Search Publications
Neon-like Iron Ion Lines Measured in NIFS/Large Helical Device (LHD) and Hinode/EUV Imaging Spectrometer (EIS)
Hara, Hirohisa; Watanabe, Tetsuya; Murakami, Izumi +7 more
Line intensities emerging from the Ne-sequence iron ion (Fe XVII) are measured in the laboratory, by the Large Helical Device at the National Institute for Fusion Science, and in the solar corona by the EUV Imaging Spectrometer (EIS) on board the Hinode mission. The intensity ratios of Fe XVII λ 204.6/λ 254.8 are derived in the laboratory by unble…
Distribution of Field-Aligned Electron Events in the High-Altitude Polar Region: Cluster Observations
Dunlop, Malcolm; Carr, Chris; Torkar, Klaus +4 more
Field-aligned electrons (FAEs) are important for the energy transport in the solar wind-magnetosphere-ionosphere coupling. However, the distribution of FAEs and the concerning physical mechanism in different altitudes of the polar region are still unclear. In this paper, data from the Cluster spacecraft were used to study the characteristics of FA…
Validation of single spacecraft methods for collisionless shock velocity estimation
Pope, Simon A.; Walker, Simon N.; Collinson, Glyn +1 more
The velocity of a collisionless shock (CS) is an important parameter in the determination of the spatial scales of the shock. The spatial scales of the shock determine the processes that guide the energy dissipation, which is related to the nature of the shock. During the pre-ISEE era, estimations of relative shock-spacecraft velocity (VSh
Running of featureful primordial power spectra
Mena, Olga; Boubekeur, Lotfi; Gariazzo, Stefano +2 more
Current measurements of the temperature and polarization anisotropy power spectra of the cosmic microwave background (CMB) seem to indicate that the naive expectation for the slow-roll hierarchy within the most simple inflationary paradigm may not be respected in nature. We show that a primordial power spectrum with localized features could in pri…
A Long-Term Decrease of the Mid-Size Segmentation Lengths Observed in the He II (30.4 nm) Solar EUV Emission
Didkovsky, Leonid; Wieman, Seth; Korogodina, Elena
Power spectra of segmentation-cell length (a dominant length scale of EUV emission in the transition region) from full-disk He II extreme ultraviolet (EUV) images observed by the Extreme ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Ob…
Is the Pollock's paradigm of X-ray emission for O stars correct?
Kholtygin, A. F.; Ryspaeva, E. B.
We considered the mechanism of the formation of the X-ray emission for massive stars. The X-ray spectra of 25 O stars were extracted from the archive of XMM-Newton data obtained in 2000-2014. We determined the distribution of the ratio of half-width at half-maximum to the wind terminal velocity for strong isolated spectral lines in the spectra of …
Dust and gas environment of the young embedded cluster IRAS 18511+0146
Testi, L.; Walmsley, C. M.; Vig, S. +2 more
Context. Since massive and intermediate mass stars form in clusters, a comparative investigation of the environments of the young embedded cluster members can reveal significant information about the conditions under which stars form and evolve.
Aims: IRAS 18511+0146 is a young embedded (proto)cluster located at 3.5 kpc surrounding what appea…
Absolute Dimensions of the F-type Eclipsing Binary V2154 Cygni
Torres, Guillermo; Bright, Jane C.
We report spectroscopic observations of the 2.63 day, detached, F-type main-sequence eclipsing binary V2154 Cyg. We use our observations together with existing uvby photometric measurements to derive accurate absolute masses and radii for the stars that are good to better than 1.5%. We obtain masses of {M}1=1.269+/- 0.017 {M}⊙
A three-dimensional orbit for the binary star Alpha Andromedae
Branham, Richard L., Jr.
Stars that are both spectroscopic and optical binaries present a means to determine simultaneously the masses of the components and the distance of the system independent of trigonometric parallax. Alpha Andromedae (Alpheratz) represents such a system and, moreover, the primary is the brightest of the mercury-manganese stars. An orbit, based on 42…
SG1120-1202: Mass-quenching as Tracked by UV Emission in the Group Environment at z=0.37
Tran, Kim-Vy H.; Gonzalez, Anthony H.; Monroe, Jonathan T.
We use the Hubble Space Telescope to obtain WFC3/F390W imaging of the supergroup SG1120-1202 at z=0.37, mapping the UV emission of 138 spectroscopically confirmed members. We measure total (F390W-F814W) colors and visually classify the UV morphology of individual galaxies as “clumpy” or “smooth.” Approximately 30% of the members have pockets of UV…