Search Publications
A Deep Chandra ACIS Survey of M51
Kuntz, K. D.; Long, Knox S.; Kilgard, Roy E.
We have obtained a deep X-ray image of the nearby galaxy M51 using Chandra. Here we present the catalog of X-ray sources detected in these observations and provide an overview of the properties of the point-source population. We find 298 sources within the D 25 radii of NGC 5194/5, of which 20% are variable, a dozen are classical transi…
Narrowband Gyrosynchrotron Bursts: Probing Electron Acceleration in Solar Flares
Kontar, Eduard P.; Fleishman, Gregory D.; Nita, Gelu M. +1 more
Recently, in a few case studies we demonstrated that gyrosynchrotron microwave emission can be detected directly from the acceleration region when the trapped electron component is insignificant. For the statistical study reported here, we have identified events with steep (narrowband) microwave spectra that do not show a significant trapped compo…
Analysis of Flows inside Quiescent Prominences as Captured by Hinode/Solar Optical Telescope
Longcope, D. W.; McKenzie, D. E.; Freed, M. S. +1 more
Developing an understanding of how magnetic fields can become entangled in a prominence is important for predicting a possible eruption. This work investigates the kinetic energy and vorticity associated with plasma motion residing inside quiescent prominences (QPs). These plasma flow characteristics can be utilized to improve our understanding of…
Association of 3He-Rich Solar Energetic Particles with Large-scale Coronal Waves
Mason, Glenn M.; Bučík, Radoslav; Wiedenbeck, Mark E. +1 more
Small, 3He-rich solar energetic particle (SEP) events have been commonly associated with extreme-ultraviolet (EUV) jets and narrow coronal mass ejections (CMEs) that are believed to be the signatures of magnetic reconnection, involving field lines open to interplanetary space. The elemental and isotopic fractionation in these events are…
Relationship Between Chromospheric Evaporation and Magnetic Field Topology in an M-Class Solar Flare
Kosovichev, Alexander G.; Sadykov, Viacheslav M.; Sharykin, Ivan N. +2 more
Chromospheric evaporation is observed as Doppler blueshift during solar flares. It plays a key role in the dynamics and energetics of solar flares; however, its mechanism is still unknown. In this paper, we present a detailed analysis of spatially resolved multi-wavelength observations of chromospheric evaporation during an M 1.0-class solar flare…
Models of the η Corvi Debris Disk from the Keck Interferometer, Spitzer, and Herschel
Bryden, G.; Lebreton, J.; Boccaletti, A. +4 more
Debris disks are signposts of analogs to small-body populations of the solar system, often, however, with much higher masses and dust production rates. The disk associated with the nearby star η Crv is especially striking, as it shows strong mid- and far-infrared excesses despite an age of ∼1.4 Gyr. We undertake constructing a consistent model of …
ZFIRE: The Kinematics of Star-forming Galaxies as a Function of Environment at z ∼ 2
Kewley, Lisa J.; Allen, Rebecca J.; Kacprzak, Glenn G. +12 more
We perform a kinematic analysis of galaxies at z ∼ 2 in the COSMOS legacy field using near-infrared (NIR) spectroscopy from Keck/MOSFIRE as part of the ZFIRE survey. Our sample consists of 75 Ks-band selected star-forming galaxies from the ZFOURGE survey with stellar masses ranging from log(M ⋆/M ⊙) = 9.0-11.0, 28 of which ar…
Solar Jet-Coronal Hole Collision and a Closely Related Coronal Mass Ejection
Chen, Yao; Zheng, Ruisheng; Du, Guohui +1 more
Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using high-quality imaging data from the Atmospheric Imaging Assembly/Solar Dynamics Observatory, we sho…
Empirically Estimated Far-UV Extinction Curves for Classical T Tauri Stars
France, Kevin; Brown, Alex; Herczeg, Gregory +3 more
Measurements of extinction curves toward young stars are essential for calculating the intrinsic stellar spectrophotometric radiation. This flux determines the chemical properties and evolution of the circumstellar region, including the environment in which planets form. We develop a new technique using H2 emission lines pumped by stell…
New Spectroscopic Technique Based on Coaddition of Surface Brightness Fluctuations: NGC 4449 and its Stellar Tidal Stream
Romanowsky, Aaron J.; Brodie, Jean P.; Arnold, Jacob A. +5 more
We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities of galaxies of low surface brightness effects both to galaxies and streams beyond the Local Group. The distance to these systems makes them unsuitable for targeting ind…