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Pseudostreamers as the Source of a Separate Class of Solar Coronal Mass Ejections
Wang, Y. -M.
Using white-light and extreme-ultraviolet imaging observations, we confirm that pseudostreamers (streamers that separate coronal holes of the same polarity) give rise to a different type of coronal mass ejection (CME) from that associated with helmet streamers (defined as separating coronal holes of opposite polarity). Whereas helmet streamers are…
A Pilot Survey for C III] Emission in the Reionization Era: Gravitationally Lensed z ∼ 7-8 Galaxies in the Frontier Fields Cluster Abell 2744
Stark, Daniel P.; Ellis, Richard S.; Belli, Sirio +1 more
We report results of a search for C iii] λ λ 1907, 1909 Å emission using Keck’s MOSFIRE spectrograph in a sample of 7 {{z}phot}∼ 7-8 candidates (H∼ 27) lensed by the Hubble Frontier Field cluster Abell 2744. Earlier work has suggested the promise of using the C iii] doublet for redshift confirmation of galaxies in the reionization era g…
Extremely Large EUV Late Phase of Solar Flares
Wang, Yuming; Shen, Chenglong; Liu, Rui +3 more
The second peak in the Fe xvi 33.5 nm line irradiance observed during solar flares by the Extreme-Ultraviolet Variability Experiment (EVE) is known as the EUV late phase. Our previous paper in 2013 by Liu et al. found that the main emissions in the late phase are originated from large-scale loop arcades that are closely connected to but different …
Velocity resolved [C ii], [C i], and CO observations of the N159 star-forming region in the Large Magellanic Cloud: a complex velocity structure and variation of the column densities
Wiesemeyer, Helmut; Güsten, Rolf; Okada, Yoko +4 more
Context. The [C ii] 158 µm fine structure line is one of the dominant cooling lines in star-forming active regions. Together with models of photon-dominated regions, the data is used to constrain the physical properties of the emitting regions, such as the density and the radiation field strength. According to the modeling, the [C ii] 158 &m…
The Flare-ona of EK Draconis
Ayres, Thomas R.
EK Draconis (HD 129333: G1.5 V) is a well-known young (50 Myr) solar analog. In 2012, Hubble Space Telescope returned to EK Dra to follow up a far-ultraviolet (FUV) SNAPshot visit by Cosmic Origins Spectrograph (COS) two years earlier. The brief SNAP pointing had found surprisingly redshifted, impulsively variable subcoronal “hot-line” emission of…
The growth index of matter perturbations using the clustering of dark energy
Basilakos, Spyros
We have put forward a new unified framework which provides a consistent and rather complete account of the growth index of matter perturbations in the regime where the dark energy is allowed to have clustering. In particular, we find that the growth index is not only affected by the cosmological parameters but rather it depends on the choice of th…
Radio Timing and Optical Photometry of the Black Widow System PSR J1953+1846A in the Globular Cluster M71
Dalessandro, E.; Ransom, S. M.; Ferraro, F. R. +6 more
We report on the determination of the astrometric, spin, and orbital parameters for PSR J1953+1846 A, a “black widow” binary millisecond pulsar in the globular cluster M71. By using the accurate position and orbital parameters obtained from radio timing, we identified the optical companion in Advanced Camera for Surveys/Hubble Space Telescope imag…
Observations and Modeling of North-South Asymmetries Using a Flux Transport Dynamo
Tripathi, Durgesh; Shetye, Juie; Dikpati, Mausumi
The peculiar behavior of solar cycle 23 and its prolonged minima has been one of the most studied problems over the past few years. In the present paper, we study the asymmetries in active region magnetic flux in the northern and southern hemispheres during the complete solar cycle 23 and the rising phase of solar cycle 24. During the declining ph…
Mars thermospheric scale height: CO Cameron and CO2+ dayglow observations from Mars Express
Montmessin, F.; Bertaux, J. -L.; Gérard, J. -C. +3 more
The CO Cameron (170-270 nm) and CO2+ ultraviolet doublet (298 and 299 nm) emissions have been observed on the Mars dayside with Mars Express Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument in the limb viewing mode. These ultraviolet emissions ultimately arise from the excitation…
Multiscale study of electron energization during unsteady reconnection events
Lapenta, Giovanni; El-Alaoui, Mostafa; Walker, Raymond J. +2 more
Understanding particle acceleration in the magnetotail during substorms requires knowledge of changes in the global magnetospheric configuration and the local regions of intense fields and microinstabilities caused by processes associated with reconnection. We simulated a substorm on 15 February 2008 by coupling the University of California, Los A…