搜索结果: 1-12 共查到“天体物理学 quasars”相关记录12条 . 查询时间(0.257 秒)
Auto-Guiding System for CQUEAN (Camera for QUasars in EArly uNiverse)
instrumentation: CCD camera — techniques: photometric — telescopes — auto-guiding
2011/10/20
To perform imaging observation of optically red objects such as high redshift quasars and brown dwarfs, the Center for the Exploration of the Origin of the Universe (CEOU) recently developed an optica...
Can axion-like particles explain the alignments of the polarisations of light from quasars?
axion-like particles explain alignments polarisations
2011/9/30
The standard axion-like particle explanation of the observed large-scale coherent orientations of quasar polarisation vectors is ruled out by the recent measurements of vanishing of circular polarisat...
H$\beta$ Line Widths as an Orientation Indicator for Low-Ionization Broad Absorption Line Quasars
Orientation Indicator Low-Ionization Absorption Line Quasars
2011/1/11
There is evidence from radio-loud quasars to suggest that the distribution of the H$\beta$ broad emission line (BEL) gas is arranged in a predominantly planar orientation, and this result may well als...
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...