Results 41 to 50 of about 9,171,233 (161)
The Astrophysical Journal, 2023 Despite the 30 yr history of ultraluminous X-ray sources (ULXs) studies, issues such as the majority of their physical natures (i.e., neutron stars, stellar-mass black holes, or intermediate black holes) as well as the accretion mechanisms are still ...
Chen-Hsun Ma +3 more
doaj +1 more source
Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves ...
S. Komossa, Francesca Civano
wiley +1 more source
The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of active galactic nuclei (AGN) ranging from radio to hard X‐ray wavelengths.
Ezequiel Treister +2 more
wiley +1 more source
Ultraluminous X-ray sources and star formation [PDF]
Monthly Notices of the Royal Astronomical Society, 2004 Chandra observations of the Cartwheel galaxy reveal a population of ultraluminous X-ray sources (ULXs) with lifetimes < 10^7 yr associated with a spreading wave of star formation which began some 3 x 10^8 yr ago. A population of high-mass X-ray binaries provides a simple model: donor stars of initial masses M_2 > 15 Msun transfer mass on their ...
openaire +3 more sources
Constraining Soft and Hard X-Ray Irradiation in Ultraluminous X-Ray Sources [PDF]
The Astrophysical Journal, 2021 Abstract Most ultraluminous X-ray sources (ULXs) are argued to be powered by supercritical accretion onto compact objects. One of the key questions regarding these objects is whether or not the hard X-rays are geometrically beamed toward the symmetric axis.
Yanli Qiu, Hua Feng
openaire +2 more sources
The Astrophysical Journal, 2023 We have conducted long-slit spectroscopic observations and analyzed archival radio data for the ultraluminous X-ray source (ULX) NGC 4861 X-1. Our spectral line analysis unveils NGC 4861 X-1 as the fourth ULX situated within an X-ray photoionized nebula,
Hang Gong +7 more
doaj +1 more source
Long-term X-ray variability of ultraluminous X-ray sources [PDF]
Monthly Notices of the Royal Astronomical Society, 2015 15 pages, 8 figures; accepted for publication in ...
Hu, CP +5 more
openaire +4 more sources
Bubble Nebulae around Ultraluminous X-Ray Sources
, 2002 International audienceThe nature of extra-nuclear ultraluminous X-ray sources (ULX) in nearby galaxies continues to be an enigma, since their adopted isotropic high-energy output would surpass the Eddington limit of even the most massive stellar black ...
Pakull, M. W., Mirioni, Laurent
core +3 more sources
The Circumnuclear Environment of IRAS 20551‐4250: A Case Study of AGN/Starburst Connection for JWST
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 We present a general review of the current knowledge of IRAS 20551‐4250 and its circumnuclear environment. This Ultraluminous Infrared Galaxy is one of the most puzzling sources of its class in the nearby Universe: the near‐IR spectrum is typical of a galaxy experiencing a very intense starburst, but a highly obscured active nucleus is identified ...
E. Sani, E. Nardini, Antonis Georgakakis
wiley +1 more source
A Practical Guide to the Massive Black Hole Cosmic History
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 I review our current understanding of massive black hole (MBH) formation and evolution along the cosmic history. After a brief introductory overview of the relevance of MBHs in the hierarchical structure formation paradigm, I discuss the main viable channels for seed BH formation at high redshift and for their subsequent mass growth and spin evolution.
A. Sesana, Francesco Shankar
wiley +1 more source