Search Publications
Styles and timing of volatile-driven activity in the eastern Hellas region of Mars
Crown, David A.; Bleamaster, Leslie F.; Mest, Scott C.
Recent analyses of Mars Global Surveyor and Mars Odyssey data sets provide new insights into the geologic evolution of the eastern Hellas region of Mars, in particular, the role of volatiles. Here, we present results of our recent work and integrate these with previous studies by various investigators to provide a synthesis of the history of volat…
Stephan's Quintet with XMM-Newton
Pietsch, W.; Breitschwerdt, D.; Trinchieri, G. +1 more
The prototype compact group known as Stephan's Quintet (SQ) was observed with XMM-Newton in order to complement the excellent resolution of Chandra with high sensitivity to extended emission. SQ is a dynamic environment whose main effect, at both X-ray and optical wavelengths, appears to be ISM stripping. This is manifested by: 1) secular evolutio…
New Geoeffective Parameters of Very Fast Halo Coronal Mass Ejections
Cho, K. -S.; Kim, Y. -H.; Moon, Y. -J. +4 more
We have examined the physical characteristics of very fast coronal mass ejections (CMEs) and their geoeffective parameters. For this we consider SOHO LASCO CMEs whose speeds are larger than 1300 km s-1. By examining all SOHO EIT and SOHO LASCO images of the CMEs, we selected 38 front-side very fast CMEs and then examined their associati…
Double Star/Cluster observation of neutral sheet oscillations on 5 August 2004
Balogh, A.; Zhang, T. L.; Nakamura, R. +8 more
Previous Cluster observations have shown that the flapping motions of the Earth's magnetotail are of internal origin and that kink-like waves are emitted from the central part of the tail and propagate toward the tail flanks. The newly launched Double Star Program (DSP) TC-1 satellite allows us to investigate neutral sheet at 10-13 Re in the tail.…
Proper Motions of the HH 47 Jet Observed with the Hubble Space Telescope
Hartigan, Patrick; Bally, John; Reipurth, Bo +2 more
We present a proper-motion study of the shock waves within the classic stellar jet HH 47 based on Hubble Space Telescope (HST) Hα and [S II] images of the region taken over two epochs. Individual knots within the jet and in the bow shock/Mach disk working surface of HH 47A move significantly in the 5 yr that separate the images, and the excellent …
Large-Scale Activity in the Bastille Day 2000 Solar Event
Grechnev, V. V.; Chertok, I. M.
We have analyzed dimmings, i.e., regions of temporarily reduced brightness, and manifestations of a coronal wave in the famous event of 14 July 2000 using images produced with the EUV telescope SOHO/EIT. Our analysis was inspired by a paper by Andrews (2001, Solar Phys. 204, 181 (Paper I)), in which this event was studied using running-difference …
The Optical Counterpart of M101 ULX-1
Chu, You-Hua; Kuntz, K. D.; Gruendl, Robert A. +4 more
We have identified the optical counterpart of the ultraluminous X-ray source M101 ULX-1 (CXOKM101 J140332.37+542102), by comparing Hubble Space Telescope Advanced Camera for Surveys images with Chandra ACIS-S images. The optical counterpart has V=23.75 and colors consistent with those for a mid-B supergiant. Archival Wide Field Planetary Camera 2 …
Detection of a Hot Binary Companion of η Carinae
Hillier, D. John; Gull, Theodore R.; Sonneborn, George +2 more
We report the detection of a hot companion of η Carinae using high-resolution spectra (905-1180 Å) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. Observations were obtained at two epochs of the 2024 day orbit: 2003 June, during ingress to the 2003.5 X-ray eclipse, and 2004 April, several months after egress. These data …
Identification of the optical counterparts of high-mass X-ray binaries through optical photometry and spectroscopy
Reig, P.; Negueruela, I.; Manousakis, A. +2 more
We present the results of our search for optical counterparts to high-mass X-ray transient sources discovered by various X-ray missions. We obtained CCD images of the X-ray fields through BVR and Hα filters to identify early-type stars in the R-Hα versus B-V colour-colour diagram. We also obtained medium-resolution spectroscopy of the candidates i…
Anomalous resistivity due to nonlinear lower-hybrid drift waves
Vaivads, A.; Büchner, J.; Silin, I.
The generation of anomalous collision rate and resistivity by lower-hybrid drift waves is investigated. A general expression involving particle density and current perturbations and electromagnetic field fluctuations is used to estimate the effective collision frequency. Results of Vlasov-code simulations and Cluster spacecraft measurements sugges…