Search Publications
A Cold, Tenuous Solar Flare: Acceleration Without Heating
Kontar, Eduard P.; Fleishman, Gregory D.; Nita, Gelu M. +1 more
We report the observation of an unusual cold, tenuous solar flare, which reveals itself via numerous and prominent non-thermal manifestations, while lacking any noticeable thermal emission signature. RHESSI hard X-rays and 0.1-18 GHz radio data from OVSA and Phoenix-2 show copious electron acceleration (1035 electrons s-1 abo…
A View of the Narrow-line Region in the Infrared: Active Galactic Nuclei with Resolved Fine-structure Lines in the Spitzer Archive
Elbaz, D.; Sturm, E.; Armus, L. +5 more
We queried the Spitzer archive for high-resolution observations with the Infrared Spectrograph of optically selected active galactic nuclei (AGNs) for the purpose of identifying sources with resolved fine-structure lines that would enable studies of the narrow-line region (NLR) at mid-infrared wavelengths. By combining 298 Spitzer spectra with 6 I…
Evolution of Brightest Cluster Galaxy Structural Parameters in the Last ~6 Gyr: Feedback Processes Versus Merger Events
Cava, A.; Varela, J.; Moles, M. +4 more
We present results on the evolution of the structural parameters of two samples of brightest cluster galaxies (BCGs) in the last 6 Gyr. The nearby sample of BCGs consists of 69 galaxies from the WINGS survey spanning a redshift range of 0.04 < z < 0.07. The intermediate-redshift (0.3 < z < 0.6) sample is formed by 20 BCGs extracted fro…
Characterization of Seven Ultra-wide Trans-Neptunian Binaries
Kavelaars, J. J.; Petit, Jean-Marc; Jones, Lynne +3 more
The low-inclination component of the Classical Kuiper Belt is host to a population of extremely widely separated binaries. These systems are similar to other trans-Neptunian binaries (TNBs) in that the primary and secondary components of each system are of roughly equal size. We have performed an astrometric monitoring campaign of a sample of seve…
X-Ray Activity Phased with Planet Motion in HD 189733?
Günther, H. M.; Pillitteri, I.; Cohen, O. +2 more
We report on the follow-up XMM-Newton observation of the planet-hosting star HD 189733 we obtained in 2011 April. We observe a flare just after the secondary transit of the hot Jupiter. This event shares the same phase and many of the characteristics of the flare we observed in 2009. We suggest that a systematic interaction between planet and stel…
The Carbon Monoxide Abundance in Comet 103P/Hartley 2 During the EPOXI Flyby
Stern, S. A.; Feldman, P. D.; A'Hearn, M. F. +2 more
We report the detection of several emission bands in the CO Fourth Positive Group from comet 103P/Hartley 2 during ultraviolet spectroscopic observations from the Hubble Space Telescope on 2010 November 4 near the time of closest approach by NASA's EPOXI spacecraft. The derived CO/H2O ratio is 0.15%-0.45%, which places 103P/Hartley 2 am…
The Gas-Galaxy Connection at z abs = 0.35: O VI and H I Absorption toward J 0943+0531
Sembach, K. R.; Prochaska, J. X.; Tripp, T. M. +4 more
We present observations of H I and O VI absorption systems proximate to a galaxy at z gal = 0.3529. The absorption was detected serendipitously in Cosmic Origins Spectrograph observations of the low-z QSO J 0943 + 0531 (z qso = 0.564). The data show two separate clouds along the sightline at an impact parameter of 95 kpc from…
Luminous Satellites of Early-type Galaxies. I. Spatial Distribution
Treu, T.; Auger, M. W.; Fassnacht, C. D. +2 more
We study the spatial distribution of faint satellites of intermediate redshift (0.1 < z < 0.8), early-type galaxies, selected from the GOODS fields. We combine high-resolution Hubble Space Telescope images and state-of-the-art host subtraction techniques to detect satellites of unprecedented faintness and proximity to intermediate redshift h…
The Structure of the Accretion Disk in the Lensed Quasar SBS 0909+532
Kochanek, C. S.; Arribas, S.; Acosta-Pulido, J. +7 more
We derive the size and temperature profile of the accretion disk of the lensed quasar SBS 0909+532 by measuring the wavelength dependence (chromaticity) of the microlensing magnification produced by the stars in the lens galaxy. After correcting for extinction using the flux ratios of 14 emission lines, we observe a marked change in the B-A flux r…
A Coronal Seismological Study with Streamer Waves
Feng, S. W.; Chen, Y.; Li, B. +4 more
We present a novel method to evaluate the Alfvén speed and the magnetic field strength along the streamer plasma sheet in the outer corona. The method is based on recent observations of streamer waves, which are regarded as the fast kink body mode carried by the plasma sheet structure and generated upon the impact of a fast coronal mass ejection (…