VARYING [C II]/[N II] LINE RATIOS IN THE INTERACTING SYSTEM BR1202-0725 AT z = 4.7
- Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
- NRAO, Pete V. Domenici Array Science Center, P.O. Box O, Socorro, NM 87801 (United States)
- Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany)
- IRAM, 300 rue de la piscine, F-38406 Saint-Martin d'Hères (France)
- Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)
- Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)
We study the properties of the interstellar medium in the interacting system BR1202-0725 at z = 4.7 via its [N II] and [C II] fine-structure line emission. This system consists of a QSO, a sub-mm galaxy (SMG), and two Lyα emitters (LAEs). Such a diversity in galaxy properties makes BR1202-0725 a unique laboratory of star formation and galaxy evolution at high redshift. We present ionized nitrogen ([N II] 205 μm) observations of this system, obtained with the IRAM Plateau de Bure Interferometer. We find no [N II] emission at the quasar location, but tentative [N II] line detections associated with the SMG and one of the LAEs. Together with available ionized carbon ([C II] 158 μm) Atacama Large Millimeter Array observations of this system, we find the following: the [C II]/[N II] luminosity ratio is >5.5 for the QSO and the SMG, but it is as low as ∼2 in the LAE, suggesting that, in this source, most of the [C II] emission is associated with the ionized medium (H II regions) rather than the neutral one (photon-dominated regions). This study demonstrates the importance of combined studies of multiple fine-structure lines in order to pin down the physical properties of the interstellar medium in distant galaxies.
- OSTI ID:
- 22363988
- Journal Information:
- Astrophysical Journal Letters, Vol. 782, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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