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A Long Look at NGC 3783 with the XMM-Newton Reflection Grating Spectrometer
Rasmussen, Andrew P.; Kahn, Steven M.; Behar, Ehud +5 more
A long 280 ks observation of the Seyfert 1 galaxy NGC 3783 with XMM-Newton is reported. We focus on the oxygen line complex between 17 and 24 Å as measured with the Reflection Grating Spectrometer. Accurate absorption column densities and emission-line fluxes are obtained. We explore several options for the geometry and physical form of the emitti…
Kinematically quiet haloes around z~ 2.5 radio galaxies. Keck spectroscopy
Pentericci, L.; Humphrey, A.; Villar-Martín, M. +3 more
We present the results of the kinematic study of the extended gas in a sample of 10 high-redshift radio galaxies (z~ 2.5) based on high signal-to-noise ratio Keck II and Very Large Telescope (VLT) long-slit spectroscopy. In addition to the typical high surface brightness kinematically perturbed regions (FWHM and velocity shifts >1000 km s-…
Spectroscopic Confirmation of a Substantial Population of Luminous Red Galaxies at Redshifts z>~2
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +10 more
We confirm spectroscopically the existence of a population of galaxies at z>~2 with rest-frame optical colors similar to normal nearby galaxies. The galaxies were identified by their red near-infrared colors in deep images obtained with the Infrared Spectrometer and Array Camera on the Very Large Telescope of the field around the foreground clu…
The Cepheid Distance to NGC 1637: A Direct Test of the Expanding Photosphere Method Distance to SN 1999em
Leonard, Douglas C.; Tanvir, Nial R.; Kanbur, Shashi M. +1 more
Type II-plateau supernovae (SNe II-P) are the classic variety of core-collapse events that result from isolated, massive stars with thick hydrogen envelopes intact at the time of explosion. Their distances are now routinely estimated through two techniques: the expanding photosphere method (EPM), a primary distance-determining method, and the rece…
The Nature of E+A Galaxies in Intermediate-Redshift Clusters
Franx, Marijn; Kelson, Daniel D.; Tran, Kim-Vy H. +2 more
Combining Hubble Space Telescope WFPC2 mosaics with extensive ground-based spectroscopy, we study the nature of E+A galaxies in three intermediate-redshift clusters (z=0.33, 0.58, and 0.83). From a sample of ~500 confirmed cluster members, we isolate 46 E+A candidates to determine the E+A fraction and study their physical properties. Spectral type…
Coronal dimming and the coronal mass ejection onset
Simnett, G. M.; Harrison, R. A.; Bryans, P. +1 more
A set of five observations of extreme-ultraviolet (EUV) coronal dimming associated with coronal mass ejection (CME) activity is examined. Using spectroscopic data, plasma characteristics across a broad range of temperatures from 20 000 K to 2 million K are determined. The dimming events are found to coincide in time, and to coincide spatially, wit…
Forecasting solar wind structures and shock arrival times using an ensemble of models
Dryer, M.; Smith, Z.; Fry, C. D. +3 more
Forecasting the time of arrival at Earth of interplanetary shocks following solar metric type II activity is an important first step in the establishment of an operational space weather prediction system. The quality of the forecasts is of utmost importance. The performances of the shock time of arrival (STOA) and interplanetary shock propagation …
Acceleration of coronal mass ejections
Chen, James; Krall, Jonathan
The acceleration of coronal mass ejections (CMEs) is examined focusing on three specific questions raised by observations: (1) what determines the height beyond which a CME exhibits no rapid acceleration, (2) why is the main acceleration of CMEs typically limited to below 2-3 solar radii, and (3) are distinct mechanisms required to explain the app…
Complex C: A Low-Metallicity, High-Velocity Cloud Plunging into the Milky Way
Tripp, Todd M.; Jenkins, Edward B.; Linsky, J. L. +8 more
We present evidence that high-velocity cloud (HVC) complex C is a low-metallicity gas cloud that is plunging toward the disk and beginning to interact with the ambient gas that surrounds the Milky Way. This evidence begins with a new high-resolution (7 km s-1 FWHM) echelle spectrum of 3C 351 obtained with the Space Telescope Imaging Spe…
Jupiter's polar auroral emissions
Kim, J.; Clarke, J. T.; Cowley, S. W. H. +3 more
This paper reports a study of Jupiter's polar auroral emissions observed in an extended series of FUV images. They were obtained on seven days, during winter 2000-2001, with the STIS camera on board the Hubble Space Telescope. The fixed pointing yielded highly accurate and consistent tracking of emisson features as Jupiter rotated, allowing the an…