Search Publications
The Gini Coefficient as a Morphological Measurement of Strongly Lensed Galaxies in the Image Plane
Florian, Michael K.; Gladders, Michael D.; Li, Nan
Characterization of the morphology of strongly lensed galaxies is challenging because images of such galaxies are typically highly distorted. Lens modeling and source plane reconstruction is one approach that can provide reasonably undistorted images from which morphological measurements can be made, though at the expense of a highly spatially var…
A 17 June 2011 polar jet and its presence in the background solar wind
Jackson, B. V.; Buffington, A.; Hick, P. P. +3 more
High-speed jet responses in the polar solar wind are enigmatic. Here we measure a jet response that emanates from the southern polar coronal hole on 17 June 2011 at the extreme speed of over 1200 km/s. This response was recorded from the Sun-Earth line in Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) and Large Angle and Spectro…
The Time-evolution of HH 2 from Four Epochs of HST Images
Velázquez, P. F.; Bally, J.; Raga, A. C. +2 more
We have analyzed four epochs of Hα and [S II] Hubble Space Telescope images of the HH 1/2 outflow (covering a time interval from 1994 to 2014) to determine proper motions and emission line fluxes of the knots of HH 2. We find that our new proper motions agree surprisingly well with the motions measured by Herbig & Jones, although there is part…
High-resolution HI and CO observations of high-latitude intermediate-velocity clouds
Kerp, J.; Winkel, B.; Ben Bekhti, N. +1 more
Context. Intermediate-velocity clouds (IVCs) are HI halo clouds that are likely related to a Galactic fountain process. In-falling IVCs are candidates for the re-accretion of matter onto the Milky Way.
Aims: We study the evolution of IVCs at the disk-halo interface, focussing on the transition from atomic to molecular IVCs. We compare an atom…
The Goodness of Simultaneous Fits in ISIS
Rothschild, Richard E.; Fürst, Felix; Klochkov, Dmitry +15 more
In a previous work, we introduced a tool for analyzing multiple datasets simultaneously, which has been implemented into ISIS. This tool was used to fit many spectra of X-ray binaries. However, the large number of degrees of freedom and individual datasets raise an issue about a good measure for a simultaneous fit quality. We present three ways to…
An Observational Study of the Recurring Formation and Dissipation of a Dynamic Filament
Wang, Jingxiu; Zhang, Jie; Zhou, Guiping
Based on observations at the Hα wavelength from the Hinode spacecraft, we report here the detailed process of a dynamical filament that showed repeated appearance and dissipation in a filament channel. First, Hα short fibrils spreading in the pre-formed filament channel joined into longer threads. The joining process was found to be accompanied by…
Large-scale fluctuations in the number density of galaxies in independent surveys of deep fields
Baryshev, Yu. V.; Shirokov, S. I.; Lovyagin, N. Yu. +1 more
New arguments supporting the reality of large-scale fluctuations in the density of the visible matter in deep galaxy surveys are presented. A statistical analysis of the radial distributions of galaxies in the COSMOS and HDF-N deep fields is presented. Independent spectral and photometric surveys exist for each field, carried out in different wave…
Statistical Analysis of Periodic Oscillations in LASCO Coronal Mass Ejection Speeds
Shanmugaraju, A.; Gopalswamy, N.; Michalek, G. +2 more
A large set of coronal mass ejections (CMEs, 3463) has been selected to study their periodic oscillations in speed in the Solar and Heliospheric Observatory (SOHO) mission's Large Angle and Spectrometric Coronagraph (LASCO) field of view. These events, reported in the SOHO/LASCO catalog in the period of time 1996 - 2004, were selected based on hav…
Linking the structural properties of galaxies and their star formation histories with STAGES
Bell, Eric F.; Wolf, Christian; Aragón-Salamanca, Alfonso +5 more
We study the links between star formation history and structure for a large mass-selected galaxy sample at 0.05 ≤ zphot ≤ 0.30. The galaxies inhabit a very broad range of environments, from cluster cores to the field. Using Hubble Space Telescope (HST) images, we quantify their structure following Hoyos et al., and divide them into dist…
Is the Stellar System WR 11 a Gamma-Ray Source?
Benaglia, Paula
Many early-type stars are in systems; some of them have been indicated as putative high-energy emitters. The radiation would be produced at the region where two stellar winds collide. Compelling evidence of such emission was found only for the colliding-wind binary (CWB) Eta Car, which was associated to a GeV source. Very recently, the closest CWB…