ALMA [C II] 158 µm Detection of a Redshift 7 Lensed Galaxy behind RXJ1347.1-1145
Carilli, Chris; Fontana, Adriano; Treu, Tommaso; Bradač, Maruša; Vallini, Livia; Ferrara, Andrea; Huang, Kuang-Han; Ryan, Russell; Gonzalez, Anthony H.; Jones, Tucker; Quinn Finney, Emily; Hoag, Austin; Lemaux, Brian C.; Borello Schmidt, Kasper; Wagg, Jeff; Dijkstra, Mark; Garcia-Appadoo, Diego
United States, Chile, Sweden, Italy, Germany, United Kingdom, Norway, Japan
Abstract
We present the results of ALMA spectroscopic follow-up of a z = 6.766 Lyα emitting galaxy behind the cluster RX J1347.1-1145. We report the detection of [C II] 158 μm line fully consistent with the Lyα redshift and with the peak of the optical emission. Given the magnification of μ = 5.0 ± 0.3, the intrinsic (corrected for lensing) luminosity of the [C II] line is L [C II] = {1.4}-0.3+0.2× {10}7 {L}⊙ , roughly ∼5 times fainter than other detections of z ∼ 7 galaxies. The result indicates that low L [C II] in z ∼ 7 galaxies compared to the local counterparts might be caused by their low metallicities and/or feedback. The small velocity offset ({{Δ }}v={20}-40+140 {km} {{{s}}}-1) between the Lyα and [C II] line is unusual, and may be indicative of ionizing photons escaping.
These observations are based on the following ALMA data: ADS/JAO.ALMA#2015.1.00091.S. They are also associated with programs Spitzer #90009, 60034, 00083, 50610, 03550, 40593, and HST # GO10492, GO11591, GO12104, and GO13459. Furthermore based on multi-year KECK programs.