Search Publications
HST/WFPC2 imaging of the dwarf satellites And XI and And XIII: horizontal branch morphology and RR Lyraes
Sarajedini, A.; Yang, S. -C.
We present a study of the stellar populations in two faint M31 dwarf satellites, Andromeda XI and Andromeda XIII. Using archival images from the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope, we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new te…
Phase space structure of the electron diffusion region in reconnection with weak guide fields
Egedal, J.; Daughton, W.; Ng, J. +1 more
Kinetic simulations of magnetic reconnection provide detailed information about the electric and magnetic structure throughout the simulation domain, as well as high resolution profiles of the essential fluid parameters including the electron and ion densities, flows, and pressure tensors. However, the electron distribution function, f(v), within …
Infrared excess around nearby red giant branch stars and Reimers law
Groenewegen, M. A. T.
Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, but for stars with initial masses below ~1 M⊙, the mass loss on the first red giant branch (RGB) actually dominates mass loss on the AGB. Nevertheless, mass loss on the RGB is still often parameterised by a simple Reimers law in stellar evolu…
Investigation of air temperature on the nightside of Venus derived from VIRTIS-H on board Venus-Express
Drossart, P.; Piccioni, G.; Lebonnois, S. +3 more
We present the spatial distribution of air temperature on Venus' night side, as observed by the high spectral resolution channel of VIRTIS (Visible and Infrared Thermal Imaging Spectrometer), or VIRTIS-H, on board the ESA mission Venus Express. The present work extends the investigation of the average thermal fields in the northern hemisphere of V…
Globules and pillars seen in the [CII] 158 µm line with SOFIA
Hill, T.; Lebouteiller, V.; Cormier, D. +22 more
Molecular globules and pillars are spectacular features, found only in the interface region between a molecular cloud and an H II-region. Impacting far-ultraviolet (FUV) radiation creates photon-dominated regions (PDRs) on their surfaces that can be traced by typical cooling lines. With the GREAT receiver onboard SOFIA we mapped and spectrally res…
The gas-to-dust mass ratio of Centaurus A as seen by Herschel
Boquien, M.; Roussel, H.; Cooray, A. +20 more
We present photometry of the nearby galaxy NGC 5128 (Centaurus A) observed with the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on board the Herschel Space Observatory, at 70, 160, 250, 350 and 500 µm, as well as new CO J= 3-2 observations taken with the HARP-B instrume…
Gullies and their relationships to the dust-ice mantle in the northwestern Argyre Basin, Mars
Hiesinger, H.; Reiss, D.; Raack, J.
We investigated gullies and their relationships to the atmospherically derived dust-ice mantle and aeolian features in the northwestern part of the Argyre basin. A detailed morphologic map of the Argyre study region allowed us to constrain the stratigraphic relationships and relative ages of gullies. In addition, we investigated the morphologic ch…
Jet Rotation Investigated in the Near-ultraviolet with the Hubble Space Telescope Imaging Spectrograph
Bacciotti, Francesca; Coffey, Deirdre; Eislöffel, Jochen +2 more
We present results of the second phase of our near-ultraviolet investigation into protostellar jet rotation using the Hubble Space Telescope Imaging Spectrograph. We obtain long-slit spectra at the base of five T Tauri jets to determine if there is a difference in radial velocity between the jet borders which may be interpreted as a rotation signa…
Variations of the interstellar extinction law within the nearest kiloparsec
Gontcharov, G. A.
Multicolor photometry from the Tycho-2 and 2MASS catalogues for 11 990 OB and 30 671 K-type red giant branch stars is used to detect systematic large-scale variations of the interstellar extinction law within the nearest kiloparsec. The characteristic of the extinction law, the total-to-selective extinction ratio Rv, which also characterizes the s…
Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line
Heinzel, P.; Schmieder, B.; Gunár, S. +2 more
Aims: We analyze the dynamics of the prominence fine structures of a quiescent prominence observed on April 26, 2007 during a coordinated campaign of several spaceborne and ground-based instruments. We use Lyman spectra observed by SOHO/SUMER and the Hα line spectra obtained by MSDP spectrograph working at the Meudon Solar Tower.
Methods…