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Candidates of z ~= 5.5-7 Galaxies in the Hubble Space Telescope Ultra Deep Field
Yan, Haojing; Windhorst, Rogier A.
We report results from our z~=5.5-7 galaxy search in the Hubble Space Telescope Ultra Deep Field (UDF). Using the 400 orbit of Advanced Camera for Surveys data, we found 108 plausible 5.5<=z<=6.5 (or z~=6 for short) candidates to mAB(z850)=30.0 mag. The contamination to the sample, due to either image artifacts or known…
Hubble Space Telescope STIS Ultraviolet Spectral Evidence of Outflow in Extreme Narrow-Line Seyfert 1 Galaxies. II. Modeling and Interpretation
Leighly, Karen M.
We present modeling to explore the conditions of the broad-line-emitting gas in two extreme narrow-line Seyfert 1 galaxies, using the observational results described in the first paper of this series. Photoionization modeling using CLOUDY was conducted for the broad blueshifted wind lines and the narrow, symmetric, rest-wavelength-centered disk li…
A Numerical Study of the Breakout Model for Coronal Mass Ejection Initiation
Antiochos, S. K.; Phillips, A.; MacNeice, P. +3 more
A leading theory for the initiation of coronal mass ejections (CMEs) is the breakout model, in which magnetic reconnection above a filament channel is responsible for disrupting the coronal magnetic field. We present the first simulations of the complete breakout process including the initiation, the plasmoid formation and ejection, and the eventu…
Surprising Sun: A New Step Towards a Complete Picture?
García, R. A.; Turck-Chièze, S.; Piau, L. +5 more
Important revisions of the solar model ingredients have appeared recently. We first show that the updated CNO composition suppresses the anomalous position of the Sun in the known galactic enrichment. The following law, He/H=0.075+44.6 O/H in number fraction, is now compatible with all the indicators. We then suggest some directions of investigati…
The host galaxies of luminous quasars
Baum, Stefi A.; O'Dea, Christopher P.; Dunlop, James S. +5 more
We present the results of a deep Hubble Space Telescope (HST)/Wide Field and Planetary Camera 2 imaging study of 17 quasars at z~= 0.4, designed to determine the properties of their host galaxies. The sample consists of quasars with absolute magnitudes in the range -24 >=MV>=- 28, allowing us to investigate host galaxy properties …
Disk and Halo Wide Binaries from the Revised Luyten Catalog: Probes of Star Formation and MACHO Dark Matter
Gould, Andrew; Chanamé, Julio
We present a catalog of 1147 candidate common proper motion binaries selected from the revised New Luyten Two-Tenths Catalog (NLTT). Among these, we identify 999 genuine physical pairs using the measured proper-motion difference and the relative positions of each binary's components on a reduced proper motion (RPM) diagram. The RPM positions also …
A multiwavelength study of solar flare waves. II. Perturbation characteristics and physical interpretation
Magdalenić, J.; Vršnak, B.; Hanslmeier, A. +2 more
The study of solar flare waves - globally propagating wave-like disturbances usually observed in Hα as Moreton waves - has recently come back into focus prompted by the observation of coronal waves in the EUV with the SOHO/EIT instrument (``EIT waves"), and in several additional wavelength channels. We study 12 flare wave events in order to determ…
An Unveiling Event in the Type 2 Active Galactic Nucleus NGC 4388:A Challenge for a Parsec-Scale Absorber
Fiore, F.; Elvis, Martin; Miller, J. M. +3 more
We present two Rossi X-Ray Timing Explorer (RXTE) Proportional Counter Array (PCA) observations of the type 2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state. The observations were triggered by a detection in the 1.5-3 keV band of the RXTE all-sky monitor. NGC 4388 was found at a somewhat high continuum level [f(2-10 keV)=8…
Discovery of Face-on Counterparts of Chain Galaxies in the Tadpole Advanced Camera for Surveys Field
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Hirst, Amelia C.
The background field of the Tadpole galaxy image taken with the Hubble Space Telescope Advanced Camera for Surveys contains 87 clump clusters that are probably low-inclination versions of the 69 chain galaxies that we found in a previous paper. This conclusion follows from the similarity in colors and apparent magnitudes of the brightest clumps in…
Radar: The Cassini Titan Radar Mapper
Lorenz, R. D.; Soderblom, L. A.; Ostro, S. J. +19 more
The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will pr…