Search Publications
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…
X-Ray Absorption by the Low-Redshift Intergalactic Medium: A Numerical Study of the Λ Cold Dark Matter Model
Davé, Romeel; Weinberg, David H.; Chen, Xuelei +1 more
Using a hydrodynamic simulation of a cold dark matter universe with a cosmological constant, we investigate the ``X-ray forest'' absorption imprinted on the spectra of background quasars by the intervening intergalactic medium (IGM), at redshift z~0. In agreement with previous studies, we find that O VII and O VIII produce the strongest absorption…
The Contribution of Polar Plumes to the Fast Solar Wind
Lemaire, P.; Gabriel, A. H.; Bely-Dubau, F.
The Doppler dimming technique is used for the first time to study ultraviolet polar plumes in the height range of 1.05-1.35 Rsolar, using observations from the spectrometer SUMER on the Solar and Heliospheric Observatory. It is found that, contrary to a number of published suggestions, outflow velocities in the plumes exceed those in th…
The Internal Ultraviolet-Optical Color Dispersion: Quantifying the Morphological K-Correction
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +2 more
We present a quantitative measure of the internal color dispersion within galaxies, which quantifies differences in galaxy morphology as a function of observed wavelength. We apply this statistic to a sample of local galaxies with archival images at 1500 and 2500 Å from the Ultraviolet Imaging Telescope and ground-based B-band observations in orde…