Results 21 to 30 of about 86,681 (283)
THE PROPERTIES OF QUASAR HOSTS AT THE PEAK OF THE QUASAR ACTIVITY [PDF]
The Astrophysical Journal, 2009 We present near-infrared imaging obtained with ESO VLT/ISAAC of a sample of 16 low luminosity radio-quiet quasars at the epoch around the peak of the quasar activity (2 < z < 3), aimed at investigating their host galaxies. For 11 quasars, we are able to detect the host galaxies and derive their properties, while for the other five quasars, upper ...
Kotilainen J. K. +5 more
openaire +5 more sources
European Journal of Neuroscience, Volume 56, Issue 12, Page 6141-6161, December 2022., 2022 Chemical synapses are tiny and overcrowded environments enriched with thousands of protein species. Many efforts have been devoted to developing sensors and actuators able to evaluate and control synaptic communication. Most of these recent tools are based on the engineering of one or more specific synaptic proteins used to target active moieties to ...
Jacopo Lamanna +3 more
wiley +1 more source
Galaxies, 2021 The radiative and jet power in active galactic nuclei is generated by accretion of material on to supermassive galactic-centre black holes. For quasars, where the radiative power is by definition very high, objects with high radio luminosities form 10 ...
Gülay Gürkan +5 more
doaj +1 more source
The Astrophysical Journal, 2002 In a survey of quasar candidates selected by matching the FIRST and 2MASS catalogs, we have found two extraordinarily red quasars. FIRST J013435.7-093102 is a 1 Jy source at z=2.216 and has B-K > 10, while FIRST J073820.1+275045 is a 2.5 mJy source at z=1.985 with B-K = 8.4.
Mark Lacy +9 more
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The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5
The Astrophysical Journal Supplement Series, 2023 The identification of bright quasars at z ≳ 6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang.
Eduardo Bañados +22 more
doaj +1 more source
A Hubble Diagram for Quasars [PDF]
Frontiers in Astronomy and Space Sciences, 2015 The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4) and that of the Cosmic Microwave Background (z ~ 1,100). Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as "standard candles" by employing the non-linear relation between their ...
Guido Risaliti +4 more
openaire +10 more sources
The Astrophysical Journal, 2023 We present, for the first time, dark matter halo (DMH) mass measurement of quasars at z ∼ 6 based on a clustering analysis of 107 quasars. Spectroscopically identified quasars are homogeneously extracted from the Hyper Suprime-Cam Strategic Survey ...
Junya Arita +12 more
doaj +1 more source
Target Selection and Validation of DESI Quasars
The Astrophysical Journal, 2023 The Dark Energy Spectroscopic Instrument (DESI) survey will measure large-scale structures using quasars as direct tracers of dark matter in the redshift range 0.9 < z < 2.1 and using Ly α forests in quasar spectra at z > 2.1.
Edmond Chaussidon +56 more
doaj +1 more source
The Quasar-LBG Two-point Angular Cross-correlation Function at z ~ 4 in the COSMOS Field [PDF]
, 2015 In order to investigate the origin of quasars, we estimate the bias factor for low-luminosity quasars at high redshift for the first time. In this study, we use the two-point angular cross-correlation function (CCF) for both low-luminosity quasars at ...
Akiyama, M. +17 more
core +3 more sources
Symposium - International Astronomical Union, 1994 I review recent results for quasars and discuss how they are related to activity in galaxies. Topics included are studies of quasar host galaxies with HST; searches for quasars in the Hubble Deep Field; evolution of the quasar luminosity function; news highlights from astro-ph; and current observational research problems and their relation to ...
openaire +3 more sources