Search Publications
The Supermassive Black Hole in M84 Revisited
Barth, Aaron J.; Sarzi, Marc; Walsh, Jonelle L.
The mass of the central black hole in the giant elliptical galaxy M84 has previously been measured by two groups using the same observations of emission-line gas with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, giving strongly discrepant results: Bower et al. found M BH = (1.5+1.1 -0.6<…
Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging of a Growing Compact Galaxy at z = 1.9
van Dokkum, Pieter G.; Brammer, Gabriel
We present HST/WFC3 grism near-IR spectroscopy of the brightest galaxy at z > 1.5 in the GOODS-South WFC3 ERS grism pointing. The spectrum is of remarkable quality and shows the redshifted Balmer lines Hβ, Hγ, and Hδ in absorption at z = 1.902 ± 0.002. The absorption lines can be produced by a post-starburst stellar population with a luminosity…
The Einstein Cross: Constraint on Dark Matter from Stellar Dynamics and Gravitational Lensing
Miller, Bryan W.; van de Ven, Glenn; Cappellari, Michele +3 more
We present two-dimensional line-of-sight stellar kinematics of the lens galaxy in the Einstein Cross, obtained with the GEMINI 8 m telescope, using the GMOS integral-field spectrograph. The stellar kinematics extend to a radius of 4'' (with 0farcs2 spaxels), covering about two-thirds of the effective (or half-light) radius Re ~= 6'' of …
Weak-lensing Mass Measurements of Substructures in Coma Cluster with Subaru/Suprime-cam
Okabe, N.; Futamase, T.; Okura, Y.
We obtain the projected mass distributions for two Subaru/Suprime-Cam fields in the southwest region (r <~ 60') of the Coma Cluster (z = 0.0236) by weak-lensing analysis and we detect eight subclump candidates. We quantify the contribution of background large-scale structure (LSS) on the projected mass distributions using Sloan Digital Sky Surv…
On the Relative Constancy of the Solar Wind Mass Flux at 1 AU
Wang, Y. -M.
Employing solar wind measurements from the Advanced Composition Explorer and Ulysses, photospheric magnetic data, and conservation laws along open field lines, we confirm that the energy and mass flux densities at the Sun increase roughly linearly with the footpoint field strength, B 0. This empirical result has a number of important ph…
Imaging Redshift Estimates for BL Lacertae Objects
Meisner, Aaron M.; Romani, Roger W.
We have obtained high dynamic range, good natural seeing i' images of BL Lacertae objects (BL Lacs) to search for the active galactic nucleus host and thus constrain the source redshift. These objects are drawn from a sample of bright flat-spectrum radio sources that are either known (via recent Fermi Large Area Telescope observations) gamma-ray e…
Search for Gamma-ray Emission from Magnetars with the Fermi Large Area Telescope
Ozaki, M.; Troja, E.; Caraveo, P. A. +136 more
We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi energy range are estimated between ~10
Statistical Properties of Solar Active Regions Obtained from an Automatic Detection System and the Computational Biases
Liu, Yang; Wang, Yuming; Zhang, Jie
We have developed a computational software system to automate the process of identifying solar active regions (ARs) and quantifying their physical properties based on high-resolution synoptic magnetograms constructed from Michelson Doppler Imager (MDI; on board the SOHO spacecraft) images from 1996 to 2008. The system, based on morphological analy…
A Variable Black Hole X-ray Source in an NGC 1399 Globular Cluster
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +2 more
We have discovered an accreting black hole (BH) in a spectroscopically confirmed globular cluster (GC) in NGC 1399 through the monitoring of its X-ray activity. The source, with a peak luminosity of L X ~= 2 × 1039 erg s-1, reveals an order of magnitude change in the count rate within sime10 ks in a Chandra obser…
Searching for Far-ultraviolet Auroral/Dayglow Emission from HD 209458b
France, Kevin; Stocke, John T.; Wolven, Brian C. +5 more
We present recent observations from the Hubble Space Telescope-Cosmic Origins Spectrograph aimed at characterizing the auroral emission from the extrasolar planet HD 209458b. We obtained medium-resolution (R ~ 20,000) far-ultraviolet (1150-1700 Å) spectra at both the Phase 0.25 and Phase 0.75 quadrature positions as well as a stellar baseline meas…