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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…
Detection of He II λ4686 in η Carinae
Steiner, J. E.; Damineli, A.
We report the detection of the emission line He II λ4686 in η Carinae. The equivalent width of this line is ~100 mÅ along most of the 5.5 yr cycle and jumps to ~900 mÅ just before phase 1.0, followed by a brief disappearance. The similarity between the intensity variations of this line and those of the X-ray light curve is remarkable, suggesting t…
Temperature gradients in XMM-Newton observed REFLEX-DXL galaxy clusters at z ∼ 0.3
Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H. +3 more
We present XMM-Newton results on the temperature profiles of a volume-limited sample of galaxy clusters at redshifts z∼0.3, selected from the REFLEX survey (REFLEX-DXL sample). In the spectral analysis, where only the energies above 1 keV were considered, we obtained consistent results for the temperature derived from the pn, MOS1 and MOS2 data. U…
A phase-resolved XMM-Newton campaign on the colliding-wind binary HD 152248
Gosset, E.; Rauw, G.; Vreux, J. -M. +2 more
We report the first results of an XMM-Newton monitoring campaign of the open cluster NGC 6231 in the Sco OB 1 association. This first paper focuses on the massive colliding-wind binary HD 152248, which is the brightest X-ray source of the cluster. The campaign, with a total duration of 180 ks, was split into six separate observations, following th…
Modeling the interstellar-interplanetary helium 58.4 nm resonance glow: Towards a reconciliation with particle measurements.
Raymond, J. C.; Bertaux, J. L.; Lallement, R. +3 more
Pioneering observations of the diffuse HeI-58.4 nm background radiation were performed with a series of satellites in the 70's. Today, their published results on the flow of interstellar helium atoms in the heliosphere are still in contradiction with (i) the results of the particle experiments, i.e. in situ detection of neutrals and pickup ions; (…
A Supernova Factory in the Merger System Arp 299
Teng, Stacy H.; Neff, Susan G.; Ulvestad, James S.
We have imaged the nearby galaxy merger Arp 299 at arcsecond and milliarcsecond resolution, using both the Very Large Array (VLA) and the Very Long Baseline Array. The large-scale radio emission from the merger contains five bright, compact radio sources embedded in diffuse emission, with diameters less than 200 pc. Supernova rates of 0.1-1 yr
Photospheric Shear Flows along the Magnetic Neutral Line of Active Region 10486 prior to an X10 Flare
Xu, Yan; Cao, Wenda; Yang, Guo +3 more
We present high spatial resolution observations of proper motions in the solar NOAA Active Region 10486 using a high-order adaptive optics system, frame selection, and speckle-masking image reconstruction. The data were obtained with the Dunn Solar Telescope of the National Solar Observatory/Sacramento Peak on 2003 October 29. The resolution of th…