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Characterizing the Low-Redshift Intergalactic Medium toward PKS 1302-102
Weiner, Benjamin J.; Chen, Hsiao-Wen; Mulchaey, John S. +2 more
We present a detailed analysis of the intergalactic metal-line absorption systems in the archival HST STIS and FUSE ultraviolet spectra of the low-redshift quasar PKS 1302-102 (zQSO = 0.2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field. There are 15 strong Lyα absorbers with…
Solar Rotation Rate and Its Gradients During Cycle 23
Basu, Sarbani; Antia, H. M.; Chitre, S. M.
Available helioseismic data now span almost the entire solar activity cycle 23, making it possible to study solar-cycle-related changes of the solar rotation rate in detail. In this paper we study how the solar rotation rate, in particular, the zonal flows, change with time. In addition to the zonal flows that show a well-known pattern in the sola…
Searching for Dark Matter with X-Ray Observations of Local Dwarf Galaxies
Profumo, S.; Jeltema, T. E.
A generic feature of weakly interacting massive particle (WIMP) dark matter models is the emission of photons over a broad energy band resulting from the stable yields of dark matter pair annihilation. Inverse Compton scattering off cosmic microwave background photons of energetic electrons and positrons produced in dark matter annihilation is exp…
Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic Plane
Kaaret, Philip; Walter, Roland; Tomsick, John A. +2 more
We report on the results of observations of hard X-ray sources in the Galactic plane with the Chandra X-Ray Observatory. The hard X-ray "IGR" sources were discovered by the INTEGRAL satellite, and the goals of the Chandra observations are to provide subarcsecond localizations to obtain optical and infrared counterparts and to provide constraints o…
Luminosity Indicators in the Ultraviolet Spectra of Type Ia Supernovae
Filippenko, Alexei V.; Foley, Ryan J.; Jha, Saurabh W.
We present a complete sample of International Ultraviolet Explorer and Hubble Space Telescope ultraviolet (UV) spectra of Type Ia supernovae (SNe Ia) through 2004. We measure the equivalent width (EW) and blueshifted velocity of the minimum of the one strong UV feature, Fe II λ3250. We also quantify the slope of the near-UV spectra using a new par…
Stellar Exotica in 47 Tucanae
Zurek, David R.; Shara, Michael M.; Long, Knox S. +3 more
We present far-ultraviolet (FUV) spectroscopy obtained with HST for 48 blue objects in the core of 47 Tuc. Based on their position in a FUV-optical color-magnitude diagram, these were expected to include cataclysmic variables (CVs), blue stragglers (BSs), white dwarfs (WDs), and other exotic objects. For a subset of these sources, we also construc…
Changes of Magnetic Structure in Three Dimensions Associated with the X3.4 Flare of 2006 December 13
Jing, Ju; Wang, Haimin; Kubo, Masahito +2 more
Recent observations demonstrated that sunspot structure can change rapidly and irreversibly after flares. One of the most puzzling results is the increase in magnetic shear around the flaring magnetic polarity inversion line after flares. However, all these observations were made at the photosphere level. In this Letter, we study the altitude vari…
Comparing Suzaku and XMM-Newton Observations of the Soft X-Ray Background: Evidence for Solar Wind Charge Exchange Emission
Henley, David B.; Shelton, Robin L.
We present an analysis of a pair of Suzaku spectra of the soft X-ray background (SXRB), obtained from pointings on and off a nearby shadowing filament in the southern Galactic hemisphere. Because of the different Galactic column densities in the two pointing directions, the observed emission from the Galactic halo has a different shape in the two …
Multiple and Precessing Collimated Outflows in the Planetary Nebula IC 4634
Guerrero, Martín A.; Chu, You-Hua; Miranda, Luis F. +6 more
With its remarkable double-S shape, IC 4634 is an archetype of point-symmetric planetary nebulae (PNe). In this paper, we present a detailed study of this PN using archival HST WFPC2 and ground-based narrowband images to investigate its morphology, and long-slit spectroscopic observations to determine its kinematics and to derive its physical cond…
Angular Diameters of the G Subdwarf µ Cassiopeiae A and the K Dwarfs σ Draconis and HR 511 from Interferometric Measurements with the CHARA Array
Gies, Douglas R.; Henry, Todd; Jao, Wei-Chun +13 more
Using the longest baselines of the CHARA Array, we have measured the angular diameter of the G5 V subdwarf µ Cas A, the first such determination for a halo population star. We compare this result to new diameters for the higher metallicity K0 V stars, σ Dra and HR 511, and find that the metal-poor star, µ Cas A, has an effective temper…