Search Publications
The High-Velocity Outflow of PG 1211+143 May Not Be That Fast
Kaspi, Shai; Behar, Ehud
We analyze the X-ray spectrum of the quasar PG 1211+143 observed with the CCD and grating spectrometers on board XMM-Newton. Using an ion-by-ion fitting model, we find an outflow component of about 3000 km s-1, which includes absorption lines of K and L shell ions of the astrophysically abundant elements. We also identify and include in…
Absolute motions of globular clusters. II. HST astrometry and VLT radial velocities in NGC 6397
Anderson, J.; Milone, A. P.; Bedin, L. R. +5 more
In this paper we present a new, accurate determination of the three components of the absolute space velocity of the Galactic globular cluster NGC 6397 (l≃338°, b≃-12°). We used three HST/WFPC2 fields with multi-epoch observations to obtain astrometric measurements of objects in three different fields in this cluster. The identification of 33 back…
Nature of magnetic fluctuations in Saturn's middle magnetosphere
Russell, C. T.; Dougherty, M. K.; Leisner, J. S. +2 more
The saturnian magnetosphere contains a rich array of plasma wave and MHD wave phenomena. These waves are fed by mass loading in the region of the E ring starting with Enceladus at 3.9 Saturn radii (Rs). In this paper we examine the nature of these waves in what we term to be the middle magnetosphere from just outside the mass loading at Enceladus …
Orientation, location, and velocity of Saturn's bow shock: Initial results from the Cassini spacecraft
Russell, C. T.; Dougherty, M. K.; Tsurutani, B. T. +8 more
The Cassini spacecraft commenced its tour of the planet Saturn on 1 July 2004 (GMT). During the insertion orbit, the Cassini magnetometer (MAG), radio/plasma wave experiment (RPWS), and plasma spectrometer (CAPS) obtained in situ measurements of the magnetic field and plasma conditions associated with Saturn's environment. Analysis of the magnetic…
X-Ray-selected Intermediate-Redshift Groups of Galaxies
Mulchaey, John S.; Rosati, Piero; Lubin, Lori M. +2 more
We present spectroscopic confirmation of nine moderate-redshift galaxy groups and poor clusters selected from the ROSAT Deep Cluster Survey. The groups span the redshift range z~0.23-0.59 and have between 4 and 20 confirmed members. The velocity dispersions of these groups range from ~125 to 650 km s-1. Similar to X-ray groups at low re…
Origin of the turbulent spectra in the high-altitude cusp: Cluster spacecraft observations
Balogh, A.; Dandouras, I.; Lavraud, B. +6 more
High-resolution magnetic field data from Cluster Flux Gate Magnetometer (FGM) and the Spatio-Temporal Analysis of Field Fluctuations (STAFF) instruments are used to study turbulent magnetic field fluctuations during the high-altitude cusp crossing on 17 March 2001. Despite the quiet solar wind conditions, the cusp was filled with magnetic field tu…
Photometry of Magellanic Cloud clusters with the Advanced Camera for Surveys - II. The unique LMC cluster ESO 121-SC03
Mackey, A. D.; Gilmore, G. F.; Payne, M. J.
We present the results of photometric measurements from images of the Large Magellanic Cloud (LMC) cluster ESO 121-SC03 taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. Our resulting colour-magnitude diagram (CMD) reaches 3 mag below the main-sequence turn-off, and represents by far the deepest observation of this cl…
A Close Look at the Population of Supersoft and Quasi-soft X-Ray Sources Observed in M31 with XMM-Newton
Orio, Marina
The deepest X-ray images of M31, obtained with XMM-Newton, are examined to derive spectral and statistical properties of the population of the very soft X-ray sources. When classifying supersoft X-ray sources (SSSs) with criteria based on the same hardness ratios defined for recent Chandra observations, one-quarter of the selected SSSs turn out to…
Stellar archaeology: the evolving spectrum of FG Sagittae
Jeffery, C. S.; Schönberner, D.
Over an interval of 120 years, the extraordinary object
Multi-wavelength afterglow observations of the high redshift GRB 050730
McBreen, S.; Bremer, M.; Tanvir, N. +22 more
Context: .GRB 050730 is a long duration high-redshift burst (z=3.967) that was discovered by Swift. The afterglow shows variability and was well monitored over a wide wavelength range. We present comprehensive temporal and spectral analysis of the afterglow of GRB 050730 including observations covering the wavelength range from the millimeter to X…