VLA and ALMA imaging of intense galaxy-wide star Formation in z~2 galaxies

Rujopakarn, W, Dunlop, J S, Rieke, G H, Ivison, R J, Cibinel, A and et al, (2016) VLA and ALMA imaging of intense galaxy-wide star Formation in z~2 galaxies. Astrophysical Journal, 833 (1). p. 12. ISSN 0004-637X

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Abstract

We present ~02."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 mainsequence SFGs. The typical galactic-average SFR surface density is 2.5 Me 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 extinctionindependent 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 Me yr−1 ) above which a significant population of more compact SFGs appears to emerge.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Q Science > QB Astronomy > QB0460 Astrophysics
Q Science > QB Astronomy > QB0495 Descriptive astronomy > QB0856 Galaxies
Depositing User: Anna Cibinel
Date Deposited: 03 Feb 2017 12:40
Last Modified: 07 Mar 2017 19:46
URI: http://sro.sussex.ac.uk/id/eprint/65888

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