Search Publications
A Relationship Between Supermassive Black Hole Mass and the Total Gravitational Mass of the Host Galaxy
Crampton, David; Simard, Luc; Bandara, Kaushala
We investigate the correlation between the mass of a central supermassive black hole (SMBH) and the total gravitational mass of the host galaxy (M tot). The results are based on 43 galaxy-scale strong gravitational lenses from the Sloan Lens ACS Surveys (SLACS) Survey whose black hole masses were estimated through two scaling relations:…
The Galactic Positron Annihilation Radiation and the Propagation of Positrons in the Interstellar Medium
Rothschild, R. E.; Higdon, J. C.; Lingenfelter, R. E.
The ratio of the luminosity of diffuse 511 keV positron annihilation radiation, measured by INTEGRAL in its four years, from a Galactic "positron bulge" (<1.5 kpc) compared to that of the disk is ~1.4. This ratio is roughly 4 times larger than that expected simply from the stellar bulge-to-disk ratio of ~0.33 of the Galactic supernovae (SNe), w…
Galaxy Clusters in the Swift/Burst Alert Telescope Era: Hard X-rays in the Intracluster Medium
Böhringer, H.; Greiner, J.; Moretti, A. +6 more
We report the detection of 10 clusters of galaxies in the ongoing Swift/Burst Alert Telescope (BAT) all-sky survey. This sample, which mostly comprises merging clusters, was serendipitously detected in the 15-55 keV band. We use the BAT sample to investigate the presence of excess hard X-rays above the thermal emission. The BAT clusters do not sho…
Evidence of Widespread Hot Plasma in a Nonflaring Coronal Active Region from Hinode/X-Ray Telescope
Testa, Paola; Reale, Fabio; Parenti, Susanna +1 more
Nanoflares, short and intense heat pulses within spatially unresolved magnetic strands, are now considered a leading candidate to solve the coronal heating problem. However, the frequent occurrence of nanoflares requires that flare-hot plasma be present in the corona at all times. Its detection has proved elusive until now, in part because the int…
The End of Nucleosynthesis: Production of Lead and Thorium in the Early Galaxy
Roederer, Ian U.; Frebel, Anna; Christlieb, Norbert +4 more
We examine the Pb and Th abundances in 27 metal-poor stars (-3.1< [Fe/H] <-1.4) whose very heavy metal (Z > 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from Hubble Space Telescope/Space Telescope Imaging Spectrograph, Keck/High Resolution Echelle Spectrograph, and Very Large Teles…
Hinode X-Ray Telescope Detection of Hot Emission from Quiescent Active Regions: A Nanoflare Signature?
Klimchuk, J. A.; Golub, L.; Schmelz, J. T. +4 more
The X-Ray Telescope (XRT) on the Japanese/USA/UK Hinode (Solar-B) spacecraft has detected emission from a quiescent active region core that is consistent with nanoflare heating. The fluxes from 10 broadband X-ray filters and filter combinations were used to construct differential emission measure (DEM) curves. In addition to the expected active re…
Imaging The Molecular Gas in a z = 3.9 Quasar Host Galaxy at 0farcs3 Resolution: A Central, Sub-Kiloparsec Scale Star Formation Reservoir in APM 08279+5255
Lewis, Geraint F.; Walter, Fabian; Carilli, Christopher L. +1 more
We have mapped the molecular gas content in the host galaxy of the strongly lensed high-redshift quasar APM 08279+5255 (z = 3.911) with the Very Large Array at 0farcs3 resolution. The CO(J = 1 → 0) emission is clearly resolved in our maps. The CO(J = 1 → 0) line luminosity derived from these maps is in good agreement with a previous single-dish me…
Calibration Of [O IV] 26 µm as a Measure of Intrinsic Active Galactic Nucleus Luminosity
Rigby, J. R.; Aniano, G.; Diamond-Stanic, A. M.
We compare [O IV] 25.89 µm emission line luminosities with very hard (10-200 keV) X-rays from Swift, INTEGRAL, and BeppoSAX for a complete sample of 89 Seyferts from the Revised Shapley-Ames sample. Using Seyfert 1s, we calibrate [O IV] as a measure of active galactic nucleus (AGN) intrinsic luminosity, for particular use in high-obscuration…
The UDF05 Follow-Up of the Hubble Ultra Deep Field. II. Constraints on Reionization from Z-Dropout Galaxies
Panagia, N.; Gardner, Jonathan P.; Ferguson, H. C. +12 more
We detect three (plus one less certain) z 850-dropout sources in two separate fields (Hubble Ultra Deep Field and NICP34) of our UDF05 Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer images. These z ~ 7 Lyman-break Galaxy (LBG) candidates allow us to constrain the Luminosity Function (LF) of the star-forming ga…
The Evolution Of Massive Young Stellar Objects in the Large Magellanic Cloud. I. Identification and Spectral Classification
Brandner, Wolfgang; Chu, You-Hua; Gruendl, Robert A. +5 more
We present and categorize Spitzer infrared spectrometer spectra of 294 objects in the Large Magellanic Cloud (LMC) to create the largest and most complete catalog of massive young stellar object (YSO) spectra in the LMC. Target sources were identified from infrared photometry and multiwavelength images indicative of young, massive stars highly ens…