Search Publications
The Structural Properties of Isolated Galaxies, Spiral-Spiral Pairs, and Mergers: The Robustness of Galaxy Morphology during Secular Evolution
Conselice, C. J.; Hernández-Toledo, H. M.; Avila-Reese, V. +1 more
We present a structural analysis of nearby galaxies in spiral-spiral pairs in optical BVRI bands and compare them with the structures of isolated spiral galaxies and galaxies in ongoing mergers. We use these comparisons to determine how galaxy structure changes during galaxy interactions and mergers. We analyze light concentration (C), asymmetry (…
The Gamma-Ray Giant Flare from SGR 1806-20: Evidence of Crustal Cracking via Initial Timescales
Kataria, D. O.; Zane, Silvia; Schwartz, Steven J. +6 more
Soft γ-ray repeaters (SGRs) are neutron stars that emit short (<~1 s) and energetic (<~1042 ergs s-1) bursts of soft γ-rays. Only four of them are currently known. Occasionally, SGRs have been observed to emit much more energetic ``giant flares'' (~1044-1045 ergs s-1). These are exceptio…
XMM-Newton study of the two-dimensional structure of the REFLEX-DXL galaxy clusters
Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H.
We carry out a two-dimensional study of temperature, entropy, and pressure distributions in a nearly volume-limited subsample of REFLEX clusters at redshift 0.3, the REFLEX-DXL. We use the observations gained by XMM-Newton, which cover the central 1{-}2× r500. We define the substructure in both entropy and pressure as a deviation from t…
Old Globular Clusters Masquerading as Young in NGC 4365?
Forbes, Duncan A.; Brodie, Jean P.; Beasley, Michael A. +5 more
High signal-to-noise ratio, low-resolution spectra have been obtained for 22 globular clusters (GCs) in NGC 4365. Some of these were selected as probable representatives of an intermediate-age (2-5 Gyr), extremely metal-rich GC subpopulation. The presence of such a subpopulation had been inferred from the unusual optical and near-infrared color di…
Hubble Space Telescope imaging of globular cluster candidates in low surface brightness dwarf galaxies
Sharina, M. E.; Makarov, D. I.; Puzia, T. H.
Fifty-seven nearby low surface brightness dwarf galaxies (-10⪆ MV⪆ -16) were searched for globular cluster candidates (GCCs) using Hubble Space Telescope WFPC2 imaging in V and I. The sample consists of 18 dwarf spheroidal (dSph), 36 irregular (dIrr), and 3 "transition" type (dIrr/dSph) galaxies with angular sizes less than 3.7 kpc situ…
The DEEP2 Galaxy Redshift Survey: Discovery of Luminous, Metal-poor Star-forming Galaxies at Redshifts z ~ 0.7
Hoyos, C.; Koo, D. C.; Willmer, C. N. A. +2 more
We have discovered a sample of 17 metal-poor, yet luminous, star-forming galaxies at redshifts z~0.7. They were selected from the initial phase of the DEEP2 survey of 3900 galaxies and the Team Keck Redshift Survey (TKRS) of 1536 galaxies as those showing the temperature-sensitive [O III] λ4363 auroral line. These rare galaxies have blue luminosit…
XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U 1700-37 at low flux
Kaper, L.; van der Klis, M.; Barr, P. +4 more
We present results of a monitoring campaign of the high-mass X-ray binary system
X-Ray/Ultraviolet Observing Campaign of the Markarian 279 Active Galactic Nucleus Outflow: A Global-Fitting Analysis of the Ultraviolet Absorption
Laor, Ari; Scott, Jennifer E.; Kriss, Gerard A. +12 more
We present an analysis of the intrinsic UV absorption in the Seyfert 1 galaxy Mrk 279 based on simultaneous long observations with the Hubble Space Telescope (41 ks) and the Far Ultraviolet Spectroscopic Explorer (91 ks). To extract the line-of-sight covering factors and ionic column densities, we separately fit two groups of absorption lines: the…
Martian variable features: New insight from the Mars Express Orbiter and the Mars Exploration Rover Spirit
Greeley, Ronald; Whelley, Patrick L.; Neakrase, Lynn D. V. +12 more
Linear, low-albedo patterns (termed dark wind streaks) formed on the floor of Gusev crater between September 2003 and February 2004, as seen on High Resolution Stereo Camera images taken on board the Mars Express Orbiter. Pancam images from the Mars Exploration Rover Spirit show that the rover crossed a dark streak during its traverse to Bonnevill…
The composition and size distribution of the dust in the coma of Comet Hale Bopp
Waters, L. B. F. M.; Dominik, C.; de Koter, A. +2 more
We discuss the composition and size distribution of the dust in the coma of Comet Hale-Bopp. We do this using a model fit for the infrared emission measured by the Infrared Space Observatory (ISO) and the measured degree of linear polarization of scattered light at various phase angles and wavelengths. The effects of particle shape on the modeled …