The Chandra XBootes Survey - III: Optical and Near-IR Counterparts

The XBootes Survey is a 5-ks Chandra survey of the Bootes Field of the NOAO Deep Wide-Field Survey (NDWFS). This survey is unique in that it is the largest (9.3 deg^2), contiguous region imaged in X-ray with complementary deep optical and near-IR observations. We present a catalog of the optical counterparts to the 3,213 X-ray point sources detected in the XBootes survey. Using a Bayesian identification scheme, we successfully identified optical counterparts for 98% of the X-ray point sources. The optical colors suggest that the optically detected galaxies are a combination of z<1 massive early-type galaxies and bluer star-forming galaxies whose optical AGN emission is faint or obscured, whereas the majority of the optically detected point sources are likely quasars over a large redshift range. Our large area, X-ray bright, optically deep survey enables us to select a large sub-sample of sources (773) with high X-ray to optical flux ratios (f_x/f_o>10). These objects are likely high redshift and/or dust obscured AGN. These sources have generally harder X-ray spectra than sources with 0.1<f_x/f_o<10. Of the 73 X-ray sources with no optical counterpart in the NDWFS catalog, 47 are truly optically blank down to R~25.5 (the average 50% completeness limit of the NDWFS R-band catalogs). These sources are also likely to be high redshift and/or dust obscured AGN.Comment: 19 pages, 13 figures, ApJ accepted. Catalog can be found at: http://www.noao.edu/noao/noaodeep or ftp://archive.noao.edu/pub/catalogs/xbootes

Derived variants at six genes explain nearly half of size reduction in dog breeds

Selective breeding of dogs by humans has generated extraordinary diversity in body size. A number of multibreed analyses have been undertaken to identify the genetic basis of this diversity. We analyzed four loci discovered in a previous genome-wide association study that used 60,968 SNPs to identify size-associated genomic intervals, which were too large to assign causative roles to genes. First, we performed fine-mapping to define critical intervals that included the candidate genes GHR, HMGA2, SMAD2, and STC2, identifying five highly associated markers at the four loci. We hypothesize that three of the variants are likely to be causative. We then genotyped each marker, together with previously reported size-associated variants in the IGF1 and IGF1R genes, on a panel of 500 domestic dogs from 93 breeds, and identified the ancestral allele by genotyping the same markers on 30 wild canids. We observed that the derived alleles at all markers correlated with reduced body size, and smaller dogs are more likely to carry derived alleles at multiple markers. However, breeds are not generally fixed at all markers; multiple combinations of genotypes are found within most breeds. Finally, we show that 46%–52.5% of the variance in body size of dog breeds can be explained by seven markers in proximity to exceptional candidate genes. Among breeds with standard weights <41 kg (90 lb), the genotypes accounted for 64.3% of variance in weight. This work advances our understanding of mammalian growth by describing genetic contributions to canine size determination in non-giant dog breeds

The Star Formation and Nuclear Accretion Histories of Normal Galaxies in the AGES Survey

We combine IR, optical and X-ray data from the overlapping, 9.3 square degree NOAO Deep Wide-Field Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBootes Survey to measure the X-ray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 < z < 0.5. Because only the closest or brightest of the galaxies are individually detected in X-rays, we use a stacking analysis to determine the mean properties of the sample. Our results suggest that X-ray emission from spectroscopically late-type galaxies is dominated by star formation, while that from early-type galaxies is dominated by a combination of hot gas and AGN emission. We find that the mean star formation and supermassive black hole accretion rate densities evolve like (1+z)^3, in agreement with the trends found for samples of bright, individually detectable starburst galaxies and AGN. Our work also corroborates the results of many previous stacking analyses of faint source populations, with improved statistics.Comment: 19 pages, 15 figures, 3 tables, accepted for publication in Ap

Spectral energy distribution and radio halo of NGC253 at low radio frequencies

A. D. Kapinska, 'Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies', The Astrophysical Journal, Vol. 838(68), 15 pp, March 2017. The version of record is available online at doi: https://doi.org/10.3847/1538-4357/aa5f5d. © 2017. The American Astronomical Society. All rights reserved.We present new radio continuum observations of NGC253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of central starburst and extended emission. The central component, corresponding to the inner 500pc of the starburst region of the galaxy, is best modelled as an internally free-free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the NGC253 spectrum is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the SE halo, and may be indicative of synchrotron self-absorption of shock re-accelerated electrons or an intrinsic low-energy cut off of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC253 in our radio images. At 154 - 231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ~8kpc in z-direction (from major axis).Peer reviewedFinal Published versio

Evidence for genetic heterogeneity in Dent's disease

Evidence for genetic heterogeneity in Dent's disease.BackgroundDent's disease (X-linked nephrolithiasis) is a proximal tubulopathy that has been consistently associated with inactivating mutations in the CLCN5 gene encoding the ClC-5 chloride channel expressed in tubular epithelial cells.MethodsWe performed mutation analysis of the coding region of CLCN5 by DNA sequencing in 32 unrelated males, all of whom met the following three clinical criteria for the diagnosis of Dent's disease: (1) low-molecular-weight (LMW) proteinuria; (2) hypercalciuria; and (3) at least one of the following: nephrocalcinosis, kidney stones, renal insufficiency, hypophosphatemia, or hematuria.ResultsSixteen mutations (ten missense, four nonsense, two frameshift) were found in 19 patients. Mutations were confirmed by restriction analysis or allele-specific polymerase chain reaction (PCR), segregated with disease in the families, and were not polymorphisms. In the other 13 patients with Dent's disease, the coding sequence of CLCN5 was normal. In these 13 patients, we also sequenced two regions of the CLCN5 promoter (626 and 586bp, respectively, 2.1 and 1kb upstream of exon 2) containing regulatory sites [activating protein-1 (AP-1)-like, AP-4, and cyclic adenosine monophosphate (cAMP)-receptor element binding protein (CREB)] and primary and secondary transcription start sites. We found no mutations in these promoter sequences in any of the 13 patients. In one three-generation family, the absence of mutation was confirmed by sequencing in two additional affected family members, and in this family haplotype analysis excluded linkage to the region of the CLCN5 gene. There were no differences between the 19 patients with CLCN5 mutations and the 13 without mutations with regard to any clinical features of Dent's disease.ConclusionThese findings suggest that mutation in other gene(s) may be responsible for the phenotype of Dent's disease in some patients

CLCN5 chloride-channel mutations in six new North American families with X-linked nephrolithiasis

CLCN5 chloride-channel mutations in six new North American families with X-linked nephrolithiasis.BackgroundX-linked nephrolithiasis, or Dent's disease, encompasses several clinical syndromes of low molecular weight (LMW) proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure, and is associated with mutations in the CLCN5 gene encoding a kidney-specific voltage-gated chloride channel. Some patients from Europe have rickets, and all symptomatic patients confirmed by mutation analysis have been male.MethodsWe analyzed the CLCN5 DNA sequence in six new families with this disease.ResultsIn three probands, a single-base substitution yielded a nonsense triplet at codons 28, 34, and 343, respectively, and in two families, one of which was Hispanic, we found single-base deletions at codons 40 and 44, leading to premature termination of translation. In the sixth family, a single-base change from C to T predicted substitution of leucine for serine at codon 244, previously reported in two European families with prominent rickets, though this patient of Ashkenazi origin did not have rickets. Each of these mutations was confirmed by restriction endonuclease analysis, or repeat sequencing and CFLP. The R34X mutation occurred in a Canadian infant with severe rickets. The family with the R28X nonsense mutation included one woman with recurrent kidney stones and another woman with glomerular sclerosis. In another family, a woman heterozygous for the W343X mutation also had nephrolithiasis.ConclusionsThese studies expand the range of mutations identified in this disease, and broaden the phenotypic range to include clinically affected women and the first North American case with severe rickets

Dent Disease with Mutations in OCRL1

Dent disease is an X-linked renal proximal tubulopathy associated with mutations in the chloride channel gene CLCN5. Lowe syndrome, a multisystem disease characterized by renal tubulopathy, congenital cataracts, and mental retardation, is associated with mutations in the gene OCRL1, which encodes a phosphatidylinositol 4,5-bisphosphate (PIP(2)) 5-phosphatase. Genetic heterogeneity has been suspected in Dent disease, but no other gene for Dent disease has been reported. We studied male probands in 13 families, all of whom met strict criteria for Dent disease but lacked mutations in CLCN5. Linkage analysis in the one large family localized the gene to a candidate region at Xq25-Xq27.1. Sequencing of candidate genes revealed a mutation in the OCRL1 gene. Of the 13 families studied, OCRL1 mutations were found in 5. PIP(2) 5-phosphatase activity was markedly reduced in skin fibroblasts cultured from the probands of these five families, and protein expression, measured by western blotting, was reduced or absent. Slit-lamp examinations performed in childhood or adulthood for all five probands showed normal results. Unlike patients with typical Lowe syndrome, none of these patients had metabolic acidosis. Three of the five probands had mild mental retardation, whereas two had no developmental delay or behavioral disturbance. These findings demonstrate that mutations in OCRL1 can occur with the isolated renal phenotype of Dent disease in patients lacking the cataracts, renal tubular acidosis, and neurological abnormalities that are characteristic of Lowe syndrome. This observation confirms genetic heterogeneity in Dent disease and demonstrates more-extensive phenotypic heterogeneity in Lowe syndrome than was previously appreciated. It establishes that the diagnostic criteria for disorders resulting from mutations in the Lowe syndrome gene OCRL1 need to be revised