Search Publications
Evidence for Mixed Helicity in Erupting Filaments
Wang, Y. -M.; Kliem, B.; Muglach, K.
Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) …
Suzaku Observations of Four Heavily Absorbed HMXBs
Kallman, T. R.; Mushotzky, R. F.; Morris, D. C. +4 more
We report on Suzaku observations of four unidentified sources from the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) and Swift-Burst Array Telescope Galactic plane surveys. All the sources have a large neutral hydrogen column density and show properties consistent with being supergiant X-ray binaries or supergiant fast X-ray transient…
The X-Ray Point-Source Population of NGC 1365: The Puzzle of Two Highly-Variable Ultraluminous X-Ray Sources
Komossa, S.; Strateva, Iskra V.
We present 26 point-sources discovered with Chandra within 200'' (≈20 kpc) of the center of the barred supergiant galaxy NGC 1365. The majority of these sources are high-mass X-ray binaries, containing a neutron star or a black hole accreting from a luminous companion at a sub-Eddington rate. Using repeat Chandra and XMM-Newton, as well as optical…
The Relation Between Magnetic Fields and Coronal Activities in the Polar Coronal Hole
Shimojo, Masumi; Tsuneta, Saku
We investigated the relation between polar magnetic fields and polar coronal activities based on Stokes maps of photospheric and chromospheric lines, simultaneous X-ray and EUV images. These images are taken with Hinode and Solar and Heliospheric Observatory. With careful co-alignment between these images, we found that the X-ray jets, the X-ray b…
Infrared Studies of Molecular Shocks in the Supernova Remnant HB21. I. Thermal Admixture of Shocked H2 Gas in the North
Koo, Bon-Chul; Lee, Ho-Gyu; Moon, Dae-Sik +2 more
We present near- and mid-infrared observations on the shock-cloud interaction region in the northern part of the supernova remnant HB21, performed with the infrared camera (IRC) aboard the AKARI satellite and the wide-field infrared camera (WIRC) at the Palomar 5 m telescope. The IRC 7 µm (S7), 11 µm (S11), and 15 µm (L15) band i…
Measurements of Absorption of Acoustic Waves in Sunspots with Direction Filters and Cross Correlation
Liang, Zhi-Chao; Chou, Dean-Yi; Sun, Ming-Tsung +1 more
Observations show that the power of solar acoustic waves is reduced inside magnetic regions. Several mechanisms, including absorption, emissivity reduction, and local suppression, may contribute to the observed power reduction in magnetic regions. So far there is no way to distinguish absorption from emissivity reduction in a magnetic region. In t…
AK Sco, First Detection of a Highly Disturbed Atmosphere in a Pre-Main-Sequence Close Binary
Gómez de Castro, Ana I.
AK Sco is a unique source: a ~10 Myr old pre-main-sequence (PMS) spectroscopic binary composed of two nearly equal F5 stars that at periastron are separated by barely 11 stellar radii, so the stellar magnetospheres fill the Roche lobe at periastron. The orbit is not yet circularized (e = 0.47) and very strong tides are expected. This makes AK Sco …
Measurement of Low Signal-To-Noise Ratio Solar p-Modes in Spatially Resolved Helioseismic Data
Hill, F.; Appourchaux, T.; Salabert, D. +1 more
We present an adaptation of the rotation-corrected, m-averaged spectrum technique designed to observe low signal-to-noise ratio (S/N), low-frequency solar p-modes. The frequency shift of each of the 2l + 1 m spectra of a given (n, l) multiplet is chosen that maximizes the likelihood of the m-averaged spectrum. A high S/N can result from combining …
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…