Search Publications
The HST/ACS Coma Cluster Survey - VI. Colour gradients in giant and dwarf early-type galaxies
Jogee, S.; Ferguson, H. C.; Peletier, R. F. +17 more
Using deep, high-spatial-resolution imaging from the Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) Coma Cluster Treasury Survey, we determine colour profiles of early-type galaxies in the Coma cluster. From 176 galaxies brighter than MF814W(AB)=-15 mag that are either spectroscopically confirmed members of Coma or identif…
Altitude Distribution of the Auroral Acceleration Potential Determined from Cluster Satellite Data at Different Heights
Karlsson, Tomas; Fazakerley, Andrew; Nilsson, Hans +6 more
Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 RE altitudes, or by wave electric fields. Although aurora was studied by man…
Spectral and timing properties of the accreting X-ray millisecond pulsar IGR J17511-3057
Stella, L.; Bozzo, E.; Kuiper, L. +6 more
Context. IGR J17511-3057 is the second X-ray transient accreting millisecond pulsar discovered by INTEGRAL. It was in outburst for about a month beginning on September 13, 2009.
Aims: We analyze the spectral and timing properties of the object and the characteristics of X-ray bursts with the aim to constrain the physical processes responsible…
Horizontal flow fields observed in Hinode G-band images. I. Methods
Verma, M.; Denker, C.
Context. The interaction of plasma motions and magnetic fields is an important mechanism, which drives the solar activity in all its facets. For example, photospheric flows are responsible for the advection of magnetic flux, the redistribution of flux during the decay of sunspots, and the build-up of magnetic shear in flaring active regions.
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HIFI detection of hydrogen fluoride in the carbon star envelope IRC +10216
Waters, L. B. F. M.; Teyssier, D.; Cernicharo, J. +5 more
We report the detection of emission in the J = 1-0 rotational transition of hydrogen fluoride (HF), together with observations of the J = 1-0 to J = 3-2 rotational lines of H35Cl and H37Cl, towards the envelope of the carbon star IRC +10216. High-sensitivity, high-spectral resolution observations have been carried out with th…
Dynamics and circulation regimes of terrestrial planets
Read, P. L.
By the study of simple analogues, either in the form of simplified numerical models or laboratory experiments, considerable insights may be gained as to the likely roles of planetary size, rotation, thermal stratification and other factors in determining the principal length scales, styles of global circulation and dominant waves and instability p…
Pre-flare Activity and Magnetic Reconnection during the Evolutionary Stages of Energy Release in a Solar Eruptive Flare
Joshi, Bhuwan; Veronig, Astrid M.; Tiwari, Sanjiv Kumar +3 more
In this paper, we present a multi-wavelength analysis of an eruptive white-light M3.2 flare that occurred in active region NOAA 10486 on 2003 November 1. The excellent set of high-resolution observations made by RHESSI and the TRACE provides clear evidence of significant pre-flare activities for ~9 minutes in the form of an initiation phase observ…
Fundamental Properties of the Highly Ionized Plasmas in the Milky Way
Savage, B. D.; Lehner, N.; Howk, J. C. +1 more
The cooling transition temperature gas in the interstellar medium (ISM), traced by the high ions, Si IV, C IV, N V, and O VI, helps to constrain the flow of energy from the hot ISM with T>106 K to the warm ISM with T < 2 × 104 K. We investigate the properties of this gas along the lines of sight to 38 stars in the Milky…
Understanding the variability of nightside temperatures, NO UV and O2 IR nightglow emissions in the Venus upper atmosphere
Gérard, J. -C.; Brecht, A. S.; Bougher, S. W. +3 more
Venus Express (VEX) has been monitoring key nightglow emissions and thermal features (O2 IR nightglow, NO UV nightglow, and nightside temperatures) which contribute to a comprehensive understanding of the global dynamics and circulation patterns above ∼90 km. The nightglow emissions serve as effective tracers of Venus' middle and upper …
Evidence for Amazonian northern mid-latitude regional glacial landsystems on Mars: Glacial flow models using GCM-driven climate results and comparisons to geological observations
Head, James W.; Forget, Francois; Fastook, James L. +2 more
A fretted valley system on Mars located at the northern mid-latitude dichotomy boundary contains lineated valley fill (LVF) with extensive flow-like features interpreted to be glacial in origin. We have modeled this deposit using glacial flow models linked to atmospheric general circulation models (GCM) for conditions consistent with the depositio…