اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدX-ray Properties of Hard X-ray Selected AGN
404
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Using the latest 70 month Swift-BAT catalog we examined hard X-ray selected Seyfert I galaxies which are relatively little known and little studied, and yet potentially promising to test the ionized relativistic reflection model. From this list we chose 13 sources which have been observed by XMM-Newton for less than 20 ks, in order to explore the broad band soft to hard X-ray properties with the analysis of combined XMM-Newton and Swift data. Out of these we found seven sources which exhibit potentially promising features of the relativistic disc reflection, such as a strong soft excess, a large Compton hump and/or a broadened Fe line. Longer observations of four of these sources with the currently operating satellite missions, such as Suzaku, XMM-Newton and NuStar and two others by such future missions as ASTRO-H, will be invaluable, in order to better understand the relativistic disc reflection closest to the central black hole and constrain such important effects of strong gravity as the black hole spin.
قيم البحث
اقرأ أيضاً
We have performed a very long baseline interferometry (VLBI) survey of local (z < 0.05) ultra hard X-ray (14-195 keV) selected active galactic nuclei (AGN) from the Swift Burst Alert Telescope (BAT) using KVN, KaVA, and VLBA. We first executed fringe
surveys of 142 BAT-detected AGN at 15 or 22 GHz. Based on the fringe surveys and archival data, we find 10/279 nearby AGN (~4%) VLBI have 22 GHz flux above 30 mJy. This implies that the X-ray AGN with a bright nuclear jet are not common. Among these 10 radio-bright AGN, we obtained 22 GHz VLBI imaging data of our own for four targets and reprocessed archival data for six targets. We find that, although our 10 AGN observed with VLBI span a wide range of pc-scale morphological types, they lie on a tight linear relation between accretion luminosity and nuclear jet luminosity. Our result suggests that a powerful nuclear radio jet correlates with the accretion disc luminosity. We also probed the fundamental plane of black hole activity at VLBI scales (e.g., few milli-arcsecond). The jet luminosity and size distribution among our sample roughly fit into the proposed AGN evolutionary scenario, finding powerful jets after the blow-out phase based on the Eddington ratio (lambda_{Edd})-hydrogen column density (N_{H}) relation. In addition, we find some hints of gas inflow or galaxy-galaxy merger in the majority of our sample. This implies that gas supply via tidal interactions in galactic scale may help the central AGN to launch a powerful parsec-scale jet.
We present the host galaxy molecular gas properties of a sample of 213 nearby (0.01<z< 0.05) hard X-ray selected AGN galaxies, drawn from the 70-month catalog of Swift-BAT, with 200 new CO(2-1) line measurements obtained with the JCMT and APEX telesc
opes. We find that AGN in massive galaxies tend to have more molecular gas, and higher gas fractions, than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies with no evidence of AGN feedback affecting the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (~5% vs. 49%). The likelihood of a given galaxy hosting an AGN (L_bol>10^44 erg/s) increases by ~10-100 between a molecular gas mass of 10^8.7 Msun and 10^10.2 Msun. Higher Eddington ratio AGN galaxies tend to have higher molecular gas masses and gas fractions. Higher column density AGN galaxies (Log NH>23.4) are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy wide molecular gas. The significant average link of host galaxy molecular gas supply to SMBH growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties and the redshift evolution of star formation and SMBH growth.
We have analyzed the NVSS and SUMSS data at 1.4 GHz and 843 MHz for a well defined complete sample of hard X-ray AGN observed by INTEGRAL. A large number (70/79) of sources are detected in the radio band, showing a wide range of radio morphologies, f
rom unresolved or slightly resolved cores to extended emission over several hundreds of kpc scales. The radio fluxes have been correlated with the 2-10 keV and 20-100 keV emission, revealing significant correlations with slopes consistent with those expected for radiatively efficient accreting systems. The high energy emission coming from the inner accretion regions correlates with the radio emission averaged over hundreds of kpc scales (i.e., thousands of years).
Using a sample of 63 AGNs extracted from the $Einstein$ Extended Medium Sensitivity Survey (EMSS), we study the X-ray spectral properties of X-ray selected AGN in the 0.1$-$2.4 keV ROSAT band. These objects are all the EMSS AGN detected with more tha
n 300 net counts in ROSAT PSPC images available from the public archive (as of May 31, 1995). A Maximum-Likelihood analysis is used to find the mean power-law spectral index $<alpha_p>$ and the intrinsic dispersion $sigma_p$. We find $<alpha_p>$=1.42 with $sigma_p$=0.44. This value is significantly steeper ($Delta alpha sim$0.4) than the mean $Einstein$/IPC spectral index obtained applying the ML analysis on the whole sample of EMSS AGN. This result shows that the soft excess already noted in optically selected AGN is present also in X-ray selected AGN. The relatively high value obtained for the intrinsic dispersion confirms that in the soft band AGN are characterized by a variety of spectral indices and the increase with respect to results obtained from the analysis of Einstein data ($Delta sigma_p sim$0.16) suggests a further broadening of the spectral index distribution as one moves to softer energies. A comparison between the mean spectral index of Radio-quiet and Radio-loud subsamples shows that the mean index of the RL sample is flatter than that of RQ, both in the IPC ($Delta alpha sim$0.3) and in the PSPC ($Delta alpha sim$0.4) data. This suggests that the additional X-ray component in RL AGN dominates the X-ray emission of RL AGN over almost two decades of energy ($sim$0.1$-$10 keV).
We use data from the All Wavelength Extended Groth Strip International Survey to construct stacked X-ray maps of optically bright active galaxies (AGN) and an associated control sample of galaxies at high redshift (z less than 0.6). From our analysis
of the surface brightness profiles obtained from these X-ray maps, we find evidence of feedback from the active nuclei. We find that excluding galaxies and AGN, residing in group environments, from our samples enhances the significance of our detection. Our results support the tentative findings of Chatterjee et al. who use X-ray selected AGN for their analysis. We discuss the implications of these results in the context of quantifying AGN feedback and show that the current method can be used to extract X-ray source population in high redshift galaxies.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
