Search Publications
The correlation between coronal Doppler shifts and the supergranular network
Peter, H.; Lemaire, P.; Aiouaz, T.
We examine properties of line profiles as found with large raster scans of the solar corona acquired by the UV spectrometer SUMER on board SOHO. The observed regions include an equatorial coronal hole, a polar coronal hole, as well as surrounding quiet Sun areas. In order to reveal the network and remove strong local brightenings, a filter is appl…
The Discovery of More than 2000 White Dwarfs in the Globular Cluster ω Centauri
Prada Moroni, P. G.; Pulone, L.; Stetson, P. B. +9 more
We present deep multiband (F435W, F625W, and F658N) photometric data of the globular cluster ω Cen collected with the Advanced Camera for Surveys on board the Hubble Space Telescope. We identified in the (F435W - F625W, F435W)-plane more than 2000 white dwarf (WD) candidates using three out of nine available pointings. Such a large sample appears …
Further evidence for the presence of a neutron star in 4U 2206+54 . INTEGRAL and VLA observations
Mirabel, I. F.; Reig, P.; Torrejón, J. M. +5 more
The majority of High Mass X-ray Binaries (HMXBs) behave like X-ray pulsars, revealing that they contain a magnetised neutron star. Among the four HMXBs showing neither pulsations nor the characteristics of accreting black holes, there is the unusual HMXB
Discovery and study of the accreting pulsar 2RXP J130159.6-635806
Revnivtsev, M.; Lutovinov, A.; Chernyakova, M. +1 more
We report on analysis of the poorly studied source 2RXP J130159.6-635806 at different epochs with ASCA, BeppoSAX, XMM-Newton and INTEGRAL. The source shows coherent X-ray pulsations at a period ~700 s with an average spin-up rate of about . A broad-band (1-60 keV) spectral analysis of 2RXP J130159.6-635806 based on almost simultaneous XMM-Newton a…
A Multiwavelength Study of PSR B0628-28: The First Overluminous Rotation-powered Pulsar?
Becker, Werner; Jessner, Axel; Kramer, Michael +2 more
The ROSAT source RX J0630.8-2834 was suggested by positional coincidence to be the X-ray counterpart of the pulsar PSR B0628-28. This association, however, was regarded to be unlikely on the basis of the computed energetics of the putative X-ray counterpart. In this paper we report on multiwavelength observations of PSR B0628-28 made with the ESO …
Discovery of Multiple Coaxial Rings in the Quadrupolar Planetary Nebula NGC 6881
Kwok, Sun; Su, Kate Y. L.
We report the discovery of multiple two-dimensional rings in the quadrupolar planetary nebula NGC 6881. As many as four pairs of rings are seen in the bipolar lobes, and three rings are seen in the central torus. While the rings in the lobes have the same axis as one pair of the bipolar lobes, the inner rings are aligned with the other pair. The t…
Supersolar Metallicity in the NLS1 Galaxy Markarian 1044
Pogge, Richard W.; Nicastro, Fabrizio; Mathur, Smita +3 more
We present measurements of the metallicity of the circumnuclear gas in the narrow-line Seyfert 1 (NLS1) galaxy Markarian 1044 using O VI column density measurements from the Far Ultraviolet Spectroscopic Explorer (FUSE) together with C IV, N V, and H I measurements from the Hubble Space Telescope (HST). From the absorption lines we find that the c…
Water clouds and dust aerosols observations with PFS MEX at Mars
Grigoriev, A.; Lellouch, E.; Piccioni, G. +18 more
Observations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrare…
The Lens Galaxy in PG 1115+080 is an Ellipse
Kochanek, Christopher S.; Falco, Emilio E.; Yoo, Jaiyul +1 more
We use the structure of the Einstein ring image of the quasar host galaxy in the four-image quasar lens PG 1115+080 to determine the angular structure of the gravitational potential of the lens galaxy. We find that it is well described as an ellipsoid and that the best-fit nonellipsoidal models are consistent with the ellipsoidal model. We find up…
The Reverse Shock of SNR 1987A at 18 Years after Outburst
Smith, Nathan; Zhekov, Svetozar A.; Heng, Kevin +3 more
We use low-dispersion spectra obtained at the Magellan Observatory to study the broad Hα emission from the reverse shock of the infant supernova remnant SNR 1987A. These spectra demonstrate that the spatiokinematic structure of the reverse shock can be distinguished from that of the circumstellar ring and hot spots, even at ground-based spatial re…