We report a highly significant (>10sigma) spatial correlation between galaxies with S350 mum >= 30 mJy detected in the equatorial fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) with estimated redshifts ≳ 1.5, and Sloan Digital Sky Survey (SDSS) or Galaxy And Mass Assembly (GAMA) galaxies at 0.2 <= z <= 0.6. The significance of the cross-correlation is much higher than those reported so far for samples with non-overlapping redshift distributions selected in other wavebands. Extensive, realistic simulations of clustered sub-mm galaxies amplified by foreground structures confirm that the cross-correlation can be explained by weak gravitational lensing (mu < 2). The simulations also show that the measured amplitude and range of angular scales of the signal are larger than can be accounted for by galaxy-galaxy weak lensing. However, for scales ≲ 2 arcmin, the signal can be reproduced if SDSS/GAMA galaxies act as signposts of galaxy groups/clusters with halo masses in the range 1013.2-1014.5 M&sun;. The signal detected on larger scales appears to reflect the clustering of such haloes.
González Nuevo, J., Lapi, A., Negrello, M., Danese, L., De Zotti, G., Amber, S., et al. (2014). Herschel-ATLAS/GAMA: SDSS cross-correlation induced by weak lensing. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 442, 2680 [10.1093/mnras/stu1041].
Herschel-ATLAS/GAMA: SDSS cross-correlation induced by weak lensing
LAPI, ANDREA;
2014-01-01
Abstract
We report a highly significant (>10sigma) spatial correlation between galaxies with S350 mum >= 30 mJy detected in the equatorial fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) with estimated redshifts ≳ 1.5, and Sloan Digital Sky Survey (SDSS) or Galaxy And Mass Assembly (GAMA) galaxies at 0.2 <= z <= 0.6. The significance of the cross-correlation is much higher than those reported so far for samples with non-overlapping redshift distributions selected in other wavebands. Extensive, realistic simulations of clustered sub-mm galaxies amplified by foreground structures confirm that the cross-correlation can be explained by weak gravitational lensing (mu < 2). The simulations also show that the measured amplitude and range of angular scales of the signal are larger than can be accounted for by galaxy-galaxy weak lensing. However, for scales ≲ 2 arcmin, the signal can be reproduced if SDSS/GAMA galaxies act as signposts of galaxy groups/clusters with halo masses in the range 1013.2-1014.5 M&sun;. The signal detected on larger scales appears to reflect the clustering of such haloes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
