Search Publications
A New 3D Multi-fluid Model: A Study of Kinetic Effects and Variations of Physical Conditions in the Cometary Coma
Huang, Z.; Jia, X.; Bieler, A. +8 more
Physics-based numerical coma models are desirable whether to interpret the spacecraft observations of the inner coma or to compare with the ground-based observations of the outer coma. In this work, we develop a multi-neutral-fluid model based on the BATS-R-US code of the University of Michigan, which is capable of computing both the inner and out…
The Molecular Baryon Cycle of M82
Chisholm, John; Matsushita, Satoki
Baryons cycle into galaxies from the intergalactic medium and are converted into stars; a fraction of the baryons are ejected out of galaxies by stellar feedback. Here we present new high-resolution (3.″9 68 pc) 12CO(2-1) and 12CO(3-2) images that probe these three stages of the baryon cycle in the nearby starburst M82. We co…
A Nanoflare-based Cellular Automaton Model and the Observed Properties of the Coronal Plasma
Klimchuk, James A.; López Fuentes, Marcelo
We use the cellular automaton model described in López Fuentes & Klimchuk to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active reg…
Correlation of Coronal Plasma Properties and Solar Magnetic Field in a Decaying Active Region
Warren, Harry P.; Ugarte-Urra, Ignacio; Young, Peter R. +2 more
We present the analysis of a decaying active region observed by the EUV Imaging Spectrometer on Hinode during 2009 December 7-11. We investigated the temporal evolution of its structure exhibited by plasma at temperatures from 300,000 to 2.8 million degrees, and derived the electron density, differential emission measure, effective electron temper…
The Extreme Ultraviolet Variability of Quasars
O'Dea, Christopher P.; Zhang, Shaohua; Muzahid, Sowgat +2 more
We study the extreme ultraviolet (EUV) variability (rest frame wavelengths 500-920 Å) of high-luminosity quasars using Hubble Space Telescope (HST) (low to intermediate redshift sample) and Sloan Digital sky Survey (SDSS) (high redshift sample) archives. The combined HST and SDSS data indicates a much more pronounced variability when the sampling …
First Observational Signature of Rotational Deceleration in a Massive, Intermediate-age Star Cluster in the Magellanic Clouds
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
While the extended main-sequence turnoffs (eMSTOs) found in almost all 1-2 Gyr old star clusters in the Magellanic Clouds are often explained by postulating extended star formation histories (SFHs), the tight subgiant branches (SGBs) seen in some clusters challenge this popular scenario. Puzzlingly, the SGB of the eMSTO cluster NGC 419 is signific…
The X-Ray Luminosity Function of M37 and the Evolution of Coronal Activity in Low-mass Stars
Agüeros, Marcel A.; Núñez, Alejandro
We use a 440.5 ks Chandra observation of the ≈500 Myr old open cluster M37 to derive the X-ray luminosity functions of its ≤1.2 {M}⊙ stars. Combining detections of 162 M37 members with upper limits for 160 non-detections, we find that its G, K, and M stars have a similar median (0.5-7 keV) X-ray luminosity {L}{{X}}={10}…
Validation of the Coronal Thick Target Source Model
Xu, Yan; Fleishman, Gregory D.; Gary, Dale E. +1 more
We present detailed 3D modeling of a dense, coronal thick-target X-ray flare using the GX Simulator tool, photospheric magnetic measurements, and microwave imaging and spectroscopy data. The developed model offers a remarkable agreement between the synthesized and observed spectra and images in both X-ray and microwave domains, which validates the…
The Fate of a Red Nugget: In Situ Star Formation of Satellites around a Massive Compact Galaxy
Morishita, Takahiro; Ichikawa, Takashi
To study the accretion phase for local massive galaxies, we search accreting satellites around a massive compact galaxy ({M}*∼ 3.9× {10}10{M}⊙ ), spectroscopically confirmed ({z}{{spec}}=1.9213) in the eXtreme Deep Field, which has been originally reported in Szomoru et al. We detect 1369 satellite candi…
Coronal Magnetic Fields Derived from Simultaneous Microwave and EUV Observations and Comparison with the Potential Field Model
Shibasaki, Kiyoto; Shiota, Daikou; Nozawa, Satoshi +2 more
We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA …