Search Publications
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 (…
Asteroseismology of the Transiting Exoplanet Host HD 17156 with Hubble Space Telescope Fine Guidance Sensor
Nelan, Edmund P.; Gilliland, Ronald L.; Christensen-Dalsgaard, Jørgen +5 more
Observations conducted with the Fine Guidance Sensor on the Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in 2008 December on the host star of the transiting exoplanet HD 17156b. During this time, 1.0 × 1012 photons (corrected for detector dead time) were …
The Non-segregated Population of Blue Straggler Stars in the Remote Globular Cluster Palomar 14
Ferraro, Francesco R.; Lanzoni, Barbara; Beccari, Giacomo +5 more
We used deep wide-field observations obtained with the Canada-France-Hawaii Telescope to study the blue straggler star (BSS) population in the innermost 5 arcmin of the remote Galactic globular cluster Palomar 14. The BSS radial distribution is found to be consistent with that of the normal cluster stars, showing no evidence of central segregation…
Hemispheric Helicity Trend for Solar Cycle 24
Zhang, Mei; Hao, Juan
Using vector magnetograms obtained with the Spectro-polarimeter (SP) on board Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions that occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active reg…
Discovery and Analysis of 21 µm Feature Sources in the Magellanic Clouds
Gordon, Karl D.; Matsuura, Mikako; Volk, Kevin +15 more
Spitzer Space Telescope mid-infrared spectroscopy has been obtained for 15 carbon-rich protoplanetary nebulae (PPNe) in the Large Magellanic Cloud (LMC) and for two other such stars in the Small Magellanic Cloud (SMC). Of these 17 PPNe, the unidentified 21 µm feature is strong in 7 spectra, weak in 2 spectra, and very weak or questionable in…
Dust Production and Mass Loss in the Galactic Globular Cluster 47 Tucanae
van Loon, J. Th.; Zijlstra, A. A.; Boyer, M. L. +1 more
Dust production among post-main-sequence stars is investigated in the Galactic globular cluster 47 Tucanae (NGC 104) based on infrared photometry and spectroscopy. We identify metallic iron grains as the probable dominant opacity source in these winds. Typical evolutionary timescales of asymptotic giant branch stars suggest the mass-loss rates we …