Search Publications
Star formation triggered by H II regions in our Galaxy. First results for N49 from the Herschel infrared survey of the Galactic plane
Testi, L.; Zavagno, A.; Ward-Thompson, D. +18 more
Context. It has been shown that by means of different physical mechanisms the expansion of H ii regions can trigger the formation of new stars of all masses. This process may be important to the formation of massive stars but has never been quantified in the Galaxy.
Aims: We use Herschel-PACS and -SPIRE images from the Herschel infrared surve…
Ooty Interplanetary Scintillation - Remote-Sensing Observations and Analysis of Coronal Mass Ejections in the Heliosphere
Manoharan, P. K.
In this paper, I investigate the three-dimensional evolution of solar wind density and speed distributions associated with coronal mass ejections (CMEs). The primary solar wind data used in this study has been obtained from the interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, which is capable of measuring scintilla…
A scenario of planet erosion by coronal radiation
Eiroa, C.; Ribas, I.; Solano, E. +4 more
Context. According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long-term erosion effects have been made yet.
Aims: We analyze the current distribution of planetary mass with X-ray irradiation of the atmospheres to make an observational ass…
Evidence for Steady Heating: Observations of an Active Region Core with Hinode and TRACE
Winebarger, Amy R.; Warren, Harry P.; Brooks, David H.
The timescale for energy release is an important parameter for constraining the coronal heating mechanism. Observations of "warm" coronal loops (~1 MK) have indicated that the heating is impulsive and that coronal plasma is far from equilibrium. In contrast, observations at higher temperatures (~3 MK) have generally been consistent with steady hea…
The 3-5 MHz global reflectivity map of Mars by MARSIS/Mars Express: Implications for the current inventory of subsurface H 2O
Pommerol, A.; Plaut, J. J.; Safaeinili, A. +6 more
We extracted the surface echo power from 2 years of MARSIS measurements. The retrieved values are calibrated to compensate for changes in the distance of the spacecraft to the surface and for the attenuation of the signal by the ionosphere. The results are used to build the first global map of surface echo power at 3-5 MHz. The surface echo power …
Non-local Thermal Equilibrium Model Atmospheres for the Hottest White Dwarfs: Spectral Analysis of the Compact Component in Nova V4743 Sgr
Nelson, T.; Rauch, T.; Werner, K. +4 more
Half a year after its outburst in 2002 September, nova V4743 Sgr evolved into the brightest supersoft X-ray source in the sky with a flux maximum around 30 Å. We calculated grids of synthetic energy distributions based on non-local thermal equilibrium model atmospheres for the analysis of the hottest white dwarfs (WDs) and present the result of fi…
The 3-D structure of SN 1987A's inner ejecta
Spyromilio, J.; Fransson, C.; Jerkstrand, A. +2 more
Context. Observing the inner ejecta of a supernova is possible only in a handful of nearby supernova remnants. The core-collapse explosion mechanism has been extensively explored in recent models and predict large asymmetries. SN 1987A is the first modern stellar explosion that has been continuously observed from its beginning to the supernova rem…
Bars in early- and late-type discs in COSMOS
Kneib, J. -P.; Aussel, H.; Le Floc'h, E. +20 more
We investigate the (large-scale) bar fraction in a mass-complete sample of M > 1010.5 Msolar disc galaxies at 0.2 < z < 0.6 in the Cosmological Evolution Survey (COSMOS) field. The fraction of barred discs strongly depends on mass, disc morphology and specific star formation rate (SSFR). At intermediate stellar mass …
Broad H I Absorbers as Metallicity-independent Tracers of the Warm-Hot Intergalactic Medium
Shull, J. Michael; Danforth, Charles W.; Stocke, John T.
Thermally broadened Lyα absorbers (BLAs) offer an alternative method to highly ionized metal lines for tracing the warm-hot intergalactic medium (WHIM) at T>105 K. However, observing BLAs requires data of high quality and accurate continuum definition to detect the low-contrast features, and a good knowledge of the velocity structure…
On the Progenitor and Early Evolution of the Type II Supernova 2009kr
Sollerman, J.; Gal-Yam, A.; Smartt, S. J. +15 more
We identify a source coincident with SN 2009kr in Hubble Space Telescope pre-explosion images. The object appears to be a single point source with an intrinsic color V - I = 1.1 ± 0.25 and MV = -7.6 ± 0.6. If this is a single star, it would be a yellow supergiant of log L/L sun ~ 5.1 and a mass of 15+5 -4