43,318 research outputs found
The HST Cosmos Project: Contribution from the Subaru Telescope
The Cosmic Evolution Survey (COSMOS) is a Hubble Space Telescope (HST)
treasury project.The COSMOS aims to perform a 2 square degree imaging survey of
an equatorial field in (F814W) band, using the Advanced Camera for Surveys
(ACS). Such a wide field survey, combined with ground-based photometric and
spectroscopic data, is essential to understand the interplay between large
scale structure, evolution and formation of galaxies and dark matter. In 2004,
we have obtained high-quality, broad band images of the COSMOS field ( and ) using Suprime-Cam on the Subaru
Telescope, and we have started our new optical multi-band program, COSMOS-21 in
2005. Here, we present a brief summary of the current status of the COSMOS
project together with contributions from the Subaru Telescope. Our future
Subaru program, COSMOS-21, is also discussed briefly.Comment: 4 pages, 3 figures, to appear in the Proceedings of the 6th East
Asian Meeting on Astronomy, JKAS, 39, in pres
Large Structures and Galaxy Evolution in COSMOS at z < 1.1
We present the first identification of large-scale structures (LSS) at z in the Cosmic Evolution Survey (COSMOS). The structures are identified
from adaptive smoothing of galaxy counts in the pseudo-3d space
(,z) using the COSMOS photometric redshift catalog. The
technique is tested on a simulation including galaxies distributed in model
clusters and a field galaxy population -- recovering structures on all scales
from 1 to 20\arcmin without {\it a priori} assumptions for the structure size
or density profile. Our procedure makes {\bf no} {\it a priori} selection on
galaxy spectral energy distribution (SED, for example the Red Sequence),
enabling an unbiased investigation of environmental effects on galaxy
evolution. The COSMOS photometric redshift catalog yields a sample of
galaxies with redshift accuracy, at z down to I mag. Using this sample of galaxies,
we identify 42 large-scale structures and clusters. abstract truncated for
astroph 25 line limit -- see preprintComment: 72 pages with 29 pages of figures, for cosmos apj suppl special issu
The XMM-Newton Wide-Field Survey in the COSMOS Field: Statistical Properties of Clusters of Galaxies
We present the results of a search for galaxy clusters in the first 36 XMM-Newton pointings on the Cosmic Evolution Survey (COSMOS) field. We reach a depth for a total cluster flux in the 0.5-2 keV band of 3 × 10^(-15) ergs cm^(-2) s^(-1), having one of the widest XMM-Newton contiguous raster surveys, covering an area of 2.1 deg^2. Cluster candidates are identified through a wavelet detection of extended X-ray emission. Verification of the cluster candidates is done based on a galaxy concentration analysis in redshift slices of thickness 0.1-0.2 in redshift, using the multiband photometric catalog of the COSMOS field and restricting the search to z S)-log S distribution compares well with previous results, although yielding a somewhat higher number of clusters at similar fluxes. The X-ray luminosity function of COSMOS clusters matches well the results of nearby surveys, providing a comparably tight constraint on the faint-end slope of α = 1.93 ± 0.04. For the probed luminosity range of (8 × 10^(42))-(2 × 10^(44)) ergs s^(-1), our survey is in agreement with and adds significantly to the existing data on the cluster luminosity function at high redshifts and implies no substantial evolution at these luminosities to z = 1.3
Lyman Alpha Emitters at Redshift 5.7 in the COSMOS Field
We present results from a narrow-band optical survey of a contiguous area of
1.95 deg^2, covered by the Cosmic Evolution Survey (COSMOS). Both optical
narrow-band (lambda_c = 8150 AA and Delta_lambda = 120 AA) and broad-band (B,
V, g', r', i', and z') imaging observations were performed with the Subaru
prime-focus camera, Suprime-Cam on the Subaru Telescope. We provide the largest
contiguous narrow-band survey, targetting Ly alpha emitters (LAEs) at z~5.7. We
find a total of 119 LAE candidates at z~5.7. Over the wide-area covered by this
survey, we find no strong evidence for large scale clustering of LAEs. We
estimate a star formation rate (SFR) density of ~7*10^-4 M_sun yr^-1 Mpc^-3 for
LAEs at z~5.7, and compare it with previous measurements.Comment: 26 pages, 19 figures. to appear in the ApJ Supplement COSMOS Special
Issu
The Cosmic Evolution Survey (COSMOS) -- Overview
The Cosmic Evolution Survey (COSMOS) is designed to probe the correlated
evolution of galaxies, star formation, active galactic nuclei (AGN) and dark
matter (DM) with large-scale structure (LSS) over the redshift range z
to 6. The survey includes multi-wavelength imaging and spectroscopy from X-ray
to radio wavelengths covering a 2 \sq\deg area, including HST imaging. Given
the very high sensitivity and resolution of these datasets, COSMOS also
provides unprecedented samples of objects at high redshift with greatly reduced
cosmic variance, compared to earlier surveys. Here we provide a brief overview
of the survey strategy, the characteristics of the major COSMOS datasets, and
summarize the science goals.Comment: 22 pages, 3 figure
Radio and Millimeter Observations of the COSMOS Field
The Cosmic Evolution Survey (COSMOS) targets an equatorial two square degree field covering the full electromagnetic spectrum. Here we present first results from observations of the COSMOS field in the millimeter and centimeter regime done with the IRAM 30m/MAMBO array and NRAO's Very Large Array (VLA) at 250GHz and 1.4GHz, respectively
Seeing the sky through Hubble's eye: The COSMOS SkyWalker
Large, high-resolution space-based imaging surveys produce a volume of data
that is difficult to present to the public in a comprehensible way. While
megapixel-sized images can still be printed out or downloaded via the World
Wide Web, this is no longer feasible for images with 10^9 pixels (e.g., the
Hubble Space Telescope Advanced Camera for Surveys [ACS] images of the Galaxy
Evolution from Morphology and SEDs [GEMS] project) or even 10^10 pixels (for
the ACS Cosmic Evolution Survey [COSMOS]). We present a Web-based utility
called the COSMOS SkyWalker that allows viewing of the huge ACS image data set,
even through slow Internet connections. Using standard HTML and JavaScript, the
application successively loads only those portions of the image at a time that
are currently being viewed on the screen. The user can move within the image by
using the mouse or interacting with an overview image. Using an astrometrically
registered image for the COSMOS SkyWalker allows the display of calibrated
world coordinates for use in science. The SkyWalker "technique" can be applied
to other data sets. This requires some customization, notably the slicing up of
a data set into small (e.g., 256^2 pixel) subimages. An advantage of the
SkyWalker is the use of standard Web browser components; thus, it requires no
installation of any software and can therefore be viewed by anyone across many
operating systems.Comment: 4 pages, 2 figures, accepted for publication in PAS
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