Search Publications
A Model for Dissipation of Solar Wind Magnetic Turbulence by Kinetic Alfvén Waves at Electron Scales: Comparison with Observations
Saur, Joachim; Schreiner, Anne
In hydrodynamic turbulence, it is well established that the length of the dissipation scale depends on the energy cascade rate, I.e., the larger the energy input rate per unit mass, the more the turbulent fluctuations need to be driven to increasingly smaller scales to dissipate the larger energy flux. Observations of magnetic spectral energy dens…
The Infrared and Radio Flux Densities of Galactic H II regions
Makai, Z.; Anderson, L. D.; Mascoop, J. L. +1 more
We derive infrared and radio flux densities of all ∼1000 known Galactic H II regions in the Galactic longitude range 17\buildrel{\circ}\over{.} 5< {\ell }< 65^\circ . Our sample comes from the Wide-Field Infrared Survey Explorer (WISE) catalog of Galactic H II regions. We compute flux densities at six wavelengths in the infrared (Spitzer GLI…
Observations of the Coronal Mass Ejection with a Complex Acceleration Profile
Reva, A. A.; Kirichenko, A. S.; Ulyanov, A. S. +1 more
We study the coronal mass ejection (CME) with a complex acceleration profile. The event occurred on 2009 April 23. It had an impulsive acceleration phase, an impulsive deceleration phase, and a second impulsive acceleration phase. During its evolution, the CME showed signatures of different acceleration mechanisms: kink instability, prominence dra…
An Active Galactic Nucleus Caught in the Act of Turning Off and On
Greene, Jenny E.; Stern, Daniel; Comerford, Julia M. +5 more
We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z = 0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events that could have been triggered by a past interaction with the companion galaxy that is currently located 12.5 kpc away. We originally ta…
Are Internetwork Magnetic Fields in the Solar Photosphere Horizontal or Vertical?
Lites, B. W.; Borrero, J. M.; Danilovic, S. +1 more
Using many observations obtained during 2007 with the Spectro-Polarimeter of the Hinode Solar Optical Telescope, we explore the angular distribution of magnetic fields in the quiet internetwork regions of the solar photosphere. Our work follows from the insight of Stenflo, who examined only linear polarization signals in photospheric lines, thereb…
Search for Hydrogenated C60 (Fulleranes) in Circumstellar Envelopes
Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza +1 more
The recent detection of fullerene (C60) in space and the positive assignment of five diffuse interstellar bands to {{{C}}}60+ reinforce the notion that fullerene-related compounds can be efficiently formed in circumstellar envelopes and be present in significant quantities in the interstellar medium. Experimental s…
The Radial Distributions of the Two Main-sequence Components in the Young Massive Star Cluster NGC 1856
Milone, Antonino P.; Deng, Licai; de Grijs, Richard +1 more
The recent discovery of double main sequences in the young, massive star cluster NGC 1856 has caught significant attention. The observations can be explained by invoking two stellar generations with different ages and metallicities or by a single generation of stars composed of two populations characterized by different rotation rates. We analyzed…
Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster
Crnojević, D.; Sand, D. J.; Simon, J. D. +10 more
We analyze the optical counterpart to the ultra-compact high velocity cloud AGC 226067, utilizing imaging taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The color-magnitude diagram of the main body of AGC 226067 reveals an exclusively young stellar population, with an age of ∼7-50 Myr, and is consistent with a meta…
The Asymmetric Bow Shock/Pulsar Wind Nebula of PSR J2124-3358
Slane, Patrick; Romani, Roger W.; Green, Andrew W.
We describe new measurements of the remarkable Hα/UV/X-ray bow shock and pulsar wind nebula (PWN) of the isolated millisecond pulsar (MSP) PSR J2124-3358. Chandra X-ray Observatory imaging shows a one-sided jet structure with a softer equatorial outflow. KOALA integral field unit spectroscopy shows that non-radiative emission dominates the bow sho…
Solar Tornadoes Triggered by Interaction between Filaments and EUV Jets
Zhang, Jun; Yan, Xiaoli; Xue, Jianchao +2 more
We investigate the formations and evolutions of two successive solar tornadoes in/near AR 12297 during 2015 March 19-20. Recurrent EUV jets close to two filaments were detected along a large-scale coronal loop prior to the appearances of the tornadoes. Under the disturbances from the activities, the filaments continually ascended and finally inter…