28 research outputs found
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Super-resolving <i>Herschel</i> imaging: a proof of concept using Deep Neural Networks
Wide-field sub-millimetre surveys have driven many major advances in galaxy evolution in the past decade, but without extensive follow-up observations the coarse angular resolution of these surveys limits the science exploitation. This has driven the development of various analytical deconvolution methods. In the last half a decade Generative Adversarial Networks have been used to attempt deconvolutions on optical data. Here we present an autoencoder with a novel loss function to overcome this problem in the sub-millimeter wavelength range. This approach is successfully demonstrated on Herschel SPIRE 500μm COSMOS data, with the super-resolving target being the JCMT SCUBA-2 450μm observations of the same field. We reproduce the JCMT SCUBA-2 images with high fidelity using this autoencoder. This is quantified through the point source fluxes and positions, the completeness and the purity
Revisiting the Color-Color Selection: Submillimeter and AGN Properties of NUV-r-J Selected Quiescent Galaxies
We examine the robustness of the color-color selection of quiescent galaxies
(QGs) against contamination of dusty star-forming galaxies using the latest
submillimeter data. We selected 18,304 QG candidates out to 3 using the
commonly adopted selection based on the high-quality multi-wavelength
COSMOS2015 catalog. Using extremely deep 450 and 850 m catalogs from the
latest JCMT SCUBA-2 Large Programs, S2COSMOS, and STUDIES, as well as ALMA
submillimeter, VLA 3 GHz, and MIPS 24 m catalogs, we identified
luminous dusty star-forming galaxies among the QG candidates. We also conducted
stacking analyses in the SCUBA-2 450 and 850 m images to look for
less-luminous dusty galaxies among the QG candidates. By cross-matching to the
24 m and 3 GHz data, we were able to identify a sub-group of
"IR-radio-bright" QGs who possess a strong 450 and 850 m stacking signal.
The potential contamination of these luminous and less-luminous dusty galaxies
accounts for approximately 10% of the color-selected QG candidates. In
addition, there exists a spatial correlation between the luminous star-forming
galaxies and the QGs at a kpc scale. Finally, we found a high QG
fraction among radio AGNs at 1.5. Our data show a strong correlation
between QGs and radio AGNs, which may suggest a connection between the
quenching process and the radio-mode AGN feedback.Comment: This paper is accepted for publication on Ap
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). II. Structural Properties and Near-infrared Morphologies of Faint Submillimeter Galaxies
We present structural parameters and morphological properties of faint 450 μm selected submillimeter galaxies (SMGs) from the JCMT Large Program, STUDIES, in the COSMOS-CANDELS region. Their properties are compared to an 850 μm selected and a matched star-forming samples. We investigate stellar structures of 169 faint 450 μm sources (S 450 = 2.8–29.6 mJy; S/N > 4) at z 2 mJy) and more extended than the star-forming galaxies in the same redshift range. For the stellar mass and SFR-matched sample at z sime 1 and z sime 2, the size differences are marginal between faint SMGs and the matched galaxies. Moreover, faint SMGs have similar Sérsic indices and projected axis ratios as star-forming galaxies with the same stellar mass and SFR. Both SMGs and the matched galaxies show high fractions (~70%) of disturbed features at z sime 2, and the fractions depend on the SFRs. These suggest that their star formation activity is related to galaxy merging and the stellar structures of SMGs are similar to those of star-forming galaxies. We show that the depths of submillimeter surveys are approaching the lower luminosity end of star-forming galaxies, allowing us to detect galaxies on the main sequence
Recombinational Landscape and Population Genomics of Caenorhabditis elegans
Recombination rate and linkage disequilibrium, the latter a function of population genomic processes, are the critical parameters for mapping by linkage and association, and their patterns in Caenorhabditis elegans are poorly understood. We performed high-density SNP genotyping on a large panel of recombinant inbred advanced intercross lines (RIAILs) of C. elegans to characterize the landscape of recombination and, on a panel of wild strains, to characterize population genomic patterns. We confirmed that C. elegans autosomes exhibit discrete domains of nearly constant recombination rate, and we show, for the first time, that the pattern holds for the X chromosome as well. The terminal domains of each chromosome, spanning about 7% of the genome, exhibit effectively no recombination. The RIAILs exhibit a 5.3-fold expansion of the genetic map. With median marker spacing of 61 kb, they are a powerful resource for mapping quantitative trait loci in C. elegans. Among 125 wild isolates, we identified only 41 distinct haplotypes. The patterns of genotypic similarity suggest that some presumed wild strains are laboratory contaminants. The Hawaiian strain, CB4856, exhibits genetic isolation from the remainder of the global population, whose members exhibit ample evidence of intercrossing and recombining. The population effective recombination rate, estimated from the pattern of linkage disequilibrium, is correlated with the estimated meiotic recombination rate, but its magnitude implies that the effective rate of outcrossing is extremely low, corroborating reports of selection against recombinant genotypes. Despite the low population, effective recombination rate and extensive linkage disequilibrium among chromosomes, which are techniques that account for background levels of genomic similarity, permit association mapping in wild C. elegans strains
Does country of origin matter to Singaporean consumers in evaluating food products?
This study examines the influence of Country of Origin (COO) relative to other attributes on Singaporean consumers’ evaluation of food
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). II. Structural Properties and Near-infrared Morphologies of Faint Submillimeter Galaxies
We present structural parameters and morphological properties of faint 450 μm selected submillimeter galaxies (SMGs) from the JCMT Large Program, STUDIES, in the COSMOS-CANDELS region. Their properties are compared to an 850 μm selected and a matched star-forming samples. We investigate stellar structures of 169 faint 450 μm sources (S 450 = 2.8-29.6 mJy; S/N > 4) at z 2 mJy) and more extended than the star-forming galaxies in the same redshift range. For the stellar mass and SFR-matched sample at z ≃ 1 and z ≃ 2, the size differences are marginal between faint SMGs and the matched galaxies. Moreover, faint SMGs have similar Sérsic indices and projected axis ratios as star-forming galaxies with the same stellar mass and SFR. Both SMGs and the matched galaxies show high fractions (∼70%) of disturbed features at z ≃ 2, and the fractions depend on the SFRs. These suggest that their star formation activity is related to galaxy merging and the stellar structures of SMGs are similar to those of star-forming galaxies. We show that the depths of submillimeter surveys are approaching the lower luminosity end of star-forming galaxies, allowing us to detect galaxies on the main sequence