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Quasars may answer how starburst galaxies were extinguished
Quasars answer starburst galaxies extinguished
2017/9/1
Some of the biggest galaxies in the universe are full of extinguished stars. But nearly 12 billion years ago, soon after the universe first was created, these massive galaxies were hotspots that brewe...
Boss quasars track the expanding universe: The most precise measurement yet
Boss quasars track expanding universe The most precise measurement yet
2014/4/16
The Baryon Oscillation Spectroscopic Survey (BOSS), the largest component of the third Sloan Digital Sky Survey (SDSS-III), pioneered the use of quasars to map density variations in intergalactic gas ...
Structure Function and Variability Mechanism of Quasars from SDSS Stripe 82
Structure Function Variability Mechanism Quasars
2011/10/13
Theoretical predictions for the ensemble quasar structure function are tested using multi-epoch observations of Stripe 82 collected by the Sloan Digital Sky Survey. We reanalyze the entire available v...
Far-infrared and Molecular CO Emission From the Host Galaxies of Faint Quasars at z~6
Far-infrared Molecular CO Emission Host Galaxies Faint Quasars
2011/10/21
We present new millimeter and radio observations of nine z~6 quasars discovered in deep optical and near-infrared surveys. We observed the 250 GHz continuum in eight of the nine objects and detected t...
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...
Investigation of the errors in SDSS proper-motion measurements using samples of quasars
Investigation of the errors in SDSS proper-motion measurements using samples of quasars
2011/10/17
We investigate in detail the probability distribution function (pdf) of the proper-motion measurement errors in the SDSS+USNO-B proper-motion catalog of \citet{mun04} using clean quasar samples. The p...
The Demographics of Broad-Line Quasars in the Mass-Luminosity Plane. I. Testing FWHM-Based Virial Black Hole Masses
Demographics Broad-Line Quasars Mass-Luminosity Plane
2011/10/13
We jointly constrain the LF and BHMF of quasars using a Bayesian approach that describes the underlying active BHMF and Eddington ratio distribution to match the observed distributions in the quasar m...
Astroinformatics of galaxies and quasars: a new general method for photometric redshifts estimation
cosmology observations galaxies:redshifts
2011/7/19
With the availability of the huge amounts of data produced by current and future large multi-band photometric surveys, photometric redshifts have become a crucial tool for extragalactic astronomy and ...
BLR Physical Conditions in Extreme Population A Quasars: a Method to Estimate Central Black Hole Mass at High Redshift
Physical Conditions Extreme Population Quasars
2011/10/10
We describe a method for determination of physical conditions in the broad line regions of a significant subsample of Seyfert-1 nuclei and quasars. Several diagnostic ratios based on intermediate (AlI...
Astroinformatics of galaxies and quasars: a new general method for photometric redshifts estimation
cosmology: observations galaxies: redshifts methods: data mining surveys
2011/10/10
With the availability of the huge amounts of data produced by current and future large multi-band photometric surveys, photometric redshifts have become a crucial tool for extragalactic astronomy and ...
The impact of quasars on their galaxy neighbors is an important factor in the understanding of the galaxy evolution models. The aim of this work is to characterize the close environments of quasars at...
The host galaxies and black-hole:galaxy mass ratios of luminous quasars at z~4
galaxies: active – galaxies: fundamental parameters – galaxies: high-redshift –galaxies: photometry – infrared: galaxies – quasars: general
2011/10/8
We present and analyse the deepest, high-quality Ks-band images ever obtained of luminous quasars at z~4, in an attempt to determine the basic properties of their host galaxies less than 1 Gyr after t...
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...
Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBH) have to be assembled within the first eight hundred million years. Under our standard gala...
Discovering the missing 2.2quasars by combining optical variability and optical/near-IR colors
Discovering missing quasars combining variability optical/near-IR colors
2011/9/27
The identifications of quasars in the redshift range 2.2are known to be very inefficient as their optical colors are indistinguishable from those of stars. Recent studies have proposed to use opt...