PG 0844+349 revisited – is there any outflow?

¹ Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany e-mail: wpb@mpe.mpg.de
² University of Science and Technology of China, HeFei, Anhui 230026, PR China e-mail: twang@ustc.edu.cn
³ Astronomy Department, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, USA e-mail: grupe@astro.psu.edu

Received: 4 July 2005
Accepted: 29 November 2005

Abstract

Aims.The detection of high velocity absorption lines from highly ionized material has been reported recently from the X-ray spectrum of the narrow line Seyfert 1 galaxy PG 0844+349 and were interpreted as a relativistic outflow from the source. We studied this outflow because it would have important implications for our understanding of narrow line Seyfert 1 galaxies.

Methods.To address the reality of these absorption features, we analyzed a long XMM observation with the MOS cameras on this object.

Results.We did not detect the absorption lines claimed, and a re-analysis of the previous data set with the most recent detector calibrations did not confirm the earlier results. The X-ray spectra can be well modeled with a power law plus a bremsstrahlung component. With this description, the soft and the harder 2-10 keV X-ray flux changed by a similar fraction (25%) between the two observations with only small changes in the spectral form. An analysis of the hardness ratio variations within a single observation does not show any strong correlation between the hardness ratio and the continuum luminosity and we do not detect substantial lags between the hard and soft band fluxes.