Search Publications
On the origin of the featureless soft X-ray excess emission from the Seyfert 1 galaxy ESO 198-G24
Dewangan, Gulab C.; Laha, Sibasish; Kembhavi, Ajit K.
We present medium- and high-resolution X-ray spectral study of a Seyfert 1 galaxy ESO 198-G24 using a long (∼122 ks) XMM-Newton observation performed in 2006 February. The source has a prominent featureless soft X-ray excess below 2 keV. This makes the source well suited to investigate the origin of the soft excess. Two physical models - blurred r…
Vibrationally Excited Molecular Hydrogen near Herschel 36
Snow, Theodore P.; Rachford, Brian L.; Ross, Teresa L.
We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme rovibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, with this component presumably lying near the…
Statistical altitude distribution of Cluster auroral electric fields, indicating mainly quasi-static acceleration below 2.8 RE and Alfvénic above
Karlsson, T.; Li, B.; Masson, A. +3 more
Results are presented from a statistical study of high-altitude electric fields and plasma densities using Cluster satellite data collected during 9.5 years between 2 and 4 RE. The average electric fields are most intense on the nightside and associated with an extensive plasma density cavity, with densities of 1 cm-3 or less…
Case study of climatic changes in Martian fluvial systems at Xanthe Terra
Kereszturi, Akos
An unnamed valley system was analyzed in Xanthe Terra south of Havel Vallis on Mars where three separate episodes of fluvial activity could be identified with different morphology, water source and erosional processes, inferring formation under different climatic conditions. The oldest scattered valleys (1. group) form interconnecting network and …
Kinetic model of Janaki et al.'s bifurcated current sheet
Dasgupta, B.; Yoon, P. H.; Janaki, M. S.
Space satellite observations show that current sheets in the space plasma environment are often characterized by bifurcated structures. In a recent paper a two-fluid model of the bifurcated current sheet was constructed on the basis of the pseudo potential method. A straightforward generalization of Janaki et al.'s two-fluid model to kinetic forma…
Two numerical models designed to reproduce Saturn ring temperatures as measured by Cassini-CIRS
Altobelli, Nicolas; Flandes, A.; Leyrat, C. +7 more
We present two numerical models designed to reproduce the temperatures of the illuminated Saturn rings as measured by the CASSINI-CIRS instrument. Our models are constrained by all available temperature measurements performed on the illuminated rings since SOI. Both models reproduce well the variations of temperature under any illumination and obs…
Spectroscopic analysis of four post-AGB candidates
Pereira, C. B.; Arellano Ferro, A.; Muneer, S. +2 more
We have done a detailed abundance analysis of four unexplored candidate post- Asymptotic Giant Branch(AGB) stars IRAS 13110 - 6629, IRAS 17579 - 3121, IRAS 18321 - 1401 and IRAS 18489 - 0629 using high resolution spectra. We have constructed Spectral Energy Distributions (SED) for these objects using the existing photometric data combined with inf…
Constraints on the galaxy `main sequence' at z > 5: the stellar mass of HDF850.1
Serjeant, Stephen; Marchetti, Lucia
We present rest-frame optical and near-infrared detections of one of the highest redshift submm-selected galaxies to date, HDF850.1. We do not detect the previously proposed counterpart HDF850.1K in new deep J- and H-band Hubble Space Telescope Wide Field Camera 3 data, placing a strong limit of H - K > 3.8, concluding that the K-band source is…
Testing the asymmetric cone model for halo CMEs using STEREO/SECCHI coronagraphic observations
Michalek, Grzegorz; Nicewicz, Janusz
Space weather is significantly controlled by halo coronal mass ejections (HCMEs) originating close to the central meridian and directing toward the Earth. Unfortunately, coronagraphic observations (especially for HCMEs) are subject to a projection effect which makes it impossible to determine the true radial velocity and width of CMEs. However, th…
New near-infrared observations and lens-model constraints for UM673
Chen, W. P.; Koptelova, E.; Chiueh, T. +1 more
Aims: We performed a detailed photometric analysis of the lensed system
Methods: High-resolution adaptive optics images of