Abstract. The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM-Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (v ∼ 1400 km s −1 FWHM) absorption lines from highly ionized elements including hydrogen-and helium-like carbon, nitrogen, oxygen, and neon, and several iron L-shell ions (Fe xvii-xx). Also shown in the spectrum is the first astrophysical detection of a broad absorption feature around λ = 16−17Å identified as an unresolved transition array (UTA) of 2p-3d inner-shell absorption by iron M-shell ions in a much cooler medium; a feature that might be misidentified as an O vii edge when observed with moderate resolution spectrometers. No absorption edges are clearly detected in the spectrum. We demonstrate that the RGS spectrum of IRAS 13349+2438 exhibits absorption lines from at least two distinct regions, one of which is tentatively associated with the medium that produces the optical/UV reddening.
In recent years, indirect evidence has emerged suggesting that many nearby non-active galaxies harbor quiescent supermassive black holes. Knowledge of the frequency of occurrence of black holes, of their masses and spins, is of broad relevance for studying black hole growth and galaxy and AGN formation and evolution. It has been suggested that an unavoidable consequence of the existence of supermassive black holes, and the best diagnostic of their presence in nonactive galaxies, would be occasional tidal disruption of stars captured by the black holes. These events manifest themselves in form of luminous flares powered by accretion of debris from the disrupted star into the black hole.Candidate events among optically non-active galaxies emerged in the past few years. For the first time, we have looked with high spatial and spectral resolution at one of these most extreme variability events ever recorded among galaxies. Here, we report measuring a factor ∼ 200 drop in luminosity of the X-ray source RX J1242-1119 with the X-ray observatories Chandra and XMM-Newton, and perform key tests of the favored outburst scenario, tidal disruption of a star by a supermassive black hole. We show that the detected "low-state" emission has properties such that it must still be related to the flare. The power-law shaped post-flare X-ray spectrum indicates a "hardening" compared to outburst. The inferred black hole mass, the amount of liberated energy, and the duration of the event favor an accretion event of the form expected from the (partial or complete) tidal disruption of a star.
drive the ultraviolet/optical variations. However, the medium energy X-ray NVA is 2-4 times that in the ultraviolet, and the single-epoch, absorption-corrected X-ray/γ-ray luminosity is only about 1/3 that of the ultraviolet/optical/infrared, suggesting that at most ∼1/3 of the total low-energy flux could be reprocessed high-energy emission.The strong wavelength dependence of the ultraviolet NVAs is consistent with an origin in an accretion disk, with the variable emission coming from the hotter inner regions and non-variable emission from the cooler outer regions. These data, when combined with the results of disk fits, indicate a boundary between these regions near a radius of order R ≈ 0.07 lt-day. No interband lag would be expected as reprocessing (and thus propagation between regions) need not occur, and the orbital time scale of ∼1 day is consistent with the observed variability time scale. However, such a model does not immediately explain the good correlation between ultraviolet and X-ray variations.
Winds outflowing from Active Galactic Nuclei (AGNs) may carry significant amount of mass and energy out to their host galaxies. In this paper we report the detection of a sub-relativistic outflow observed in the Narrow Line Seyfert 1 Galaxy IRAS17020+4544 as a series of absorption lines corresponding to at least 5 absorption components with an unprecedented wide range of associated column densities and ionization levels and velocities in the range of 23,000-33,000 km/s, detected at X-ray high spectral resolution (E/∆E∼1000) with the ESA's observatory XMM-Newton. The charge states of the material constituting the wind clearly indicate a range of low to moderate ionization states in the outflowing gas and column densities significantly lower than observed in highly ionized ultra fast outflows. We estimate that at least one of the outflow components may carry sufficient energy to substantially suppress star formation, and heat the gas in the host galaxy. IRAS17020+4544 provides therefore an interesting example of feedback by a moderately luminous AGN hosted in a spiral galaxy, a case barely envisaged in most evolution models, which often predict that feedback processes take place in massive elliptical galaxies hosting luminous quasars in a post merger phase.
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