Search Publications
Black Hole Mass Limits for Optically Dark X-ray Bright Sources in Elliptical Galaxies
Jithesh, V.; Jeena, K.; Misra, R. +4 more
Estimation of the black hole mass in bright X-ray sources of nearby galaxies is crucial to the understanding of these systems and their formation. However, the present allowed black hole mass range spans five orders of magnitude (10 M sun < M < 105 M sun) with the upper limit obtained from dynamical friction …
The Evolution of Star Formation in Early-type Galaxies
Zheng, X. Z.; Wang, F.
How the star formation activity in early-type galaxies (ETGs) evolves over cosmic time provides observational constraints on the picture of the formation and evolution of ETGs. Using HST/ACS (Hubble Space Telescope/Advanced Camera for Surveys) imaging data from the GEMS (Galaxy Evolution from Morphology and SEDs) survey and multi-band data in the …
A Statistical Study of the si IV Resonance Line Parameters in 19 Be Stars
Antoniou, A.; Stathopoulos, D.; Danezis, E. +2 more
Using the GR model, we analyze the ultraviolet Si IV resonance lines in the spectra of 19 Be stars of different spectral subtypes, in order to detect the presence of absorption components and to analyze their characteristics. From this analysis we can calculate the values of a group of physical parameters, such as the apparent rotational and radia…
Wave signatures and electrostatic phenomena above aurora: Cluster observations and modeling
Dandouras, I.; De Keyser, J.; Maggiolo, R. +1 more
This paper reports Cluster high-altitude observations above the acceleration region of a typical monopolar electric field event at the plasma sheet boundary. The observations reveal both characteristics of waves and signatures of electrostatic acceleration. The observations can be interpreted in terms of low-frequency transverse magnetic waves on …
Modern Observations of Hubble’s First-discovered Cepheid in M31
Sabo, R.; Harris, B.; Henden, A. +9 more
We present a modern ephemeris and modern light curve of the first-discovered Cepheid variable in M31, Edwin Hubble’s M31-V1. Observers of the American Association of Variable Star Observers (AAVSO) undertook these observations during the latter half of 2010. The observations were in support of an outreach program by the Space Telescope Science Ins…
Reply to comment by R. Grard et al. on “An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe”
Morente, Juan A.; Portí, Jorge A.; Navarro, Enrique A. +1 more
Abstract Available from http://www.agu.org
Pickup Ion Observations at Solar System Bodies
Coates, Andrew
Ion pickup is one of the fundamental processes at work throughout the solar system. The ionization of neutral gas provides fresh pickup ions which then interact with the plasma environment — e.g., the solar wind or a planetary magnetosphere. Initially the motion is acceleration along the electric field, but the presence of a magnetic field eventua…
Three dimensional model of the interplanetary magnetic field and 27-day variation of the galactic cosmic ray intensity
Wawrzynczak, A.; Modzelewska, R.; Alania, M. V.
We present a model of the 27-day variation of the galactic cosmic ray (GCR) intensity for three dimensional (3-D) heliosphere with the heliolongitudinal and heliolatitudinal dependent radial solar wind speed for the period of 1995 - minimum epoch of solar activity (A>0). In the present model we implement heliolongitudinal asymmetry of solar win…
Pitch-angle diffusion coefficients from resonant interactions with electrostatic electron cyclotron harmonic waves in planetary magnetospheres
Singh, K. P.; Singhal, R. P.; Tripathi, A. K.
Pitch-angle diffusion coefficients have been calculated for resonant interaction with electrostatic electron cyclotron harmonic (ECH) waves in the magnetospheres of Earth, Jupiter, Saturn, Uranus and Neptune. Calculations have been performed at two radial distances of each planet. It is found that observed wave electric field amplitudes in the mag…
Hubble Space Telescope Imaging of Globular Clusters in Two Face-On Low Surface Brightness Galaxies UGC 5981 and UGC 6614
Kim, Ji Hoon
We present a study searching for globular cluster systems (GCSs) of two face-on low surface brightness galaxies (LSBGs), UGC 5981 and UGC 6614. Based on HST WFPC2 images of F555W and F814W filters, we detect 12 and 18 GC candidates for UGC 5981 and UGC 6614, respectively. Although these two LSBGs have very different bulge properties, they have ver…