Search Publications
3D Electron Density Distributions in the Solar Corona during Solar Minima: Assessment for More Realistic Solar Wind Modeling
Riley, Pete; Foullon, Claire; de Patoul, Judith
Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. Th…
Radial and Azimuthal Oscillations of Halo Coronal Mass Ejections in the Sun
Moon, Y. -J.; Lee, Harim; Nakariakov, V. M.
We present the first observational detection of radial and azimuthal oscillations in full halo coronal mass ejections (HCMEs). We analyze nine HCMEs well-observed by the Large Angle and Spectrometric Coronagraph (LASCO) from 2011 February to June. Using the LASCO C3 running difference images, we estimated the instantaneous apparent speeds of the H…
Erupting Filaments with Large Enclosing Flux Tubes as Sources of High-mass Three-part CMEs, and Erupting Filaments in the Absence of Enclosing Flux Tubes as Sources of Low-mass Unstructured CMEs
Hutton, Joe; Morgan, Huw
The 3-part appearance of many coronal mass ejections (CMEs) arising from erupting filaments emerges from a large magnetic flux tube structure, consistent with the form of the erupting filament system. Other CMEs arising from erupting filaments lack a clear 3-part structure and reasons for this have not been researched in detail. This paper aims to…
On the Continuum Radio Spectrum of Cas A: Possible Evidence of Non-Linear Particle Acceleration
Onić, D.; Urošević, D.
The integrated radio spectrum of Cassiopeia A in continuum was analyzed with special emphasis on possible high-frequency spectral curvature. We conclude that the most probable scenario is that Planck’s new data reveal the imprint of nonlinear particle acceleration in the case of this young Galactic supernova remnant.
The Energetics of a Global Shock Wave in the Low Solar Corona
Gallagher, Peter T.; Long, David M.; Baker, Deborah +3 more
As the most energetic eruptions in the solar system, coronal mass ejections (CMEs) can produce shock waves at both their front and flanks as they erupt from the Sun into the heliosphere. However, the amount of energy produced in these eruptions, and the proportion of their energy required to produce the waves, is not well characterized. Here we us…
Revisiting the Local Leo Cold Cloud and Revised Constraints on the Local Hot Bubble
Peek, J. E. G.; Kuntz, K. D.; Snowden, S. L. +4 more
The Local Leo Cold Cloud (LLCC, at a distance of 11-24 pc) was studied in its relation to the Local Hot Bubble (LHB) and the result suggested that much of the observed 1/4 keV emission in that direction originates in front of the cloud. This placed a strong constraint on the distribution of X-ray emission within the LHB and called into question th…
Star Formation in High-redshift Cluster Ellipticals
Moustakas, John; Dey, Arjun; Alberts, Stacey +11 more
We measure the star formation rates (SFRs) of massive (M sstarf > 1010.1 M ⊙) early-type galaxies (ETGs) in a sample of 11 high-redshift (1.0 < z < 1.5) galaxy clusters drawn from the IRAC Shallow Cluster Survey (ISCS). We identify ETGs visually from Hubble Space Telescope imaging and select likely cluster…
The Megasecond Chandra X-Ray Visionary Project Observation of NGC 3115. II. Properties of Point Sources
Romanowsky, Aaron J.; Brodie, Jean P.; Remillard, Ronald A. +7 more
We carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115 using the Megasecond Chandra X-ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136 candidate LMXBs in the field and 49 in globular clusters (GCs) above 2σ detection, with 0.3-8 keV luminosity L
First Taste of Hot Channel in Interplanetary Space
Chen, Y.; Song, H. Q.; Cheng, X. +3 more
A hot channel (HC) is a high temperature (∼10 MK) structure in the inner corona first revealed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Eruptions of HCs are often associated with flares and coronal mass ejections (CMEs). Results of previous studies have suggested that an HC is a good proxy for a magnetic flux ro…
Co-spatial Long-slit UV/Optical Spectra of Ten Galactic Planetary Nebulae with HST/STIS. II. Nebular Models, Central Star Properties, and He+CNO Synthesis
Balick, B.; Corradi, R. L. M.; Dufour, R. J. +5 more
The goal of the present study is twofold. First, we employ new HST/STIS spectra and photoionization modeling techniques to determine the progenitor masses of eight planetary nebulae (IC 2165, IC 3568, NGC 2440, NGC 3242, NGC 5315, NGC 5882, NGC 7662, and PB 6). Second, for the first time we are able to compare each object’s observed nebular abunda…