Search Publications
Abell 1201: A Minor Merger at Second Core Passage
McNamara, Brian R.; Nulsen, Paul E. J.; Murray, Stephen S. +3 more
We present an analysis of the structures and dynamics of the merging cluster Abell 1201, which has two sloshing cold fronts around a cooling core, and an offset gas core approximately 500 kpc northwest of the center. New Chandra and XMM-Newton data reveal a region of enhanced brightness east of the offset core, with breaks in surface brightness al…
Magnetic Helicity Transported by Flux Emergence and Shuffling Motions in Solar Active Region NOAA 10930
Zhang, Y.; Takizawa, K.; Kitai, R.
We present a new methodology which can determine magnetic helicity transport by the passage of helical magnetic field lines from the sub-photosphere and the shuffling motions of footpoints of preexisting coronal field lines separately. It is well known that only the velocity component, which is perpendicular to the magnetic field (υ B )…
Evolution in the Dust Lane Fraction of Edge-on L* V Spiral Galaxies Since z = 0.8
Dalcanton, J. J.; Koekemoer, A.; Böker, T. +5 more
The presence of a well-defined and narrow dust lane in an edge-on spiral galaxy is the observational signature of a thin and dense molecular disk, in which gravitational collapse has overcome turbulence. Using a sample of galaxies out to z ~ 1 extracted from the COSMOS survey, we identify the fraction of massive (L* V ) disks that displ…
Matching the Spectral Energy Distribution and P-mode Oscillation Frequencies of the Rapidly Rotating Delta Scuti Star α Ophiuchi with a Two-dimensional Rotating Stellar Model
Deupree, Robert G.; Castañeda, Diego; Peña, Fernando +1 more
Spectral energy distributions are computed using two-dimensional (2D) rotating stellar models and non-LTE plane-parallel model atmospheres. A rotating, 2D stellar model has been found that matches the observed ultraviolet and visible spectrum of α Oph. The SED match occurs for the interferometrically deduced surface shape and inclination, and is d…
The Swift Burst Alert Telescope Perspective on Non-thermal Emission in HIFLUGCS Galaxy Clusters
Sarazin, Craig L.; Okajima, Takashi; Wik, Daniel R. +5 more
The search for diffuse non-thermal, inverse Compton (IC) emission from galaxy clusters at hard X-ray energies has been underway for many years, with most detections being either of low significance or controversial. In this work, we investigate 14-195 keV spectra from the Swift Burst Alert Telescope (BAT) all-sky survey for evidence of non-thermal…
A Search for Infrared Emission from Core-collapse Supernovae at the Transitional Phase
Onaka, Takashi; Arimatsu, Ko; Matsuhara, Hideo +7 more
Most of the observational studies of supernova (SN) explosions are limited to early phases (<a few years after the explosion) of extragalactic SNe and observations of SN remnants (>100 yr) in our Galaxy or very nearby galaxies. SNe at the epoch between these two, which we call the "transitional" phase, have not been explored in detail except…
Observations of the Interaction of Acoustic Waves and Small-scale Magnetic Fields in a Quiet Sun
Kariyappa, R.; Chitta, Lakshmi Pradeep; Jefferies, Stuart M. +1 more
The effect of the magnetic field on photospheric intensity and velocity oscillations at the sites of small-scale magnetic fields (SMFs) in a quiet Sun near the solar disk center is studied. We use observations made by the G-band filter in the Solar Optical Telescope on board Hinode for intensity oscillations; Doppler velocity, magnetic field, and …
On the Detectability of a Predicted Mesolensing Event Associated with the High Proper Motion Star VB 10
Lépine, Sébastien; DiStefano, Rosanne
Extrapolation of the astrometric motion of the nearby low-mass star VB 10 indicates that sometime in late 2011 December or during the first 2-3 months of 2012, the star will make a close approach to a background point source. Based on astrometric uncertainties, we estimate a 1 in 2 chance that the distance of closest approach ρmin will …
Analysis and Modeling of Two Flare Loops Observed by AIA and EIS
Ding, M. D.; Li, Y.; Qiu, J.
We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in extreme ultraviolet (EUV) images. The UV 1600 Å emission at the feet of these loops exhibits a rapid rise, followed by enhanced emission in differ…
The Absence of Cold Dust around Warm Debris Disk Star HD 15407A
Onaka, Takashi; Takita, Satoshi; Fukagawa, Misato +5 more
We report Herschel and AKARI photometric observations at far-infrared (FIR) wavelengths of the debris disk around the F3V star HD 15407A, in which the presence of an extremely large amount of warm dust (~500-600 K) has been suggested by mid-infrared (MIR) photometry and spectroscopy. The observed flux densities of the debris disk at 60-160 µ…