A. Amvrosiadis,
E. Valiante,
J. Gonzalez-Nuevo,
S. J. Maddox,
M. Negrello,
S. A. Eales,
L. Dunne,
L. Wang,
E. van Kampen,
G. De Zotti,
M. W. L. Smith,
P. Andreani,
J. Greenslade,
C. Tai-An,
M. J. Michałowski
We present measurements of the angular correlation function of sub-millimeter (sub-mm) galaxies (SMGs) identified in four out of the five fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) - GAMA-9h, GAMA-12h, GAMA-15h and NGP - with flux densities S250μm>30 mJy at 250 μm. We show that galaxies selected at this wavelength trace the underlying matter distribution differently at low and high redshifts. We study the evolution of the clustering finding that at low redshifts sub-mm galaxies exhibit clustering strengths of r0 ∼ 2 - 3 h−1 Mpc, below z < 0.3. At high redshifts, on the other hand, we find that sub-mm galaxies are more strongly clustered with correlation lengths r0 = 8.1 ± 0.5, 8.8 ± 0.8 and 13.9 ± 3.9 h−1Mpc at z = 1 - 2, 2 - 3 and 3 - 5, respectively. We show that sub-mm galaxies across the redshift range 1 < z < 5, typically reside in dark-matter halos of mass of the order of ~ 1012.5 - 1013.0 h−1M⊙ and are consistent with being the progenitors of local massive elliptical galaxies that we see in the local Universe
A. Enia,
M. Negrello,
M. Gurwell,
S. Dye,
G. Rodighiero,
M. Massardi,
G. De Zotti,
A. Franceschini,
A. Cooray,
P. van der Werf,
M. Birkinshaw,
M. J. Michałowski,
I. Oteo
We perform lens modelling and source reconstruction of Submillimeter Array (SMA) data for a sample of 12 strongly lensed galaxies selected at 500μm in the Herschel Astrophysical Terahertz Large Area Survey H-ATLAS. A previous analysis of the same dataset used a single S\`ersic profile to model the light distribution of each background galaxy. Here we model the source brightness distribution with an adaptive pixel scale scheme, extended to work in the Fourier visibility space of interferometry. We also present new SMA observations for seven other candidate lensed galaxies from the H-ATLAS sample. Our derived lens model parameters are in general consistent with previous findings. However, our estimated magnification factors, ranging from 3 to 10, are lower. The discrepancies are observed in particular where the reconstructed source hints at the presence of multiple knots of emission. We define an effective radius of the reconstructed sources based on the area in the source plane where emission is detected above 5σ. We also fit the reconstructed source surface brightness with an elliptical Gaussian model. We derive a median value reff∼1.77kpc and a median Gaussian full width at half maximum ∼1.47kpc. After correction for magnification, our sources have intrinsic star formation rates SFR∼900−3500M⊙yr−1, resulting in a median star formation rate surface density ΣSFR∼132M⊙ yr−1 kpc−2 (or ∼218M⊙ yr−1 kpc−2 for the Gaussian fit). This is consistent with what observed for other star forming galaxies at similar redshifts, and is significantly below the Eddington limit for a radiation pressure regulated starburst.
