Download or read book Clustering of High Redshift Quasars written by John D. Timlin (III) and published by . This book was released on 2018 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we investigate the clustering of faint quasars in the early Universe and use the clustering strength to gain a better understanding of quasar feedback mechanisms and the growth of central supermassive black holes at early times in the history of the Universe. It has long been understood (e.g., Hopkins et al. 2007a) that the clustering of distant quasars can be used as a probe of different feedback models; however, until now, there was no sample of faint, high-redshift quasars with sufficient density to accurately measure the clustering strength. Therefore we conducted a new survey to increase the number density of these objects. Here, we describe the Spitzer -IRAC Equatorial Survey (SpIES) which is a moderately deep, large-area Spitzer survey which was designed to discover faint, high-redshift (2.9 = z = 5.1) quasars. SpIES spans ~115 deg^2 in the equatorial "Stripe 82" region of the Sloan Digital Sky Survey (SDSS) and probes to 5-[sigma] depths of 6.13 [mu]-Jy (21.93 AB magnitude) and 5.75 [mu]-Jy (22.0 AB magnitude) at 3.6 and 4.5 microns. At these depths, SpIES is able to observe faint quasars, and we show that SpIES recovers ~94% of the high-redshift (z 3.5), spectroscopically-confirmed quasars that lie within its footprint. SpIES is also ideally located on Stripe 82 for two reasons: It surrounds existing infrared data from the Spitzer-HETDEX Exploratory Large-area (SHELA) survey which increases the area of infrared coverage, and there is a wide range of multi-wavelength, multi-epoch ancillary data on Stripe 82 which we can use together to select high-redshift quasar candidates. To photometrically identify quasar candidates, we combined the optical data from the Sloan Digital Sky Survey and the infrared data from SpIES and SHELA and employed three machine learning algorithms. These algorithms were trained on the optical/infrared colors of known, high-redshift quasars. Using this method, we generate a sample of 1378 objects that are both faint (i 20.2) and high-redshift (2.9

Download or read book Clustering of High Redshift z 2 9 Quasars from the Sloan Digital Sky Survey written by and published by . This book was released on 2006 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the two-point correlation function of a uniformly selected sample of 4,428 optically selected luminous quasars with redshift 2.9 ≤ z ≤ 5.4 selected over 4041 deg2 from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function w{sub p}(r{sub p}) to marginalize over redshift space distortions and redshift errors. For a real-space correlation function of the form [zeta](r) = (r/r0){sup -[gamma]}, the fitted parameters in comoving coordinates are r0 = 15.2 ± 2.7 h−1 Mpc and [gamma] = 2.0 ± 0.3, over a scale range 4 ≤ r{sub p} ≤ 150 h−1 Mpc. Thus high-redshift quasars are appreciably more strongly clustered than their z ≈ 1.5 counterparts, which have a comoving clustering length r0 ≈ 6.5 h−1 Mpc. Dividing our sample into two redshift bins: 2.9 ≤ z ≤ 3.5 and z ≥ 3.5, and assuming a power-law index {gamma} = 2.0, we find a correlation length of r0 = 16.9 ± 1.7 h−1 Mpc for the former, and r0 = 24.3 ± 2.4 h−1 Mpc for the latter. Strong clustering at high redshift indicates that quasars are found in very massive, and therefore highly biased, halos. Following Martini & Weinberg, we relate the clustering strength and quasar number density to the quasar lifetimes and duty cycle. Using the Sheth & Tormen halo mass function, the quasar lifetime is estimated to lie in the range 4 ≈ 50 Myr for quasars with 2.9 ≤ z ≤ 3.5; and 30 ≈ 600 Myr for quasars with z ≥ 3.5. The corresponding duty cycles are 0.004 ≈ 0.05 for the lower redshift bin and 0.03 ≈ 0.6 for the higher redshift bin. The minimum mass of halos in which these quasars reside is 2-3 x 1012 h−1 M{sub {circle_dot}} for quasars with 2.9 ≤ z ≤ 3.5 and 4-6 x 1012 h−1 M{sub {circle_dot}} for quasars with z ≥ 3.5; the effective bias factor b{sub eff} increases with redshift, e.g., b{sub eff} ≈ 8 at z = 3.0 and b{sub eff} ≈ 16 at z = 4.5.

Download or read book High redshift Universe written by Gregory Zeimann and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the discovery of only the second radio-selected, z ~ 6 quasar. We identified the z=5.95 quasar by matching the optical detections of the deep Sloan Digital Sky Survey (SDSS) Stripe 82 with their radio counterparts in the Stripe82 VLA Survey. The discovered quasar is optically-faint, z = 22.3 and M1450 ~ -24.5, but radio-bright, with a flux density of f[subscript 1.4GHz, peak] = 0.31mJy and a radio-loudness of R ~ 1100 (where R = f[subscript 5GHz]/f2500). The i - z color of the discovered quasar places it outside the color selection criteria for existing optical surveys. We also report the discovery of an IR-selected galaxy cluster in the IRAC Distant Cluster Survey (IDCS). New data from the Hubble Space Telescope spectroscopically confirm the galaxy cluster at z = 1.89 with robust spectroscopic redshifts for seven members. The cluster exhibits a red sequence with a scatter and color indicative of a formation redshift z[subscript f]>~ 3.5. The stellar age of the early-type galaxy population is approximately consistent with those of clusters at lower redshift (1 z 1.5) suggesting that clusters at these redshifts are experiencing ongoing or increasing star formation. Finally, we present near-IR spectroscopy for 18 galaxy clusters at 1.0

Download or read book Clustering at High Redshift written by Alain Mazure and published by . This book was released on 2000 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Astronomers, astrophysicists, and other scientists and researchers from laboratories, observatories, and universities throughout North America, Europe, Asia, and the Middle East present 60 contributions addressing clustering from low to high redshift; clustering measurements in surveys; IR and sub-mm surveys; theory and models; high-redshift clusters of galaxies; QSO absorption lines; primordial galaxies; clustering around QSOs and radio galaxies; and the physics of the intra-cluster medium. Approximately 40 poster sessions are also presented. Lacks an index. Annotation c. Book News, Inc., Portland, OR (booknews.com)

Download or read book Fifty Years of Quasars written by Mauro D'Onofrio and published by Springer Science & Business Media. This book was released on 2012-09-14 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 50th anniversary of the discovery of quasars in 1963 presents an interesting opportunity to ask questions about the current state of quasar research. Formatted as a series of interviews with noted researchers in the field, each of them asked to address a specific set of questions covering topics selected by the editors, this book deals with the historical development of quasar research and discusses how advances in instrumentation and computational capabilities have benefitted quasar astronomy and have changed our basic understanding of quasars. In the last part of the book the interviews address the current topic of the role of quasars in galaxy evolution. They summarise open issues in understanding active galactic nuclei and quasars and present an outlook regarding what future observational facilities both on the ground and in space might reveal. Its interview format, the fascinating topic of quasars and black holes, and the lively recollections and at times controversial views of the contributors make this book both rewarding and a pleasure to read!

Download or read book The High redshift Quasar Luminosity Function from Multi epoch Imaging Surveys written by Yusra AlSayyad and published by . This book was released on 2016 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Upcoming time-domain imaging surveys such as the LSST will detect over a million high-redshift z > 4 quasars, making complete spectroscopic followup unfeasible. Statistical estimates such as luminosity functions and clustering measurements will require purely photometric methods for classifying quasars, estimating redshifts and estimating selection functions. We validate these methods and constrain the optical, type I quasar luminosity function (QLF) at 3.75 z 4.5 for −27.5 M_1450

Download or read book Seeing Red written by Halton C. Arp and published by Apeiron. This book was released on 1998 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Confrontation of Cosmological Theories with Observational Data written by Malcolm S. Longair and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of IAU Symposium No. 63, held in Cracow, Poland, September 10-12, 1973

Download or read book Growing Black Holes Accretion in a Cosmological Context written by Andrea Merloni and published by Springer Science & Business Media. This book was released on 2005-04-25 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supermassive black holes are now believed to play an important role in the evolution of the Universe. Every respectable galaxy hosts in its center a black hole that appears to regulate the growth of the galaxy itself. In this book, leading experts in the field review the most recent theoretical and observational results on the following topics: - formation and growth of the first black holes in the Universe and their role in the formation and evolution of galaxies - the physics of black-hole accretion and the production of relativistic jets - binary black-hole mergers and gravitational radiation. Theoretical work is supplemented by the most recent exciting results from space and ground based observatories. This volume is useful research and reference tool for the entire astrophysical community.

Download or read book High Energy Astrophysics Compact Stars And Active Galaxies Proceedings Of The 3rd Chinese Academy Of Sciences And Max planck Society Workshop written by Qi Bin Li and published by World Scientific. This book was released on 1991-08-27 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is concerned with the broad areas related to high energy astrophysics stressing the processes in the compact objects and active galaxies. The subject matter encompasses the interpretation of many high energy astrophysical processes such as accretion disk, relativistic ejection, superluminal motion, gravitational lens, clustering of galaxies and observations on binary system, cataclysmic variables, X-ray sources, QSOs and BL Lac objects.

Download or read book Modern Statistical Methods for Astronomy written by Eric D. Feigelson and published by Cambridge University Press. This book was released on 2012-07-12 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Statistical Methods for Astronomy: With R Applications.

Download or read book The Space Distribution of Quasars written by David Crampton and published by . This book was released on 1991 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Objects of High Redshift written by G.O. Abell and published by Springer. This book was released on 1980-06-30 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of IAU Symposium No. 92, held in Los Angeles, U.S.A., August 28-31, 1979

Download or read book Fundamental Parameters in Cosmology written by J. Thanh Van Tran and published by Atlantica Séguier Frontières. This book was released on 1998 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quasars Clusters and Cosmology written by Neelam Dhanda and published by . This book was released on 2010 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Clustering in the Universe written by S. Maurogordato and published by Atlantica Séguier Frontières. This book was released on 1995 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Astronomy and Astrophysics Abstracts written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-12-14 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundamental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ... The abstracts are classified under more than hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Reviews #1 "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine #1