X-Ray Absorption in the BL Lacertae Object PKS 0548-322

Details X-Ray Absorption in the BL Lacertae Object PKS 0548-322 X-Ray Absorption in the BL Lacertae Object PKS 0548-322

Aug 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998apj...502..630s&link_type=abstract

Astrophysical Journal v.502, p.630

Astronomy and Astrophysics

Astronomy

13

Galaxies: Bl Lacertae Objects: Individual Alphanumeric: Pks 0548-322, X-Rays: Galaxies

Scientific paper

We report on a high signal-to-noise ASCA spectrum of the nearby (z = 0.069) BL Lacertae object PKS 0548-322, obtained during the performance verification phase of the instrument. Our principal result is the detection of discrete absorption at ~0.6 keV. The ASCA flux of the source, F2-10 keV ~ 2.8 x 10-11 ergs cm-2 s-1, corresponds to an average intensity state with respect to previous X-ray observations. The ASCA spectrum is well fitted by a convex broken power law plus Galactic column density plus an absorption feature, modeled with either an edge at an observed energy E ~ 0.66 keV and with optical depth tau ~ 0.3 or with a line (notch) at an observed energy E ~ 0.82 keV, width Delta E = 0.1 keV (fixed), and covering fraction fc ~ 0.1. The feature is at energies higher than in previous observations, when PKS 0548-322 was slightly brighter. The observed properties of the feature are consistent with absorption by ionized gas with column density N^{{gas}}_{{H}}~1021 cm-2 and a low ionization parameter (Ux ~ 0.007), strengthening the conclusion that ionized circumnuclear gas is common in BL Lacs. A very subtle curvature is measured for the underlying ASCA continuum, with steepening Delta Gamma ~ 0.2 above 1.7 keV. However, there is no need for a curved continuum once a detailed photoionization model is fitted to the ASCA data. There is no significant contribution to the 0.6-10 keV ASCA data of PKS 0548-322 by the associated optical cluster of galaxies; the upper limit to the intergalactic gas luminosity is L^{{IGM}}_{2-10 {keV}}~ 4 x 1043 ergs s-1, about 15% of the BL Lac luminosity.

Affiliated with

Also associated with

No associations

Rating

X-Ray Absorption in the BL Lacertae Object PKS 0548-322 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with X-Ray Absorption in the BL Lacertae Object PKS 0548-322, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-Ray Absorption in the BL Lacertae Object PKS 0548-322 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1575397