Herschel extreme lensing line observations: Dynamics of two strongly lensed star-forming galaxies near redshift z = 2
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
- Space Telescope Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
- Observatoire de Paris, LERMA, CNRS, 61 Av. de l'Observatoire, F-75014 Paris (France)
- Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States)
- Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
- LERMA, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)
- Institut d'Astrophysique Spatiale, Centre Universitaire d'Orsay, F-91405 Orsay Cedex (France)
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Kapteyn Astronomical Institute, University of Groningen, 9700-AV Groningen (Netherlands)
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 with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.
- OSTI ID:
- 22356886
- Journal Information:
- Astrophysical Journal, Vol. 787, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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