Results 21 to 30 of about 329,488 (298)

The Challenge to Large Optical Telescopes from X-ray Astronomy [PDF]

, 2002
In the ROSAT era of the mid-1990's, the problems facing deep X-ray surveys could be largely solved with 10 m class telescopes. In the first decade of this new millennium, with X-ray telescopes such as the Chandra X-ray Observatory and XMM-Newton in ...
Hornschemeier, Ann E.
core   +3 more sources

BASS. XXVI. DR2 Host Galaxy Stellar Velocity Dispersions

The Astrophysical Journal Supplement Series, 2022
We present new central stellar velocity dispersions for 484 Sy 1.9 and Sy 2 from the second data release of the Swift/BAT AGN Spectroscopic Survey (BASS DR2).
Michael J. Koss, Benny Trakhtenbrot, Claudio Ricci, Kyuseok Oh, Franz E. Bauer, Daniel Stern, Turgay Caglar, Jakob S. den Brok, Richard Mushotzky, Federica Ricci, Julian E. Mejía-Restrepo, Isabella Lamperti, Ezequiel Treister, Rudolf E. Bär, Fiona Harrison, Meredith C. Powell, George C. Privon, Rogério Riffel, Alejandra F. Rojas, Kevin Schawinski, C. Megan Urry   +20 more
doaj   +1 more source

Deep ROSAT Surveys & the contribution of AGNs to the soft X-ray background [PDF]

, 2001
The ROSAT Deep Surveys in the Lockman Hole have revealed that AGNs are the main contributors (~75%) to the soft X-ray background in the 1–2 keV band. Using new optical/infrared and radio observations we have obtained a nearly complete identification (93%)
Giacconi, R., Gunn, J. E., Hasinger, G., Lehmann, I., McCaughrean, M., Schmidt, M., Schneider, D. P., Trümper, J., Zamorani, G.   +8 more
core   +1 more source

A High Fraction of Heavily X-Ray-obscured Active Galactic Nuclei

The Astrophysical Journal, 2023
We present new estimates on the fraction of heavily X-ray-obscured, Compton-thick (CT) active galactic nuclei (AGNs) out to a redshift of z ≤ 0.8. From a sample of 540 AGNs selected by mid-infrared (MIR) properties in observed X-ray survey fields, we ...
Christopher M. Carroll, Tonima T. Ananna, Ryan C. Hickox, Alberto Masini, Roberto J. Assef, Daniel Stern, Chien-Ting J. Chen, Lauranne Lanz   +7 more
doaj   +1 more source

The Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest: The X-ray Catalog [PDF]

, 2004
We present the X-ray catalog and basic results from our Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest field. Our 9 ACIS-I fields cover a contiguous solid angle of ~0.4 sq. deg.
A. J. Barger, A. T. Steffen, Barr P., Bolzonella M., Hasinger G., Kushino A., L. L. Cowie, R. F. Mushotzky, Schmidt M., Y. Yang   +9 more
core   +1 more source

Constraints From Dwarf Galaxies on Black Hole Seeding and Growth Models With Current and Future Surveys

The Astrophysical Journal, 2023
Dwarf galaxies are promising test beds for constraining models of supermassive and intermediate-mass black holes (MBHs) via their BH occupation fraction (BHOF).
Urmila Chadayammuri, Ákos Bogdán, Angelo Ricarte, Priyamvada Natarajan   +3 more
doaj   +1 more source

The detection and X-ray evolution of galaxy groups at high redshift [PDF]

, 2002
We describe some of the first X-ray detections of groups of galaxies at high redshifts (z~0.4), based on the UK deep X-ray survey of McHardy et al (1998).
A. Newsam, Allington-Smith, Avni, Bahcall, Balogh, Bower, Bower, Bower, Bower, Bryan, Burg, Burke, Burns, Canizares, Cavaliere, Cavaliere, Cole, Collins, De Grandi, Ebeling, Ebeling, Eke, Evrard, Fairley, Fukugita, Governato, Hasinger, Hasinger, Henry, I. McHardy, Jones, Jones, Jones, K. Mason, Kaiser, Kaiser, Kravtsov, L. R. Jones, Lehmann, Lloyd-Davies, Lowenstein, Madau, McHardy, Menci, Mulchaey, Mushotzky, Newsam, Pen, Ponman, Ponman, Postman, Romer, Rosati, Rosati, Scharf, Schmidt, Snowden, Tozzi, Tully, Valageas, Vikhlinin, White, White, Wu, Wu, Zamorani   +65 more
core   +2 more sources

Survey of X-ray pulsars in hard X-rays [PDF]

Proceedings of The Extreme sky: Sampling the Universe above 10 keV — PoS(extremesky2009), 2010
Results of spectral, timing and spatial analysis of X-ray pulsars in hard X-rays are briefly discussed. Using data of INTEGRAL, XMM-Newton and Chandra observatories we determined an optical counterparts and distances for several X-ray pulsars and built the spatial distribution of this class objects in the Galaxy. Variations of the cyclotron line energy
Alexander Lutovinov, Sergey Tsygankov
openaire   +1 more source

BASS. XXI. The Data Release 2 Overview

The Astrophysical Journal Supplement Series, 2022
The BAT AGN Spectroscopic Survey (BASS) is designed to provide a highly complete census of the key physical parameters of the supermassive black holes (SMBHs) that power local active galactic nuclei (AGNs) ( z ≲ 0.3), including their bolometric ...
Michael J. Koss, Benny Trakhtenbrot, Claudio Ricci, Franz E. Bauer, Ezequiel Treister, Richard Mushotzky, C. Megan Urry, Tonima T. Ananna, Mislav Baloković, Jakob S. den Brok, S. Bradley Cenko, Fiona Harrison, Kohei Ichikawa, Isabella Lamperti, Amy Lein, Julian E. Mejía-Restrepo, Kyuseok Oh, Fabio Pacucci, Ryan W. Pfeifle, Meredith C. Powell, George C. Privon, Federica Ricci, Mara Salvato, Kevin Schawinski, Taro Shimizu, Krista L. Smith, Daniel Stern   +26 more
doaj   +1 more source

An Optically Discovered Outburst from XTE J1859+226

The Astrophysical Journal, 2023
Using the Zwicky Transient Facility, in 2021 February we identified the first known outburst of the black hole X-ray transient XTE J1859+226 since its discovery in 1999. The outburst was visible at X-ray, UV, and optical wavelengths for less than 20 days,
Eric C. Bellm, Yuankun Wang, Jan van Roestel, Rebecca A. Phillipson, Michael W. Coughlin, John A. Tomsick, Steven L. Groom, Brian Healy, Josiah Purdum, Ben Rusholme, Jesper Sollerman, Peter Bealo, Stefano Lora, Eddy Muyllaert, Ivo Peretto, Erik J. Schwendeman   +15 more
doaj   +1 more source