Search Publications
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 …
A Deep Chandra ACIS Study of NGC 4151. I. The X-ray Morphology of the 3 kpc Diameter Circum-nuclear Region and Relation to the Cold Interstellar Medium
Elvis, Martin; Zezas, Andreas; Schinnerer, Eva +6 more
We report on the imaging analysis of ~200 ks sub-arcsecond resolution Chandra Advanced CCD Imaging Spectrometer (ACIS-S) observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the southwest from the nucleus, much farther than seen in earlier X-ray studies. The ter…
X-ray Properties of Narrow-line Seyfert 1 Galaxies with Very Small Broadline Widths
Wang, T. G.; Yuan, W.; Zhou, H. Y. +2 more
Narrow-line Seyfert 1 galaxies (NLS1s) with very small broadline widths (say, FWHM(Hβ) lsim1200 km s-1) represent the extreme type of Seyfert 1 galaxies that have small black hole masses (M BH) and/or high Eddington ratios (L/L Edd). Here, we study the X-ray properties of a homogeneously and optically selected samp…
Multiwavelength Observations of A0620-00 in Quiescence
Prochaska, J. Xavier; Maccarone, Thomas J.; Danforth, Charles W. +17 more
We present contemporaneous X-ray, ultraviolet, optical, near-infrared, and radio observations of the black hole binary system, A0620-00, acquired in 2010 March. Using the Cosmic Origins Spectrograph on the Hubble Space Telescope, we have obtained the first FUV spectrum of A0620-00 as well as NUV observations with the Space Telescope Imaging Spectr…
Plasma Diagnostics of an EIT Wave Observed by Hinode/EIS and SDO/AIA
Temmer, M.; Veronig, A. M.; Vršnak, B. +4 more
We present plasma diagnostics of an Extreme-Ultraviolet Imaging Telescope (EIT) wave observed with high cadence in Hinode/Extreme-Ultraviolet Imaging Spectrometer (EIS) sit-and-stare spectroscopy and Solar Dynamics Observatory/Atmospheric Imaging Assembly imagery obtained during the HOP-180 observing campaign on 2011 February 16. At the propagatin…
Spatially and Spectrally Resolved Observations of a Zebra Pattern in a Solar Decimetric Radio Burst
Chen, Bin; Jing, Ju; Gary, D. E. +1 more
We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (≈1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 2006 December 14. By using OVSA to cal…