VLA-COSMOS Project

Scientific Objective/Abstract
VLA-COSMOS Team
Papers with VLA-COSMOS Data
Poster for the VLA-COSMOS project
VLA-COSMOS Pilot Project
VLA-COSMOS Large Project
VLA-COSMOS Deep Project
Data Access
Related Links
Internal Access


Scientific Objective/Abstract

The Cosmic Evolution Survey (COSMOS) is a pan-chromatic (X-ray to mm) observational project to perform a detailed study of galaxy and super-massive black hole evolution through cosmic times, with particular emphasis on the influence of environment and large scale structure. Two cornerstones of COSMOS are the HST ACS imaging (HST Treasury project, see the dataset with the SkyWalker) and the unprecedented spectroscopy of ~40,000 sources. The areal coverage is large enough to avoid cosmic variance, and to delineate structure on the largest relevant scales (~100 Mpc comoving).

At radio wavelengths, the VLA-COSMOS Survey uses NRAO's (National Radio Astronomy Observatory) Very Large Array (VLA) to conduct state-of-the-art (1.5" resolution), deep (1 sigma ~ 10 microJy), wide-field imaging at 1.4 GHz (20cm) continuum of the COSMOS 2 square-degree deep field. This VLA Large Project is the largest radio deep field at this depth and angular resolution. It provides about 3500 compact and extended radio sources allowing the study of the dust-obscured star-formation history of galaxies and the evolution of active galactic nuclei through cosmic history.

The VLA observations represent a fundamental contribution to the COSMOS project, providing definitive answers to a number of key questions, including:

  1. the secure identification of dust-obscured galaxies and their contribution to the cosmic star formation history,
  2. the evolution of the FIR/radio correlation for star forming galaxies,
  3. the evolution of low luminosity radio AGN to high z, as well as
  4. setting the absolute astrometry for the COSMOS field.
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VLA-COSMOS Team


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Papers with VLA-COSMOS Data


  1. The VLA-COSMOS Survey: I. Radio Identifications from the Pilot Project
    (Schinnerer et al. 2004, AJ, 128, 1974)
  2. The VLA-COSMOS Survey: II. Source Catalog of the Large Project
    (Schinnerer et al. 2007, ApJS COSMOS special issue, 172, 46, full version)
  3. A Wide Angle Tail Galaxy in the COSMOS Field: Evidence for Cluster Formation
    (Smolcic et al. 2007, ApJS COSMOS special issue, 172, 295, full version)
  4. Radio and Millimeter Properties of z ~ 5.7 Ly&alpha Emitters in the COSMOS Field: Limits on Radio AGN, Submm Galaxies, and Dust Obscuration
    (Carilli et al. 2007, ApJS COSMOS special issue, 172, 518, astro-ph)
  5. COSBO: The MAMBO 1.2 Millimeter Imaging Survey of the COSMOS Field
    (Bertoldi et al., 2007, ApJS COSMOS special issue, 172, 132, ApJS)
  6. The XMM-Newton Wide-Field Survey in the COSMOS Field. IV: X-Ray Spectral Properties of Active Galactic Nuclei
    (Mainieri et al. 2007, ApJS COSMOS special issue, 172, 368, astro-ph)
  7. First Catalog of Strong Lens Candidates in the COSMOS Field
    (Faure et al. 2008, ApJS, 176, 19, astro-ph)
  8. The VLA-COSMOS Survey: III. Further Catalog Analysis and the Radio Source Counts
    (Bondi et al., 2008, ApJ, accept., astro-ph)
  9. A new method to separate star forming from AGN galaxies at intermediate redshift: The submillijansky radio population in the VLA-COSMOS survey
    (Smolcic et al., 2008, ApJS, 177, 14, astro-ph)
  10. Star Formation Rates in Lyman Break Galaxies: Radio Stacking of LBGs in the COSMOS Field and the sub-microJy Radio Source Population
    (Carilli et al., 2008, ApJL, accept., astro-ph)


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Poster for the VLA-COSMOS project


Poster of the VLA-COSMOS Large Project: Image only. (High-res jpg-file, PDF-file (Printable CMYK version)

Poster of the VLA-COSMOS Large Project: Image plus explanatory text. (High-res jpg-file, PDF-file (Printable CMYK version)

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VLA-COSMOS Pilot Project

Configuration VLA A-array (Aug. '03)
Observing time 10 hr (total)
Frequency 1.4 GHz ( = L band, 20cm)
Bandwidth 75 MHz (Multi-channel continuum mode)
Pointings 7 (hexagonal pattern)
Area ~ 0.84 sqrdeg (Diameter ~ 1 degree)
Resolution 1.9" x 1.6"; PA -23 degrees
Sensitivity 25-100 uJy/beam (inner to outermost regions)
Nr. of sources 246 sources detected, ~ 20 clearly extended
Data Products (a) flux calibrated image with absolute astrometry
(b) (parametric) source catalog (position, fluxes, sizes)
Timeline August '03: A-array observations finished
August '04: delivery of data products to community (via COSMOS archive)

Lay-out of the pointings of the VLA pilot project in the field of the COSMOS survey (indicated by broken line) onto a DSS image of the area. The cross marks the COSMOS field center. Each circle represents the primary beam of the VLA at 1.4GHz.
The S/N map of the VLA COSMOS pilot field as constructed using AIPS. Brighter colors indicate lower S/N values.

Paper published (AJ, abstract, astro-ph)

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VLA-COSMOS Large Project

Configuration VLA A-array (Oct. '04 - Jan. '05)
VLA C-array (Aug. '05 - Sep. '05)
Observing time 250 hr (A) + 25 hr (C) = 275 hr (total)
Frequency 1.4 GHz ( = L band, 20cm)
Bandwidth 75 MHz (Multi-channel continuum mode)
Pointings 23 (hexagonal pattern)
Area ~ 2 sqrdeg (1.4 x 1.4 degrees)
Resolution ~ 1.5" x 1.4"
Sensitivity mean of 10.5 (15) uJy/beam (for inner 1 (2) sqrdeg)
Nr. of sources 2,417 sources (down to 5 sigma) (3,643 sources down to 4.5 sigma)
Data Products (a) flux calibrated image with absolute astrometry
(b) (parametric) source catalog (position, fluxes, sizes)
Timeline September '05: A+C-array observations finished
January '07: delivery of data products (A+C-array) to community

The lay-out for the 23 VLA pointings covering the full COSMOS field are overlaid onto an DSS image of the field. The COSMOS HST field is indicated by a box (broken line). The 7 pointings of the 10hr VLA Pilot Project are highlighted by thicker lines. The cross marks the field center.

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Papers published (catalog: ApJS, abstract, astro-ph, completeness/source counts: abstract, astro-ph)

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VLA-COSMOS Deep Project

Configuration VLA A-array (Feb. '06 - Mar. '06)
Observing time 62 hr (to be combined with data from Large Project)
Frequency 1.4 GHz ( = L band, 20cm)
Bandwidth 75 MHz (Multi-channel continuum mode)
Pointings 7 (hexagonal pattern; same as for pilot project)
Area ~ 0.84 sqrdeg (Diameter ~ 1 degree) with double integration time
Resolution 2.5" x 2.5"
Sensitivity ~ 10 uJy/beam (inner 30')
Nr. of sources ~ 2,900 sources
Data Products (a) flux calibrated image with absolute astrometry
(b) (parametric) source catalog (position, fluxes, sizes)
combined from large and deep, not flux limited
Timeline March '06: A-array observations finished
August '08: delivery of data products (A+A+C-array) to community


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Data Access

All available data are accessible from the COSMOS archive at IPAC/IRSA.

Pilot Project Data Products: Images (SIN, TAN projection), catalog,(paper)
Large Project Data Products: Images (SIN, TAN projection), source catalog (v1.0) & (v2.0), (paper)
Deep Project Data Products: Image (SIN projection), source catalog

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Related Links

IPAC/IRSA COSMOS archive (public)
IPAC/IRSA COSMOS archive access (internal)
CENCOS COSMOS archive

NRAO Very Large Array (VLA)
NRAO VLA/VLBA Large Proposals
NRAO Data Archive

COSMOS Survey Homepage (CalTech)
COSMOS Skywalker
Bologna COSMOS site
XMM-COSMOS Homepage
zCOSMOS Homepage


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Last update, 12.12.2006, Knud Jahnke, Eva Schinnerer