Search Publications
Solar flare hard X-ray spikes observed by RHESSI: a case study
Xu, Y.; Qiu, J.; Cheng, J. X. +2 more
Context. Fast-varying hard X-ray spikes of subsecond time scales were discovered by space telescopes in the 70s and 80s, and are also observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). These events indicate that the flare energy release is fragmented.
Aims: In this paper, we analyze hard X-ray spikes observed by RHESSI to…
Two Pseudobulges in the "Boxy Bulge" Galaxy NGC 5746
Kormendy, John; Barentine, John C.
Galaxy formation and growth under the ΛCDM paradigm is expected to proceed in a hierarchical, bottom-up fashion by which small galaxies grow into large galaxies; this mechanism leaves behind large "classical bulges" kinematically distinct from "pseudobulges" grown by internal, secular processes. We use archival data (Spitzer Space Telescope 3.6 &m…
Spatially Resolved Spectroscopy of the Globular Cluster RZ 2109 and the Nature of its Black Hole
Salzer, John J.; Kundu, Arunav; Zepf, Stephen E. +7 more
We present optical Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) spectroscopy of RZ 2109, a globular cluster (GC) in the elliptical galaxy NGC 4472. This GC is notable for hosting an ultraluminous X-ray source as well as associated strong and broad [O III] λλ4959, 5007 emission. We show that the HST/STIS spectroscopy spati…
Tectonic lineament mapping of the Thaumasia Plateau, Mars: Comparing results from photointerpretation and a semi-automatic approach
Di Achille, Gaetano; Vaz, David A.; Barata, Maria Teresa +1 more
Photointerpretation is the technique generally used to map and analyze the tectonic features existent on Mars surface. In this study we compare qualitatively and quantitatively two tectonic maps based on the interpretation of satellite imagery and a map derived semi-automatically. The comparison of the two photointerpreted datasets allowed us to i…
Gemini Spectroscopic Survey of Young Star Clusters in Merging/Interacting Galaxies. IV. Stephan's Quintet
Charlton, Jane C.; Konstantopoulos, Iraklis S.; Trancho, Gelys +4 more
We present a spectroscopic survey of 21 young massive clusters and complexes and one tidal dwarf galaxy (TDG) candidate in Stephan's Quintet, an interacting compact group of galaxies. All of the selected targets lie outside the main galaxies of the system and are associated with tidal debris. We find clusters with ages between a few and 125 Myr an…
Late stages of stellar evolution - Herschel's contributions
Decin, Leen
Cool objects glow in the infrared. The gas and solid-state species that escape the stellar gravitational attraction of evolved late-type stars in the form of a stellar wind are cool, with temperatures typically ≲1500 K, and can be ideally studied in the infrared. These stellar winds create huge extended circumstellar envelopes with extents approac…
A survey of the polar cap density based on Cluster EFW probe measurements: Solar wind and solar irradiation dependence
Haaland, S.; Lybekk, B.; Pedersen, A. +1 more
The plasma density above the Earth's polar caps provide crucial information about the state of the magnetosphere. This region of space is known for its tenuous plasma and extremely low plasma densities, thus making traditional measurements with particle and plasma instruments extremely difficult. A new method based on spacecraft potential measurem…
Thermal properties of (4) Vesta derived from Herschel measurements
Valtchanov, I.; Fornasier, S.; Leyrat, C. +3 more
Aims: We report in this paper the results provided by new infrared observations of the asteroid (4) Vesta obtained between April 2010 and June 2010 with the Herschel space observatory (ESA) in the wavelength range 70-500 µm when the asteroid was seen from the Northern hemisphere. Over this period, the thermal flux of Vesta was observed …
The Invisible Monster Has Two Faces: Observations of epsilon Aurigae with the Herschel Space Observatory
Stencel, R. E.; Hoard, D. W.; Ladjal, D. +1 more
We present Herschel Space Observatory photometric observations of the unique, long-period eclipsing binary star epsilon Aurigae. Its extended spectral energy distribution is consistent with our previously published cool (550 K) dust disk model. We also present an archival infrared spectral energy distribution of the side of the disk facing the bri…
Detached Red Giant Eclipsing Binary Twins: Rosetta Stones to the Galactic Bulge
Nataf, D. M.; Gould, A.; Pinsonneault, M. H.
We identify 34 highly-probable detached, red giant eclipsing binary pairs among 315 candidates in Devor's catalog of ≈10 000 OGLE-II eclipsing binaries. We estimate that there should be at least 200 such systems in OGLE-III. We show that spectroscopic measurements of the metallicities and radial-velocity-derived masses of these systems would indep…