Search Publications
Missions
Journals
Publication Years
Anti-planetward auroral electron beams at Saturn
Livi, S.; Krupp, N.; Dougherty, M. K. +10 more
Strong discrete aurorae on Earth are excited by electrons, which are accelerated along magnetic field lines towards the planet. Surprisingly, electrons accelerated in the opposite direction have been recently observed. The mechanisms and significance of this anti-earthward acceleration are highly uncertain because only earthward acceleration was t…
Lyman Break Galaxies under a Microscope: The Small-Scale Dynamics and Mass of an Arc in the Cluster 1E 0657-56
Lutz, D.; Genzel, R.; Saglia, R. P. +8 more
Using the near-infrared integral field spectrograph SPIFFI on the VLT, we have studied the spatially resolved dynamics in the z=3.2 strongly lensed galaxy 1E 0657-56 arc+core by observing the rest-frame optical emission lines [O III] λ5007 and Hβ. The lensing configuration suggests that the high surface brightness core is the M~20 magnified centra…
Measurements of the f-Values of the Resonance Transitions of Ni II at 1317.217 and 1370.132 Å
Tripp, Todd M.; Jenkins, Edward B.
We have retrieved high-resolution UV spectra of 69 hot stars from the HST archive and determined the strengths of the interstellar Ni II absorption features at 1317.217 Å arising from the ground 3d92D5/2 electronic state to the 3d8(1G)4p2Fo5/2 excited level. We…
Cluster PEACE observations of electron pressure tensor divergence in the magnetotail
Lucek, E.; Fazakerley, A. N.; Owen, C. J. +4 more
Cluster crossed the magnetotail neutral sheet on four occasions between 16:38 and 16:43 UT on 08/17/2003. The four-spacecraft capabilities of Cluster are used to determine spatial gradients from the magnetic field vectors and, for the first time, full electron pressure tensors. We find that the contribution to the electric field from the Hall term…
Black hole masses from reverberation mapping
Peterson, Bradley M.; Bentz, Misty C.
We review briefly how black hole masses are measured directly using reverberation mapping and indirectly through scaling relationships based on reverberation results, in particular through broad-line region radius-luminosity relationships. We discuss the nature and origin of uncertainties in these measurements, and outline current and future effor…
Chandra monitoring observations of the ultraluminous X-ray source NGC 5204 X-1
Warwick, R. S.; Roberts, T. P.; Ward, M. J. +2 more
We report the results of a two-month campaign conducted with the Chandra X-ray observatory to monitor the ultraluminous X-ray source (ULX) NGC 5204 X-1. This was composed of a 50-ks observation, followed by ten 5-ks follow-ups spaced initially at ~3, then at ~10-d intervals. The ULX flux is seen to vary by factors ~5 on time-scales of a few days, …
X-Ray Properties of Intermediate-Redshift Groups of Galaxies
Mulchaey, John S.; Rosati, Piero; Lubin, Lori M. +2 more
We have undertaken a multiwavelength project to study the relatively unknown properties of groups and poor clusters of galaxies at intermediate redshifts. In this paper, we describe the XMM-Newton observations of six X-ray-selected groups with 0.2<z<0.6. The X-ray properties of these systems are generally in good agreement with the propertie…
Properties of X-ray rich gamma ray bursts and X-ray flashes detected with BeppoSAX and Hete-2
Piro, L.; Rossi, E. M.; D'Alessio, V.
We study the spectrum of the prompt emission and the X-ray and optical afterglow fluxes of 54 X-Ray Rich Gamma Ray Burst (XRRs) and X-Ray Flashes (XRFs), observed by BeppoSAX and HETE-2. A comparison is then performed with classical Gamma Ray Bursts (GRBs). The goal of this paper is to investigate the nature of XRRs/XRFs, as high redshift GRBs or …
The star formation history of luminous infrared galaxies
Elbaz, D.; Cesarsky, C.; Charlot, S. +5 more
Aims.We constrain the past star formation histories of a sample of 25 distant (bar{z}∼ 0.7) luminous infrared galaxies (LIRGs) detected with the mid infrared cameras ISOCAM and MIPS onboard the ISO and Spitzer satellites.
Methods: .We used high-resolution VLT-FORS2 spectroscopy in addition to a comprehensive library of 200 000 model optical sp…
The Secondaries of Solar-Type Primaries. I. The Radial Velocities
Abt, Helmut A.; Willmarth, Daryl
We studied for duplicity the 167 F7-G8 IV or V primaries within 25 pc of the Sun according to their Hipparcos parallaxes and between declinations of -30° and +75°. We obtained an average of 13 coudé radial velocities with an accuracy of +/-0.10 km s-1. Combining these measures with published data, we obtained 39 single-lined and 12 doub…