X-Ray Observations of the Seyfert 1 Galaxy MCG 2-58-22

Abstract

Results of the detailed X-ray (0.1-10 keV) spectral analysis of the Seyfert 1 galaxy, MCG 2-58-22, are presented based on the EXOSAT observations on 1984 November 16-26. X-ray spectra of this source were obtained from the EXOSAT archives. Weak, soft flux (0.1-2 keV) variations were found on time scales of 2-3 days, and no variations of the hard flux were found during the EXOSAT observations. A power-law + absorption model fitted well to the combined LE + ME data sets but the hydrogen column density (N_H_) values were smaller than the Galactic N_H_ value. A power- law + fixed absorption (fixed with the Galactic N_H_ value) model does not fit well with the data sets. Variable soft excesses have been detected in this source. A two power-law model provides good fits to the soft excesses. Variations of the LE count rate are correlated with the variations of the soft spectral index (obtained from the two power-law fit) and anticorrelated with the hardness ratio of this source. A highly significant (99.9%) emission line at 5.8 +/- 0.7 keV with the measured equivalent width as 160 +/- 110 eV has been detected in the X-ray spectra of MCG 2-58-22. The significance of these results are discussed.