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Title: Herschel extreme lensing line observations: Dynamics of two strongly lensed star-forming galaxies near redshift z = 2

We report on two regularly rotating galaxies at redshift z ≈ 2, using high-resolution spectra of the bright [C II] 158 μm emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ({sup S}0901{sup )} and SDSSJ120602.09+514229.5 ({sup t}he Clone{sup )} are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of vsin (i) ≈ 120 ± 7 km s{sup –1} and a gas velocity dispersion of σ {sub g} < 23 km s{sup –1} (1σ). The best-fitting model for the Clone is a rotationally supported disk having vsin (i) ≈ 79 ± 11 km s{sup –1} and σ {sub g} ≲ 4 km s{sup –1} (1σ). However, the Clone is also consistent with a family of dispersion-dominated models having σ {sub g} = 92 ± 20 km s{sup –1}. Our results showcase the potential of the [C II] line as a kinematic probe of high-redshift galaxy dynamics: [C II] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C II] line observations withmore » ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ;  [6] ;  [7] ; ;  [8] ;  [9] ;  [10] ;  [11]
  1. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
  2. Space Telescope Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  3. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  4. Observatoire de Paris, LERMA, CNRS, 61 Av. de l'Observatoire, F-75014 Paris (France)
  5. Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States)
  6. Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
  7. LERMA, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)
  8. Institut d'Astrophysique Spatiale, Centre Universitaire d'Orsay, F-91405 Orsay Cedex (France)
  9. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  10. Kapteyn Astronomical Institute, University of Groningen, 9700-AV Groningen (Netherlands)
  11. Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22356886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DISPERSIONS; EMISSION; GALAXIES; GRAVITATIONAL LENSES; HETERODYNE RECEIVERS; RED SHIFT; ROTATION; SPACE; SPATIAL RESOLUTION; SPECTRA; STARS; VELOCITY