Search Publications
Large Disklike Galaxies at High Redshift
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +11 more
Using deep near-infrared imaging of the Hubble Deep Field-South with the Infrared Spectrometer and Array Camera on the Very Large Telescope, we find six large disklike galaxies at redshifts z=1.4-3.0. The galaxies, selected in Ks (2.2 µm), are regular and surprisingly large in the near-infrared (rest-frame optical), with face-on e…
The Effect of Proton Temperature Anisotropy on the Solar Minimum Corona and Wind
Raymond, John C.; Vásquez, Alberto M.; van Ballegooijen, Adriaan A.
A semiempirical, axisymmetric model of the solar minimum corona is developed by solving the equations for conservation of mass and momentum with prescribed anisotropic temperature distributions. In the high-latitude regions, the proton temperature anisotropy is strong and the associated mirror force plays an important role in driving the fast sola…
Chromospheric Evaporation and Warm Rain during a Solar Flare Observed in High Time Resolution with the Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory
Brosius, Jeffrey W.
We present EUV light curves, Doppler shifts, and line-broadening measurements for a flaring solar active region obtained with the Coronal Diagnostic Spectrometer (CDS) aboard the NASA ESA Solar and Heliospheric Observatory (SOHO) under conditions of (1) comprehensive temporal coverage (including the quiescent preflare, impulsive, and gradual decli…
A Chandra Study of the Complex Structure in the Core of 2A 0335+096
Mazzotta, P.; Markevitch, M.; Edge, A. C.
We present a Chandra observation of the central (r<200 kpc) region of the cluster of galaxies 2A 0335+096, rich in interesting phenomena. On large scales (r>40 kpc), the X-ray surface brightness is symmetric and slightly elliptical. The cluster has a cool, dense core; the radial temperature gradient varies with position angle. The radial met…
Gamma-Ray Lines from Asymmetric Supernovae
Fryer, Chris L.; Hungerford, Aimee L.; Warren, Michael S.
We present three-dimensional smoothed particle hydrodynamics simulations of supernova explosions from 100 s to 1 yr after core bounce. By extending our modeling efforts to a three-dimensional hydrodynamics treatment, we are able to investigate the effects of explosion asymmetries on mixing and γ-ray line emergence in supernovae. A series of initia…
The Low-Mass X-Ray Binary-Globular Cluster Connection. II. NGC 4472 X-Ray Source Properties and Source Catalogs
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J.
We present the results of a Chandra/Hubble Space Telescope (HST) study of the point sources of the Virgo Cluster giant elliptical galaxy NGC 4472. We identify 144 X-ray point sources outside the nuclear region, 72 of which are located within the HST fields. The optical data show 1102 sources, of which 829 have colors consistent with being globular…
Month-Timescale Optical Variability in the M87 Jet
Perlman, Eric S.; Sparks, William B.; Macchetto, F. Duccio +2 more
A previously inconspicuous knot in the M87 jet has undergone a dramatic outburst and now exceeds the nucleus in optical and X-ray luminosity. Monitoring of M87 with the Hubble Space Telescope and Chandra X-Ray Observatory during 2002-2003, has found month-timescale optical variability in both the nucleus and HST-1, a knot in the jet 0.82" from the…
An X-Ray Jet Discovered by Chandra in the z=4.3 Radio-selected Quasar GB 1508+5714
Schwartz, D. A.; Smith, Randall K.; Siemiginowska, Aneta +3 more
We report the Chandra discovery of an X-ray jet associated with the z=4.3 radio-loud quasar GB 1508+5714. The jet X-ray emission peaks ~2" to the southwest of the quasar core. We present archival Hubble Space Telescope Wide Field Planetary Camera 2 data of the quasar field that show no optical emission at the location of the X-ray jet. We discuss …
A Hubble Space Telescope Search for Lyman Continuum Emission from Galaxies at 1.1 < z < 1.4
Malkan, Matthew; Webb, Wayne; Konopacky, Quinn
If enough of their Lyman-limit continuum escapes, star-forming galaxies could be significant contributors to the cosmic background of ionizing photons. To investigate this possibility, we obtained the first deep imaging in the far-ultraviolet of 11 bright blue galaxies at intermediate redshift (1.1<z<1.4) with the Space Telescope Imaging Spe…
Solar and Heliospheric Observatory/Coronal Diagnostic Spectrograph and Ground-based Observations of a Two-Ribbon Flare: Spatially Resolved Signatures of Chromospheric Evaporation
Andretta, V.; Teriaca, L.; Falchi, A. +3 more
During a coordinated observing campaign (Solar and Heliospheric Observatory, SOHO JOP 139), we obtained simultaneous spectroheliograms of a solar active region in several spectral lines, sampling levels from the chromosphere to the corona. Ground-based spectroheliograms were acquired at the Dunn Solar Tower of the National Solar Observatory/Sacram…