搜索结果: 16-30 共查到“天文学 Quasars”相关记录39条 . 查询时间(0.125 秒)
Spectral variability of quasars from multi-epoch photometric data in the Sloan Digital Sky Survey Stripe 82
Spectral variability multi-epoch photometric data
2011/1/11
We present a new approach to analysing the dependence of quasar variability on rest-frame wavelengths. We exploited the spectral archive of the Sloan Digital Sky Survey (SDSS) to create a sample of mo...
Unification of Luminous Type 1 Quasars through CIV Emission
quasars general quasars emission lines quasars absorption lines line profiles radio continuum galaxies
2010/11/12
Using a sample of 30,000 quasars from the 7th Data Release of the Sloan Dig-ital Sky Survey, we explore the range of properties exhibited by high-ionization,broad emission lines, such as C IV 1549. ...
Hot-Dust-Poor Quasars in Mid-Infrared and Optically Selected Samples
galaxies evolution quasars general surveys
2010/11/9
We show that the Hot-Dust-Poor (HDP) quasars found in the X-ray selected XMM-COSMOS type
1 AGN sample are just as common in two samples selected at optical/infrared wavelengthes: the
Richards et al....
Photometric Catalogue of Quasars and Other Point Sources in the Sloan Digital Sky Survey
astronomical data bases miscellaneous – catalogues – techniques pho-tometric – methods statistical – surveys
2010/11/12
We present a catalogue of about 8.6 million unresolved photometric detections in the Sloan Digital Sky Survey Seventh Data Release classifying them into stars, galaxies and quasars using a machine lea...
[O III] Equivalent Width and Orientation Effects in Quasars
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/28
The flux of the [OIII] line is considered to be a good indicator of the bolometric emission of quasars. The observed continuum emission from the accretion disc should instead be strongly dependent on ...
Shock-in-jet model for quasars and microquasars
High Energy Astrophysical Phenomena (astro-ph.HE)
2010/12/24
We present the theoretical background and detailed equations for the synchrotron emission of a shock wave propagating in a relativistic jet. We then show how the evolution of an outburst in this shock...
Probing the accretion disk - jet connection via instabilities in the inner accretion flow. From microquasars to quasars
High Energy Astrophysical Phenomena (astro-ph.HE)
2010/12/24
We present various instability mechanisms in the accreting black hole systems which might indicate at the connection between the accretion disk and jet. The jets observed in microquasars can have a pe...
Ionization near-zones associated with quasars at z ~ 6
cosmology theory reionization galaxies formation quasars formation
2010/3/9
We analyze the size evolution of HII regions around 27 quasars between z=5.7 to 6.4 ('quasar near-zones' or NZ). We include more sources than previous studies, and we use more accurate redshifts for t...
A quasar is a black hole that draws in matter from the surrounding space. Its strong gravitational field imposes a huge kinetic energy on this matter, causing it to radiate across a wide range of wave...
Nuclear to host galaxy relation of high redshift quasars
Nuclear redshift quasars host galaxy
2009/7/9
Nuclear to host galaxy relation of high redshift quasars。
The big blue bump and soft X-ray excess of individual quasars
big blue bump individual quasars soft X-ray excess
2009/7/9
The big blue bump and soft X-ray excess of individual quasars。
The Nature of the Far-UV Break in the Energy Distribution of Quasars
Far-UV Break Quasars Energy Distribution
2009/7/9
The Nature of the Far-UV Break in the Energy Distribution of Quasars。
Near-IR spectroscopy of high redshift quasars。
The Broad Line Region of Quasars。
High-Redshift Quasars as Early Star Formation Probes
High-Redshift Quasars Early Star Formation Probes
2009/7/9
High-Redshift Quasars as Early Star Formation Probes。