Results 71 to 80 of about 63,914 (268)

Ultrafast Transitions in X‐Ray Irradiated Solids

Contributions to Plasma Physics, EarlyView.
ABSTRACT In this review, we present current developments on modeling ultrafast transitions in solids triggered by intense, atto‐ to femtosecond pulses from X‐ray free electron lasers. This specific irradiation regime requires dedicated simulation tools based on theoretical and computational methods, involving the elements of classical and quantum ...
Sebastião Antunes, Konrad J. Kapcia, Vladimir Lipp, Beata Ziaja   +3 more
wiley   +1 more source

The NH Distribution of Hard X-Ray Selected Active Galactic Nuclei in the NEP Field

The Astrophysical Journal
X-ray surveys are one of the most unbiased methods for detecting Compton-thick (CT; N _H ≥ 10 ^24 cm ^−2 ) active galactic nuclei (AGN), which are thought to comprise up to 60% of AGN within z ≲ 1.0.
Samantha Creech, Francesca Civano, Daniel R. Wik, Ross Silver, Xiurui Zhao, Rafael Ortiz III, Tonima Ananna, Norman A. Grogin, Rolf Jansen, Anton M. Koekemoer, Christopher N.A. Willmer, Rogier A. Windhorst   +11 more
doaj   +1 more source

A Tight Correlation between Millimeter and X-Ray Emission in Accreting Massive Black Holes from <100 mas Resolution ALMA Observations

The Astrophysical Journal Letters, 2023
Recent studies have proposed that the nuclear millimeter continuum emission observed in nearby active galactic nuclei (AGNs) could be created by the same population of electrons that gives rise to the X-ray emission that is ubiquitously observed in ...
Claudio Ricci, Chin-Shin Chang, Taiki Kawamuro, George C. Privon, Richard Mushotzky, Benny Trakhtenbrot, Ari Laor, Michael J. Koss, Krista L. Smith, Kriti K. Gupta, Georgios Dimopoulos, Susanne Aalto, Eduardo Ros   +12 more
doaj   +1 more source

X-RAY DETECTED ACTIVE GALACTIC NUCLEI IN DWARF GALAXIES AT 0 < z < 1 [PDF]

, 2016
We present a sample of accreting supermassive black holes (SMBHs) in dwarf galaxies at . We identify dwarf galaxies in the NEWFIRM Medium Band Survey with stellar masses of that have spectroscopic redshifts from the DEEP2 survey and lie within the region
Kris Pardo, A. Goulding, J. Greene, R. Somerville, E. Gallo, R. Hickox, B. Miller, A. Reines, J. Silverman   +8 more
semanticscholar   +1 more source

Unwrapping the X‐ray spectra of active galactic nuclei [PDF]

Astronomische Nachrichten, 2016
AbstractActive galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X‐ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity.
openaire   +3 more sources

X-Ray Unveiling Events in a z ≈ 1.6 Active Galactic Nucleus in the 7 Ms Chandra Deep Field-South

The Astrophysical Journal, 2023
We investigate the extreme X-ray variability of a z = 1.608 active galactic nucleus in the 7 Ms Chandra Deep Field-South (XID 403), which showed two significant X-ray brightening events.
Li-Ming Yu, Bin Luo, W. N. Brandt, Franz E. Bauer, D. De Cicco, A. Fabian, R. Gilli, A. Koekemoer, M. Paolillo, D. P. Schneider, O. Shemmer, P. Tozzi, Jonathan R. Trump, C. Vignali, F. Vito, J.-X. Wang, Y. Q. Xue   +16 more
doaj   +1 more source

Variability and the X-ray/UV ratio of Active Galactic Nuclei [PDF]

, 2010
The observed relation between the X-ray radiation from AGNs, originating in the corona, and the optical/UV radiation from the disk is usually described by the anticorrelation between the UV to X-ray slope alpha_ox and the UV luminosity.
Antonucci, M., Trevese, D., Turriziani, S., Vagnetti, F.   +3 more
core   +1 more source

Bolometric luminosities and Eddington ratios of X-ray selected active galactic nuclei in the XMM-COSMOS survey [PDF]

, 2012
Bolometric luminosities and Eddington ratios of both X-ray selected broad-line (Type-1) and narrow-line (Type-2) active galactic nuclei (AGN) from the XMM–Newton survey in the Cosmic Evolution Survey field are presented. The sample is composed of 929 AGN
E. Lusso, A. Comastri, B. Simmons, M. Mignoli, G. Zamorani, C. Vignali, M. Brusa, F. Shankar, D. Lutz, J. Trump, R. Maiolino, R. Maiolino, R. Gilli, M. Bolzonella, S. Puccetti, M. Salvato, C. Impey, F. Civano, M. Elvis, V. Mainieri, J. Silverman, A. Koekemoer, A. Bongiorno, A. Merloni, S. Berta, E. Floc’h, B. Magnelli, F. Pozzi, L. Riguccini   +28 more
semanticscholar   +1 more source

Extreme X-Ray Iron Lines in Active Galactic Nuclei

The Astrophysical Journal, 2002
We analyze X-ray spectra of heavily obscured (N_H > 10^{24} cm^{-2}) active galaxies obtained with Chandra, concentrating on the iron K alpha fluorescence line. We measure very large equivalent widths in most cases, up to 5 keV in the most extreme example.
Levenson, N. A., Krolik, J. H., Zycki, P. T., Heckman, T. M., Weaver, K. A., Awaki, H., Terashima, Y.   +6 more
openaire   +2 more sources

A Low‐Power Radioisotope XRF Spectrometer for Detection of Light Elements on Planetary Missions

X-Ray Spectrometry, EarlyView.
ABSTRACT Current X‐ray spectrometers for in situ geochemical analysis on planetary missions typically rely either on X‐ray tubes, which demand electrical power and add mass and thermal complexity, or on alpha particle X‐ray spectrometers (APXS) that use rare 244Cm$$ {}^{244}\mathrm{Cm} $$ sources, and come with severe concerns on radiation safety and ...
Leandro Silveri, Artem Knyazev, Hashem Alaidaros, Maryam Manzoor Amanullah, Zach Ioannou, Tengiz Ibrayev, Danish Khan, Sara Leardini, Laura Manenti, Simi Maria Emilia Mangani, Safa Naseem, Sandhya Sharma, Sara Trevisan, Alia Zino, Francesco Arneodo   +14 more
wiley   +1 more source