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Repetitive occurrence of explosive events at a coronal hole boundary
Doyle, J. G.; Popescu, M. D.; Taroyan, Y.
SUMER/SoHO data taken at a coronal hole boundary show a repetitive explosive event occurrence rate of around 3 min increasing to over 5 min towards the end of the activity. We suggest that the neighbouring oppositely directed closed and open field lines at the coronal hole boundary undergo repetitive reconnection seen as a sequence of explosive ev…
VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries
Rauch, T.; Werner, K.; Dreizler, S. +2 more
Aims.We present new medium-resolution high-S/N optical spectra of the ultracompact low-mass X-ray binaries 4U 0614+091 and 4U 1626-67, taken with the ESO Very Large Telescope. They are pure emission line spectra and the lines are identified as due to CII-IV and OII-III.
Methods: .Line identification is corroborated by first results from modeli…
Power spectrum of the SDSS luminous red galaxies: constraints on cosmological parameters
Hütsi, G.
In this paper we determine the constraints on cosmological parameters using the CMB data from the Wmap experiment together with the recent power spectrum measurement of the SDSS Luminous Red Galaxies (LRGs). Specifically, we focus on spatially flat, low matter density models with adiabatic Gaussian initial conditions. The spatial flatness is achie…
The globular cluster kinematics and galaxy dark matter content of NGC 4649 (M60)
Forbes, Duncan A.; Beasley, Michael A.; Zepf, Stephen E. +7 more
From observations with the GMOS multislit spectrograph on the Gemini North telescope, we have obtained spectra for 39 globular cluster (GC) candidates in the Virgo giant elliptical galaxy NGC 4649 (M60), of which 38 are confirmed GCs. The clusters extend out to a radius of 260 arcsec (3.5 effective radii). We find no rotation of the GC system, wit…
Quasi-periodic Oscillations and Strongly Comptonized X-Ray Emission from Holmberg IX X-1
Rao, A. R.; Dewangan, G. C.; Griffiths, R. E.
We report the discovery of a 200 mHz quasi-periodic oscillation (QPO) in the X-ray emission from a bright ultraluminous X-ray source (ULX), Holmberg IX X-1, using a long XMM-Newton observation. The QPO has a centroid at νQPO=202.5+4.9-3.8 mHz, a coherence Q≡νQPO/ΔνFWHM~9.3, and an amplitude (r…
An Ultraviolet to Mid-Infrared Study of the Physical and Wind Properties of HD 164270 (WC9) and Comparison to BD +30 3639 ([WC9])
Smith, J. D.; Morris, P. W.; Crowther, Paul A.
We present new Spitzer IRS observations of HD 164270 (WC9, WR103). A quantitative analysis of the UV, optical, near-, and mid-IR spectra of HD 164270 is presented, allowing for line blanketing and wind clumping, revealing T*~48 kK, logL/Lsolar~4.9, and M˙~10-5 Msolar yr-1 for a volume filling …
Ionospheric plasma acceleration at Mars: ASPERA-3 results
Coates, A. J.; Kallio, E.; Fedorov, A. +42 more
The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on-board the Mars Express spacecraft (MEX) measured penetrating solar wind plasma and escaping/accelerated ionospheric plasma at very low altitudes (250 km) in the dayside subsolar region. This implies a direct exposure of the martian topside atmosphere to solar wind plasma forcing leading …
The size and albedo of Rosetta fly-by target 21 Lutetia from new IRTF measurements and thermal modeling
Hora, J. L.; Mueller, M.; Adams, J. D. +3 more
Recent spectroscopic observations indicate that the M-type asteroid 21 Lutetia has a primitive, carbonaceous-chondrite-like (C-type) surface composition for which a low geometric albedo would be expected; this is incompatible with the IRAS albedo of 0.221± 0.020. From new thermal-infrared spectrophotometric measurements and detailed thermophysical…
Far-Ultraviolet and X-Ray Observations of VV 114: Feedback in a Local Analog to Lyman Break Galaxies
Ptak, A.; Meurer, G.; Aloisi, A. +4 more
We have analyzed Far Ultraviolet Spectroscopic Explorer (FUSE), XMM-Newton, and Chandra observations of VV 114, a local galaxy merger with strong similarities to typical high-redshift Lyman break galaxies (LBGs). Diffuse thermal X-ray emission encompassing VV 114 has been observed by Chandra and XMM-Newton. This region of hot (kT~0.59 keV) gas has…
Characteristics of Jovian morning bright FUV aurora from Hubble Space Telescope/Space Telescope Imaging Spectrograph imaging and spectral observations
Clarke, J. T.; Cowley, S. W. H.; Grodent, D. +3 more
Observation of an exceptionally bright (peaking at ∼1.8 MR) Jovian auroral morning arc was obtained with the Space Telescope Imaging Spectrograph (STIS) on 21 September 1999, both in the imaging and spectral modes. The images of the HST orbit are used to describe the variation of the position of the bright arc, while the time-tagged spectra are ex…