Search Publications
Analysis of Time-Distance Helioseismology for Detection of Emerging Active Regions
Kosovichev, Alexander G.; Stefan, John T.; Stejko, Andrey M.
A time-distance helioseismic technique, similar to the one used by Ilonidis et al., is applied to two independent numerical models of subsurface sound-speed perturbations to determine the spatial resolution and accuracy of phase travel time shift measurements. The technique is also used to examine pre-emergence signatures of several active regions…
OGLE-2007-BLG-224L: A Direct Test of Terrestrial Parallax
Yee, Jennifer C.; Bailey, Vanessa P.; Shan, Yutong +4 more
We present limits on the lens flux of OGLE-2007-BLG-224 based on MagAO imaging taken seven years after the microlensing event. At the time of the observations, the lens should have been separated from the microlensing source by 292 mas. However, no new sources are detected with MagAO. We place an upper limit on the lens flux of H > 20.57. This …
The Einstein Ring GAL-CLUS-022058s: a Lensed Ultrabright Submillimeter Galaxy at z = 1.4796
Rebolo, R.; Dannerbauer, H.; Díaz-Sánchez, A. +2 more
We report an ultrabright lensed submillimeter galaxy at zspec = 1.4796, identified as a result of a full-sky cross-correlation of the AllWISE and Planck compact source catalogs aimed at searching for bright submillimeter galaxies at z ~ 1.5-2.8. Atacama Pathfinder Experiment (APEX)/LABOCA observations of the candidate galaxy reveal a so…
Breaks in the X-Ray Spectra of High-redshift Blazars and the Intervening Medium
Gaur, Haritma; Pandey, Ashwani; Mohan, Prashanth
Flat-spectrum radio quasars (FSRQs) are a subclass of blazars characterized by prominent optical emission lines and a collimated large-scale jet along the observer's line of sight. An X-ray spectral flattening has been reported in FSRQs (at relatively high redshifts) that is attributable either to absorption from gas along the line of sight or to …
The Host Galaxy of the Dwarf Seyfert UGC 06728
Bentz, Misty C.
We present multi-color high-resolution imaging of the host galaxy of the dwarf Seyfert UGC 06728. As the lowest-mass black hole to be described with both a direct mass constraint and a spin constraint, UGC 06728 is an important source for comparison with black hole evolutionary models, yet little is known about the host galaxy. Using Hubble Space …
A New Method to Estimate Halo CME Mass Using Synthetic CMEs Based on a Full Ice Cream Cone Model
Moon, Yong-Jae; Lee, Jin-Yi; Cho, Il-Hyun +1 more
In this study, we suggest a new method to estimate the mass of a halo coronal mass ejection (CME) using synthetic CMEs. For this, we generate synthetic CMEs based on two assumptions: (1) the CME structure is a full ice cream cone, and (2) the CME electron number density follows a power-law distribution (ρcme = ρ0r-n
Desaturated EUV Flare Ribbons in an X-class Flare
Krucker, Säm; Schwartz, Richard A.; Torre, Gabriele
This paper studies the energy dissipation of nonthermal electrons in the chromospheric flare ribbons during the peak time of a Geostationary Operational Environmental Satellite X-class flare (SOL2011-09-06) using desaturated Solar Dynamics Observatory/Atmospheric Imaging Assembly extreme-ultraviolet (EUV) narrow-band images. The temperature distri…
ALMA Host Galaxy Observation of the Off-axis Gamma-Ray Burst XRF 020903
Urata, Yuji; Huang, Kuiyun; Chen, Jheng-Cyun
We investigated the radio properties of the host galaxy of X-ray flash, XRF 020903, which is the best example for investigating the off-axis origin of gamma-ray bursts (GRBs). Dust continuum at 233 GHz and CO are observed using the Atacama Large millimeter/submillimeter array. The molecular gas mass derived by applying the metallicity-dependent CO…
Investigating Toroidal Flows in the Sun Using Normal-mode Coupling
Mani, Prasad; Hanasoge, Shravan
Helioseismic observations have provided valuable data sets with which to pursue the detailed investigation of solar interior dynamics. Among various methods to analyze these data, normal-mode coupling has proven to be a powerful tool, used to study Rossby waves, differential rotation, meridional circulation, and nonaxisymmetric multiscale subsurfa…
Effect of Dust Size on the Near-infrared Spectra (1.0-5.0 µm) of Brown Dwarf Atmospheres
Sorahana, Satoko; Kobayashi, Hiroshi; Tanaka, Kyoko K.
In this study, we demonstrate the dependence of atmospheric dust size on the near-infrared spectra of ten L dwarfs, and constrain the sizes of dust grains in each L dwarf atmosphere. In previous studies, by comparing observed and modeled spectra, it was suggested that the deviations of their spectral shapes from theoretical prediction are general …