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VLA and ALMA IMAGING of INTENSE GALAXY-WIDE STAR FORMATION in z ∼ 2 GALAXIES

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Documents

  • W. Rujopakarn
  • J. S. Dunlop
  • G. H. Rieke
  • R. J. Ivison
  • A. Cibinel
  • K. Nyland
  • P. Jagannathan
  • J. D. Silverman
  • D. M. Alexander
  • A. D. Biggs
  • S. Bhatnagar
  • D. R. Ballantyne
  • M. Dickinson
  • D. Elbaz
  • C. C. Hayward
  • A. Kirkpatrick
  • R. J. McLure
  • M. J. Michałowski
  • N. A. Miller
  • D. Narayanan
  • F. N. Owen
  • M. Pannella
  • C. Papovich
  • A. Pope
  • U. Rau
  • B. E. Robertson
  • D. Scott
  • A. M. Swinbank
  • P. Van Der Werf
  • E. Van Kampen
  • B. J. Weiner
  • R. A. Windhorst
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Original languageEnglish
Article number12
Number of pages11
JournalThe Astrophysical Journal
Journal publication date1 Dec 2016
Volume833
Issue1
DOIs
Publication statusPublished - 1 Dec 2016

Abstract

We present ≃0.″4 resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at z = 1.3-3.0. These galaxies are selected from sensitive blank-field surveys of the 2′ ×2′ Hubble Ultra-Deep Field at λ = 5 cm and 1.3 mm using the Karl G. Jansky Very Large Array and Atacama Large Millimeter/submillimeter Array. They have star formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at z ∼ 2. Morphological classification performed on spatially resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGNs), thereby representing a diversity of z ∼ 2 SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of 4.2 ±1.8 kpc. This provides direct evidence of galaxy-wide star formation in distant blank-field-selected main-sequence SFGs. The typical galactic-average SFR surface density is 2.5 M o yr-1 kpc-2, sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGNs, which are found to be cospatial with star formation. The median extinction-independent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies, whose SFRs are 3-8 times larger, providing a constraint on the characteristic SFR (∼300 M o yr-1) above which a significant population of more compact SFGs appears to emerge.

Notes

W. Rojopakarn, et al, 'VLA AND ALMA IMAGING OF INTENSE GALAXY-WIDE STAR FORMATION IN z ∼ 2 GALAXIES'. The Astrophysical Journal, Vol. 833 12 (11 pp., December 2016, doi:10.3847/0004-637X/833/1/12. © 2016. The American Astronomical Society. All rights reserved.

ID: 11126788