We present the first cross-correlation measurement between Sloan Digital Sky Survey (SDSS) Type 1 quasars and the cosmic infrared background (CIB) measured by Herschel. The distribution of the quasars at 0.15<z<3.5 covers the redshift range where we
expect most of the CIB to originate. We detect the sub-mm emission of the quasars, which dominates on small scales, as well as correlated emission from dusty star-forming galaxies (DSFGs) dominant on larger scales. The mean sub-mm flux densities of the DR7 quasars (median redshift <z>=1.4) is $11.1^{+1.6}_{-1.4}$, $7.1^{+1.6}_{-1.3}$ and $3.6^{+1.4}_{-1.0}$ mJy at 250, 350 and 500 microns, respectively, while the mean sub-mm flux densities of the DR9 quasars (<z>=2.5) is $5.7^{+0.7}_{-0.6}$, $5.0^{+0.8}_{-0.7}$ and $1.8^{+0.5}_{-0.4}$ mJy. We find that the correlated sub-mm emission includes both the emission from satellite DSFGs in the same halo as the central quasar and the emission from DSFGs in separate halos (correlated with the quasar-hosting halo). The amplitude of the one-halo term is ~10 times smaller than the sub-mm emission of the quasars, implying the the satellites have a lower star-formation rate than the quasars. The satellite fraction for the DR7 quasars is $0.008^{+0.008}_{-0.005}$ and the host halo mass scale for the central and satellite quasars is $10^{12.36pm0.87}$ M$_{odot}$ and $10^{13.60pm0.38}$ M$_{odot}$, respectively. The satellite fraction of the DR9 quasars is $0.065^{+0.021}_{-0.031}$ and the host halo mass scale for the central and satellite quasars is $10^{12.29pm0.62}$ M$_{odot}$ and $10^{12.82pm0.39}$ M$_{odot}$, respectively. Thus, the typical halo environment of the SDSS Type 1 quasars is found to be similar to that of DSFGs, which supports the generally accepted view that dusty starburst and quasar activity are evolutionarily linked.
We present a Revised IRAS-FSC Redshift Catalogue (RIFSCz) of 60,303 galaxies selected at 60 microns from the IRAS Faint Source Catalogue (FSC). This revision merges in data from the WISE All-Sky Data Release, the Tenth SDSS Data Release (DR10), the G
ALEX All-Sky Survey Source Catalog (GASC), the 2MASS Redshift Survey (2MRS) and the Planck Catalogue of Compact Sources (PCCS). The RIFSCz consists of accurate position, ultra-violet (UV), optical, near-, mid- and far-infrared, sub-millimetre (sub-mm) and/or radio identifications, spectroscopic redshift (if available) or photometric redshift (if possible), predicted far-infrared and sub-mm fluxes ranging from 12 to 1380 microns based upon the best-fit infrared template. We also provide stellar masses, star-formation rates and dust masses derived from the optical and infrared template fits, where possible. 56 of the galaxies in the RIFSCz have spectroscopic redshifts and a further 26 have photometric redshifts obtained through the template-fitting method. At S60 > 0.36 Jy, the 90% completeness limit of the FSC, 93 of the sources in the RIFSCz have either spectroscopic or photometric redshifts. An interesting subset of the catalogue is the sources detected by Planck at sub-mm wavelengths. 1200 sources have a detection at better than 5 sigma in at least one Planck band and a further 1186 sources have detections at 3-5 sigma in at least one Planck band.
The Herschel Multi-tiered Extragalactic Survey (HerMES) is the largest Guaranteed Time Key Programme on the Herschel Space Observatory. With a wedding cake survey strategy, it consists of nested fields with varying depth and area totalling ~380 deg^2
. In this paper, we present deep point source catalogues extracted from Herschel-SPIRE observations of all HerMES fields, except for the later addition of the 270 deg^2 HeLMS field. These catalogues constitute the second Data Release (DR2) made in October 2013. A subset of these catalogues, which consists of bright sources extracted from Herschel-SPIRE observations completed by May 1, 2010 (covering ~ 74 deg^2) were released earlier in the first extensive Data Release (DR1) in March 2012. Two different methods are used to generate the point source catalogues, the SUSSEXtractor (SXT) point source extractor used in two earlier data releases (EDR and EDR2) and a new source detection and photometry method. The latter combines an iterative source detection algorithm, StarFinder (SF), and a De-blended SPIRE Photometry (DESPHOT) algorithm. We use end-to-end Herschel-SPIRE simulations with realistic number counts and clustering properties to characterise basic properties of the point source catalogues, such as the completeness, reliability, photometric and positional accuracy. Over 500, 000 catalogue entries in HerMES fields (except HeLMS) are released to the public through the HeDAM website (http://hedam.oamp.fr/herMES).
We have constructed an extended halo model (EHM) which relates the total stellar mass and star-formation rate (SFR) to halo mass (M_h). An empirical relation between the distribution functions of total stellar mass of galaxies and host halo mass, tun
ed to match the spatial density of galaxies over 0<z<2 and the clustering properties at z~0, is extended to include two different scenarios describing the variation of SFR on M_h. We also present new measurements of the redshift evolution of the average SFR for star-forming galaxies of different stellar mass up to z=2, using data from the Herschel Multi-tiered Extragalactic Survey (HerMES) for infrared-bright galaxies. Combining the EHM with the halo accretion histories from numerical simulations, we trace the stellar mass growth and star-formation history in halos spanning a range of masses. We find that: (1) The intensity of the star-forming activity in halos in the probed mass range has steadily decreased from z~2 to 0; (2) At a given epoch, halos in the mass range between a few times 10^{11} M_Sun and a few times 10^{12} M_Sun are the most efficient at hosting star formation; (3) The peak of SFR density shifts to lower mass halos over time; (4) Galaxies that are forming stars most actively at z~2 evolve into quiescent galaxies in todays group environments, strongly supporting previous claims that the most powerful starbursts at z~2 are progenitors of todays elliptical galaxies.
Cosmic magnification is due to the weak gravitational lensing of sources in the distant Universe by foreground large-scale structure leading to coherent changes in the observed number density of the background sources. Depending on the slope of the b
ackground source number counts, cosmic magnification causes a correlation between the background and foreground galaxies, which is unexpected in the absence of lensing if the two populations are spatially disjoint. Previous attempts using submillimetre (sub-mm) sources have been hampered by small number statistics. The large number of sources detected in the {it Herschel} Multi-tiered Extra-galactic Survey (HerMES) Lockman-SWIRE field enables us to carry out the first robust study of the cross-correlation between sub-mm sources and sources at lower redshifts. Using ancillary data we compile two low-redshift samples from SDSS and SWIRE with <z> ~ 0.2 and 0.4, respectively, and cross-correlate with two sub-mm samples based on flux density and colour criteria, selecting galaxies preferentially at z ~ 2. We detect cross-correlation on angular scales between ~1 and 50 arcmin and find clear evidence that this is primarily due to cosmic magnification. A small, but non-negligible signal from intrinsic clustering is likely to be present due to the tails of the redshift distribution of the sub-mm sources overlapping with those of the foreground samples.
We present a careful analysis of the point source detection limit of the AKARI All-Sky Survey in the WIDE-S 90 $mu$m band near the North Ecliptic Pole (NEP). Timeline Analysis is used to detect IRAS sources and then a conversion factor is derived to
transform the peak timeline signal to the interpolated 90 $mu$m flux of a source. Combined with a robust noise measurement, the point source flux detection limit at S/N $>5$ for a single detector row is $1.1pm0.1$ Jy which corresponds to a point source detection limit of the survey of $sim$0.4 Jy. Wavelet transform offers a multiscale representation of the Time Series Data (TSD). We calculate the continuous wavelet transform of the TSD and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above $4sigma$ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non-IRAS sources detected in Timeline Analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non-IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.
