Search Publications

X-Ray Spectroscopy in the Microcalorimeter Era. II. A New Diagnostic on Column Density from the Case A to B Transition in H- and He-like Iron
DOI: 10.3847/1538-4357/abaaac Bibcode: 2020ApJ...901...69C

Ferland, G. J.; Su, Y.; Chakraborty, P. +2 more

The Soft X-ray Spectrometer on board Hitomi, with the unprecedented resolving power of R ∼ 1250, allowed the detection of members of the Fe XXV Kα complex emission spectra from the center of the Perseus Cluster. In this paper, we introduce a novel method of measuring the column density using the optically thin (Case A) to optically thick (Case B) …

2020 The Astrophysical Journal
Hitomi 15
Hubble Space Telescope Search for Activity in High-perihelion Objects
DOI: 10.3847/1538-3881/ab7faf Bibcode: 2020AJ....159..209L

Mutchler, Max; Jewitt, David; Agarwal, Jessica +2 more

Solar system objects with perihelia beyond the orbit of Jupiter (q > 5 au) are too cold for water ice to generate an appreciable coma via sublimation. Despite this, numerous high-perihelion objects (HPOs) including many comets and recently escaped Kuiper Belt objects (Centaurs) are observed to be active out at least to the orbit of Saturn (q ∼ …

2020 The Astronomical Journal
eHST 15
Kinematical investigation of possible fast collimated outflows in twelve planetary nebulae
DOI: 10.1093/mnras/stz3326 Bibcode: 2020MNRAS.492.1957R

Chu, Y. -H.; Guerrero, M. A.; Toalá, J. A. +3 more

A significant fraction of planetary nebulae (PNe) exhibit collimated outflows, distinct narrow kinematical components with notable velocity shifts with respect to the main nebular shells typically associated with low-ionization compact knots and linear or precessing jet-like features. We present here a spatio-kinematical investigation of a sample …

2020 Monthly Notices of the Royal Astronomical Society
eHST 15
Constraining the Mass of the Emerging Galaxy Cluster SpARCS1049+56 at z = 1.71 with Infrared Weak Lensing
DOI: 10.3847/1538-4357/ab7bdb Bibcode: 2020ApJ...893...10F

Muzzin, Adam; Perlmutter, Saul; Wilson, Gillian +4 more

In the hierarchical structure formation model of the universe, galaxy clusters are assembled through a series of mergers. Accordingly, it is expected that galaxy clusters in the early universe are actively forming and dynamically young. Located at a high redshift of z = 1.71, SpARCS1049+56 offers a unique look into the galaxy cluster formation pro…

2020 The Astrophysical Journal
eHST 15
Expected performances of the Characterising Exoplanet Satellite (CHEOPS). II. The CHEOPS simulator
DOI: 10.1051/0004-6361/201936616 Bibcode: 2020A&A...635A..23F

Queloz, D.; Benz, W.; Deline, A. +14 more

Context. The CHaracterising ExOPlanet Satellite (CHEOPS) is a mission dedicated to the search for exoplanetary transits through high precision photometry of bright stars already known to host planets. The telescope will provide the unique capability of determining accurate radii for planets whose masses have already been measured from ground-based…

2020 Astronomy and Astrophysics
CHEOPS Gaia 15
Small Impact Crater Populations on Saturn's Moon Tethys and Implications for Source Impactors in the System
DOI: 10.1029/2020JE006400 Bibcode: 2020JGRE..12506400F

Ferguson, S. N.; Rhoden, A. R.; Kirchoff, M. R.

Current estimates place the ages of the inner Saturnian satellites (Mimas, Enceladus, Tethys, Dione, and Rhea) between 4.5 Gyr and 100 Myr. These estimates are based on impact crater measurements and dynamical simulations, both of which have uncertainties. Models of satellite evolution are inherently simplified and rely on uncertain or unknown par…

2020 Journal of Geophysical Research (Planets)
Cassini 15
Beyond Gaia: Asteroseismic Distances of M Giants Using Ground-based Transient Surveys
DOI: 10.3847/1538-3881/ab91bf Bibcode: 2020AJ....160...18A

Kochanek, C. S.; Huber, Daniel; Tonry, John +14 more

Evolved stars near the tip of the red giant branch show solar-like oscillations with periods spanning hours to months and amplitudes ranging from ∼1 mmag to ∼100 mmag. The systematic detection of the resulting photometric variations with ground-based telescopes would enable the application of asteroseismology to a much larger and more distant samp…

2020 The Astronomical Journal
Gaia 15
Temporal and Periodic Variation of the MCMESI for the Last Two Solar Cycles; Comparison with the Number of Different Class X-ray Solar Flares
DOI: 10.1007/s11207-020-01711-2 Bibcode: 2020SoPh..295..159K

Kilcik, Ali; Chowdhury, Partha; Sarp, Volkan +4 more

In this study we compared the temporal and periodic variations of the Maximum CME Speed Index (MCMESI) and the the number of different class (C, M, and X) solar X-ray flares for the last two solar cycles (Solar Cycles 23 and 24). To obtain the correlation between the MCMESI and solar flare numbers the cross-correlation analysis was applied to mont…

2020 Solar Physics
SOHO 15
A Fully Kinetic Perspective of Electron Acceleration around a Weakly Outgassing Comet
DOI: 10.3847/2041-8213/ab6662 Bibcode: 2020ApJ...889L..33D

Henri, Pierre; Lapenta, Giovanni; Divin, Andrey +4 more

The cometary mission Rosetta has shown the presence of higher-than-expected suprathermal electron fluxes. In this study, using 3D fully kinetic electromagnetic simulations of the interaction of the solar wind with a comet, we constrain the kinetic mechanism that is responsible for the bulk electron energization that creates the suprathermal distri…

2020 The Astrophysical Journal
Rosetta 15
The Origin of a Distributed Stellar Population in the Star-forming Region W4
DOI: 10.3847/1538-4357/aba0a3 Bibcode: 2020ApJ...899..121L

Lim, Beomdu; Lee, Jeong-Eun; Yun, Hyeong-Sik +5 more

Stellar kinematics provides the key to understanding the formation process and dynamical evolution of stellar systems. Here, we present a kinematic study of the massive star-forming region (SFR) W4 in the Cassiopeia OB6 association using the Gaia Data Release 2 and high-resolution optical spectra. This SFR is composed of a core cluster (IC 1805) a…

2020 The Astrophysical Journal
Gaia 15