Results 51 to 60 of about 323,430 (318)
The Astrophysical Journal, 2023 Strong iron lines are a common feature of the optical spectra of active galactic nuclei (AGNs) and quasars from z ∼ 6−7 to the local universe, and [Fe/Mg] ratios do not show cosmic evolution.
Jian-Min Wang +8 more
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Accretion disks around the Gibbons–Maeda–Garfinkle–Horowitz–Strominger charged black holes [PDF]
The European Physical Journal C, 2018 It seems surprising that the emissivity properties of the accretion disk (à la Page and Thorne) surrounding the Gibbons–Maeda–Garfinkle–Horowitz–Strominger (GMGHS) black holes of heterotic string theory have not yet been studied.
R. Karimov +3 more
semanticscholar +1 more source
Three-dimensional GRMHD Simulations of Neutrino-cooled Accretion Disks from Neutron Star Mergers [PDF]
, 2017 Merging binaries consisting of two neutron stars (NSs) or an NS and a stellar-mass black hole typically form a massive accretion torus around the remnant black hole or long-lived NS.
D. Siegel, B. Metzger
semanticscholar +1 more source
Properties of Circum(sub)stellar Accretion Disks
, 2002 We have completed a systematic survey for disks around young brown dwarfs and very low mass stars. By choosing a well-defined sample and by obtaining sensitive thermal IR observations, we can make an unbiased measurement of the disk fraction around such low mass objects.
Liu, Michael C. +2 more
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Mapping the Conditions for Hydrodynamic Instability on Steady-State Accretion Models of Protoplanetary Disks [PDF]
Astrophysical Journal, 2018 Hydrodynamic instabilities in disks around young stars depend on the thermodynamic stratification of the disk and on the local rate of thermal relaxation.
T. Pfeil, H. Klahr
semanticscholar +1 more source
Ionization and heating by X-rays and cosmic rays*
EPJ Web of Conferences, 2015 High-energy radiation from the central T Tauri and protostars plays an important role in shaping protoplanetary disks and influences their evolution. Such radiation, in particular X-rays and extreme-ultraviolet (EUV) radiation, is predominantly generated
Güdel Manuel
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Accurate determination of accretion and photospheric parameters in young stellar objects: The case of two candidate old disks in the Orion Nebula Cluster [PDF]
, 2013 Context. Current planet formation models are largely based on the observational constraint that protoplanetary disks have a lifetime of ~3 Myr. Recent studies, however, report the existence of pre-main-sequence stars with signatures of accretion ...
C. Manara +7 more
semanticscholar +1 more source
The Disks and Accretion Behavior of Young Stellar Objects [PDF]
, 2011 Zirkumstellare Scheiben spielen eine entscheidende Rolle im Prozess der Sternentstehung und gelten darüberhinaus als die Geburtsstätten neuer Planetensysteme. Notwendig zum Verständnis der Planetenund Sternentstehung ist daher das Wissen um die Entwicklung zirkumstellarer Akkretionsscheiben in Abhängigkeit von der stellaren Umgebung.
openaire +1 more source
Alignment of Stellar and AGN Accretion Disks from SDSS Data [PDF]
Proceedings of the International Astronomical Union, 2009 Lagos, Padilla & Cora (2009) show that if alignments between the galaxy kinematics and the AGN system were to occur, massive galaxies should host BHs with high spin values, regardless of the detailed physics of the BH. Since the BH spin regulates the mass-to-energy conversion (Marconi et al. 2004) and possibly the existence of radio jets (Sikora et
Claudia del P. Lagos +3 more
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LAMOST Reveals Long-lived Protoplanetary Disks
The Astronomical JournalWhile both observations and theories demonstrate that protoplanetary disks are not expected to live much longer than ∼10 Myr, several examples of prolonged disks have been observed in the past.
Xiao-Long Wang +4 more
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