Search Publications
Longitudinal Drifts of Streamers across the Heliospheric Current Sheet
Morgan, Huw
Potential field source surface (PFSS) extrapolations of the photospheric magnetic field provide a qualitatively correct model of the coronal magnetic structure. We show that the magnetic structure provided by PFSS describes a framework within which high-density coronal streamers are distributed. However, the density structures have considerable fr…
A Search for Lyman Break Galaxies in the Chandra Deep Field South Using Swift Ultraviolet/Optical Telescope
Gronwall, Caryl; Hornschemeier, Ann E.; Basu-Zych, Antara R. +2 more
While the Swift satellite is primarily designed to study gamma-ray bursts, its ultraviolet and optical imaging and spectroscopy capabilities are also being used for a variety of scientific programs. In this study, we use the UV/Optical Telescope (UVOT) instrument on board Swift to discover 0.5 < z < 2 Lyman break galaxies (LBGs). UVOT has co…
INTEGRAL Observations of the γ-Ray Binary 1FGL J1018.6-5856
Rea, Nanda; Torres, Diego F.; Li, Jian +5 more
The Fermi Large Area telescope (Fermi-LAT) collaboration has recently reported that one of their detected sources, namely, 1FGL J1018.6-5856, is a new gamma-ray binary similar to LS 5039. This has prompted efforts to study its multi-frequency behavior. In this report, we present the results from 5.78 Ms International Gamma-Ray Astrophysics Laborat…
Spatially Resolved Star Formation History Along the Disk of M82 Using Multi-band Photometric Data
Mayya, Y. D.; Rosa-González, D.; Rodríguez-Merino, L. H.
We present results on the star formation history and extinction in the disk of M82 over spatial scales of 10'' (~180 pc). Multi-band photometric data covering the far-ultraviolet to the near-infrared bands were fitted to a grid of synthetic spectral energy distributions. We obtained distribution functions of age and extinction for each of the 117 …
Large-scale Shock-ionized and Photoionized Gas in M83: The Impact of Star Formation
Mutchler, Max; McCarthy, Patrick J.; Blair, William P. +20 more
We investigate the ionization structure of the nebular gas in M83 using the line diagnostic diagram, [O III](5007 Å)/Hβ versus [S II](6716 Å+6731 Å)/Hα, with the newly available narrowband images from the Wide Field Camera 3 (WFC3) of the Hubble Space Telescope (HST). We produce the diagnostic diagram on a pixel-by-pixel (0farcs2 × 0farcs2) basis …
Estimation of the Reconnection Electric Field in the 2003 October 29 X10 Flare
Krucker, Säm; Cheng, C. Z.; Yang, Ya-Hui +1 more
The electric field in the reconnecting current sheet of the 2003 October 29 X10 flare is estimated to be a few kV m-1 in this study, based on the rate of change in the photospheric magnetic flux in the newly brightened areas of Transition Region and Coronal Explorer (TRACE) UV ribbons. For comparison, the motion speed of Reuven Ramaty H…
The Disappearing Solar Filament of 2003 June 11: A Three-body Problem
Panasenco, O.; Balasubramaniam, K. S.; Pevtsov, A. A. +2 more
The eruption of a large quiescent filament on 2003 June 11 was preceded by the birth of a nearby active region—a common scenario. In this case, however, the filament lay near a pre-existing active region and the new active region did not destabilize the filament by direct magnetic connection. Instead it appears to have done so indirectly via magne…
Analysis of SOHO/MDI and TRACE Observations of Sunspot Torsional Oscillation in AR10421
Kosovichev, A. G.; Gopasyuk, O. S.
Rotation of the leading sunspot of active region NOAA 10421 was investigated using magnetograms and Dopplergrams from the MDI instrument of the Solar and Heliospheric Observatory, and white-light images from the Transition Region and Coronal Explorer (TRACE). The vertical, radial, and azimuthal axisymmetrical components of both magnetic and veloci…
A Hard and Variable X-ray Emission from the Massive Emission-line Star HD 157832
Motch, C.; Lopes de Oliveira, R.
We report the discovery with XMM-Newton of a hard-thermal (T ~ 130 MK) and variable X-ray emission from the Be star HD 157832, a new member of the puzzling class of γ-Cas-like Be/X-ray systems. Recent optical spectroscopy reveals the presence of a large/dense circumstellar disk seen at intermediate/high inclination. With a B1.5V spectral type, HD …
Formation of a Propeller Structure by a Moonlet in a Dense Planetary Ring
Kokubo, Eiichiro; Michikoshi, Shugo
The Cassini spacecraft discovered a propeller-shaped structure in Saturn's A ring. This propeller structure is thought to be formed by gravitational scattering of ring particles by an unseen embedded moonlet. Self-gravity wakes are prevalent in dense rings due to gravitational instability. Strong gravitational wakes affect the propeller structure.…