Joint Astrophysical Colloquium
NOEMA Redshift Measurements of Bright Herschel Galaxies
Pierre Cox (Institut d’Astrophysique de Paris)
Thursday 10/10/2019 @ 11:30, Sala IV piano Battiferro
Using the IRAM Northern Extended Millimeter Array (NOEMA), we are currently conducting a Large Program to measure redshifts for ~160 bright galaxies detected in Herschel surveys with S_500 um > 80 mJy. We will here present results from a Pilot Program, where we measured reliable spectroscopic redshifts for eleven H-ATLAS selected galaxies, which are derived from scans of the 3 and 2-mm bands, covering up to 31 GHz in each band, and are based on the detection of at least two emission lines. The spectroscopic redshifts are in the range 2.08<z<4.05 with a median redshift of z=2.9+-0.7. The majority of the sources are single, and unresolved or barely resolved on sales of 10 kpc. In one field, two galaxies with different redshifts were detected, and, in two other cases, the sources are found to binary galaxies with separations of 140 kpc. For the majority of the sources, the linewidths are large, with a mean value for the CO FHWM of 700+-300 km/s. We will describe the nature of the sources, using currently available ancillary data, to determine if they are lensed or hyper-luminous galaxies. Future prospects based on these efficient measurements of redshifts of high-z galaxies using NOEMA will be outlined, including a short update on the on-going, comprehensive survey, z-GAL, aiming at deriving reliable spectroscopic redshifts for all the brightest Herschel galaxies.