Search Publications
HINODE Observations of Coherent Lateral Motion of Penumbral Filaments During an X-Class Flare
Tiwari, Sanjiv Kumar; Venkatakrishnan, P.; Gosain, S.
The X-3.4 class flare of 2006 December 13 was observed with a high cadence of 2 minutes at 0.2 arcsec resolution by HINODE/SOT FG instrument. The flare ribbons could be seen in G-band images also. A careful analysis of these observations after proper registration of images shows flare-related changes in penumbral filaments of the associated sunspo…
The Magellanic Bridge as a Damped Lyman Alpha System: Physical Properties of Cold Gas Toward PKS 0312-770
Kobulnicky, Henry A.; Charlton, Jane C.; Bland-Hawthorn, Joss +2 more
We measure the physical properties of a local multicomponent absorption-line system at V sun ~200 km s-1 toward the quasar PKS 0312-770 behind the Magellanic Bridge (MB) using Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) spectroscopy in conjunction with photoionization modeling. At an impact parameter of…
Chirality of Intermediate Filaments and Magnetic Helicity of Active Regions
Chae, Jongchul; Lim, Eun-Kyung
Filaments that form either between or around active regions (ARs) are called intermediate filaments. Even though there have been many theoretical studies, the origin of the chirality of filaments is still unknown. We investigated how intermediate filaments are related to their associated ARs, especially from the point of view of magnetic helicity …
Rates of Photospheric Magnetic Flux Cancellation Measured with Hinode
Chae, Jongchul; Litvinenko, Yuri E.; Park, Soyoung
Photospheric magnetic flux cancellation on the Sun is generally believed to be caused by magnetic reconnection occurring in the low solar atmosphere. Individual canceling magnetic features are observationally characterized by the rate of flux cancellation. The specific cancellation rate, defined as the rate of flux cancellation divided by the inte…
Magnetic Nested-Wind Scenarios for Bipolar Outflows: Preplanetary and YSO Nebular Shaping
Frank, Adam; Balick, Bruce; De Marco, Orsola +3 more
We present results of a series of magnetohydrodynamic (MHD) and hydrodynamic (HD) 2.5 dimensional simulations of the morphology of outflows driven by nested wide-angle winds, i.e., winds that emanate from a central star as well as from an orbiting accretion disk. While our results are broadly relevant to nested-wind systems, we have tuned the para…
Host Galaxies of z = 4 Quasars
McLeod, K. K.; Bechtold, Jill
We have undertaken a project to investigate the host galaxies and environments of a sample of quasars at z ~ 4. In this paper, we describe deep near-infrared imaging of 34 targets using the Magellan I and Gemini North telescopes. We discuss in detail special challenges of distortion and nonlinearity that must be addressed when performing point-spr…
TeV Gamma-Ray Emission from Vela X: Leptonic or Hadronic?
Zhang, L.; Yang, X. C.
We study nonthermal photon emission properties from Vela X in both a leptonic and a hadronic-leptonic model. In the leptonic model, it is difficult to reproduce the observed photon spectrum from X-ray to TeV bands using reasonable model parameters; the model results can compare with either the observed data at the TeV band (the total energy of ele…
Statistics of Density Fluctuations During the Transition from the Outer Solar Corona to the Interplanetary Space
Bruno, R.; Carbone, V.; Antonucci, E. +2 more
This paper investigates the evolution of the plasma density fluctuations of the fast and slow solar wind from the solar corona into the interplanetary space. The study is performed by comparing the low-frequency spectra and the phase correlation of the proton density oscillations, measured in the inner heliosphere with the Helios 2 in situ instrum…
Line-of-Sight Shell Structure of the Cygnus Loop
Katsuda, Satoru; Uchida, Hiroyuki; Tsunemi, Hiroshi +3 more
We conducted a comprehensive study on the shell structure of the Cygnus Loop using 41 observation data obtained by the Suzaku and the XMM-Newton satellites. To investigate the detailed plasma structure of the Cygnus Loop, we divided our fields of view into 1042 box regions. From the spectral analysis, the spectra obtained from the limb of the Loop…
Chandra's Close Encounter with the Disintegrating Comets 73P/2006 (Schwassmann-Wachmann 3) Fragment B and C/1999 S4 (LINEAR)
Bodewits, D.; Christian, D. J.; Dennerl, K. +2 more
On 2006 May 23, we used the ACIS-S instrument on Chandra to study the X-ray emission from the B fragment of comet 73P/2006 (Schwassmann-Wachmann 3) (73P/B). We obtained a total of 20 ks of Chandra observation time of Fragment B, and also investigated contemporaneous Advanced Composition Explorer and Solar and Heliospheric Observatory solar wind ph…