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Register a new userXMM-Newton observation of the deep minimum state of PG 2112+059: A spectrum dominated by reflection from the accretion disk?
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N. Schartel
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We analyse a 75ks XMM-Newton observation of PG 2112+059 performed in November 2005 and compare it with a 15ks XMM-Newton observation taken in May 2003. PG 2112+059 was found in a deep minimum state as its 0.2-12 keV flux decreased by a factor of 10 in comparison to the May 2003 observation. During the deep minimum state the spectra show strong emission in excess of the continuum in the 3-6 keV region. The excess emission corresponds to an EW = 26.1 keV whereas its shape resembles that of heavily absorbed objects. The spectra of both observations of PG 2112+059 can be explained statistically by a combination of two absorbers where one shows a high column density, $N_{H} sim 4.5 times 10^{23} cm^{-2}$, and the other high ionisation parameters. As the ionisation parameter of the high flux state, $xi sim 34 erg cm s^{-1}$, is lower than the value found for the deep minimum state, $xi sim 110 erg cm s^{-1}$, either the absorbers are physically different or the absorbing material is moving with respect to the X-ray source. The spectra can also be explained by a continuum plus X-ray ionised reflection on the accretion disk, seen behind a warm absorber. The ionisation parameter of the high state ($xi sim 5.6 erg cm s^{-1}$) is higher than the ionisation parameter of the deep minimum state ($xi sim 0.2 erg cm s^{-1}$), as expected for a stationary absorber. The values found for the ionisation parameters are in the range typical for AGNs. The spectra observed during the deep minimum state are reflection dominated and show no continuum emission. These can be understood in the context of light bending near the supermassive black hole as predicted by Minutti and Fabian.
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XMM-Newton successfully detected the minimum state of PG 2112+059 during a short snapshot observation and performed a long follow-up observation. The high signal-to-noise spectra are modelled assuming different emission scenarios and compared with archival spectra taken by XMM-Newton and Chandra. The PG 2112+059 X-ray spectra acquired in May 2007 allowed the detection of a weak iron fluorescent line, which is interpreted as being caused by reflection from neutral material at some distance from the primary X-ray emitting source. The X-ray spectra of PG 2112+059 taken at five different epochs during different flux states can be interpreted within two different scenarios. The first consists of two layers of ionised material with column densities of N_H ~5 x 10^22 cm^-2 and N_H ~3.5 x 10^23 cm^-2, respectively. The first layer is moderately ionised and its ionisation levels follow the flux changes, while the other layer is highly ionised and does not show any correlation with the flux of the source. The spectra can also be interpreted assuming reflection by an ionised accretion disk seen behind a warm absorber. The warm absorber ionisation is consistent with being correlated with the flux of the source, which provides an additional degree of self-consistency with the overall reflection-based model. We explain the spectral variability with light bending according to the models of Miniutti and Fabian and constrain the black hole spin to be a/M > 0.86. Both scenarios also assume that a distant cold reflector is responsible for the Fe K alpha emission line. Light bending provides an attractive explanation of the different states of PG 2112+059 and may also describe the physical cause of the observed properties of other X-ray weak quasars.
We study the connection between the X-ray and UV properties of the broad absorption line (BAL) wind in the highly X-ray variable quasar PG 2112+059 by comparing Chandra-ACIS data with contemporaneous UV HST/STIS spectra in three different epochs. We observe a correlation whereby an increase in the equivalent-widths (EWs) of the BALs is accompanied by a redder UV spectrum. The growth in the BALs EWs is also accompanied by a significant dimming in soft X-ray emission (<2 keV), consistent with increased absorption. Variations in the hard X-ray emission (>2 keV) are only accompanied by minor spectral variations of the UV-BALs and do not show significant changes in the EW of BALs. These trends suggest a wind-shield scenario where the outflow inclination with respect to the line of sight is decreasing and/or the wind mass is increasing. These changes elevate the covering fraction and/or column densities of the BALs and are likely accompanied by a nearly contemporaneous increase in the column density of the shield.
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We want to explore the geometrical structure and mutual interactions of the innermost components of the broad line radio galaxy (BLRG) 3C 215, with particular interest in the accretion and ejection mechanisms involving the central supermassive black hole (SMBH). We compare these observational features with the ones of the RQ Seyfert 1 galaxies. Investigating their differences it is possible to understand more about the jet launching mechanisms, and why this phenomenon is efficient only in a small fraction of all the AGNs. Using high quality data from a $sim60$ ks observation with XMM-Newton, we carried out a detailed X-ray spectral analysis of 3C 215 in the broad energy range $0.5-10$ keV. We modeled the spectrum with an absorbed double power-law model for the primary continuum, reprocessed by reflection from ionized and cold neutral material and modified by relativistic blurring. We also compared our results with the ones obtained with previous multi-wavelength observations. We obtain a primary continuum photon index from the corona $Gamma_1=1.97pm0.06$ and evidence of a jet contribution, modeled as a power law with photon index $Gamma_2simeq1.29$. The reflector, possibly the accretion disk and portions of the broad-line region (BLR), is ionized ($logxi=2.31_{-0.27}^{+0.37} mathrm{erg s^{-1} cm}$) and relatively distant from the SMBH ($R_{in}>38 R_g$), where $R_g=GM_{BH}/c^2$ is the gravitational radius. The obscuring torus seems patchy, dust-poor and inefficient, while the jet emission shows a twisted and knotted geometry. We propose three scenarios in order to describe these characteristics: 1.) ADAF state in the inner disk; 2.) Slim accretion disk; 3.) sub-pc SMBH binary system (SMBHB).
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