Search Publications
Suzaku Observations of the Prototype Wind-blown Bubble NGC 6888
Zhekov, Svetozar A.; Park, Sangwook
We present an analysis of the Suzaku observations of the prototype wind-blown bubble NGC 6888 which is based both on use of standard spectral models and on a direct comparison of theoretical models with observations. The X-ray spectra of NGC 6888 are soft and most of the X-rays are in the 0.3-1.5 keV energy range. But, hard X-rays (1.5-4.0 keV) ar…
Keck Spectroscopy of Lyman-break Galaxies and Its Implications for the UV-continuum and Lyα Luminosity Functions at z > 6
Ouchi, Masami; Shimasaku, Kazuhiro; Jiang, Linhua +6 more
We present Keck spectroscopic observations of z > 6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z' = 27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Lyα emission lines at 6 <= z <= 6.4. …
Vector Magnetic Fields of A Solar Polar Region
Wang, Jingxiu; Jin, Chunlan
We study the vector magnetic fields of a solar polar region (PR) based on Solar Optical Telescope/Spectro-Polarimeter measurements. To better understand the polar magnetic properties, we compare the observed polar field with that in two solar quiet regions at the limb (QRL) and the disk center (QRD), and with that in a region of a low-latitude cor…
A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line
Shull, J. Michael; Danforth, Charles W.; Stocke, John T. +4 more
Thermally broadened Lyα absorbers (BLAs) offer an alternate method to using highly ionized metal absorbers (O VI, O VII, etc.) to probe the warm-hot intergalactic medium (WHIM, T = 105-107 K). Until now, WHIM surveys via BLAs have been no less ambiguous than those via far-UV and X-ray metal-ion probes. Detecting these weak, b…
Constraining Saturn's Core Properties by a Measurement of Its Moment of Inertia—Implications to the Cassini Solstice Mission
Helled, R.
Knowledge of Saturn's axial moment of inertia can provide valuable information on its internal structure. We suggest that Saturn's angular momentum may be determined by the Solstice Mission (Cassini XXM) by measuring Saturn's pole precession rate and the Lense-Thirring acceleration on the spacecraft, and therefore put constraints on Saturn's momen…
A Dwarf Nova in the Globular Cluster M13
Knigge, C.; van den Berg, M.; Servillat, M. +4 more
Dwarf novae (DNe) in globular clusters (GCs) seem to be rare with only 13 detections in the 157 known Galactic GCs. We report the identification of a new DN in M13, the 14th DN identified in a GC to date. Using the 2 m Faulkes Telescope North, we conducted a search for stars in M13 that show variability over a year (2005-2006) on timescales of day…
The M81 Group Dwarf Irregular Galaxy DDO 165. II. Connecting Recent Star Formation with Interstellar Medium Structures and Kinematics
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +8 more
We compare the stellar populations and complex neutral gas dynamics of the M81 group dIrr galaxy DDO 165 using data from the Hubble Space Telescope and the Very Large Array. Cannon et al. in Paper I of this series identified two kinematically distinct H I components, multiple localized high velocity gas features, and eight H I holes and shells (th…
The X-Ray Counterpart of the High-B Pulsar PSR J0726-2612
van Kerkwijk, M. H.; Speagle, J. S.; Kaplan, D. L.
Middle-aged, cooling neutron stars are observed both as relatively rapidly spinning radio pulsars and as more slowly spinning, strongly magnetized isolated neutron stars (INSs), which stand out by their thermal X-ray spectra. The difference between the two classes may be that the INSs initially had much stronger magnetic fields, which decayed. To …
Herschel Observations of the T Cha Transition Disk: Constraining the Outer Disk Properties
Henning, Thomas; Pinte, Christophe; Cieza, Lucas A. +7 more
T Cha is a nearby (d ~ 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huélamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel pho…
Detection of Brown Dwarf Like Objects in the Core of NGC 3603
McCarthy, Patrick J.; Calzetti, Daniela; Whitmore, Bradley C. +23 more
We used near-infrared data obtained with the Wide Field Camera 3 on the Hubble Space Telescope to identify objects having the colors of brown dwarfs (BDs) in the field of the massive galactic cluster NGC 3603. These are identified through a combination of narrow- and medium-band filters which span the J and H bands and are particularly sensitive t…