Search Publications
The X-Ray Emissions from the M87 Jet: Diagnostics and Physical Interpretation
Perlman, Eric S.; Wilson, Andrew S.
We reanalyze the deep Chandra observations of the M87 jet, first examined by Wilson & Yang in 2002. By employing an analysis chain that also includes image deconvolution, knots HST-1 and I are fully separated from adjacent emission. We derive the spatially resolved X-ray spectrum of the jet using the most recent response functions and find sli…
An HST Search for Supernovae Accompanying X-Ray Flashes
Cenko, S. B.; Peterson, B. A.; Price, P. A. +24 more
We present the results from a Hubble Space Telescope ACS search for supernovae associated with X-ray flashes 020903, 040701, 040812, and 040916. We find strong evidence that XRF 020903 (z=0.25) was associated with a SN 1998bw-like supernova and confirm this using optical spectroscopy at t~25 days. We find no evidence, however, for SN 1998bw-like s…
Kelu-1 Is a Binary L Dwarf: First Brown Dwarf Science from Laser Guide Star Adaptive Optics
Leggett, S. K.; Liu, Michael C.
We present near-infrared (1-2.4 µm) imaging of the L dwarf Kelu-1 obtained with the Keck sodium laser guide star adaptive optics (LGS AO) system as part of a high angular resolution survey for substellar binaries. Kelu-1 was one of the first free-floating L dwarfs identified, and the origin of its overluminosity compared to objects of simila…
Magnetic Reconnection Rate and Flux-Rope Acceleration of Two-Ribbon Flares
Lin, Jun; Xu, Yan; Qiu, Jiong +3 more
Forbes & Lin derived simple equations to link the properties of magnetic reconnection in the corona to observed signatures of solar flares. We measured the photospheric magnetic fields and the flare ribbon separation speeds then applied these equations to derive two physical terms for the magnetic reconnection rates: the rate of magnetic flux …
Detection of Ne VIII in the Low-Redshift Warm-Hot Intergalactic Medium
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D. +2 more
High-resolution FUSE and STIS observations of the bright QSO HE 0226-4110 (zem=0.495) reveal the presence of a multiphase absorption-line system at zabs(OVI)=0.20701 containing absorption from H I (Lyα to Lyθ), C III, O III, O IV, O VI, N III, Ne VIII, Si III, S VI, and possibly S V. Single-component fits to the Ne VIII and O…
Weak-Lensing Analysis of the z~=0.8 Cluster CL 0152-1357 with the Advanced Camera for Surveys
Ford, H. C.; Demarco, R.; Rosati, P. +5 more
We present a weak-lensing analysis of the X-ray-luminous cluster CL 0152-1357 at z~=0.84 using Hubble Space Telescope/Advanced Camera for Surveys (ACS) observations. The unparalleled resolution and sensitivity of ACS enable us to measure weakly distorted, faint background galaxies to the extent that the number density reaches ~175 arcmin-2
A Young Brown Dwarf Companion to DH Tauri
Kobayashi, Naoto; Usuda, Tomonori; Pyo, Tae-Soo +20 more
We present the detection of a young brown dwarf companion, DH Tau B, associated with the classical T Tauri star DH Tau. Near-infrared coronagraphic observations with CIAO on the Subaru Telescope have revealed DH Tau B with H=15 mag located 2.3" (330 AU) away from the primary, DH Tau A. Comparing its position with a Hubble Space Telescope archive i…
A Chandra Study of the Multicomponent X-Ray Emission from the X-shaped Radio Galaxy 3C 403
Hardcastle, M. J.; Worrall, D. M.; Murray, S. S. +1 more
We present results from a 49.4 ks Chandra ACIS-S observation of the nearby (z=0.059) X-shaped FR type II (FR II) radio galaxy 3C 403. This is the first Chandra observation of an X-shaped radio galaxy, and one of the goals of this pioneering study is to determine the relationship between the X-ray-emitting gas and the X-shaped radio morphology. We …
An X-Ray Variable Millisecond Pulsar in the Globular Cluster 47 Tucanae: Closing the Link to Low-Mass X-Ray Binaries
Bogdanov, Slavko; van den Berg, Maureen; Grindlay, Jonathan E.
We report the discovery of peculiar X-ray spectral variability in the binary radio millisecond pulsar PSR J0024-7204W in the globular cluster 47 Tuc. The observed emission consists of a dominant nonthermal component, which is eclipsed for a portion of the orbit, and a thermal component, which appears to be persistent. We propose that the nontherma…
Moving Magnetic Features around Sunspots
Shine, Richard A.; Hagenaar, Hermance J.
We study statistical properties of small-scale magnetic features around sunspots using time sequences of high-resolution magnetograms of eight sunspots made with the Michelson Doppler Imager (MDI) on board SOHO. Flow maps around the spots are also derived from cross-correlation analysis of MDI continuum or TRACE white light and used for comparison…