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Gamma Cas Stars as Be+White Dwarf Binary Systems
Gies, Douglas R.; Wang, Luqian; Klement, Robert
The origin of the bright and hard X-ray emission flux among the γ Cas subgroup of B-emission line (Be) stars may be caused by gas accretion onto an orbiting white dwarf (WD) companion. Such Be+WD binaries are the predicted outcome of a second stage of mass transfer from a helium star mass donor to a rapidly rotating mass gainer star. The stripped …
The Green Bank North Celestial Cap Survey. VII. 12 New Pulsar Timing Solutions
Ransom, S. M.; Kaplan, D. L.; McLaughlin, M. A. +22 more
We present timing solutions for 12 pulsars discovered in the Green Bank North Celestial Cap 350 MHz pulsar survey, including six millisecond pulsars (MSPs), a double neutron star (DNS) system, and a pulsar orbiting a massive white dwarf companion. Timing solutions presented here include 350 and 820 MHz Green Bank Telescope data from initial confir…
CECILIA: The Faint Emission Line Spectrum of z 2-3 Star-forming Galaxies
Maseda, Michael V.; Steidel, Charles C.; Law, David R. +7 more
We present the first results from Chemical Evolution Constrained Using Ionized Lines in Interstellar Aurorae (CECILIA), a Cycle 1 JWST NIRSpec/MSA program that uses ultra-deep ~30 hr G235M/F170LP observations to target multiple electron temperature-sensitive auroral lines in the spectra of 33 galaxies at z ~ 1-3. Using a subset of 23 galaxies, we …
X-Ray Detection of the Galaxy's Missing Baryons in the Circumgalactic Medium of L* Galaxies
Bianchi, S.; Piconcelli, E.; Nicastro, Fabrizio +10 more
The number of baryons hosted in the disks of galaxies is lower than expected based on the mass of their dark matter halos and the fraction of baryon-to-total matter in the Universe, giving rise to the so-called galaxy missing-baryon problem. The presence of cool circumgalactic matter gravitationally bound to its galaxy's halo up to distances of at…
A Measurement of the Cosmic Optical Background and Diffuse Galactic Light Scaling from the R < 50 au New Horizons-LORRI Data
Cooray, Asantha; Zemcov, Michael; Symons, Teresa +2 more
Direct photometric measurements of the cosmic optical background (COB) provide an important point of comparison to both other measurement methodologies and models of cosmic structure formation, and permit a cosmic consistency test with the potential to reveal additional diffuse sources of emission. The COB has been challenging to measure from Eart…
Magnetic Activity Evolution of Solar-like Stars. I. S ph-Age Relation Derived from Kepler Observations
van Saders, Jennifer; García, Rafael A.; Breton, Sylvain N. +9 more
The ages of solar-like stars have been at the center of many studies such as exoplanet characterization or Galactic-archeology. While ages are usually computed from stellar evolution models, relations linking ages to other stellar properties, such as rotation and magnetic activity, have been investigated. With the large catalog of 55,232 rotation …
A New Study on a Type Iax Stellar Remnant and its Probable Association with SN 1181
Hillier, D. John; Parker, Quentin A.; Ritter, Andreas +4 more
We report observations and modeling of the stellar remnant and presumed double-degenerate merger of Type Iax supernova Pa 30, which is the probable remnant of SN 1181 AD. It is the only known bound stellar SN remnant and the only star with Wolf-Rayet features that is neither a planetary nebula central star nor a massive Population I progenitor. We…
The CGM2 Survey: Quenching and the Transformation of the Circumgalactic Medium
Tripp, Todd M.; Prochaska, J. Xavier; Tejos, Nicolas +9 more
This study addresses how the incidence rate of strong O VI absorbers in a galaxy's circumgalactic medium (CGM) depends on galaxy mass and, independently, on the amount of star formation in the galaxy. We use Hubble Space Telescope/Cosmic Origins Spectrograph absorption spectroscopy of quasars to measure O VI absorption within 400 projected kpc and…
The Q Branch Cooling Anomaly Can Be Explained by Mergers of White Dwarfs and Subgiant Stars
Blouin, Simon; Shen, Ken J.; Breivik, Katelyn
Gaia's exquisite parallax measurements allowed for the discovery and characterization of the Q branch in the Hertzsprung-Russell diagram, where massive C/O white dwarfs (WDs) pause their dimming due to energy released during crystallization. Interestingly, the fraction of old stars on the Q branch is significantly higher than in the population of …
Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf
Meisner, Aaron M.; Cushing, Michael C.; Kirkpatrick, J. Davy +24 more
We present the discovery of CWISE J050626.96+073842.4 (CWISE J0506+0738), an L/T transition dwarf with extremely red near-infrared colors discovered through the Backyard Worlds: Planet 9 citizen science project. Photometry from UKIRT and CatWISE give a (J - K)MKO color of 2.97 ± 0.03 mag and a J MKO - W2 color of 4.93 ± 0.02 …