Abstract
Dust emission at submillimetre wavelengths allows us to trace the early
phases of star formation in the Universe. In order to understand the
physical processes involved in this mode of star formation, it is
essential to gain knowledge about the dark matter structures - most
importantly their masses - that submillimetre galaxies live in. Here we
use the magnification effect of gravitational lensing to determine the
average mass and dust content of submillimetre galaxies with 250 μm
flux densities of S250 > 15 mJy selected using data from
the Herschel Multi-tiered Extragalactic Survey. The positions of
hundreds of submillimetre foreground lenses are cross-correlated with
the positions of background Lyman-break galaxies at z ˜ 3-5
selected using optical data from the Canada-France-Hawaii Telescope
Legacy Survey. We detect a cross-correlation signal at the 7σ
level over a sky area of 1 deg2, with ˜80 per cent of
this signal being due to magnification, whereas the remaining ˜20
per cent comes from dust extinction. Adopting some simple assumptions
for the dark matter and dust profiles and the redshift distribution
enables us to estimate the average mass of the haloes hosting the
submillimetre galaxies to be log
10[M200/M⊙] = 13.17+
0.05- 0.08(stat.) and their average dust mass fraction
(at radii of >10 kpc) to be Mdust/M200 ≈ 6
× 10-5. This supports the picture that submillimetre
galaxies are dusty, forming stars at a high rate, reside in massive
group-sized haloes and are a crucial phase in the assembly and evolution
of structure in the Universe.
| Original language | English |
|---|---|
| Pages (from-to) | 3230-3237 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 429 |
| Publication status | Published - 1 Mar 2013 |
Keywords
- gravitational lensing: weak
- galaxies: high-redshift
- submillimetre: galaxies