Search Publications
XMM-Newton Observations of Ultraluminous X-Ray Sources in Nearby Galaxies
Feng, Hua; Kaaret, Philip
We examined X-ray spectral and timing properties of ultraluminous X-ray sources (ULXs) in nearby galaxies in XMM-Newton archival data. There appear to be three distinct classes of spectra. One class shows emission from hot, diffuse plasma. This thermal emission is similar to that seen from recent supernovae; the temperatures are in the range 0.6-0…
Fe K emission in the ultraluminous infrared galaxy Arp 220
Sanders, D. B.; Iwasawa, K.; Miniutti, G. +3 more
Prominent Fe Kα line emission is detected in the XMM-Newton spectrum of the ultraluminous infrared galaxy Arp 220. The centroid of the line is found at an energy of 6.7 keV and the equivalent width of the line is EW ~ 1.9 keV (at 3.5σ significance). A few other spectral features are found at various degrees of significance in the lower energy rang…
Initial results of a survey of equatorial noise emissions observed by the Cluster spacecraft
de Conchy, Y.; Santolík, O.; Němec, F. +3 more
Initial results of a survey of equatorial noise emissions are presented. These plasma wave emissions are observed in the inner magnetosphere close to the geomagnetic equator at frequencies below the local lower hybrid frequency. We use the data recorded by the four Cluster spacecraft during the first 24 months of measurements. The data set was pro…
Highly Ionized High-Velocity Clouds: Hot Intergalactic Medium or Galactic Halo?
Shull, J. Michael; Giroux, Mark L.; Collins, Joseph A.
We use spectroscopic data from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) to study the wide range of ionization states of the ``highly ionized high-velocity clouds'' (HVCs). Studied extensively in O VI absorption, these clouds are usually assumed to be infalling gas in the Galactic halo at distances less tha…
Young Super Star Clusters in the Starburst of M82: The Catalog
Tenorio-Tagle, G.; Melo, V. P.; Muñoz-Tuñón, C. +1 more
Recent results from the Hubble Space Telescope (HST) have resolved starbursts as collections of compact young stellar clusters. Here we present a photometric catalog of the young stellar clusters in the nuclear starburst of M82, observed with the HST WFPC2 in Hα (F656N) and in four optical broadband filters. We identify 197 young super stellar clu…
The Ne/O abundance ratio in the quiet Sun
Young, P. R.
Context: .
Aims: .To determine the neon-to-oxygen abundance in the quiet Sun, a proxy for the photospheric abundance ratio.
Methods: .An emission measure method applied to extreme ultraviolet emission lines of Ne iv-vi and O iii-v ions observed by the Coronal Diagnostic Spectrometer on the SOHO satellite.
Results: .The average Ne/O abu…
Rapid Penumbral Decay Associated with an X2.3 Flare in NOAA Active Region 9026
Liu, Chang; Yang, Guo; Denker, Carsten +2 more
We present observations of rapid penumbral decay associated with a major flare in solar NOAA Active Region 9026 on 2000 June 6. Within 1.5 hr, an X2.3 flare accompanied by an 11° long filament eruption and a full-halo coronal mass ejection (CME) originated near the neutral line of a large δ-spot region, which was associated with significant change…
INTEGRAL spectroscopy of the accreting millisecond pulsar XTE J1807-294 in outburst
Goldoni, P.; Bonnet-Bidaud, J. M.; Kuiper, L. +6 more
The transient X-ray accreting millisecond pulsar XTE J1807-294 was observed during its February/March 2003 outburst by INTEGRAL, partly simultaneously with the XMM-Newton and RXTE satellites. We present here the first study of the 0.5-200 keV broad-band spectra of the source. On February 28, the source spectrum was consistent with thermal Comptoni…
Characterizing a new class of variability in GRS 1915+105 with simultaneous INTEGRAL/RXTE observations
Belloni, T.; Rodriguez, J.; Mirabel, I. F. +14 more
We report on the analysis of 100 ks INTEGRAL observations of the Galactic microquasar
Ice Age Epochs and the Sun's Path through the Galaxy
Gies, D. R.; Helsel, J. W.
We present a calculation of the Sun's motion through the Milky Way over the last 500 million yr. The integration is based on estimates of the Sun's current position and speed from measurements with Hipparcos and on a realistic model for the Galactic gravitational potential. We estimate the times of the Sun's past spiral arm crossings for a range o…