Search Publications
Water vapor mapping on Mars using OMEGA/Mars Express
Bibring, J. -P.; Gondet, B.; Langevin, Y. +8 more
A systematic mapping of water vapor on Mars has been achieved using the imaging spectrometer OMEGA aboard the Mars Express spacecraft, using the depth of the 2.6 µm ( ν1, ν3) band of H 2O. We report results obtained during two periods: (1) Ls=330-40° (January-June 2004), before and after the equinox, and (2) …
Coronal Holes and Solar Wind High-Speed Streams: II. Forecasting the Geomagnetic Effects
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan
We present a simple method of forecasting the geomagnetic storms caused by high-speed streams (HSSs) in the solar wind. The method is based on the empirical correlation between the coronal hole area/position and the value of the Dst index, which is established in a period of low interplanetary coronal mass ejection (ICME) activity. On average, the…
Chandra and XMM-Newton detection of large-scale diffuse X-ray emission from the Sombrero galaxy
Wang, Q. Daniel; Li, Zhiyuan; Hameed, Salman
We present an X-ray study of the massive edge-on Sa galaxy, Sombrero (M 104; NGC 4594), based on XMM-Newton and Chandra observations. A list of 62 XMM-Newton and 175 Chandra discrete X-ray sources is provided, the majority of which are associated with the galaxy. Spectral analysis is carried out for relatively bright individual sources and for an …
Observations Supporting the Role of Magnetoconvection in Energy Supply to the Quiescent Solar Atmosphere
Wilhelm, Klaus; McIntosh, Scott W.; Armstrong, James D. +4 more
Identifying the two physical mechanisms behind the production and sustenance of the quiescent solar corona and solar wind poses two of the outstanding problems in solar physics today. We present analysis of spectroscopic observations from the Solar and Heliospheric Observatory that are consistent with a single physical mechanism being responsible …
Local Helioseismology and Correlation Tracking Analysis of Surface Structures in Realistic Simulations of Solar Convection
Zhao, Junwei; Kosovichev, Alexander G.; Georgobiani, Dali +3 more
We apply time-distance helioseismology, local correlation tracking, and Fourier spatial-temporal filtering methods to realistic supergranule scale simulations of solar convection and compare the results with high-resolution observations from the Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI). Our objective is to investiga…
Deep XMM-Newton and Chandra Observations of Cl J1226.9+3332: A Detailed X-Ray Mass Analysis of a z = 0.89 Galaxy Cluster
Maughan, B. J.; Jones, L. R.; Jones, C. +1 more
Deep XMM-Newton and Chandra observations of Cl J1226.9+3332 at z=0.89 have enabled the most detailed X-ray mass analysis of any such high-redshift galaxy cluster. The XMM-Newton temperature profile of the system shows no sign of central cooling, with a hot core and a radially declining profile. A temperature map shows asymmetry with a hot region t…
XMM-Newton Observations Reveal the X-Ray Counterpart of the Very High Energy Gamma-Ray Source HESS J1640-465
Funk, S.; Reimer, O.; Hinton, J. A. +4 more
We present X-ray observations of the as of yet unidentified very high energy (VHE) γ-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ks XMM-Newton observation of HESS J1640-465 in 2005 September represents a signifi…
The Source of Saturn’s G Ring
Porco, Carolyn C.; Hedman, Matthew M.; Burns, Joseph A. +6 more
The origin of Saturn’s narrow G ring has been unclear. We show that it contains a bright arc located 167,495.6 ± 1.3 km from Saturn’s center. This longitudinally localized material is trapped in a 7:6 corotation eccentricity resonance with the satellite Mimas. The cameras aboard the Cassini spacecraft mainly observe small (1 to 10 micrometers) dus…
Virgo's Intracluster Globular Clusters as Seen by the Advanced Camera for Surveys
Ferguson, Henry C.; Williams, Benjamin F.; Freeman, Ken C. +11 more
We report the discovery of four candidate intracluster globular clusters (IGCs) in a single deep HST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, has a magnitude near the peak of the Virgo globular cluster luminosity function, has a radial profile that is best fitted by a King model, and is surrounded by an exces…
Surface Brightness Fluctuations from Archival ACS Images: A Stellar Population and Distance Study
Blakeslee, John; Cantiello, Michele; Raimondo, Gabriella +2 more
We derive surface brightness fluctuations (SBF) and integrated magnitudes in the V and I bands using Advanced Camera for Surveys (ACS) archival data. The sample includes 14 galaxies covering a wide range of physical properties: morphology, total absolute magnitude, and integrated color. We take advantage of the latter characteristic of the sample …