2003/06/05 by G. Chartas, W. N. Brandt, S. C. Gallagher · 9 citations
Physics and Astronomy · #Absorption (acoustics) #Absorption spectroscopy #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Ionization #Line (geometry) #Outflow #Quasar #Spectral line #astro-ph
paper · pdf · doi:10.1086/377299
published as Astrophys.J. 595 (2003) 85-93 · 15 pages, includes 7 figures, Accepted for publication in ApJ
arxiv created 2003/06/05 · openalex publication_date 2003/09/16 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report on an observation of the broad absorption line (BAL) quasar PG 1115+080 performed with the XMM-Newton observatory. Spectral analysis reveals the second case of a relativistic X-ray-absorbing outflow in a BAL quasar. The first case was revealed in a recent observation of APM 08279+5255 with the Chandra X-Ray Observatory . As in the case of APM 08279+5255, the observed flux of PG 1115+080 is greatly magnified by gravitational lensing. The relatively high redshift ( z = 1.72) of the quasar places the redshifted energies of resonant absorption features in a sensitive portion of the XMM-Newton spectral response. The spectrum indicates the presence of complex low-energy absorption in the 0.2-0.6 keV observed energy band and high-energy absorption in the 2-5 keV observed energy band. The high-energy absorption is best modeled by two Gaussian absorption lines with rest-frame energies of 7.4 and 9.5 keV. Assuming that these two lines are produced by resonant absorption due to Fe XXV Kα, we infer that the X-ray absorbers are outflowing with velocities of ~ 0.10 c and ~ 0.34 c , respectively. We have detected significant variability of the energies and widths of the X-ray BALs in PG 1115+080 and APM 08279+5255 over timescales of 19 and 1.8 weeks (proper time), respectively. The BAL variability observed from APM 08279+5255 supports our earlier conclusion that these absorbers are most likely launched at relatively small radii of ≲10 16 ( M bh / M 8 ) 1/2 cm. A comparison of the ionization properties and column densities of the low-energy and high-energy absorbers indicates that these absorbers are likely distinct; however, higher spectral resolution is needed to confirm this result. Finally, we comment on prospects for constraining the kinematic and ionization properties of these X-ray BALs with the next generation of X-ray observatories.