Search Publications
AXPs and X-ray-dim isolated neutron stars: recent XMM-Newton and Chandra results
Haberl, F.
To date more than half a dozen X-ray-dim isolated neutron stars are known. Their X-ray spectra are characterized by soft blackbody-like emission ( kT∼50-120 eV) without indication for harder, non-thermal components. These stars apparently show no radio emission and no association with supernova remnants. Four of them exhibit pulsations in their X-…
Interstellar Atomic Abundances
Jenkins, Edward B.
A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the interstellar medium. By comparing these abundances with reference values in the Sun, we find that some elements have ab…
Structuring the HD 141569 A circumstellar dust disk. Impact of eccentric bound stellar companions
Augereau, J. C.; Papaloizou, J. C. B.
Scattered light images of the optically thin dust disk around the 5 Myr old star
A Multiwavelength Scattered Light Analysis of the Dust Grain Population in the GG Tauri Circumbinary Ring
Duchêne, G.; Ghez, A. M.; Macintosh, B. A. +1 more
We present the first 3.8 µm image of the dusty ring surrounding the young binary system GG Tau, obtained with the W. M. Keck II 10 m telescope's adaptive optics system. This is the longest wavelength at which the ring has been detected in scattered light so far, allowing a multiwavelength analysis of the scattering properties of the dust gra…
Star formation rates of distant luminous infrared galaxies derived from Hα and IR luminosities
Elbaz, D.; Flores, H.; Cesarsky, C. J. +4 more
We present a study of the star formation rate (SFR) for a sample of 16 distant galaxies detected by ISOCAM at 15 µm in the CFRS0300+00 and CFRS1400+52 fields. Their high quality and intermediate resolution VLT/FORS spectra have allowed a proper correction of the Balmer emission lines from the underlying absorption. Extinction estimates using…
Radio Observation of Electron Acceleration at Solar Flare Reconnection Outflow Termination Shocks
Mann, Gottfried; Aurass, Henry
Using meter-wave solar radio spectral observations of the 2001 September 28 flare, we discuss simultaneously appearing type II-like bursts observed at 40-80 MHz and ~300 MHz as radio signatures of the upper and lower reconnection outflow termination shock (TS). The features are identified during the impulsive phase but well after the regular trave…
The Space Density of High-redshift QSOs in the Great Observatories Origins Deep Survey
Stern, D.; Alexander, D. M.; Treister, E. +14 more
We present a sample of 17 high-redshift (3.5<~z<~5.2) quasi-stellar object (QSO) candidates in the 320 arcmin2 area of the Great Observatories Origins Deep Survey, selected in the magnitude range 22.45<z850<25.25 using deep imaging with the Advanced Camera for Surveys on board the Hubble Space Telescope and the Ad…
A Transition to a Low/Soft State in the Ultraluminous Compact X-Ray Source Holmberg II X-1
Dewangan, Gulab C.; Griffiths, Richard E.; Miyaji, Takamitsu +1 more
We present three XMM-Newton observations of the ultraluminous compact X-ray source Holmberg II X-1 in its historical brightest and faintest states. The source was in its brightest state in 2002 April with an isotropic X-ray luminosity of ~2×1040 ergs s-1 but changed to a peculiar low/soft state in 2002 September in which the …
The atmospheric signature of Io's Prometheus plume and anti-jovian hemisphere: evidence for a sublimation atmosphere
Ballester, Gilda E.; Spencer, John R.; Howell, Robert R. +4 more
Using the Hubble Space Telescope's Space Telescope Imaging Spectrograph we have obtained for the first time spatially resolved 2000-3000 Å spectra of Io's Prometheus plume and adjoining regions on Io's anti-jovian hemisphere in the latitude range 60° N-60° S, using a 0.1″ slit centered on Prometheus and tilted roughly 45° to the spin axis. The SO …
The Birth of a Super-Star Cluster: NGC 5253
Turner, Jean L.; Beck, Sara C.
We present images of the 7 mm free-free emission from the radio ``supernebula'' in NGC 5253 made with the Very Large Array and the Pie Town link. The images reveal structure in the nebula, which has a <=1 pc (~50 mas radius) core requiring the excitation of 1200 O7 stars. The nebula is elongated, with an arc of emission curving to the northeast…