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University of Massachusetts Amherst

Series

2008

Galaxies: evolution

Articles 1 - 3 of 3

Full-Text Articles in Astrophysics and Astronomy

Spitzer Irac Infrared Colours Of Submillimetre-Bright Galaxies, Min Yun, I Aretxaga, Mln Ashby, J Austermann, Gg Fazio, M Giavalisco, Js Huang, Dh Hughes, S Kim, Jd Lowenthal, T Perera, K Scott, G Wilson, Jd Younger Jan 2008

Spitzer Irac Infrared Colours Of Submillimetre-Bright Galaxies, Min Yun, I Aretxaga, Mln Ashby, J Austermann, Gg Fazio, M Giavalisco, Js Huang, Dh Hughes, S Kim, Jd Lowenthal, T Perera, K Scott, G Wilson, Jd Younger

Astronomy Department Faculty Publication Series

High-redshift submillimetre-bright galaxies identified by blank field surveys at millimetre and submillimetre wavelengths appear in the region of the Infra Red Array Camera (IRAC) colour–colour diagrams previously identified as the domain of luminous active galactic nuclei (AGNs). Our analysis using a set of empirical and theoretical dusty starburst spectral energy distribution (SED) models shows that power-law continuum sources associated with hot dust heated by young (≲100 Myr old), extreme starbursts at z > 2 also occupy the same general area as AGNs in the IRAC colour–colour plots. A detailed comparison of the IRAC colours and SEDs demonstrates that the two populations …


The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimeter Galaxies, Jd Younger, Gg Fazio, Dj Wilner, Mln Ashby, R Blundell, Ma Gurwell, Js Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Gw Wilson, Min Yun Jan 2008

The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimeter Galaxies, Jd Younger, Gg Fazio, Dj Wilner, Mln Ashby, R Blundell, Ma Gurwell, Js Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present high-resolution submillimeter interferometric imaging of two of the brightest high-redshift submillimeter galaxies known: GN 20 and AzTEC1 at 0.8'' and 0.3'' resolution, respectively. Our data—the highest resolution submillimeter imaging of high-redshift sources accomplished to date—were collected in three different array configurations: compact, extended, and very extended. We derive angular sizes of 0.6'' and 1.0'' for GN 20 and 0.3'' and 0.4'' for AzTEC1 from modeling their visibility functions as a Gaussian and an elliptical disk, respectively. Because both sources are B-band dropouts, they likely lie within a relatively narrow redshift window around z ~ 4, which indicates …


Star Formation Rates In Lyman Break Galaxies: Radio Stacking Of Lbgs In The Cosmos Field And The Sub-Mu Jy Radio Source Population, Cl Carilli, N Lee, P Capak, E Schinnerer, Ks Lee, H Mccraken, Min Yun, N Scoville, V Smolcic, M Giavalisco, A Datta, Y Taniguchi, Cm Urry Jan 2008

Star Formation Rates In Lyman Break Galaxies: Radio Stacking Of Lbgs In The Cosmos Field And The Sub-Mu Jy Radio Source Population, Cl Carilli, N Lee, P Capak, E Schinnerer, Ks Lee, H Mccraken, Min Yun, N Scoville, V Smolcic, M Giavalisco, A Datta, Y Taniguchi, Cm Urry

Astronomy Department Faculty Publication Series

We present an analysis of the radio properties of large samples of Lyman break galaxies (LBGs) at z ~ 3, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of the z ~ 3 LBGs (U-band dropouts), with a 1.4 GHz flux density of 0.90 ± 0.21 μJy. The stacked emission is unresolved, with a size <1, or a physical size <8 kpc. The total star formation rate implied by this radio luminosity is 31 ± 7 M yr−1, based on the radio-FIR correlation in low-redshift star-forming galaxies. The star formation rate derived from a similar analysis of the UV luminosities is 17 M yr−1, without any correction for …