Search Publications
Determination of Prominence Plasma β from the Dynamics of Rising Plumes
Tripathi, Durgesh; Hillier, Andrew; Hillier, Richard
Observations by the Hinode satellite show in great detail the dynamics of rising plumes, dark in chromospheric lines, in quiescent prominences that propagate from large (~10 Mm) bubbles that form at the base of the prominences. These plumes present a very interesting opportunity to study magnetohydrodynamic (MHD) phenomena in quiescent prominences…
Chandra Observations of Five INTEGRAL Sources: New X-Ray Positions for IGR J16393-4643 and IGR J17091-3624
Rahoui, F.; Tomsick, J. A.; Rodriguez, J. +1 more
The Chandra High Resolution Camera observed the fields of five hard X-ray sources in order to help us obtain X-ray coordinates with subarcsecond precision. These observations provide the most accurate X-ray positions known for IGR J16393-4643 and IGR J17091-3624. The obscured X-ray pulsar IGR J16393-4643 lies at R.A. (J2000) = 16h39
Sizes, Half-mass Densities, and Mass Functions of Star Clusters in the Merger Remnant NGC 1316: Clues to the Fate of Second-generation Globular Clusters
Goudfrooij, Paul
We study mass functions of globular clusters derived from Hubble Space Telescope/Advanced Camera for Surveys images of the early-type merger remnant galaxy NGC 1316, which hosts a significant population of metal-rich globular clusters of intermediate age (~3 Gyr). For the old, metal-poor ("blue") clusters, the peak mass of the mass function {\cal …
Sound-speed Inversion of the Sun Using a Nonlocal Statistical Convection Theory
Deng, Licai; Christensen-Dalsgaard, Jørgen; Zhang, Chunguang +1 more
Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convecti…
Possible Detection of an Emission Cyclotron Resonance Scattering Feature from the Accretion-powered Pulsar 4U 1626-67
Mihara, T.; Tashiro, M. S.; Yamada, S. +7 more
We present analysis of 4U 1626-67, a 7.7 s pulsar in a low-mass X-ray binary system, observed with the hard X-ray detector of the Japanese X-ray satellite Suzaku in 2006 March for a net exposure of ~88 ks. The source was detected at an average 10-60 keV flux of ~4 × 10-10 erg cm-2 s-1. The phase-averaged spectrum i…
Probing the M_BH-σ* Relation in the Non-local Universe Using Red QSOs
Lacy, Mark; Canalizo, Gabriela; Hiner, Kyle D. +3 more
We describe a method to measure the M_BH-σ* relation in the non-local universe using dust-obscured QSOs. We present results from a pilot sample of nine Two Micron All Sky Survey red QSOs with redshifts 0.14 < z < 0.37. We find that there is an offset (0.8 dex, on average) between the position of our objects and the local relation …
Late-time Light Curves of Type II Supernovae: Physical Properties of Supernovae and Their Environment
Barlow, Michael J.; Panagia, Nino; Meixner, Margaret +9 more
We present BVRIJHK-band photometry of six core-collapse supernovae, SNe 1999bw, 2002hh, 2003gd, 2004et, 2005cs, and 2006bc, measured at late epochs (>2 yr) based on the Hubble Space Telescope (HST), and the Gemini North, and WIYN telescopes. We also show the JHK light curves of supernova impostor SN 2008S up to day 575 because it was serendipit…
On Molecular Hydrogen Formation and the Magnetohydrostatic Equilibrium of Sunspots
Lin, H.; Jaeggli, S. A.; Uitenbroek, H.
We have investigated the problem of sunspot magnetohydrostatic equilibrium with comprehensive IR sunspot magnetic field survey observations of the highly sensitive Fe I lines at 15650 Å and nearby OH lines. We have found that some sunspots show isothermal increases in umbral magnetic field strength which cannot be explained by the simplified sunsp…
Thermal and Chemical Structure Variations in Titan's Stratosphere during the Cassini Mission
Teanby, N. A.; Flasar, F. M.; Preka-Papadema, P. +12 more
We have developed a line-by-line Atmospheric Radiative Transfer for Titan code that includes the most recent laboratory spectroscopic data and haze descriptions relative to Titan's stratosphere. We use this code to model Cassini Composite Infrared Spectrometer data taken during the numerous Titan flybys from 2006 to 2012 at surface-intercepting ge…
An Interpretation of the Possible Mechanisms of Two Ground-level Enhancement Events
Gan, W. Q.; Moon, Y. -J.; Firoz, Kazi A. +1 more
We have carried out this work to clarify the possible mechanisms of two important high-energy particle events (GLE69 2005 January 20, 06:46 UT and GLE70 2006 December 13, 02:45 UT). For this purpose, the cosmic-ray intensities registered by neutron monitors at several sites have been analyzed and studied with concurrent solar flares of different e…