Search Publications
GEMS Imaging of Red-Sequence Galaxies at z~0.7: Dusty or Old?
Bell, Eric F.; Somerville, Rachel S.; Wisotzki, Lutz +13 more
We have used the 30'×30' Hubble Space Telescope image mosaic from the Galaxy Evolution from Morphology and Spectral energy distributions (GEMS) project in conjunction with the COMBO-17 deep photometric redshift survey to define a sample of nearly 1500 galaxies with 0.65<=z<=0.75. With this sample, we can study the distr…
Long-Term Cosmic-Ray Modulation in the Heliosphere
Ferreira, S. E. S.; Potgieter, M. S.
A time-dependent model based on a numerical solution of Parker's transport equation is used to model the modulation of cosmic-ray protons, electrons, and helium for full 11 year and 22 year modulation cycles using a compound approach. This approach incorporates the concept of propagating diffusion barriers, increases in the heliospheric magnetic f…
The XMM-Newton Iron Line Profile of NGC 3783
Nandra, K.; Turner, T. J.; Reeves, J. N. +3 more
We report on observations of the iron K line in the nearby Seyfert 1 galaxy, NGC 3783, obtained in a long, two-orbit (~240 ks) XMM-Newton observation. The line profile obtained exhibits two strong narrow peaks at 6.4 and 7.0 keV, with measured line equivalent widths of 120 and 35 eV, respectively. The 6.4 keV emission is the Kα line from near neut…
A Constant Bar Fraction out to Redshift z ~ 1 in the Advanced Camera for Surveys Field of the Tadpole Galaxy
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Hirst, Amelia C.
Barlike structures were investigated in a sample of 186 disk galaxies larger than 0.5" that are in the I-band image of the Tadpole galaxy taken with the Hubble Space Telescope Advanced Camera for Surveys. We found 22 clear cases of barred galaxies, 21 galaxies with small bars that appear primarily as isophotal twists in a contour plot, and 11 case…
The First IBIS/ISGRI Soft Gamma-Ray Galactic Plane Survey Catalog
Hill, A. B.; Walter, R.; Malaguti, G. +16 more
We report the first high-energy survey catalog obtained with the IBIS gamma-ray imager on board INTEGRAL. The analysis has been performed on the first-year Core Program ISGRI data comprising both Galactic Plane Scan and Galactic Centre Deep Exposure pointings for a total exposure time exceeding 5 Ms. This initial survey has revealed the presence o…
Observational Consequences of a Magnetic Flux Rope Emerging into the Corona
Gibson, S. E.; Fan, Y.; Mandrini, C. +2 more
We show that a numerical simulation of a magnetic flux rope emerging into a coronal magnetic field predicts solar structures and dynamics consistent with observations. We first consider the structure, evolution, and relative location and orientation of S-shaped, or sigmoid, active regions and filaments. The basic assumptions are that (1) X-ray sig…
On the Relation between Filament Eruptions, Flares, and Coronal Mass Ejections
Xu, Yan; Yang, Guo; Jing, Ju +2 more
We present a statistical study of 106 filament eruptions, which were automatically detected by a pattern recognition program implemented at Big Bear Solar Observatory using Hα full-disk data from 1999 to 2003. We compare these events with Geostationary Operational Environmental Satellite soft X-ray time profiles, solar-geophysical data (SGD) solar…
Evidence of Black Hole Spin in GX 339-4: XMM-Newton/EPIC-pn and RXTE Spectroscopy of the Very High State
Belloni, T.; Wijnands, R.; Fabian, A. C. +9 more
We have analyzed spectra of the Galactic black hole GX 339-4 obtained through simultaneous 76 ks XMM-Newton/EPIC-pn and 10 ks Rossi X-Ray Timing Explorer observations during a bright phase of its 2002-2003 outburst. An extremely skewed, relativistic Fe Kα emission line and ionized disk reflection spectrum are revealed in these spectra. Self-consis…
Highly Ionized Gas Surrounding High-Velocity Cloud Complex C
Richter, Philipp; Tripp, Todd M.; Sembach, Kenneth R. +3 more
We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high-, intermediate-, and low-ion absorption in high-velocity cloud (HVC) Complex C along the lines of sight toward five active galaxies. Our purpose is to investigate the idea that Complex C is surrounded by an envelope of highly ionized material, arising…
Star Formation at z ~ 6: The Hubble Ultra Deep Parallel Fields
van Dokkum, P.; Bouwens, R. J.; Illingworth, G. D. +8 more
We report on the i-dropouts detected in two exceptionally deep Advanced Camera for Surveys fields (B435, V606, i775, and z850 with 10σ limits of 28.8, 29.0, 28.5, and 27.8, respectively) taken in parallel with the Ultra Deep Field Near-Infrared Camera and Multi-Object Spectrometer observations. Using an …