Search Publications
A Monte Carlo Markov Chain Based Investigation of Black Hole Spin in the Active Galaxy NGC 3783
Fabian, Andrew C.; Brenneman, Laura W.; Reynolds, Christopher S. +4 more
The analysis of relativistically broadened X-ray spectral features from the inner accretion disk provides a powerful tool for measuring the spin of supermassive black holes in active galactic nuclei (AGNs). However, AGN spectra are often complex and careful analysis employing appropriate and self-consistent models is required if one has to obtain …
Overdensities of Y-dropout Galaxies from the Brightest-of-Reionizing Galaxies Survey: A Candidate Protocluster at Redshift z ≈ 8
Shull, J. M.; Treu, T.; Carollo, C. M. +8 more
Theoretical and numerical modeling of the assembly of dark-matter halos predicts that the most massive and luminous galaxies at high redshift are surrounded by overdensities of fainter companions. We test this prediction with Hubble Space Telescope observations acquired by our Brightest-of-Reionizing Galaxies (BoRG) survey, which identified four v…
A Double Cluster at the Core of 30 Doradus
Panagia, N.; Anderson, J.; Lennon, D. J. +7 more
Based on an analysis of data obtained with the Wide Field Camera 3 on the Hubble Space Telescope we report the identification of two distinct stellar populations in the core of the giant H II region 30 Doradus in the Large Magellanic Cloud. The most compact and richest component coincides with the center of R136 and is ~1 Myr younger than a second…
Detection of Elements at All Three r-process Peaks in the Metal-poor Star HD 160617
Roederer, Ian U.; Lawler, James E.
We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detected previously in halo stars, and the elements tellurium, osmium, iridium, and platinum, which have been detected previously. Absorption lines of these elements are foun…
Herschel-ATLAS: Toward a Sample of ~1000 Strongly Lensed Galaxies
Rodighiero, G.; Frayer, D. T.; Sutherland, W. +39 more
While the selection of strongly lensed galaxies (SLGs) with 500 µm flux density S 500 > 100 mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is i…
Observations and Magnetic Field Modeling of a Solar Polar Crown Prominence
van Ballegooijen, Adriaan; Su, Yingna
We present observations and magnetic field modeling of the large polar crown prominence that erupted on 2010 December 6. Combination of Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and STEREO_Behind/EUVI allows us to see the fine structures of this prominence both at the limb and on the disk. We focus on the structures and d…
A Statistical Study of Solar Electron Events over One Solar Cycle
Krucker, Säm; Lin, R. P.; Mason, Glenn M. +1 more
We survey the statistical properties of 1191 solar electron events observed by the WIND 3DP instrument from <1 keV to gsim300 keV for a solar cycle (1995 through 2005). After taking into account times of high background, the corrected occurrence frequency of solar electron events versus peak flux exhibits a power-law distribution over three ord…
Reconstructing the Near-infrared Background Fluctuations from Known Galaxy Populations Using Multiband Measurements of Luminosity Functions
Ricotti, Massimo; Kashlinsky, Alexander; Helgason, Kari
We model fluctuations in the cosmic infrared background (CIB) arising from known galaxy populations using 233 measured UV, optical, and near-IR luminosity functions (LFs) from a variety of surveys spanning a wide range of redshifts. We compare best-fit Schechter parameters across the literature and find clear indication of evolution with redshift.…
Radio and X-Ray Observations of SN 2006jd: Another Strongly Interacting Type IIn Supernova
Chandra, Poonam; Fransson, Claes; Chevalier, Roger A. +5 more
We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope, and Expanded Very Large Array; at X-ray wavelengths with Chandra, XMM-Newton, and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction …
Outer-disk Populations in NGC 7793: Evidence for Stellar Radial Migration
Holwerda, Benne W.; Radburn-Smith, David J.; de Jong, Roelof S. +8 more
We analyzed the radial surface brightness profile of the spiral galaxy NGC 7793 using HST/ACS images from the GHOSTS survey and a new HST/WFC3 image across the disk break. We used the photometry of resolved stars to select distinct populations covering a wide range of stellar ages. We found breaks in the radial profiles of all stellar populations …