Search Publications
The Variation of Relative Magnetic Helicity around Major Flares
Yang, Guo; Jing, Ju; Wang, Haimin +5 more
We have investigated the variation of magnetic helicity over a span of several days around the times of 11 X-class flares which occurred in seven active regions (NOAA 9672, 10030, 10314, 10486, 10564, 10696, and 10720) using the magnetograms taken by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO). As a ma…
Suzaku Observations of AWM 7 Cluster of Galaxies: Temperatures, Abundances, and Bulk Motions
Ishida, Manabu; Sato, Kosuke; Ohashi, Takaya +4 more
We carried out 3 observations of the cluster of galaxies AWM 7, for the central region and 20'-east and 20'-west offset regions, with Suzaku. Temperature and abundance profiles were measured out to 27' simeq 570 h70-1kpc, which corresponded to ∼0.35r180. The temperature of the intra-cluster medium (ICM) slightly de…
a New View of the Super Star Clusters in the Low-Metallicity Galaxy SBS 0335-052
Hunt, Leslie K.; Johnson, Kelsey E.; Reines, Amy E.
We present a study of the individual super star clusters (SSCs) in the low-metallicity galaxy SBS 0335-052 using new near-infrared (near-IR) and archival optical Hubble Space Telescope observations. The physical properties of the SSCs are derived from fitting model spectral energy distributions (SEDs) to the optical photometry, as well as from the…
Anatomy of a young massive star cluster: NGC 1569-B
Larsen, S. S.; Gallagher, J. S.; Origlia, L. +1 more
We present new H-band echelle spectra, obtained with the NIRSPEC spectrograph at Keck II, for the massive star cluster `B' in the nearby dwarf irregular galaxy NGC 1569. From spectral synthesis and equivalent width measurements, we obtain abundances and abundance patterns. We derive an Fe abundance of [Fe/H] = -0.63 +/- 0.08, a supersolar [α/Fe] a…
Discontinuity in Jupiter's main auroral oval
Krupp, N.; Woch, J.; Bonfond, B. +3 more
On the basis of a series of FUV Hubble Space Telescope images obtained between 1997 and 2007 it is shown that there is a segment of the main auroral oval where the emission drops significantly from a few hundreds to a few tens of kiloRayleigh, forming a discontinuity in the oval. It is shown that the discontinuity is present in both hemispheres an…
Structural parameters for globular clusters in NGC 5128 - III. ACS surface brightness profiles and model fits
Forbes, Duncan A.; Barmby, Pauline; Harris, William E. +2 more
We present internal surface brightness profiles, based on Hubble Space Telescope/ACS imaging in the F606W bandpass, for 131 globular cluster (GC) candidates with luminosities L ~= 104-3 × 106Lsolar in the giant elliptical galaxy NGC 5128. Several structural models are fitted to the profile of each cluster and combi…
2 Years of INTEGRAL Monitoring of GRS 1915+105. I. Multiwavelength Coverage with INTEGRAL, RXTE, and the Ryle Radio Telescope
Belloni, T.; Rodriguez, J.; Cadolle Bel, M. +13 more
We report the results of simultaneous monitoring observations of the Galactic microquasar GRS 1915+105 with INTEGRAL and RXTE from 3 up to ~300 keV, and the Ryle Telescope at 15 GHz. We first identify the classes of variability in which GRS 1915+105 is found, and report some direct transitions between them. The accretion ejection connections are s…
Metallicity-corrected Tip of the Red Giant Branch Distance to NGC 4258
Madore, Barry F.; Freedman, Wendy L.; Mager, Violet A.
We have determined the distance to NGC 4258 using observations made with the Hubble Space Telescope (HST) and the Wide Field, Advanced Camera for Surveys (ACS WFC). We apply a modified technique that fully accounts for metallicity effects on the use of the luminosity of the tip of the red giant branch (TRGB) to determine one of the most precise TR…
The determination of the structure of Saturn's F ring by nearby moonlets
Charnoz, Sébastien; Murray, Carl D.; Beurle, Kevin +3 more
Saturn's narrow F ring exhibits several unusual features that vary on timescales of hours to years. These include transient clumps, a central core surrounded by a multistranded structure and a regular series of longitudinal channels associated with Prometheus, one of the ring's two `shepherding' satellites. Several smaller moonlets and clumps have…
Ejecta, Dust, and Synchrotron Radiation in SNR B0540-69.3: A More Crab-Like Remnant than the Crab
Blair, William P.; Reynolds, Stephen P.; Points, Sean +10 more
We present near- and mid-infrared observations of the pulsar-wind nebula (PWN) SNR B0540-69.3 and its associated supernova remnant made with the Spitzer Space Telescope. We report detections of the PWN with all four IRAC bands, the 24 µm band of MIPS, and the Infrared Spectrograph (IRS). We find no evidence of IR emission from the X-ray/radi…