Results 81 to 90 of about 1,130 (187)

X-Ray Polarization Variability of High Spectral Peak BL Lacertaes: Cases of 1ES 1959+650 and PKS 2155–304

The Astrophysical Journal Letters
The high-energy-peaked BL Lacertae objects (HBLs) are the main targets of the Imaging X-ray Polarimetry Explorer (IXPE) for investigating the mechanisms of radiation and particle acceleration in jets. In this Letter, we report the first IXPE observations
Xin-Ke Hu, Yu-Wei Yu, Jin Zhang, Tan-Zheng Wu, Ji-Shun Lian, Xiang-Gao Wang, Hai-Ming Zhang, En-Wei Liang   +7 more
doaj   +1 more source

ABSTRACTS

Precision Radiation Oncology, EarlyView.
wiley   +1 more source

A Long-term Study of Mrk 50: Appearance and Disappearance of Soft Excess

The Astrophysical Journal
We present an extensive temporal and spectral study of the Seyfert 1 AGN Mrk 50 using 15 yr (2007–2022) of multiwavelength observations from XMM-Newton, Swift, and NuSTAR for the first time.
Narendranath Layek, Prantik Nandi, Sachindra Naik, Arghajit Jana   +3 more
doaj   +1 more source

Discovery of Changing-look Behavior in AGN NGC 3822: A Long-term Multiwavelength Study

The Astrophysical Journal
We present a comprehensive long-term multiwavelength study of the active galactic nucleus NGC 3822, based on 17 yr (2008–2025) of X-ray, ultraviolet (UV), and optical observations. The data set includes observations from Swift , XMM - Newton, and NuSTAR,
Narendranath Layek, Prantik Nandi, Sachindra Naik, Birendra Chhotaray, Arghajit Jana, Priyadarshee P. Dash, Neeraj Kumari, C. S. Stalin, Srikanth Bandari, S. Muneer   +9 more
doaj   +1 more source

A Systematic Search for Active Galactic Nuclei Obscuration Variability in the Chandra Archive

The Astrophysical Journal
The nature of the obscuring material in active galactic nuclei (AGN) can be studied by measuring changes in the line-of-sight column density, N _H,LOS , over time. This can be accomplished by monitoring AGN over long periods of time and at all timescales.
Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Vittoria E. Gianolli, Xiurui Zhao, Marco Ajello, Indrani Pal, Ross Silver   +7 more
doaj   +1 more source

On the Extended Soft X-Ray and Fe Kα Emission in NGC 1068

The Astrophysical Journal
The soft X-ray excess and Fe K α emission lines are widely observed in Seyfert galaxies, with their origin still in debate. We present a detailed spatially resolved image and spectral analysis of the Seyfert 2 galaxy NGC 1068 using high-resolution ...
Songbo Gao, Hongxing Yin, Shaoming Hu
doaj   +1 more source

First X-Ray Polarimetric View of a Low-luminosity Active Galactic Nucleus: The Case of NGC 2110

The Astrophysical Journal
Low-luminosity active galactic nuclei (LLAGN) provide a unique view of Comptonization and nonthermal emission from accreting black holes in the low accretion rate regime.
Sudip Chakraborty, Ajay Ratheesh, Daniele Tagliacozzo, Philip Kaaret, Jakub Podgorný, Frédéric Marin, Francesco Tombesi, Steven R. Ehlert, Chien-Ting J. Chen, Dawoon E. Kim, Ioannis Liodakis, Francesco Ursini, Riccardo Middei, Alessandro Di Marco, Fabio La Monaca, Srimanta Banerjee, Keigo Fukumura, W. Peter Maksym, Romana Mikušincová, Rodrigo Nemmen, Pierre-Olivier Petrucci, Paolo Soffitta, Jiří Svoboda, Wenda Zhang   +23 more
doaj   +1 more source

X-ray properties of Red Active Galactic Nuclei

, 2001
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 the overall population has been missed. Chandra observations of a well-defined subset of these objects reveal that
Wilkes, Belinda J., Schmidt, Gary D., Cutri, Roc M., Ghosh, Himel, Hines, Dean C., Nelson, Brant, Smith, Paul   +6 more
openaire   +2 more sources

XRISM/Resolve Reveals the Complex Iron Structure of NGC 7213: Evidence for Radial Stratification between Inner Disk and Broad-line Region

The Astrophysical Journal Letters
We present the first high-resolution X-ray spectrum of NGC 7213 obtained with XRISM/Resolve, supported by simultaneous XMM-Newton, NuSTAR, and SOAR optical data.
E. Kammoun, T. Kawamuro, K. Murakami, S. Bianchi, F. Nicastro, A. Luminari, E. Aydi, M. Eracleous, O. K. Adegoke, E. Bertola, P. G. Boorman, V. Braito, G. Bruni, A. Comastri, P. Condò, M. Dadina, T. Enoto, J. A. García, V. E. Gianolli, F. A. Harrison, G. Lanzuisi, M. Laurenti, A. Marinucci, G. Mastroserio, H. Matsumoto, G. Matt, G. Matzeu, R. Middei, E. Nardini, H. Noda, H. Odaka, S. Ogawa, F. Panessa, E. Piconcelli, C. Pinto, J. M. Piotrowska, G. Ponti, C. Ricci, R. Ricci, R. Serafinelli, F. Shi, D. Stern, A. Tanimoto, Y. Terashima, R. Tomaru, F. Tombesi, A. Tortosa, Y. Ueda, F. Ursini, C. Vignali, S. Yamada, S. Yamada   +51 more
doaj   +1 more source

The X-Ray Luminosity Function of Active Galactic Nuclei

, 1999
We derive an X-ray luminosity function for active galactic nuclei (AGN) that accounts for the X-ray source counts in the 0.5-2.0 and 2-10 keV energy ranges, the redshift distribution of AGNs in the ROSAT Deep Survey (RDS), as well as the X-ray background (XRB) from 1-10 keV.
Schmidt, M., Giacconi, R., Hasinger, G., Truemper, J., Zamorani, G.   +4 more
openaire   +2 more sources