HERSCHEL OBSERVATIONS OF FAR-INFRARED COOLING LINES IN INTERMEDIATE REDSHIFT (ULTRA)-LUMINOUS INFRARED GALAXIES

Journal Article · Mon Jan 20 00:00:00 EST 2014 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/781/1/L15· OSTI ID:22364026

Rigopoulou, D.; Magdis, G. E.; Thatte, N. ^[1]; Hopwood, R.; Clements, D. ^[2]; Swinyard, B. M.; Pearson, C. ^[3]; Farrah, D. ^[4]; Huang, J. -S. ^[5]; Alonso-Herrero, A. ^[6]; Bock, J. J. ^[7]; Cooray, A. ^[8]; Griffin, M. J. ^[9]; Oliver, S.; Smith, A.; Wang, L. ^[10]; Riechers, D. ^[11]; Scott, D. ^[12]; Vaccari, M. ^[13]; Valtchanov, I. ^[14]

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1. Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
2. Physics Department, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)
3. RAL Space, Science, and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom)
4. Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)
5. National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing 100012 (China)
6. Instituto de Fisica de Cantabria, CSIC-UC, E-39006 Santander (Spain)
7. California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)
8. Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
9. School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom)
10. Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)
11. Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)
12. Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T1Z1 (Canada)
13. Astrophysics Group, Physics Department, University of the Western Cape, Private Bag X17, 7535 Bellville, Cape Town (South Africa)
14. Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain)

We report the first results from a spectroscopic survey of the [C II] 158 μm line from a sample of intermediate redshift (0.2 < 0.8) (ultra)-luminous infrared galaxies, (U)LIRGs (L {sub IR} > 10{sup 11.5} L {sub ☉}), using the Spectral and Photometric Imaging REceiver-Fourier Transform Spectrometer on board the Herschel Space Observatory. This is the first survey of [C II] emission, an important tracer of star formation, at a redshift range where the star formation rate density of the universe increases rapidly. We detect strong [C II] 158 μm line emission from over 80% of the sample. We find that the [C II] line is luminous, in the range (0.8-4) × 10{sup –3} of the far-infrared continuum luminosity of our sources, and appears to arise from photodissociation regions on the surface of molecular clouds. The L{sub [C} {sub II]}/L {sub IR} ratio in our intermediate redshift (U)LIRGs is on average ∼10 times larger than that of local ULIRGs. Furthermore, we find that the L{sub [C} {sub II]}/L {sub IR} and L{sub [CII]}/L{sub CO(1-0)} ratios in our sample are similar to those of local normal galaxies and high-z star-forming galaxies. ULIRGs at z ∼ 0.5 show many similarities to the properties of local normal and high-z star-forming galaxies. Our findings strongly suggest that rapid evolution in the properties of the star-forming regions of (U)LIRGs is likely to have occurred in the last 5 billion years.

• OSTI ID: 22364026
• Journal Information: Astrophysical Journal Letters, Vol. 781, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COOLING
DENSITY
DISSOCIATION
EMISSION
FOURIER TRANSFORM SPECTROMETERS
GALAXIES
LUMINOSITY
PHOTOMETRY
RED SHIFT
SPACE
STAR EVOLUTION
STARS
SURFACES
UNIVERSE