74 research outputs found

    A NuSTAR Survey of Nearby Ultraluminous Infrared Galaxies

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    We present a Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously possible. Six of the nine sources observed were detected sufficiently well by NuSTAR to model in detail their broadband X-ray spectra, and recover the levels of obscuration and intrinsic X-ray luminosities. Only one source (IRAS 13120–5453) has a spectrum consistent with a Compton-thick active galactic nucleus (AGN), but we cannot rule out that a second source (Arp 220) harbors an extremely highly obscured AGN as well. Variability in column density (reduction by a factor of a few compared to older observations) is seen in IRAS 05189–2524 and Mrk 273, altering the classification of these borderline sources from Compton-thick to Compton-thin. The ULIRGs in our sample have surprisingly low observed fluxes in high-energy (>10 keV) X-rays, especially compared to their bolometric luminosities. They have lower ratios of unabsorbed 2–10 keV to bolometric luminosity, and unabsorbed 2–10 keV to mid-IR [O iv] line luminosity than do Seyfert 1 galaxies. We identify IRAS 08572+3915 as another candidate intrinsically X-ray weak source, similar to Mrk 231. We speculate that the X-ray weakness of IRAS 08572+3915 is related to its powerful outflow observed at other wavelengths

    New insights from deep VLA data on the potentially recoiling black hole CID-42 in the COSMOS field

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    We present deep 3-GHz Karl G. Jansky Very Large Array (VLA) observations of the potentially recoiling black hole CID-42 in the Cosmic Evolution Survey (COSMOS) field. This galaxy shows two optical nuclei in the Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) image and a large velocity offset of ˜1300 km s-1 between the broad and narrow Hß emission line although the spectrum is not spacially resolved (Civano et al. 2010). The new 3 GHz VLA data have a bandwidth of 2 GHz and to correctly interpret the flux densities imaging was done with two different methods: multiscale multifrequency (MSMF) synthesis and spectral windows (SPWs) stacking. The final resolutions and sensitivities of these maps are 0.7 arcsec with rms = 4.6 µJy beam-1 and 0.9 arcsec with rms = 4.8 µJy beam-1, respectively. With a 7s detection, we find that the entire observed 3-GHz radio emission can be associated with the south-eastern component of CID-42, coincident with the detected X-ray emission. We use our 3 GHz data combined with other radio data from the literature ranging from 320 MHz to 9 GHz, which include the VLA, Very Long Baseline Array (VLBA) and Giant Metrewave Radio Telescope (GMRT) data, to construct a radio synchrotron spectrum of CID-42. The radio spectrum suggests a type I unobscured radio-quiet flat-spectrum active galactic nucleus (AGN) in the south-eastern component which may be surrounded by a more extended region of old synchrotron electron population or shocks generated by the outflow from the supermassive black hole (SMBH). Our data are consistent with the recoiling black hole picture but cannot rule out the presence of an obscured and radio-quiet SMBH in the north-western component

    International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

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    Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

    International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways

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    Picture-Book Professors:Academia and Children's Literature

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