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A Study of Dimmings, CMEs, and Flares during the STEREO-SOHO Quadrature
Krista, Larisza D.; Manning, Drew; West, Matthew J.
During the quadrature period (2010 December-2011 August) the STEREO-A and B satellites were approximately at right angles to the SOHO satellite. This alignment was particularly advantageous for determining the coronal mass ejection (CME) properties, since the closer a CME propagates to the plane of sky, the smaller the measurement inaccuracies are…
Bulk Properties of Pickup Ions Derived from the Ulysses Solar Wind Ion Composition Spectrometer Data
Zhang, Ming; Gedalin, Michael; Pogorelov, Nikolai V. +3 more
Nonthermal, pickup ions (PUIs) represent an energetic component of the solar wind (SW). While a number of theoretical models have been proposed to describe the PUI flow, of major importance are in situ measurements providing us with the vital source of model validation. The Solar Wind Ion Composition Spectrometer (SWICS) instrument on board the Ul…
Carbon Abundances in Compact Galactic Planetary Nebulae: An Ultraviolet Spectroscopic Study with the Space Telescope Imaging Spectrograph (STIS)
Ventura, Paolo; Shaw, Richard A.; García-Hernández, D. A. +3 more
We surveyed a sample of compact Galactic planetary nebulae (PNe) with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST) to determine their gas-phase carbon abundances. Carbon abundances in PNe constrain the nature of their asymptotic giant branch (AGB) progenitors, as well as cosmic recycling. We measured the carbon abun…
Standing Solitary Waves as Transitions to Spiral Structures in Gravitationally Unstable Accretion Disks
Deng, Hongping; Ogilvie, Gordon I.
Astrophysical disks that are sufficiently cold and dense are linearly unstable to the formation of axisymmetric rings as a result of the disk's gravity. In practice, spiral structures are formed, which may in turn produce bound fragments. We study a nonlinear dynamical path that can explain the development of spirals in a local model of a gaseous …
Bayesian Inference of Globular Cluster Properties Using Distribution Functions
Webb, Jeremy J.; Eadie, Gwendolyn M.; Rosenthal, Jeffrey S.
We present a Bayesian inference approach to estimating the cumulative mass profile and mean-squared velocity profile of a globular cluster (GC) given the spatial and kinematic information of its stars. Mock GCs with a range of sizes and concentrations are generated from lowered-isothermal dynamical models, from which we test the reliability of the…
X-Ray Redshifts of Obscured Chandra Source Catalog Active Galactic Nuclei
Buchner, Johannes; Peca, Alessandro; Cappelluti, Nico +2 more
We have computed obscured active galactic nuclei (AGN) redshifts using the XZ method, adopting a broad treatment in which we employed a wide-ranging data set and worked primarily at the XZ counts sensitivity threshold, culminating with a redshift catalog containing 121 sources that lack documented redshifts. We considered 363 obscured AGN from the…
Double Shells of the Planetary Nebula NGC 7009 Minor Axis
Otsuka, Masaaki; Hyung, Siek; Lee, Seong-Jae
We analyzed the minor-axis spectra of the elliptical planetary nebula (PN) NGC 7009 observed with Keck HIRES with a 0.″862 × 10″ slit placed at about 7.″5 and 10″ away from the center and a 0.″862 × 14″ slit at the center. The mean densities derived from the integrated [S II] 6716/6731 Å fluxes along the Keck HIRES slit length indicate a density r…
The Solar Wind at (16) Psyche: Predictions for a Metal World
Collinson, Glyn A.; Chen, Li-Jen; Jian, Lan K. +1 more
NASA's Psyche spacecraft will carry a magnetometer to main-belt asteroid (16) Psyche to search for remanent magnetic fields, and to attempt electromagnetic sounding of the interior. However, the Psyche spacecraft does not carry an instrument to measure solar wind plasmas. We thus combine data from five missions that have measured the solar wind at…
A Spectroscopic View of the JWST/GTO Strong Lensing Cluster A1489
Diaferio, Antonaldo; Geller, Margaret J.; Rines, Kenneth J. +1 more
We discuss a spectroscopic survey of the strong lensing cluster A1489 that includes redshifts for 195 cluster members along with central velocity dispersions for 188 cluster members. The caustic technique applied to the redshift survey gives the dynamical parameters M 200 = (1.25 ± 0.09) × 1015 M ⊙, R 200
Emission Line Galaxies in the SHARDS Hubble Frontier Fields. II. Limits on Lyman-continuum Escape Fractions of Lensed Emission Line Galaxies at Redshifts 2 < z < 3.5
Pérez-González, Pablo G.; Koekemoer, Anton M.; Conselice, Christopher J. +10 more
We present an investigation of escape fractions of UV photons from a unique sample of lensed low-mass emission line-selected galaxies at z < 3.5 found in the SHARDS Hubble Frontier Fields medium-band survey. We have used this deep imaging survey to locate 42 relatively low-mass galaxies down to log (M */M ⊙) = 7 in the red…