PKS 0250-225 (RA: 02h52m47.9s, Dec:-22d19m25s, J2000) was recently reported by the Fermi LAT team to have increased in flux and entered a high state (E>100MeV) (ATEL #1933). In response, Swift observed the source on Feb. 20 2009 for approximately 8.9 ks. Here we report the preliminary results to spectral fits of the Swift XRT data in the 1.0-10.0 keV range.

We analyzed the photon counting mode clean event file from the master catalog on HEASARC. Conservative source and background regions were used to create spectral files. Standard response files were used to analyze the spectra in XSPEC.

We fit the spectra with a simple power-law model that resulted in a photon index Gamma = 3.0+/-0.1, with a column density of 0.10+/-0.09 (10^22 cm**2) in the 1-10 keV range. The C-statistic was used because of the low number of counts (C-stat = 317). The total flux in the 0.1-10.0 keV range was 3.2e-13 erg/s/cm**2 giving a luminosity of approximately 1.4e45 erg/s (z = 1.427).

We note that very few observations have been made of this source in the soft X-rays in the last decade and that further monitoring may be merited.

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