Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have conducted a program to measure redshifts for thirteen bright galaxies detected in the Herschel Astrophysical Large Area Survey (H-ATLAS) with S(500)>=80mJy. We report reliable spectroscopic redshifts for twelve individual sources, which are derived from scans of the 3 and 2-mm bands, covering up to 31GHz in each band, and are based on the detection of at least two emission lines. The spectroscopic redshifts are in the range between 2.08<z<4.05 with a median value of z=2.9+/-0.6. The sources are unresolved or barely resolved on scales of 10kpc. In one field, two galaxies with different redshifts were detected. In two cases, the sources are found to be binary galaxies with projected distances of ~140kpc. The linewidths of the sources are large, with a mean value for the full width at half maximum of 700+/-300km/s and a median of 800km/s. We analyze the nature of the sources with currently available ancillary data to determine if they are lensed or hyper-luminous (LFIR>10^13^L_{sun}_) galaxies. We also present a re-analysis of the spectral energy distributions including the continuum flux densities measured at 3 and 2-mm to derive overall properties of the sources. Future prospects based on these efficient measurements of redshifts of high-z galaxies using NOEMA are outlined, including a comprehensive survey of all the brightest Herschel galaxies.
We present the first results of a program to characterize the disk and envelope structure of typical Class 0 protostars in nearby low-mass star-forming regions. We use Spitzer Infrared Spectrograph (IRS) mid-infrared spectra, high-resolution Combined Array for Research in Millimeter-wave Astronomy (CARMA) 230GHz continuum imaging, and two-dimensional radiative transfer models to constrain the envelope structure, as well as the size and mass of the circumprotostellar disk in Serpens FIRS 1. The primary envelope parameters (centrifugal radius, outer radius, outflow opening angle, and inclination) are well constrained by the spectral energy distribution (SED), including Spitzer IRAC and MIPS photometry, IRS spectra, and 1.1mm Bolocam photometry. These together with the excellent uv-coverage (4.5-500k{lambda}) of multiple antenna configurations with CARMA allow for a robust separation of the envelope and a resolved disk. The SED of Serpens FIRS 1 is best fit by an envelope with the density profile of a rotating, collapsing spheroid with an inner (centrifugal) radius of approximately 600AU, and the millimeter data by a large resolved disk with M_disk_~1.0M_{sun}_ and R_disk_~300AU.
As protostars evolve from optically faint/infrared-bright (Class I) sources to optically bright/infrared-faint (Class II) the solid material in their surrounding disks accumulates into planetesimals and protoplanets. The nearby, young Ophiuchus star-forming region contains hundreds of protostars in a range of evolutionary states. Using the Atacama Large Millimeter Array to observe their millimeter continuum emission, we have measured masses of, or placed strong upper limits on, the dust content of 279 disks. The masses follow a log-normal distribution with a clear trend of decreasing mass from less to more evolved protostellar infrared class. The (logarithmic) mean Class I disk mass, M=3.8M_{Earth}_, is about 5 times greater than the mean Class II disk mass, but the dispersion in each class is so high, {sigma}_logM_~0.8-1, that there is a large overlap between the two distributions. The disk mass distribution of flat-spectrum protostars lies in between Classes I and II. In addition, three Class III sources with little to no infrared excess are detected with low disk masses, M~0.3M_{Earth}_. Despite the clear trend of decreasing disk mass with protostellar evolutionary state in this region, a comparison with surveys of Class II disks in other regions shows that masses do not decrease monotonically with age. This suggests that the cloud-scale environment may determine the initial disk mass scale or that there is substantial dust regeneration after 1Myr.
