Bibcode
Magliocchetti, M.; Popesso, P.; Rosario, D.; Lutz, D.; Aussel, H.; Berta, S.; Altieri, B.; Andreani, P.; Cepa, J.; Castañeda, H.; Cimatti, A.; Elbaz, D.; Genzel, R.; Grazian, A.; Gruppioni, C.; Ilbert, O.; Le Floc'h, E.; Magnelli, B.; Maiolino, R.; Nordon, R.; Poglitsch, A.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Sanchez-Portal, M.; Santini, P.; Förster Schreiber, N. M.; Sturm, E.; Tacconi, L.; Valtchanov, I.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 433, Issue 1, p.127-137
Advertised on:
7
2013
Citations
20
Refereed citations
18
Description
By making use of Herschel PACS Evolutionary Probe observations of the
COSMOS and Extended Groth Strip fields, we have estimated the dependence
of the clustering properties of FIR-selected sources on their 100 μm
fluxes. Our analysis shows a tendency for the clustering strength to
decrease with limiting fluxes. By assuming a power-law slope with
γ = 1.8 for the two-point correlation function ξ(r) =
(r/r0)-γ, we find: r0(S100
μm ≥ 8 mJy) = 4.3+0.7-0.7 Mpc and
r0(S100 μ m ≥ 5 mJy) =
5.8+1.8-2.0. These values convert into minimum
halo masses Mmin ˜ 1011.6 M⊙
for sources brighter than 8 mJy and Mmin ˜
1012.4 M⊙ for fainter, S100 μm
≥ 5 mJy galaxies. We show such an increase of the clustering strength
to be due to an intervening population of z ˜ 2 sources, which are
very strongly clustered and whose relative contribution, equal to about
10 per cent of the total counts at S100 μm ≥ 2 mJy,
rapidly decreases for brighter flux cuts. By removing such a
contribution, we find that z ≲ 1 far-infrared (FIR) galaxies have
approximately the same clustering properties, irrespective of their flux
level. The above results were then used to investigate the intrinsic
dependence on cosmic epoch of the clustering strength of dusty
star-forming galaxies between z ˜ 0 and z ˜ 2.5. This was
done by comparing our data set with IRAS in the local universe and with
sources selected at 160 μm in the GOODS-South at z ≃ 2. In order
to remove any bias in the selection process, the adopted sample only
includes galaxies observed at the same rest-frame wavelength, λ
˜ 60 μm, which have comparable luminosities and therefore star
formation rates (SFR ≳ 100 M⊙ yr-1). Our
analysis shows that the same amount of (intense) star-forming activity
takes place in extremely different environments at the different
cosmological epochs. For z ≲ 1, the hosts of such star-forming
systems are small, Mmin ˜ 1011
M⊙, isolated galaxies. High (z ˜ 2) redshift star
formation instead seems to uniquely take place in extremely
massive/cluster-like haloes, Mmin ˜ 1013.5
M⊙, which are associated with the highest peaks of the
density fluctuation field at those epochs.
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Evolution of Galaxies
Galaxy evolution is a crucial topic in modern extragalactic astrophysics, linking cosmology to the Local Universe. Their study requires collecting statistically significant samples of galaxies of different luminosities at different distances. It implies the ability to observe faint objects using different techniques, and at different wavelengths
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