Search Publications
Lunar mare deposits associated with the Orientale impact basin: New insights into mineralogy, history, mode of emplacement, and relation to Orientale Basin evolution from Moon Mineralogy Mapper (M3) data from Chandrayaan-1
Head, James W.; Mustard, John; Clark, Roger +6 more
Moon Mineralogy Mapper (M3) image and spectral reflectance data are combined to analyze mare basalt units in and adjacent to the Orientale multiring impact basin. Models are assessed for the relationships between basin formation and mare basalt emplacement. Mare basalt emplacement on the western nearside limb began prior to the Oriental…
A weakened cascade model for turbulence in astrophysical plasmas
Howes, G. G.; Dorland, W.; Tenbarge, J. M.
A refined cascade model for kinetic turbulence in weakly collisional astrophysical plasmas is presented that includes both the transition between weak and strong turbulence and the effect of nonlocal interactions on the nonlinear transfer of energy. The model describes the transition between weak and strong MHD turbulence and the complementary tra…
Redshift Evolution of the Galaxy Velocity Dispersion Function
Brinchmann, Jarle; van Dokkum, Pieter G.; Franx, Marijn +9 more
We present a study of the evolution of the galaxy velocity dispersion function (VDF) from z = 0 to z = 1.5 using photometric data from the Ultra-Deep and the NEWFIRM Medium-Band Survey in the COSMOS field. The VDF has been measured locally using direct kinematic measurements from the Sloan Digital Sky Survey (SDSS), but direct studies of the VDF a…
Population Parameters of Intermediate-age Star Clusters in the Large Magellanic Cloud. II. New Insights from Extended Main-sequence Turnoffs in Seven Star Clusters
Chandar, Rupali; Goudfrooij, Paul; Puzia, Thomas H. +1 more
We discuss new photometry from high-resolution images of seven intermediate-age (1-2 Gyr) star clusters in the Large Magellanic Cloud taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. We fit color-magnitude diagrams (CMDs) with several different sets of theoretical isochrones and determine systematic uncertainties for…
The Globular Cluster NGC 2419: A Crucible for Theories of Gravity
Dalessandro, E.; Bellazzini, M.; Chapman, S. C. +3 more
We present the analysis of a kinematic data set of stars in the globular cluster NGC 2419, taken with the DEep Imaging Multi-Object Spectrograph at the Keck II telescope. Combined with a reanalysis of deep Hubble Space Telescope and Subaru Telescope imaging data, which provide an accurate luminosity profile of the cluster, we investigate the valid…
Gemini/GMOS imaging of globular cluster systems in five early-type galaxies*
Forbes, Duncan A.; Zepf, Stephen E.; Gebhardt, Karl +7 more
In this paper, we present deep high-quality photometry of globular cluster systems (GCSs) belonging to five early-type galaxies, covering a range of mass and environment. Photometric data were obtained with the Gemini North and Gemini South telescopes in the filter passbands g', r' and i'. The combination of these filters with good seeing conditio…
Detection of Emerging Sunspot Regions in the Solar Interior
Zhao, Junwei; Ilonidis, Stathis; Kosovichev, Alexander
Sunspots are regions where strong magnetic fields emerge from the solar interior and where major eruptive events occur. These energetic events can cause power outages, interrupt telecommunication and navigation services, and pose hazards to astronauts. We detected subsurface signatures of emerging sunspot regions before they appeared on the solar …
AEGIS: Demographics of X-ray and Optically Selected Active Galactic Nuclei
Koekemoer, Anton M.; Weiner, Benjamin J.; Nandra, Kirpal +19 more
We develop a new diagnostic method to classify galaxies into active galactic nucleus (AGN) hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hβ ratio with rest-frame U - B color. This can be used to robustly select AGNs in galaxy samples at intermediate redshifts (z < 1). We compare the result of this opti…
Quantitative Examination of a Large Sample of Supra-arcade Downflows in Eruptive Solar Flares
Savage, Sabrina L.; McKenzie, David E.
Sunward-flowing voids above post-coronal mass ejection flare arcades were first discovered using the soft X-ray telescope aboard Yohkoh and have since been observed with TRACE (extreme ultraviolet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (soft X-rays). Supra-arcade downflow (SAD) observations suggest that they are…
A tale of two GRB-SNe at a common redshift of z=0.54
Im, M.; Melandri, A.; Pian, E. +71 more
We present ground-based and Hubble Space Telescope optical observations of the optical transients (OTs) of long-duration Gamma Ray Bursts (GRBs) 060729 and 090618, both at a redshift of z= 0.54. For GRB 060729, bumps are seen in the optical light curves (LCs), and the late-time broad-band spectral energy distributions (SEDs) of the OT resemble tho…