Search Publications
Implications of the Low-frequency Turnover in the Spectrum of Radio Knot C in DG Tau
Björnsson, C. -I.
The synchrotron spectrum of radio knot C in the protostellar object DG Tau has a low-frequency turnover. This is used to show that its magnetic field strength is likely to be at least 10 mG, which is roughly two orders of magnitude larger than previously estimated. The earlier, lower value is due to an overestimate of the emission volume together …
Chandra X-Ray Observations of V830 Tau: A T Tauri Star Hosting an Evanescent Planet
Skinner, Stephen L.; Güdel, Manuel
The radial velocity study by Donati et al. (2016) reported the detection of a close-in giant planet in a 4.93 day orbit around the ~2 Myr old weak-lined T Tauri star V830 Tau. Because of the stringent timescale constraints that a very young host star like V830 Tau would place on hot-Jupiter formation models and inward-migration mechanisms, indepen…
XMM Observation of the Supernova Remnant J0454-6713 and the Adjacent N9 Superbubble
Foster, Adam R.; Smith, Randall K.; Points, Sean D. +1 more
The Large Magellanic Cloud supernova remnant J0454-6713 abutting the H II region N9 has been observed with XMM-Newton. Two groups of lines from Fe XVII account for half the emission and lines from Fe XVIII, O VII, and O VIII are also clearly detected with the XMM RGS. Isothermal equilibrium fits of the EPIC spectra reproduce the basic spectral for…
The Effects of Magnetic Boundary on the Uniform Distribution of Energetic Particle Intensities Observed by Multiple Spacecraft
Wang, Yang; Lyu, Dan; Xiao, Boxi +1 more
In the decay phase of solar energetic particle (SEP) events, particle intensities observed by widely separated spacecraft usually present comparable intensities (within a factor of 2-3) that evolve similarly in time. The phenomenon of SEP events is called a reservoir, which could be observed frequently in intensive gradual SEP events. In this work…
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