Search Publications
An Observed Link between Active Galactic Nuclei and Violent Disk Instabilities in High-redshift Galaxies
Dickinson, Mark; Daddi, Emanuele; Juneau, Stéphanie +7 more
We provide evidence for a correlation between the presence of giant clumps and the occurrence of active galactic nuclei (AGNs) in disk galaxies. Giant clumps of 108-109 M ⊙ arise from violent gravitational instability in gas-rich galaxies, and it has been proposed that this instability could feed supermassive black…
Spitzer Evidence for a Late-heavy Bombardment and the Formation of Ureilites in η Corvi at ~1 Gyr
Manoj, P.; Sitko, M. L.; Watson, D. M. +7 more
We have analyzed Spitzer and NASA/IRTF 2-35 µm spectra of the warm, ~350 K circumstellar dust around the nearby MS star η Corvi (F2V, 1.4 ± 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at ~3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive com…
Multiwavelength Variations of 3C 454.3 during the 2010 November to 2011 January Outburst
Gurwell, Mark A.; Grupe, Dirk; Agudo, Iván +6 more
We present multiwavelength data of the blazar 3C 454.3 obtained during an extremely bright outburst from 2010 November through 2011 January. These include flux density measurements with the Herschel Space Observatory at five submillimeter-wave and far-infrared bands, the Fermi Large Area Telescope at γ-ray energies, Swift at X-ray, ultraviolet (UV…
Classification of X-Ray Sources in the XMM-Newton Serendipitous Source Catalog
Lin, Dacheng; Webb, Natalie A.; Barret, Didier
We carry out classification of 4330 X-ray sources in the 2XMMi-DR3 catalog. They are selected under the requirement of being a point source with multiple XMM-Newton observations and at least one detection with the signal-to-noise ratio larger than 20. For about one-third of them we are able to obtain reliable source types from the literature. They…
Red and Dead: The Progenitor of SN 2012aw in M95
Sollerman, J.; Inserra, C.; Smartt, S. J. +17 more
Core-collapse supernovae (SNe) are the spectacular finale to massive stellar evolution. In this Letter, we identify a progenitor for the nearby core-collapse SN 2012aw in both ground-based near-infrared and space-based optical pre-explosion imaging. The SN itself appears to be a normal Type II Plateau event, reaching a bolometric luminosity of 10<…
Spatially Resolved Stellar, Dust, and Gas Properties of the Post-interacting Whirlpool Galaxy System
Lebouteiller, Vianney; Wilson, Christine D.; Baes, Maarten +15 more
Using infrared imaging from the Herschel Space Observatory, observed as part of the Very Nearby Galaxies Survey, we investigate the spatially resolved dust properties of the interacting Whirlpool galaxy system (NGC 5194 and NGC 5195), on physical scales of ~1 kpc. Spectral energy distribution modeling of the new infrared images in combination with…
Hot Disks and Delayed Bar Formation
Weiner, Benjamin J.; Abraham, Roberto G.; Elmegreen, Bruce G. +4 more
We present observational evidence for the inhibition of bar formation in dispersion-dominated (dynamically hot) galaxies by studying the relationship between galactic structure and host galaxy kinematics in a sample of 257 galaxies between 0.1 < z <= 0.84 from the All-Wavelength Extended Groth Strip International Survey and the Deep Extragal…
The Submillimeter and Millimeter Excess of the Small Magellanic Cloud: Magnetic Dipole Emission from Magnetic Nanoparticles?
Hensley, Brandon; Draine, B. T.
The Small Magellanic Cloud (SMC) has surprisingly strong submillimeter- and millimeter-wavelength emission that is inconsistent with standard dust models, including those with emission from spinning dust. Here, we show that the emission from the SMC may be understood if the interstellar dust mixture includes magnetic nanoparticles, emitting magnet…
Black Hole Powered Nebulae and a Case Study of the Ultraluminous X-Ray Source IC 342 X-1
Feng, Hua; Grisé, Fabien; Kaaret, Philip +6 more
We present new radio, optical, and X-ray observations of three ultraluminous X-ray sources (ULXs) that are associated with large-scale nebulae. We report the discovery of a radio nebula associated with the ULX IC 342 X-1 using the Very Large Array (VLA). Complementary VLA observations of the nebula around Holmberg II X-1, and high-frequency Austra…
Interstellar H I and H2 in the Magellanic Clouds: An Expanded Sample Based on Ultraviolet Absorption-line Data
Welty, Daniel E.; Wong, Tony; Xue, Rui
We have determined column densities of H I and/or H2 for sight lines in the Magellanic Clouds from archival Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer spectra of H I Lyα and H2 Lyman-band absorption. Together with some similar data from the literature, we now have absorption-based N(H I) and/or N(H…