Download or read book Galaxy Clustering with Spectroscopic and Photometric Redshift Surveys written by Adrian Ashley Collister and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxy Clustering with Photometric Surveys Using PDF Redshift Information written by and published by . This book was released on 2016 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are $\Delta z=0.1$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.
Download or read book The Canada France Deep Fields Photometric Redshift Survey microform an Investigation of Galaxy Evolution Using Photometric Redshifts written by Mark Brodwin and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2004 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress in the study of galaxy evolution has traditionally followed from improvements in spectroscopic measurement techniques and subsequent groundbreaking surveys. The advent of large format CCD detectors, coupled with the demonstrated success of the photometric redshift method, has given rise to a new, potentially very powerful alternative. It has, in fact, motivated the present detailed investigation of the potential of photometric redshift surveys to complement, or in some cases, supersede traditional spectroscopic surveys in galaxy evolution studies. This Thesis describes a new deep, wide-field, multi-colour imaging survey, 10 times deeper and 30 times larger than its spectroscopic predecessor, the Canada-France Redshift Survey (CFRS). Highly accurate photometric redshifts, calibrated using hundreds of spectroscopic CFRS galaxies, were measured for tens of thousands of objects, with typical dispersions of only sigma/(1 + z) & lsim; 0.06 to IAB = 24 for z & le; 1.3. For the 1- and 2-point statistics of the galaxy distribution studied in this Thesis, the measurement accuracy is limited not by the photometric redshift error, but rather by the effect of cosmic variance, whose contribution to the total error budget is dominant. Therefore, future studies will be well served by adopting the photometric redshift approach, the efficiency of which will enable them to survey the hundreds or thousands of square degrees required to obtain a fair sample of the Universe. We measure the evolution of galaxy correlations with redshift, a primary observable of the structure formation process, correcting for the dilutive effect of photometric redshift errors on the clustering signal. The high z & sim; 3 correlation amplitude seen in this work provides compelling evidence for the biased galaxy formation paradigm. The measured galaxy correlations from 0 & lsim; z & lsim; 3 are in excellent agreement with the findings of the largest, state-of-the-art spectroscopic studies. A new Bayesian method to measure the galaxy redshift distribution is developed. The accuracy of the method, which incorporates the full redshift likelihood function of each galaxy in an iterative analysis, is demonstrated in extensive Monte Carlo simulations. IAB and RAB redshift distributions, along with the run of median redshifts, are measured in various magnitude ranges, with special attention given to quantifying both random and systematic errors.
Download or read book Optimizing Spectroscopic and Photometric Galaxy Surveys written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of multiple cosmological probes can produce measurements of cosmological parameters much more stringent than those possible with any individual probe. We examine the combination of two highly correlated probes of late-time structure growth: (i) weak gravitational lensing from a survey with photometric redshifts and (ii) galaxy clustering and redshift space distortions from a survey with spectroscopic redshifts. We choose generic survey designs so that our results are applicable to a range of current and future photometric redshift (e.g. KiDS, DES, HSC, Euclid) and spectroscopic redshift (e.g. DESI, 4MOST, Sumire) surveys. Combining the surveys greatly improves their power to measure both dark energy and modified gravity. An independent, non-overlapping combination sees a dark energy figure of merit more than 4 times larger than that produced by either survey alone. The powerful synergies between the surveys are strongest for modified gravity, where their constraints are orthogonal, producing a non-overlapping joint figure of merit nearly 2 orders of magnitude larger than either alone. Our projected angular power spectrum formalism makes it easy to model the cross-correlation observable when the surveys overlap on the sky, producing a joint data vector and full covariance matrix. We calculate a same-sky improvement factor, from the inclusion of these cross-correlations, relative to non-overlapping surveys. We find nearly a factor of 4 for dark energy and more than a factor of 2 for modified gravity. The exact forecast figures of merit and same-sky benefits can be radically affected by a range of forecasts assumption, which we explore methodically in a sensitivity analysis. We show that that our fiducial assumptions produce robust results which give a good average picture of the science return from combining photometric and spectroscopic surveys.
Download or read book Photometric Calibration Procedures written by Velma I. Burns and published by . This book was released on 1972 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmological Physics written by J. A. Peacock and published by Cambridge University Press. This book was released on 1999 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative introduction to contemporary cosmology for advanced undergraduate and graduate students.
Download or read book Wide Field Surveys in Cosmology written by Stéphane Colombi and published by Atlantica Séguier Frontières. This book was released on 1998 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Pan Chromatic View of Clusters of Galaxies and the Large Scale Structure written by Manolis Plionis and published by Springer. This book was released on 2008-02-17 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reviews presented in this volume cover a huge range of cluster of galaxies topics. Readers will find the book essential reading on subjects such as the physics of the ICM gas, the internal cluster dynamics, and the detection of clusters using different observational techniques. The expert chapter authors also cover the huge advances being made in analytical or numerical modeling of clusters, weak and strong lensing effects, and the large scale structure as traced by clusters.
Download or read book Combining Spectroscopic and Imaging Galaxy Surveys for Improved Measurements of Large scale Structure written by Justin Myles and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxy imaging surveys represent a promising opportunity for testing cosmological models, but suffer from significant challenges associated with galaxy redshift uncertainty. I present improved techniques for the use of spectroscopic redshifts for measurements of large-scale structure with galaxy imaging surveys. I additionally present the results of the application of these techniques to data from the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey (DES). The results of my work are photometric redshift measurements of the approximately 100 million galaxies comprising the DES Year 3 Weak Lensing Source Galaxy Catalog, constraints on parameters of the Lambda-CDM cosmological model based on the gravitational lensing and clustering of the DES Year 3 source and lens galaxy catalogs, an algorithm for propagating uncertainties that have been measured in simulations to analogous measurements on data, and measurements of the incidence of projection effects in optically detected clusters of galaxies. I argue that continued development of the methods I have worked on is a promising path toward a conclusive test of Lambda-CDM with galaxy surveys.
Download or read book Photometric Redshifts and High Redshift Galaxies written by Ray J. Weymann and published by . This book was released on 1999 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 52 papers respond to the explosion of the search for and discovery of high redshift galaxies and the application of broad-band photometry to obtain remarkably reliable estimates of the redshifts of galaxies at all redshifts, spurred not only by the Hubble Deep Fields, but also by the advent of wide-field CCDs on ground-based telescopes and the development of sensitive infrared, submillimeter, and millimeter instrumentation. They discuss techniques, findings, and integrating new data into existing models of galaxy formation and evolution.
Download or read book The Discovery of Cosmic Voids written by Laird A. Thompson and published by Cambridge University Press. This book was released on 2020-12-10 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The large-scale structure of the Universe is dominated by vast voids with galaxies clustered in knots, sheets, and filaments, forming a great 'cosmic web'. In this personal account of the major astronomical developments leading to this discovery, we learn from Laird A. Thompson, a key protagonist, how the first 3D maps of galaxies were created. Using non-mathematical language, he introduces the standard model of cosmology before explaining how and why ideas about cosmic voids evolved, referencing the original maps, reproduced here. His account tells of the competing teams of observers, racing to publish their results, the theorists trying to build or update their models to explain them, and the subsequent large-scale survey efforts that continue to the present day. This is a well-documented account of the birth of a major pillar of modern cosmology, and a useful case study of the trials surrounding how this scientific discovery became accepted.
Download or read book Galaxies at High Redshift written by I. Pérez-Fournon and published by Cambridge University Press. This book was released on 2003-03-20 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.
Download or read book Wide Field Spectroscopy And The Distant Universe Proceedings Of The 35th Herstmonceux Conference written by S Maddox and published by World Scientific. This book was released on 1995-05-31 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies represent the most readily visible fabric of the cosmos. Their morphological types, luminosities and environmental surroundings contain valuable clues as to their origin and evolution. Locally, a strong correlation is seen between galaxy morphology and environmental location; this may have been molded at surprisingly modest redshifts. Spectroscopic and photometric studies of deep fields also suggest remarkably recent changes in the galaxy population. The associated growth of structure during the same interval can be tracked via X-ray studies of distant clusters of galaxies.Very recently, impressive observational facilities have been completed, each of which has extended the astronomers' dataset to look-back times where such evolutionary effects can be studied.This volume discusses surveys which share a common theme — the need for a large number of ground-based spectra. It focuses on the various approaches via a single theme concerned with the evolution of galaxies and their distribution. In the near future, impressive new observational facilities will be able to generate large statistical spectroscopic surveys, and the aim of this volume is to assess the scientific impact that ongoing and future spectroscopic surveys can make. Emphasis is placed on the role of non-optical and satellite facilities and the co-ordination of international efforts.
Download or read book A Photometric Redshift Galaxy Catalog from the Red Sequence Cluster Survey written by and published by . This book was released on 2005 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg2. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts
Download or read book Higher Resolution Photometric Redshifts for Cosmological Surveys written by Alex Alarcon Gonzalez and published by . This book was released on 2019 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This PhD thesis is focused on the measurement of photometric redshifts in imaging galaxy surveys and its applications to extract cosmological information. In the first part of this thesis we forecast a galaxy survey with very precise redshift information, which can come either from spectroscopy or many narrow band images, using the Fisher matrix formalism. We use galaxy clustering, how galaxies group together in space, dividing a sample into two subsamples using other observable parameters. Using two overlapping subsamples reduces the sample variance in the observables, which improves the precision with which one can measure the expansion and growth history of the universe. In the second part of this thesis we measure highly precise photometric redshifts using the data from a novel imaging galaxy survey PAUS that contains a unique set of 40 narrow band filters. We develop two algorithms which use maximum likelihood or Bayesian evidence statistics to infer the redshift probability of each galaxy, which requires modeling both the continuum and emission line galaxy flux. The algorithm contains several corrections to account for systematic effects present in the data calibration which are tested in simulations developed for this purpose. The measurement of PAUS redshifts enables the science of the galaxy survey and can also be used to calibrate the redshift distribution of lensing surveys. The last part of this thesis implements for the first time a hierarchical Bayesian model in an N-body simulation to measure the redshift distribution of a lensing survey using both photometric and density information. Weak lensing is a very powerful tool to extract cosmological information, but it is very sensitive to any bias in the mean redshift of a sample of source galaxies. This method consistently combines all sources of information and merges the main techniques used in the literature to estimate redshift distributions.
Download or read book Outskirts of Galaxy Clusters IAU C195 written by International Astronomical Union. Colloquium and published by Cambridge University Press. This book was released on 2004-12-16 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the International Astronomical Union Colloquium no. 195, held in Torino, Italy in 2004. The meeting investigated the formation of galaxies within a full cosmological context, focusing on the outer regions of galaxy clusters. The observed correlation of optical and radio properties of galaxies with their environment indicates that the formation and evolution of galaxies is intimately linked to the formation of large scale structure. With chapters written by leading authorities in the field, this timely volume investigates the role of the environment in determining the properties of galaxies. It describes the distribution of matter and galaxies on the largest scales in the Universe, the processes of cluster and galaxy formation, their role and interplay. This is a valuable collection of review articles for professional astronomers.
Download or read book Photometric Redshifts and Clustering of Emission Line Galaxies Selected Jointly by DES and EBOSS written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71\% and 68\% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a mean redshift of 0.8 and 0.87, with 15 and 13\% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6
