Search Publications
Observing the Modification of the Acoustic Cutoff Frequency by Field Inclination Angle
McIntosh, Scott W.; Jefferies, Stuart M.
We use observations of a sunspot from the Transition Region and Coronal Explorer (TRACE) spacecraft to demonstrate observationally the modification of the acoustic cutoff frequency in the lower solar chromosphere by the changing the inclination of the magnetic field as first predicted theoretically by Bel & Leroy.
Interferometric 890 µm Images of High-Redshift Submillimeter Galaxies
Le Floc'h, E.; Yun, M. S.; Scott, D. +12 more
We present high-resolution 890 µm images of two 20 mJy submillimeter galaxies, SMM J123711+622212 and MIPS J142824.0+352619, obtained using the Submillimeter Array (SMA). Using submillimeter interferometric observations with an angular resolution of 2.5", the coordinates of these high-redshift sources are determined with an accuracy of 0.2".…
Converging Motion of Hα Conjugate Kernels: The Signature of Fast Relaxation of a Sheared Magnetic Field
Wang, Haimin; Ji, Haisheng; Huang, Guangli +4 more
In this Letter, we present the results from a high-cadence (~40 ms) Hα blue-wing observation of an M1.1-class solar flare, which occurred in NOAA AR 10687 on 2004 November 1. In collaboration with RHESSI, the observation was made with the Hα Fine Structure Telescope at the GanYu Solar Station of the Purple Mountain Observatory. For this flare, a p…
Dissipation of the Perpendicular Turbulent Cascade in the Solar Wind
Hollweg, Joseph V.; Smith, Charles W.; Vasquez, Bernard J. +1 more
The core solar wind protons are observed to be heated perpendicularly to the magnetic field. This is taken to be a signature of the cyclotron damping of the turbulent fluctuations, which are thought to be responsible for the heating. At the same time, it is commonly accepted that the turbulent cascade produces mostly highly oblique (quasi-two-dime…
On the Rates of Coronal Mass Ejections: Remote Solar and In Situ Observations
Cane, H. V.; Gopalswamy, N.; Richardson, I. G. +2 more
We compare the rates of coronal mass ejections (CMEs) as inferred from remote solar observations and interplanetary CMEs (ICMEs) as inferred from in situ observations at both 1 AU and Ulysses from 1996 through 2004. We also distinguish between those ICMEs that contain a magnetic cloud (MC) and those that do not. While the rates of CMEs and ICMEs t…
Mass along the Line of Sight to the Gravitational Lens B1608+656: Galaxy Groups and Implications for H0
McKean, J. P.; Fassnacht, C. D.; Readhead, A. C. S. +3 more
We report the discovery of four groups of galaxies along the line of sight to the B1608+656 gravitational lens system. One group is at the redshift of the primary lensing galaxy (z=0.631) and appears to have a low mass, with eight spectroscopically confirmed members and an estimated velocity dispersion of 150+/-60 km s-1. The three othe…
The Rate of Type Ia Supernovae at High Redshift
Tonry, John L.; Barris, Brian J.
We derive the rates of Type Ia supernovae (SNe Ia) over a wide range of redshifts using a complete sample from the IfA Deep Survey. This sample of more than 100 SNe Ia is the largest set ever collected from a single survey and therefore uniquely powerful for a detailed supernova rate (SNR) calculation. Measurements of the SNR as a function of cosm…
Differential Microlensing of the Continuum and Broad Emission Lines in SDSS J0924+0219, the Most Anomalous Lensed Quasar
Keeton, Charles R.; Schechter, Paul L.; Burles, Scott +1 more
SDSS J092455.87+021924.9 is the most glaring example of a gravitational lens with anomalous flux ratios; optical broadband photometry shows image D to be a factor of 12 fainter than expected for smooth lens potentials. We report spectroscopy showing that the anomaly is present in the broad emission line flux ratios as well. There are differences b…
The Statistical Relationship between the Photospheric Magnetic Parameters and the Flare Productivity of Active Regions
Jing, Ju; Wang, Haimin; Song, Hui +2 more
Using line-of-sight Michelson Doppler Imager (MDI) magnetograms of 89 active regions and Solar Geophysical Data (SGD) flare reports, we explored, for the first time, the magnitude scaling correlations between three parameters of magnetic fields and the flare productivity of solar active regions. These parameters are (1) the mean value of spatial m…
2MASS J22521073-1730134: A Resolved L/T Binary at 14 Parsecs
Burgasser, Adam J.; Reid, I. Neill; Cruz, K. L. +1 more
NICMOS images of the nearby late-type L dwarf 2MASS J22521073-1730134 (DENIS-P J225210.73-173013.4) show that it is a close double, separation 0.13". The companion is 1.0 mag fainter than the primary in the F110W passband and 1.55 mag fainter in the F170M images. The latter passband is centered on the 1.6 µm methane band. The small separatio…