Search Publications
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…
Speckle Observations of Binary Stars with the WIYN Telescope. IV. Differential Photometry
Horch, Elliott P.; van Altena, William F.; Meyer, Reed D.
Five hundred seventy-six magnitude difference measures are presented for 260 binary stars. These measures are derived from CCD-based speckle observations taken at the WIYN 3.5 m telescope at Kitt Peak National Observatory during the period 1997-2000. Separations of the systems range from over 1" down to near the diffraction limit of the telescope.…
XMM-Newton observations of polars in low accretion states
Cropper, Mark; Wu, Kinwah; Ramsay, Gavin +3 more
<heading id="h0" level="1">ABSTARCT</heading> We have made a series of snap-shot observations of 37 polars using XMM-Newton. We found that 16 of these systems were in a low, or much reduced, accretion state. Of those, six were not detected in X-rays. This suggests that in any survey of polars, around half will be in a low accretion sta…
A CNO Dichotomy among O2 Giant Spectra in the Magellanic Clouds
Walborn, Nolan R.; Massey, Philip; Howarth, Ian D. +4 more
From a survey of the 3400 Å region in the earliest O-type spectra, we have found that two of the four O2 giants observed in the Large Magellanic Cloud have O IV lines there that are stronger than the N IV lines, while the other two have the opposite. A Small Magellanic Cloud counterpart also has N IV stronger than O IV. Inspection of the blue spec…
Multi-wavelength analysis of the dust emission in the Small Magellanic Cloud
Boulanger, F.; Lagache, G.; Cambrésy, L. +2 more
We present an analysis of dust grain emission in the diffuse interstellar medium of the Small Magellanic Cloud (SMC). This study is motivated by the availability of 170 µm ISOPHOT data covering a large part of the SMC, with a resolution making it possible to disentangle the diffuse medium from the star forming regions. After data reduction a…