An ALMA survey of sub-millimetre Galaxies in the Extended Chandra Deep Field South: the far-infrared properties of SMGs

Autor(en)

A. M. Swinbank, J. M. Simpson, I. Smail, Helmut Dannerbauer, Christopher M. Harrison, J. A. Hodge, A. Karim, F Walter, David M Alexander, W. N. Brandt, Carlos De Breuck, E. da Cunha, S. C. Chapman, K. E. K. Coppin, A. L. R. Danielson, Roberto Decarli, T. R. Greve, Rob J. Ivison, K. K. Knudsen, C. D. P. Lagos, E. Schinnerer, A. P. Thomson, J. L. Wardlow, A. Weiss, Paul, van der Werf

Abstrakt

We exploit Atacama Large Millimeter Array (ALMA) 870 μm observations of sub-millimetre sources in the Extended Chandra Deep Field South to investigate the far-infrared properties of high-redshift sub-millimetre galaxies (SMGs). Using the precisely located 870 μmALMA positions of 99 SMGs, together with 24μm and radio imaging, we deblend the Herschel/SPIRE imaging to extract their far-infrared fluxes and colours. The median redshifts for ALMA LESS (ALESS) SMGs which are detected in at least two SPIRE bands increases with wavelength of the peak in their spectral energy distributions (SEDs), with z = 2.3 ± 0.2, 2.5 ± 0.3 and 3.5 ± 0.5 for the 250, 350 and 500 μm peakers, respectively. 34 ALESS SMGs do not have a >3σ counterpart at 250, 350 or 500 μm. These galaxies have a median photometric redshift derived from the rest-frame UV-mid-infrared SEDs of z = 3.3 ± 0.5, which is higher than the full ALESS SMG sample; z = 2.5 ± 0.2. We estimate the far-infrared luminosities and characteristic dust temperature of each SMG, deriving L

_IR = (3.0 ± 0.3) × 10

¹² L

_⊙ (SFR = 300 ± 30M

_⊙ yr

^-1) and T

_d = 32 ± 1K. The characteristic dust temperature of these high-redshift SMGs is ΔT

_d = 3-5K lower than comparably luminous galaxies at z = 0, reflecting the more extended star formation in these systems. We show that the contribution of S

_870μm ≤ 1 mJy SMGs to the cosmic star formation budget is 20 per cent of the total over the redshift range z ~ 1-4. Adopting an appropriate gas-to-dust ratio, we estimate a typical molecular mass of the ALESS SMGs of M

_H

₂

= (4.2 ± 0.4) × 10

¹⁰M

_⊙. Finally, we show that SMGs with S

_870μm > 1mJy (L

_IR > 10

¹² L

_⊙) contain ~ 10 per cent of the z ~ 2 volume-averaged H

₂ mass density.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Durham University, Max-Planck-Institut für Astronomie, Rheinische Friedrich-Wilhelms-Universität Bonn, Pennsylvania State University, University of Hertfordshire, European Southern Observatory (Germany), Max-Planck-Institut für Radioastronomie, Dalhousie University, University College London, University of Edinburgh, Chalmers University of Technology, University of Copenhagen, Leiden University

Journal

Monthly Notices of the Royal Astronomical Society

Band

438

Seiten

1267-1287

Anzahl der Seiten

21

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stt2273

Publikationsdatum

02-2014

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/97a2d486-a878-4c5b-8792-510e9615927f