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110 - F. Tombesi 2012
We present a comparison of the parameters of accretion disc outflows and the jet of the broad-line radio galaxy 3C 111 on sub-pc scales. We make use of published X-ray observations of ultra-fast outflows (UFOs) and new 43GHz VLBA images to track the jet knots ejection. We find that the superluminal jet coexists with the mildly relativistic outflows on sub-pc scales, possibly indicating a transverse stratification of a global flow. The two are roughly in pressure equilibrium, with the UFOs potentially providing additional support for the initial jet collimation. The UFOs are much more massive than the jet, but their kinetic power is probably about an order of magnitude lower, at least for the observations considered here. However, their momentum flux is equivalent and both of them are powerful enough to exert a concurrent feedback impact on the surrounding environment. A link between these components is naturally predicted in the context of MHD models for jet/outflow formation. However, given the high radiation throughput of AGNs, radiation pressure should also be taken into account. From the comparison with the long-term 2-10keV RXTE light curve we find that the UFOs are preferentially detected during periods of increasing flux. We also find the possibility to place the UFOs within the known X-ray dips-jet ejection cycles, which has been shown to be a strong proof of the disc-jet connection, in analogue with stellar-mass black holes. However, given the limited number of observations presently available, these relations are only tentative and additional spectral monitoring is needed to test them conclusively.
73 - F. Tombesi 2011
From the spectral analysis of long Suzaku observations of five radio-loud AGNs we have been able to discover the presence of ultra-fast outflows with velocities ~0.1c in three of them, namely 3C 111, 3C 120 and 3C 390.3. They are consistent with bein g accretion disk winds/outflows. We also performed a follow-up on 3C 111 to monitor its outflow on ~7days time-scales and detected an anti-correlated variability of a possible relativistic emission line with respect to blue-shifted Fe K features, following a flux increase. This provides the first direct evidence for an accretion disk-wind connection in an AGN. The mass outflow rate of these outflows can be comparable to the accretion rate and their mechanical power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, they can possibly play a significant role in the expected feedback from AGNs and can give us further clues on the relation between the accretion disk and the formation of winds/jets.
183 - F. Tombesi 2011
We present the spectral analysis of three Suzaku XIS observations of 3C 111 requested to monitor the predicted variability of its ultra-fast outflow on ~7 days time-scales. We detect an ionized iron emission line in the first observation and a blue-s hifted absorption line in the second, when the flux is ~30% higher. The location of the material is constrained at <0.006pc from the variability. Detailed modelling support an identification with ionized reflection off the accretion disc at ~20-100r_g from the black hole and a highly ionized and massive ultra-fast outflow with velocity ~0.1c, respectively. The outflow is most probably accelerated by radiation pressure, but additional magnetic thrust can not be excluded. The measured high outflow rate and mechanical energy support the claims that disc outflows may have a significant feedback role. This work provides the first direct evidence for an accretion disc-outflow connection in a radio-loud AGN, possibly linked also to the jet activity.
186 - R. M. Sambruna 2011
We present a long Suzaku observation of 3C 382. A Swift BAT spectrum from the 58-month survey is also analyzed, together with an archival XMM-Newton EPIC exposure. Our main result is the finding with Suzaku of a broad FeK line with a relativistic pro file consistent with emission from an accretion disk at tens of gravitational radii from the central black hole. The XIS data indicate emission from highly ionized iron and allow us to set tight, albeit model-dependent, constraints on the inner and outer radii of the disk reflecting region, r_in~10r_g and r_out~20r_g, respectively, and on the disk inclination, i~30deg. Two ionized reflection components are possibly observed, with similar contributions of ~10% to the total continuum. A highly ionized one, with log_xi~3, which successfully models the relativistic line and a mildly ionized one, with log_xi~1.5, which models the narrow Fe K line and high energy hump. When both these components are included, there is no further requirement for an additional black body soft excess below 2keV. The Suzaku data confirm the presence of a warm absorber previously known from grating studies. After accounting for all the spectral features, the intrinsic photon index of the X-ray continuum is ~1.8 with a cutoff energy at ~200keV, consistent with Comptonization models and excluding jet-related emission up to these energies. Comparison of the X-ray properties of 3C 382 and other BLRGs to Seyferts confirms the idea that the distinction between radio-loud and radio-quiet AGN at X-rays is blurred.
We present XMM and Suzaku observations of the Broad-Line Radio Galaxy (BLRG) 3C390.3. The Fe Ka line has a width FWHM ~ 8,800 km/s, consistent within a factor two with the width of the double-peaked H_alpha line, suggesting an origin from the Broad L ine Region. The data show for the first time a weak, broad bump extending from 5 to 7 keV. When fitted with a Gaussian, its centroid energy is 6.6 keV in the sources rest-frame with FWHM of 43,000 km/s and EW of 50 eV; its most likely interpretation is emission from He-like Fe (Fe XXV), suggesting the presence of an ionized medium in the inner regions of 3C390.3. The broad-band 0.5-100 keV continuum is well described by a single power law with photon index Gamma=1.6 and cutoff energy 157 keV, plus cold reflection with strength R=0.5. In addition, ionized reflection is required to account for the 6.6 keV bump in the broad-band continuum, yielding an ionization parameter xi ~ 2700 ergs cm s^-1; the inner radius of the ionized reflector is constrained to be larger than 20 r_G, although this result depends on the assumed emissivity profile of the disk. If true, we argue that the lack of broad Fe K emission from within 20 r_G indicates that the innermost regions of the disk in 3C390.3 are obscured and/or poorly illuminated. While the SED of 3C390.3 is generally dominated by accretion-related continuum, during accretion low states the jet can significantly contribute in the optical to X-ray bands via synchrotron self-Compton emission. (Abridged)
69 - R. M. Sambruna 2007
This paper presents multiwavelength imaging and broad-band spectroscopy of the relativistic jets in the two nearby radio galaxies 3C 371 and PKS 2201+044, acquired with Chandra, HST, VLA, and Merlin. Radio polarization images are also available. The two sources stand out as intermediate between FRIs and FRIIs; their cores are classified as BL Lacs, although broad and narrow optical emission lines were detected at times. The multiwavelength images show jet morphologies with the X-ray emission peaking closer to the nucleus than the longer wavelengths. The jets are resolved at all wavelengths in a direction perpendicular to the jet axis. The jets SEDs are consistent with a single spectral component from radio to X-rays, interpreted as synchrotron emission. The SEDs show a progressive softening from the inner to the outer regions of the jet, indicating that the electron break energy moves to lower energies with distance from the core. Overall, the X-ray and multiwavelength properties of the jets of 3C 371 and PKS 2201+044 appear intermediate between those of FRIs and FRIIs.
83 - R. M. Sambruna 2007
The BL Lac S5 2007+777 was observed by us with Chandra, to find the X-ray counterpart to its 18 radio jet, and study its structure. Indeed, a bright X-ray jet was discovered in the 33 ks ACIS-S image of the source. We present its properties and briefly discuss the implications.
187 - R. M. Sambruna 2007
We present the results of the analysis of an archival 15 ks XMM-Newton observation of the nearby (z=0.057) radio-loud source 3C445, optically classified as a Broad-Line Radio Galaxy. While the RGS data are of insufficient quality to allow a meaningfu l analysis, the EPIC data show a remarkable X-ray spectrum. The 2-10 keV continuum is described by a heavily absorbed (Nh~ 1e22 - 1e23 cm-2) power law with photon index Gamma ~1.4, and strong (R~2) cold reflection. A narrow, unresolved Fe Kalpha emission line is detected, confirming previous findings, with EW 120eV. A soft excess is present below 2 keV over the extrapolation of the hard X-ray power law, which we model with a power law with the same photon index as the hard power law, absorbed by a column density Nh=6e20 cm-2 in excess to Galactic. A host of emission lines are present below 2 keV, confirming previous indications from ASCA, due to H- and He-like O, Mg, and Si. We attribute the origin of the lines to a photoionized gas, with properties very similar to radio-quiet obscured AGN. Two different ionized media, or a single stratified medium, are required to fit the soft X-ray data satisfactorily. The similarity of the X-ray spectrum of 3C445 to Seyferts underscores that the central engines of radio-loud and radio-quiet AGN similarly host both cold and warm gas.
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