Search Publications
Eruption of a Kink-unstable Filament in NOAA Active Region 10696
van Driel-Gesztelyi, Lidia; Démoulin, Pascal; Török, Tibor +2 more
We present rapid-cadence Transition Region and Coronal Explorer (TRACE) observations that show evidence of a filament eruption from NOAA active region 10696, accompanied by an X2.5 flare, on 2004 November 10. The eruptive filament, which manifests as a fast coronal mass ejection some minutes later, rises as a kinking structure with an apparently e…
Cassini Magnetometer Observations During Saturn Orbit Insertion
Russell, C. T.; Dougherty, M. K.; Balogh, A. +15 more
Cassini's successful orbit insertion has provided the first examination of Saturn's magnetosphere in 23 years, revealing a dynamic plasma and magnetic environment on short and long time scales. There has been no noticeable change in the internal magnetic field, either in its strength or its near-alignment with the rotation axis. However, the exter…
An Overabundance of Transient X-Ray Binaries within 1 Parsec of the Galactic Center
Brandt, W. N.; Muno, M. P.; Baganoff, F. K. +4 more
During 5 years of Chandra observations, we have identified seven X-ray transients located within 23 pc of Sgr A*. These sources each vary in luminosity by more than a factor of 10 and have peak X-ray luminosities greater than 5×1033 ergs s-1, which strongly suggests that they are accreting black holes or neutron stars. The pe…
The mass of the missing baryons in the X-ray forest of the warm-hot intergalactic medium
Elvis, Martin; Zezas, Andreas; Marshall, Herman +7 more
Recent cosmological measurements indicate that baryons comprise about four per cent of the total mass-energy density of the Universe, which is in accord with the predictions arising from studies of the production of the lightest elements. It is also in agreement with the actual number of baryons detected at early times (redshifts z > 2). Close …
A Census of Optical and Near-Infrared Selected Star-forming and Passively Evolving Galaxies at Redshift z ~ 2
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +3 more
Using the extensive multiwavelength data in the GOODS-North field, including our ground-based rest-frame UV spectroscopy and near-IR imaging, we construct and draw comparisons between samples of optical and near-IR selected star-forming and passively evolving galaxies at redshifts 1.4<~z<~2.6. We find overlap at the 70%-80% level in samples …
Measuring the Three-dimensional Structure of Galaxy Clusters. I. Application to a Sample of 25 Clusters
Sereno, Mauro; Bautz, Mark W.; Longo, Giuseppe +1 more
We discuss a method to constrain the intrinsic shapes of galaxy clusters by combining X-ray and Sunyaev-Zel'dovich observations. The method is applied to a sample of 25 X-ray-selected clusters, with measured Sunyaev-Zel'dovich temperature decrements. The sample turns out to be slightly biased, with strongly elongated clusters preferentially aligne…
Eclipsing binaries as standard candles. HD 23642 and the distance to the Pleiades
Maxted, P. F. L.; Southworth, J.; Smalley, B.
We present a reanalysis of the light curves of HD 23642, a detached eclipsing binary star in the Pleiades open cluster, with emphasis on a detailed error analysis. We compare the masses and radii of the two stars to predictions of stellar evolutionary models and find that the metal and helium abundances of the Pleiades are approximately solar. We …
The Physical Properties and Effective Temperature Scale of O-Type Stars as a Function of Metallicity. II. Analysis of 20 More Magellanic Cloud Stars and Results from the Complete Sample
Massey, Philip; Pauldrach, A. W. A.; Bresolin, Fabio +3 more
In order to determine the physical properties of the hottest and most luminous stars and understand how these properties change as a function of metallicity, we have analyzed HST/UV and high-S/N optical spectra of an additional 20 Magellanic Cloud stars, doubling the sample presented in the first paper in this series. Our analysis uses non-LTE lin…
The October 28, 2003 extreme EUV solar flare and resultant extreme ionospheric effects: Comparison to other Halloween events and the Bastille Day event
Tsurutani, B. T.; Didkovsky, L.; Judge, D. L. +16 more
Some of the most intense solar flares measured in 0.1 to 0.8 nm x-rays in recent history occurred near the end of 2003. The Nov 4 event is the largest in the NOAA records (X28) and the Oct 28 flare was the fourth most intense (X17). The Oct 29 flare was class X7. These flares are compared and contrasted to the July 14, 2000 Bastille Day (X10) even…
Titan's internal structure inferred from a coupled thermal-orbital model
Sotin, Christophe; Lunine, Jonathan I.; Tobie, Gabriel +2 more
Through coupled thermal and orbital calculations including a full description of tidal dissipation, heat transfer and the H 2O sbnd NH 3 phase diagram, we propose a model for the internal structure and composition of Titan testable with Cassini-Huygens measurements. The high value of Titan's orbital eccentricity provides a st…