Search Publications
Interstellar Absorption-Line Evidence for High-Velocity Expanding Structures in the Carina Nebula Foreground
Walborn, Nolan R.; Smith, Nathan; Gull, Theodore R. +3 more
The extreme, high-velocity interstellar absorption-line profiles toward η Carinae and 16 neighboring stars in Trumpler 16 are examined, including several new sight lines observed in the ultraviolet with the Hubble Space Telescope or in the optical from the Magellan and European Southern Observatories. No two sight lines are identical, but many vel…
GRB 050713A: High-Energy Observations of the Gamma-Ray Burst Prompt and Afterglow Emission
Gehrels, N.; Pagani, C.; Stamerra, A. +14 more
Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow-field instruments 72.6 s after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously…
Measuring the Balmer Jump and the Effective Gravity in FGK Stars
Bessell, Michael S.
It is difficult to accurately measure the effective gravity (logg) in late-type stars using broadband (e.g., UBV or SDSS) or intermediate-band (uvby) photometric systems, especially when the stars can cover a range of metallicities and reddenings. However, simple spectroscopic observational and data reduction techniques can yield accurate values f…
The Far-Infrared Properties of Spatially Resolved AKARI Observations
Lee, H. M.; White, G. J.; Wang, L. +31 more
We present spatially resolved observations of IRAS sources from the Japanese infrared astronomy satellite AKARI All-Sky Survey during the performance verification phase of the mission. We extracted reliable point sources matched with the IRAS point source catalogue. By comparing IRAS and AKARI fluxes, we found that the flux measurements of some IR…
Nucleonic gamma-ray production in pulsar wind nebulae
Santangelo, A.; Aharonian, F.; Horns, D. +1 more
Observations of the inner radian of the Galactic disk at very high energy (VHE) gamma-rays have revealed at least 16 new sources. Besides shell type super-nova remnants, pulsar wind nebulae (PWN) appear to be a dominant source population in the catalogue of VHE gamma-ray sources. Except for the Crab nebula, the newly discovered PWN are resolved at…
Lensing Signals in the Hubble Ultra Deep Field Using All Second-Order Shape Deformations
Anderson, Jay; Irwin, John; Shmakova, Marina
The long exposure times of the Hubble Ultra Deep Field (UDF) together with empirically derived position-dependent point-spread functions have enabled us to measure two distinct nonlinear shape distortions of galaxies. We have previously argued that nonlinear lensing from small (109-1010 Msolar) dense objects in the…
A review of SOHO/UVCS observations of sungrazing comets
Bemporad, A.; Poletto, G.; Giordano, S. +1 more
In the last 10 years more than 1000 sungrazing comets have been discovered by the LASCO coronagraphs aboard SOHO the spacecraft; from this huge amount of data it has been possible to study the common origin of these comets and to explain some of the main peculiarities observed in their lightcurves. Moreover, the UV Coronagraph Spectrometer (UVCS) …
Surface Brightness Profiles for a Sample of LMC, SMC, and Fornax Galaxy Globular Clusters
Gebhardt, K.; Noyola, E.
We use Hubble Space Telescope archival images to measure central surface brightness profiles of globular clusters around satellite galaxies of the Milky Way. We report results for 21 clusters around the LMC, five around the SMC, and four around the Fornax dwarf galaxy. The profiles were obtained using a recently developed technique based on measur…
Spectra of polar heliospheric fields and implications for field structure
Giacalone, Joe; Jokipii, J. R.; Goldstein, Melvyn L. +2 more
The predictions of the ``Fisk'' model for a peak at the equatorial solar rotation frequency in the spectrum of the latitudinal component of the heliospheric magnetic field were found to give values significantly larger than those observed. The observed values were statistically the same as observed in the ecliptic and were consistent with random f…
A Search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey
Teplitz, Harry I.; Siana, Brian; Malkan, Matthew A. +4 more
We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110-H160>=2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 σ sensitivities of J110=25.8 and H160=25.6 (AB). Distinguishing th…