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Related papers: Prevalence of High X-ray Obscuring Columns among A…

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We report the results of a search for pure rotational molecular hydrogen emission from the circumstellar environments of young stellar objects with disks using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared…

The 6 cm and 20 cm radio continuum properties of all 85 galaxies with reported 22 GHz H2O maser emission and luminosity distance D > 0.5 Mpc are studied. For the total of 55 targets for which both 6 cm and 20 cm measurements exist and for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 J. S. Zhang , C. Henkel , Q. Guo , J. Wang

We present the multi-epoch analysis of 13 variable, nearby (z<0.1), Compton-thin (22<logN_H<24) active galactic nuclei (AGN) selected from the 105-month BAT catalog. Analyzing all available archival soft and hard X-ray observations, we…

High Energy Astrophysical Phenomena · Physics 2024-03-12 A. Pizzetti , N. Torres-Alba , S. Marchesi , J. Buchner , I. Cox , X. Zhao , S. Neal , D. Sengupta , R. Silver , M. Ajello

We study the comoving space density of X-ray-selected luminous active galactic nuclei (AGNs) and the obscured AGN fraction at high redshifts ($3 < z < 5$) in the Subaru/{\it XMM-Newton} Deep Survey (SXDS) field. From an X-ray source catalog…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Kazuo Hiroi , Yoshihiro Ueda , Masayuki Akiyama , Mike G. Watson

We present a study of optically selected dual AGN with projected separations of 3--97~kpc. Using multi-wavelength (MWL) information (optical, X-rays, mid-IR), we characterized the intrinsic nuclear properties of this sample and compared…

We report H$_2$O maser line observations of the bright-rimmed globule IC 1396 N using a ground-space interferometer with the 10-m RadioAstron radio telescope as the space-based element. The source was not detected on projected baselines…

Astrophysics of Galaxies · Physics 2017-06-21 O. S. Bayandina , I. E. Val'tts , S. E. Kurtz , G. M. Rudnitskij , A. V. Alakoz

The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of…

Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift type-2 quasars in the Subaru XMM-Newton Deep Field (SXDF). To filter out starburst contaminants, we use a bayesian method to fit the spectral…

We present the results of optical spectroscopic identifications of a bright subsample of 2-10keV hard X-ray selected sources from the ASCA Medium Sensitivity Survey in the northern sky. The flux limit of the subsample is 3*10^-13 erg s^-1…

Astrophysics · Physics 2009-11-10 Masayuki Akiyama , Yoshihiro Ueda , Kouji Ohta , Tadayuki Takahashi , Toru Yamada

We study the column densities of neutral atomic, molecular, and warm ionized Galactic gas through their continuous absorption of extragalactic X-ray spectra at |b| > 25 degrees. For N(H,21cm) < 5x10^20 cm^-2 there is an extremely tight…

Astrophysics · Physics 2014-10-13 John S. Arabadjis , Joel N. Bregman

Heavily obscured Active Galactic Nuclei (AGN), especially Compton-thick sources with line-of-sight column density ($N_{\rm H,los}$) $>$ 10$^{24}$ cm$^{-2}$, are critical to understanding supermassive black hole (SMBH) growth and the origin…

The X-ray Background has been resolved in the 0.5-5keV band and found to consist mostly of both unabsorbed and absorbed AGN with column densities <1e23. This contrasts with the local AGN population where the column density range extends to…

Astrophysics · Physics 2009-11-10 A. C. Fabian , M. A. Worsley

We consider the Comptonisation of the photons that make up the relativistically blurred reflection that is commonly detected from the accretion discs of AGN by the coronae of energetic particles believed to give rise to the powerful X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-23 D. R. Wilkins , L. C. Gallo

We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…

Astrophysics of Galaxies · Physics 2023-07-05 Ross Silver , Núria Torres-Alba , Xiurui Zhao , Stefano Marchesi , Andrealuna Pizzetti , Isaiah Cox , Marco Ajello

We present X-ray spectra of 185 bright sources detected in the XMM-Newton deep survey of the Chandra Deep Field South, combining the three EPIC cameras. The 2-10 keV flux limit of the sample is 2e-15 erg/s/cm2. The sources are distributed…

AGNs exhibit a wide range of black hole masses and inflow/outflow properties. It is now possible to probe regions close to the event horizons of nearby SMBHs using VLBI with earth-sized baselines, as performed by the EHT. This study…

High Energy Astrophysical Phenomena · Physics 2025-05-23 Bidisha Bandyopadhyay , Christian Fendt , Dominik R. G. Schleicher , Neil M. Nagar , Felipe Agurto-Sepulveda , Javier Pedreros

A fraction of active galactic nuclei (AGN) have double-peaked H$\alpha$, H$\beta$ and Mg II broad lines attributed to emission from rotating gas in the accretion disk. Using optical spectroscopy of a flux-limited sample of AGN selected via…

We present a novel and powerful constraint on the physics of supermassive black hole (BH) accretion disks. We show that in the outer disk (radii $R \gtrsim 0.01\,$pc or $\gtrsim 1000\,R_{G}$), models supported by thermal or radiation…

High Energy Astrophysical Phenomena · Physics 2026-04-30 Philip F. Hopkins , Dalya Baron , Joanna M. Piotrowska

Extremely strong ionized Fe emission lines, with the equivalent width reaching about 4000 eV, were discovered with ASCA from a few Galactic compact objects, including AX J2315-0592, RX J1802.1+1804 and AX J1842.8-0423. These objects are…

Astrophysics · Physics 2009-11-06 Yukikatsu. Terada , M. Ishida , K. Makishima , T. Imanari , R. Fujimoto , K. Matsuzaki , H. Kaneda

There is substantial evidence for a connection between star formation in the nuclear region of a galaxy and growth of the central supermassive black hole. Furthermore, starburst activity in the region around an active galactic nucleus (AGN)…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Jonathan N. Armour , David R. Ballantyne