[Paper Review] A JVLA 10~degree^2 deep survey

M. J. Jarvis, S. Bhatnagar+11 more|arXiv (Cornell University)|Jan 16, 2014

Galaxies: Formation, Evolution, Phenomena3 references3 citations

TL;DR

This paper proposes a 10 square degree deep radio survey using the Karl Jansky Very Large Array (JVLA) at L-band to achieve 1.5 µJy sensitivity, enabling the detection of star-forming galaxies out to z ~ 1 and luminous infrared galaxies out to z ~ 6. The survey will provide a complete census of star-formation and AGN activity across cosmic time, with full-Stokes polarization and spectral-line capabilities, addressing cosmic variance and enabling high dynamic range imaging via advanced direction-dependent calibration techniques.

ABSTRACT

(Abridged)One of the fundamental challenges for astrophysics in the 21st century is finding a way to untangle the physical processes that govern galaxy formation and evolution. Given the importance and scope of this problem, the multi-wavelength astronomical community has used the past decade to build up a wealth of information over specific extragalactic deep fields to address key questions in galaxy formation and evolution. These fields generally cover at least 10square degrees to facilitate the investigation of the rarest, typically most massive, galaxies and AGN. Furthermore, such areal coverage allows the environments to be fully accounted for, thereby linking the single halo to the two-halo terms in the halo occupation distribution. Surveys at radio wavelengths have begun to lag behind those at other wavelengths, especially in this medium-deep survey tier. However, the survey speed offered by the JVLA means that we can now reach a point where we can begin to obtain commensurate data at radio wavelengths to those which already exists from the X-ray through to the far-infrared over ~10 square degrees. We therefore present the case for a 10 square degree survey to 1.5uJy at L-band in A or B Array, requiring ~4000 hours to provide census of star-formation and AGN-accretion activity in the Universe. For example, the observations will allow galaxies forming stars at 10Msolar/yr to be detected out to z~1 and luminous infrared galaxies (1000Msolar/yr to be found out to z~6. Furthermore, the survey area ensures that we will have enough cosmic volume to find these rare sources at all epochs. The bandwidth will allow us to determine the polarisation properties galaxies in the high-redshift Universe as a function of stellar mass, morphology and redshift.

Motivation & Objective

• To overcome the current lack of deep, wide-area radio surveys by providing a 10 deg² survey with sensitivity to detect star-formation and AGN activity across cosmic time.
• To enable a complete census of radio-loud sources, including rare, high-redshift galaxies and AGN, by covering sufficient volume to minimize cosmic variance.
• To achieve high dynamic range imaging in Stokes I, Q, U, and V through advanced direction-dependent calibration and A-projection techniques.
• To provide a commensurate radio data set with existing multi-wavelength surveys (e.g., COSMOS, XMM-LSS, ECDFS) for multi-band analysis.
• To support future citizen science initiatives like Radio Galaxy Zoo by providing high-redshift radio source catalogs.

Proposed method

• Conduct a deep, wide-area JVLA survey over 10 deg² at L-band (1-2 GHz) with a target sensitivity of 1.5 µJy per beam.
• Use A-projection calibration within CASA to correct for frequency-dependent off-axis complex gain and polarization leakage as a function of parallactic angle.
• Apply direction-dependent calibration using MeqTrees and HPC-optimized pipelines to mitigate artifacts from strong sources and sidelobes.
• Mosaic multiple pointings across the survey field using full-Stokes, full-bandwidth data to achieve thermal-noise-limited imaging.
• Leverage existing deep optical and X-ray data from fields like XMM-LSS and ECDFS to enable cross-identification and environmental studies.
• Integrate survey data into citizen science platforms such as Radio Galaxy Zoo for source morphology and redshift characterization.

Experimental results

Research questions

• RQ1 What is the complete evolution of the radio luminosity function of star-forming galaxies and AGN from z = 0 to z = 6?
• RQ2 How does the star-formation rate density evolve across cosmic time, and how does it correlate with galaxy environment and morphology?
• RQ3 What are the polarisation properties of high-redshift galaxies as a function of stellar mass, morphology, and redshift?
• RQ4 How can direction-dependent calibration techniques achieve dynamic ranges exceeding 3 million:1 in complex, source-rich fields?
• RQ5 To what extent can deep radio surveys at 10 deg² overcome cosmic variance in detecting rare, massive galaxies and AGN?

Key findings

• The survey will detect star-forming galaxies at 10 M⊙ yr⁻¹ out to z ~ 1 and luminous infrared galaxies at 1000 M⊙ yr⁻¹ out to z ~ 6, enabling a complete census of high-activity sources.
• With 4000 hours of integration, the survey will achieve a sensitivity of 1.5 µJy at L-band, sufficient to probe the faint end of the radio luminosity function across cosmic time.
• Direction-dependent calibration using A-projection enables dynamic ranges of up to 3,200,000:1, eliminating PSF-like artifacts from strong sources and sidelobes.
• The survey will provide full-Stokes, full-bandwidth imaging, allowing polarisation studies of high-redshift galaxies as a function of mass and morphology.
• The 10 deg² area ensures sufficient cosmic volume to detect rare, high-mass galaxies and AGN at all redshifts, minimizing cosmic variance.
• The survey fields (XMM-LSS and ECDFS) are ideal due to existing deep multi-wavelength data, enabling robust cross-identification and environmental analysis.