362 research outputs found
HerMES: Current Cosmic Infrared Background Estimates Can be Explained by Known Galaxies and their Faint Companions at z < 4
We report contributions to cosmic infrared background (CIB) intensities
originating from known galaxies and their faint companions at submillimeter
wavelengths. Using the publicly-available UltraVISTA catalog, and maps at 250,
350, and 500 {\mu}m from the \emph{Herschel} Multi-tiered Extragalactic Survey
(HerMES), we perform a novel measurement that exploits the fact that
uncatalogued sources may bias stacked flux densities --- particularly if the
resolution of the image is poor --- and intentionally smooth the images before
stacking and summing intensities. By smoothing the maps we are capturing the
contribution of faint (undetected in K_S ~ 23.4) sources that are physically
associated, or correlated, with the detected sources. We find that the
cumulative CIB increases with increased smoothing, reaching 9.82 +- 0.78, 5.77
+- 0.43, and 2.32 +- 0.19 at 250, 350, and 500 {\mu}m
at 300 arcsec FWHM. This corresponds to a fraction of the fiducial CIB of 0.94
+- 0.23, 1.07 +- 0.31, and 0.97 +- 0.26 at 250, 350, and 500 {\mu}m, where the
uncertainties are dominated by those of the absolute CIB. We then propose, with
a simple model combining parametric descriptions for stacked flux densities and
stellar mass functions, that emission from galaxies with log(M/Msun) > 8.5 can
account for the most of the measured total intensities, and argue against
contributions from extended, diffuse emission. Finally, we discuss prospects
for future survey instruments to improve the estimates of the absolute CIB
levels, and observe any potentially remaining emission at z > 4.Comment: Accepted to ApJL. 6 Pages, 3 figure
Have we seen all the galaxies that comprise the cosmic infrared background at 250 ”m â€Î»â€ 500 ”m?
The cosmic infrared background (CIB) provides a fundamental observational constraint on the star formation history of galaxies over cosmic history. We estimate the contribution to the CIB from catalogued galaxies in the COSMOS field by using a novel map fitting technique on the Herschel SPIRE maps. Prior galaxy positions are obtained using detections over a large range in wavelengths in the Ksâ3âGHz range. Our method simultaneously fits the galaxies, the system foreground, and the leakage of flux from galaxies located in masked areas and corrects for an âoverfittingâ effect not previously accounted for in stacking methods. We explore the contribution to the CIB as a function of galaxy survey wavelength and depth. We find high contributions to the CIB with the deep r (mAB †26.5), Ks (mAB †24.0), and 3.6âÎŒm (mAB †25.5) catalogues. We combine these three deep catalogues and find a total CIB contributions of 10.5 ± 1.6, 6.7 ± 1.5, and 3.1 ± 0.7ânWmâ2 srâ1 at 250, 350, and 500âÎŒm, respectively. Our CIB estimates are consistent with recent phenomenological models, prior based SPIRE number counts and with (though more precise than) the diffuse total measured by FIRAS. Our results raise the interesting prospect that the CIB contribution at λâ€500ÎŒm from known galaxies has converged. Future large-area surveys like those with the Large Synoptic Survey Telescope are therefore likely to resolve a substantial fraction of the population responsible for the CIB at 250âÎŒm †λ †500âÎŒm
De effectiviteit van re-integratietraining versus boostersessies na kortdurende klinische psychotherapie: een gerandomiseerd klinisch onderzoek
Abstract
BACKGROUND: Standardised evaluation studies performed in the Netherlands in a large number of inpatient and day-treatment hospitals providing psychotherapy have shown significant symptomatic improvements in patients between the date of entry to the studies and follow-up after one year. However, the work situation of ex-patients hardly changed and a large number of patients were still receiving psychotherapy.
AIM: To examine the effectiveness of a specifically designed course of re-integration training.
METHOD: A group of 128 patients were assigned randomly either to a re-integration training course aimed at improved functioning at work and improved relationships, or to booster sessions. Outcome measures were symptom level, work status, absence from work, and further psychotherapy. results After two years the number of patients in paid employment remained the same (76%) in the re-integration training course and increased from 67 to 87% in the booster sessions. Attendance was significantly higher in the booster sessions than in the re-integration training. There were no differences in the other outcome measures.
CONCLUSION: We conclude that re-integration training was no more effective than the booster sessions. Our hypothesis is that continuity of care (therapists plus programme) explains the favourable result of the booster sessions
Nonperturbative Superpotentials and Compactification to Three Dimensions
We consider four-dimensional N=2 supersymmetric gauge theories with gauge
group U(N) on R^3 x S^1, in the presence of a classical superpotential. The
low-energy quantum superpotential is obtained by simply replacing the adjoint
scalar superfield in the classical superpotential by the Lax matrix of the
integrable system that underlies the 4d field theory. We verify in a number of
examples that the vacuum structure obtained in this way matches precisely that
in 4d, although the degrees of freedom that appear are quite distinct. Several
features of 4d field theories, such as the possibility of lifting vacua from
U(N) to U(tN), become particularly simple in this framework. It turns out that
supersymmetric vacua give rise to a reduction of the integrable system which
contains information about the field theory but also about the Dijkgraaf-Vafa
matrix model. The relation between the matrix model and the quantum
superpotential on R^3 x S^1 appears to involve a novel kind of mirror symmetry.Comment: LaTeX, 45 pages, uses AmsMath, minor correction, reference adde
280 GHz Focal Plane Unit Design and Characterization for the SPIDER-2 Suborbital Polarimeter
We describe the construction and characterization of the 280 GHz bolometric
focal plane units (FPUs) to be deployed on the second flight of the
balloon-borne SPIDER instrument. These FPUs are vital to SPIDER's primary
science goal of detecting or placing an upper limit on the amplitude of the
primordial gravitational wave signature in the cosmic microwave background
(CMB) by constraining the B-mode contamination in the CMB from Galactic dust
emission. Each 280 GHz focal plane contains a 16 x 16 grid of corrugated
silicon feedhorns coupled to an array of aluminum-manganese transition-edge
sensor (TES) bolometers fabricated on 150 mm diameter substrates. In total, the
three 280 GHz FPUs contain 1,530 polarization sensitive bolometers (765 spatial
pixels) optimized for the low loading environment in flight and read out by
time-division SQUID multiplexing. In this paper we describe the mechanical,
thermal, and magnetic shielding architecture of the focal planes and present
cryogenic measurements which characterize yield and the uniformity of several
bolometer parameters. The assembled FPUs have high yields, with one array as
high as 95% including defects from wiring and readout. We demonstrate high
uniformity in device parameters, finding the median saturation power for each
TES array to be ~3 pW at 300 mK with a less than 6% variation across each array
at one standard deviation. These focal planes will be deployed alongside the 95
and 150 GHz telescopes in the SPIDER-2 instrument, slated to fly from McMurdo
Station in Antarctica in December 2018
Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER
We describe 280 GHz bolometric detector arrays that instrument the
balloon-borne polarimeter SPIDER. A primary science goal of SPIDER is to
measure the large-scale B-mode polarization of the cosmic microwave background
in search of the cosmic-inflation, gravitational-wave signature. 280 GHz
channels aid this science goal by constraining the level of B-mode
contamination from galactic dust emission. We present the focal plane unit
design, which consists of a 1616 array of conical, corrugated feedhorns
coupled to a monolithic detector array fabricated on a 150 mm diameter silicon
wafer. Detector arrays are capable of polarimetric sensing via waveguide
probe-coupling to a multiplexed array of transition-edge-sensor (TES)
bolometers. The SPIDER receiver has three focal plane units at 280 GHz, which
in total contains 765 spatial pixels and 1,530 polarization sensitive
bolometers. By fabrication and measurement of single feedhorns, we demonstrate
14.7 FHWM Gaussian-shaped beams with 1% ellipticity in a 30%
fractional bandwidth centered at 280 GHz. We present electromagnetic
simulations of the detection circuit, which show 94% band-averaged,
single-polarization coupling efficiency, 3% reflection and 3% radiative loss.
Lastly, we demonstrate a low thermal conductance bolometer, which is
well-described by a simple TES model and exhibits an electrical noise
equivalent power (NEP) = 2.6 10 W/,
consistent with the phonon noise prediction.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 201
The star formation rates of QSOs
We examine the far-infrared (FIR) properties of a sample of 5391 optically selected QSOs in the 0.5 44.7, using SPIRE data from Herschel-ATLAS. We split the sample in a grid of 74 luminosityâredshift bins and compute the average opticalâIR spectral energy distribution (SED) in each bin. By normalizing an intrinsic active galactic nucleus (AGN) template to the AGN optical power (at 5100 Ă
), we decompose the total IR emission (LIR; 8â1000 ”m) into an AGN (LIR, AGN) and star-forming component (LIR, SF). We find that the AGN contribution to LIR increases as a function of AGN power, manifesting as a reduction of the âFIR bumpâ in the average QSO SEDs. We note that LIR, SF does not correlate with AGN power; the mean star formation rates (SFRs) of AGN host galaxies are a function of redshift only and they range from âŒ6âMââyrâ1 at z ⌠0 to a plateau of âČ 200âMââyrâ1 at z ⌠2.6. Our results indicate that the accuracy of FIR emission as a proxy for SFR decreases with increasing AGN luminosity. We show that, at any given redshift, observed trends between IR luminosity (whether monochromatic or total) and AGN power (in the optical or X-rays) can be explained by a simple model which is the sum of two components: (i) the IR emission from star formation, uncorrelated with AGN power and (ii) the IR emission from AGN, directly proportional to AGN power in the optical or X-rays
HELP: the Herschel Extragalactic Legacy Project
We present the Herschel Extragalactic Legacy Project (HELP). This project collates, curates, homogenizes, and creates derived data products for most of the premium multiwavelength extragalactic data sets. The sky boundaries for the first data release cover 1270âdeg2 defined by the Herschel SPIRE extragalactic survey fields; notably the Herschel Multi-tiered Extragalactic Survey (HerMES) and the Herschel Atlas survey (H-ATLAS). Here, we describe the motivation and principal elements in the design of the project. Guiding principles are transparent or âopenâ methodologies with care for reproducibility and identification of provenance. A key element of the design focuses around the homogenization of calibration, meta data, and the provision of information required to define the selection of the data for statistical analysis. We apply probabilistic methods that extract information directly from the images at long wavelengths, exploiting the prior information available at shorter wavelengths and providing full posterior distributions rather than maximum-likelihood estimates and associated uncertainties as in traditional catalogues. With this project definition paper, we provide full access to the first data release of HELP; Data Release 1 (DR1), including a monolithic map of the largest SPIRE extragalactic field at 385âdeg2 and 18 million measurements of PACS and SPIRE fluxes. We also provide tools to access and analyse the full HELP data base. This new data set includes far-infrared photometry, photometric redshifts, and derived physical properties estimated from modelling the spectral energy distributions over the full HELP sky. All the software and data presented is publicly available
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the treesââ„â10âcm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
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