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Spectral and temporal variations of the isolated neutron star RX J0720.4-3125: new XMM-Newton observations
Haberl, F.; de Vries, C. P.; Vink, J. +5 more
Context: In the past, the isolated, radio-quiet neutron star RX J0720.4-3125 showed variations in its spectral parameters (apparent radius, temperature of the emitting area and equivalent width of the absorption feature) seen in the X-ray spectra, not only during the spin period of 8.39 s, but also over time scales of years. New X-ray observations…
ChaMPlane Deep Galactic Bulge Survey. I. Faint Accretion-driven Binaries in the Limiting Window
van den Berg, Maureen; Grindlay, Jonathan E.; Hong, Jae Sub
We have carried out a deep X-ray and optical survey with Chandra and HST of low-extinction regions in the Galactic bulge. Here we present the results of a search for low-luminosity (LX lsim 1034 erg s-1) accreting binaries among the Chandra sources in the region closest to the Galactic center, at an angular offset …
Newly Identified Star Clusters in M33. II. Radial Hubble Space Telescope/Advanced Camera for Surveys Fields
Sarajedini, Ata; Holtzman, Jon A.; Garnett, Donald R. +1 more
We present integrated photometry and color-magnitude diagrams (CMDs) for 161 star clusters in M33, of which 115 were previously uncataloged, using the Advanced Camera For Surveys Wide Field Channel onboard the Hubble Space Telescope. The integrated V-band magnitudes of these clusters range from MV ~-9 to as faint as MV ~-4, e…
Energetic ions trapped in Saturn's inner magnetosphere
Krupp, N.; Krimigis, S.; Armstrong, T. P. +4 more
The low-energy magnetospheric measurement system (LEMMS) of the magnetosphere imaging instrument (MIMI) aboard the Cassini orbiter observed energetic ions and electrons during Saturn orbit insertion (SOI) of July 1, 2004. Salient features of the trapped ion fluxes observed in the L=2-4 RS region include the occurrence of two distinct co…
SCP 06F6: A Carbon-rich Extragalactic Transient at Redshift z sime 0.14?
Wheatley, Peter J.; Gänsicke, Boris T.; Marsh, Thomas R. +1 more
We show that the spectrum of the unusual transient SCP 06F6 is consistent with emission from a cool, optically thick and carbon-rich atmosphere if the transient is located at a redshift of z ≈ 0.14. The implied extragalactic nature of the transient rules out novae, shell flashes, and V838 Mon-like events as causes of the observed brightening. The …
Geologic features of Wudalianchi volcanic field, northeastern China: Implications for Martian volcanology
Xiao, Long; Wang, Chunzeng
Wudalianchi volcanic field, located in northeast China, consists of 14 Quaternary volcanoes with each volcano as a steep-sided scoria cone surrounded by gently sloping lava flows. Each cone is topped with a bowl-shaped or funnel-shaped crater. The volcanic cones are constructed by the accumulation of tephra and other ejecta. In this paper, their g…
Clouds and Aerosols in Saturn's Atmosphere
Baines, K. H.; Sánchez-Lavega, A.; West, R. A. +1 more
In this chapter we review the photochemical and thermochemical equilibrium theories for the formation of condensate clouds and photochemical haze in Saturn's upper troposphere and stratosphere and show the relevant observations from ground-based and spacecraft instruments. Based on thermochemical equilibrium models we expect ammonia ice crystals t…
Optical spectroscopy of the quiescent counterpart to EXO0748-676
Torres, M. A. P.; Steeghs, D.; Bassa, C. G. +1 more
We present phase resolved optical spectroscopy and X-ray timing of the neutron star X-ray binary EXO0748-676 after the source returned to quiescence in the autumn of 2008. The X-ray light curve displays eclipses consistent in orbital period, orbital phase and duration with the predictions and measurements before the return to quiescence. Hα and He…
Electron optical study of the Venus Express ASPERA-4 Electron Spectrometer (ELS) top-hat electrostatic analyser
Kataria, D. O.; Barabash, Stas; Coates, Andrew J. +6 more
The performance of the Venus Express (VEX) ASPERA-4 Electron Spectrometer (ELS) is different from the nominal response shown by the ASPERA-3 ELS aboard Mars Express due to machining tolerance. Up to now, the precise mechanism for this was unknown and, therefore, the results of the experimental calibration could not be supported with a theoretical …
Results from DROXO. II. [Ne II] and X-ray emission from ρ Ophiuchi young stellar objects
Testi, L.; Micela, G.; Sciortino, S. +3 more
Context: The infrared [Ne II] and [Ne III] fine structure lines at 12.81 µm and 15.55 µm have recently been theoretically predicted to trace the circumstellar disk gas subject to X-ray heating and ionization.
Aims: We observationally investigate the origin of the neon fine structure line emission by comparing observations with mode…