Search Publications
Improved input to the empirical coronal mass ejection (CME) driven shock arrival model from CME cone models
St. Cyr, O. C.; Gopalswamy, N.; Michalek, G. +4 more
We study the Sun-Earth travel time of interplanetary shocks driven by coronal mass ejections (CMEs) using empirical cone models. Three different cone models have been used to obtain the radial speeds of the CMEs, which are then used as input to the empirical shock arrival (ESA) model to obtain the Sun to Earth travel time of the shocks. We compare…
Understanding the Nuclear Gas Dispersion in Early-Type Galaxies in the Context of Black Hole Demographics
van der Marel, Roeland P.; Verdoes Kleijn, Gijs A.; Noel-Storr, Jacob
The majority of nearby early-type galaxies contain detectable amounts of emission-line gas at their centers. The nuclear gas kinematics form a valuable diagnostic of the central black hole (BH) mass. Here we analyze and model Hubble Space Telescope STIS observations of a sample of 27 galaxies; 16 Fanaroff-Riley Type I radio galaxies and 11 (more) …
A model of the ionosphere of Saturn's rings and its implications
Luhmann, J. G.; Tokar, R. L.; Johnson, R. E. +2 more
The detection of cold O2+ and O + ions in the vicinity of Saturn's rings during the Cassini Orbiter orbit insertion confirmed expectations that the rings would have a water product atmosphere and ionosphere. These observations prompted a new look at their origin and nature by Johnson et al. [Johnson, R.E., Luhmann, J.G., Tokar, R.L., Bo…
Have we detected the most luminous ULX so far?
Cappi, M.; Ponti, G.; Fabian, A. C. +4 more
We report the XMM-Newton detection of a moderately bright X-ray source (F0.5-7 ~ 8.2 × 10-14ergcm-2s-1) superimposed on the outer arms of the inactive spiral galaxy MCG-03-34-63 (z = 0.0213). It is clearly offset from the nucleus (by about 19 arcsec) but well within the D25 ellipse of the gala…
NGC 7419: a young open cluster with a number of very young intermediate mass pre-MS stars
Mathew, Blesson; Subramaniam, Annapurni; Ramya, S. +1 more
We present a photometric and spectroscopic study of the young open cluster NGC 7419, which is known to host a large number of classical Be stars for reasons not well understood. Based on CCD photometric observations of 327 stars in UBV passbands, we estimated the cluster parameters as, reddening [E(B - V)] = 1.65 +/- 0.15 mag and distance = 2900 +…
The Spatial Distribution of Faint Fuzzy Star Clusters in NGC 5195
Hwang, Narae; Lee, Myung Gyoon
We present a study of a faint fuzzy star cluster system in the nearby SB0 galaxy NGC 5195 interacting with the famous spiral galaxy NGC 5194 (M51), based on HST ACS BVI mosaic images taken by the Hubble Heritage Team. We have found about 50 faint fuzzy star clusters around NGC 5195 that are larger than typical globular clusters with effective radi…
FUSE Spectroscopy of the White Dwarf in U Geminorum
Brammer, Gabriel; Long, Knox S.; Froning, Cynthia S.
Observations of U Gem with FUSE confirm that the WD is heated by the outburst and cools during quiescence. At the end of an outburst, the best uniform-temperature WD model fits to the data indicate a temperature of 41,000-47,000 K, while in midquiescence, the temperature is 28,000-31,000 K, depending on the gravity assumed for the WD. Photospheric…
The GLE on Oct. 28, 2003 - radio diagnostics of relativistic electron and proton injection
Mann, G.; Aurass, H.; Warmuth, A. +1 more
Timing discrepancies between signatures of accelerated particles at the sun and the arrival times of the particles at near-earth detectors are a matter of fundamental interest for space-weather applications. The solar injection times of various components of energetic particles were derived by Klassen et al. (2005, JGR, 110, A09S04) for the Octobe…
An XMM-Newton survey of broad iron lines in AGN
Nandra, K.; Turner, T. J.; Reeves, J. N. +2 more
We report on the iron Kα line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM-Newton spectra. Once appropriate soft X-ray absorption, narrow 6.4 keV emission and associated Compton reflection are acc…
Interaction of the Solar Wind with Weak Obstacles: Hybrid Simulations for Weakly Active Comets and for Mars
Kührt, E.; Motschmann, U.
Obstacles in the solar wind are weak when their extension is small or comparable to the characteristic ion gyroradii. In this case interactions involve kinetic features, and hybrid models are an adequate description. A hybrid code operating on a curvilinear 3D grid and its application to solar wind interaction with weak obstacles is discussed. The…