24 research outputs found

    The CatWISE Preliminary Catalog: Motions from WISE and NEOWISE Data

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    CatWISE is a program to catalog sources selected from combined WISE and NEOWISE all-sky survey data at 3.4 and 4.6 μm (W1 and W2). The CatWISE Preliminary Catalog consists of 900,849,014 sources measured in data collected from 2010 to 2016. This data set represents four times as many exposures and spans over 10 times as large a time baseline as that used for the AllWISE Catalog. CatWISE adapts AllWISE software to measure the sources in coadded images created from six-month subsets of these data, each representing one coverage of the inertial sky, or epoch. The catalog includes the measured motion of sources in eight epochs over the 6.5 yr span of the data. From comparison to Spitzer, signal-to-noise ratio = 5 limits in magnitudes in the Vega system are W1 = 17.67 and W2 = 16.47, compared to W1 = 16.96 and W2 = 16.02 for AllWISE. From comparison to Gaia, CatWISE positions have typical accuracies of 50 mas for stars at W1 = 10 mag and 275 mas for stars at W1 = 15.5 mag. Proper motions have typical accuracies of 10 mas yr⁻¹ and 30 mas yr⁻¹ for stars with these brightnesses, an order of magnitude better than from AllWISE. The catalog is available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive

    Planck 2015 results I. Overview of products and scientific results

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    The European Space Agency's Planck satellite, which is dedicated to studying the early Universe and its subsequent evolution, was launched on 14 May 2009. It scanned the microwave and submillimetre sky continuously between 12 August 2009 and 23 October 2013. In February 2015, ESA and the Planck Collaboration released the second set of cosmology products based on data from the entire Planck mission, including both temperature and polarization, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the main characteristics of the data and the data products in the release, as well as the associated cosmological and astrophysical science results and papers. The data products include maps of the cosmic microwave background (CMB), the thermal Sunyaev-Zeldovich effect, diffuse foregrounds in temperature and polarization, catalogues of compact Galactic and extragalactic sources (including separate catalogues of Sunyaev-Zeldovich clusters and Galactic cold clumps), and extensive simulations of signals and noise used in assessing uncertainties and the performance of the analysis methods. The likelihood code used to assess cosmological models against the Planck data is described, along with a CMB lensing likelihood. Scientific results include cosmological parameters derived from CMB power spectra, gravitational lensing, and cluster counts, as well as constraints on inflation, non-Gaussianity, primordial magnetic fields, dark energy, and modified gravity, and new results on low-frequency Galactic foregrounds

    An overdensity of Lyman break galaxies around the hot dust-obscured galaxy WISE J224607.56 052634.9

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    We report the identification of Lyman break galaxy (LBG) candidates around the most luminous hot dust-Obscured galaxy (Hot DOG) known, WISE J224607.56 052634.9 (W2246 0526) at z'., ='., 4.601, using deep r-, i-, and z-band imaging from the Gemini Multi-Object Spectrograph South (GMOS-S). We used the surface density of LBGs to probe the megaparsec-scale environment of W2246 0526 to characterize its richness and evolutionary state. We identified LBG candidates in the vicinity of W2246 0526 using the selection criteria developed in the Subaru Deep Field and in the Subaru XMM-Newton Deep Field, slightly modified to account for the difference between the filters used, and we find 37 and 55 LBG candidates, respectively. Matching to the z-band depths of those studies, this corresponds to δ = 5.81.9+2.4 times the surface density of LBGs expected in the field. Interestingly, the Hot DOG itself, as well as a confirmed neighbor, do not satisfy either LBG selection criteria, suggesting we may be missing a large number of companion galaxies. Our analysis shows that we have mostly likely only found those with a higher than average intergalactic medium (IGM) optical depth or moderately high dust obscuration. The number density of LBG candidates is not concentrated around W2246 0526, suggesting an early evolutionary stage for the proto-cluster, that the Hot DOG may not be the most massive galaxy, or that the Hot DOG may be affecting the IGM transparency in its vicinity. The overdensity around W2246 0526 is comparable to overdensities found around other Hot DOGs and is somewhat higher than what is typically found for radio galaxies and luminous quasars at a similar redshift

    Super-Eddington Accretion in the WISE-selected Extremely Luminous Infrared Galaxy W2246-0526

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    We use optical and near-infrared spectroscopy to observe rest-UV emission lines and estimate the black hole mass of WISEA J224607.56−052634.9 (W2246−0526) at z = 4.601, the most luminous hot, dust-obscured galaxy yet discovered by WISE. From the broad component of the Mg ii 2799 Å emission line, we measure a black hole mass of log(M BH/M ☉) = 9.6 ± 0.4. The broad C iv 1549 Å line is asymmetric and significantly blueshifted. The derived M BH from the blueshift-corrected broad C iv line width agrees with the Mg ii result. From direct measurement using a well-sampled SED, the bolometric luminosity is 3.6 × 1014 L ☉. The corresponding Eddington ratio for W2246−0526 is λ Edd = L AGN/L Edd = 2.8. This high Eddington ratio may reach the level where the luminosity is saturating due to photon trapping in the accretion flow and may be insensitive to the mass accretion rate. In this case, the M BH growth rate in W2246−0526 would exceed the apparent accretion rate derived from the observed luminosity

    Discovery of a Low-redshift Hot Dust-obscured Galaxy

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    We report the discovery of the hyperluminous, highly obscured active galactic nuclei (AGN) WISE J190445.04+485308.9 (W1904+4853, hereafter, L bol ∼ 1.1 × 1013 L ⊙) at z = 0.415. Its well-sampled spectral energy distribution (SED) is dominated by infrared dust emission, though broad emission lines are detected in the optical spectra. These features suggest that W1904+4853 contains an actively accreting supermassive black hole hidden in its dusty cocoon, resembling the observed properties of hot dust-obscured galaxies (Hot DOGs), a population previously only identified at z > 1.0. Using the broad component of the Mg ii 2798 Å emission line, we estimate a black hole mass of log ( M BH / M ⊙ ) = 8.4 ± 0.4 . The corresponding Eddington ratio (η) of 1.4 − 0.7 + 1.3 implies that the central black hole accretion is at the theoretical limit of isotropic accretion. The rest-frame UV-optical SED also indicates that the host galaxy of W1904+4853 harbors strong star formation activity at the rate of 6-84 M ⊙ yr−1 with an independent estimate of star formation rate up to ∼45 M ⊙ yr−1 using the [O ii] emission line. With an estimated stellar mass of 3 × 1010 M ⊙, the host galaxy appears to be a starburst system with respect to the main sequence of the star-forming galaxies at the same redshift. Although blueshifted and asymmetric [O iii] emission provides evidence of an outflow, we estimate it to be an order of magnitude smaller than the star formation rate, indicating that the current obscured AGN activity at the center has not yet produced significant feedback on the host galaxy star formation activity. W1904+4853 supports the interpretation that Hot DOGs are a rare transitional phase of AGN accretion in galaxy evolution, a phase that can persist into the present-day Universe.</p
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