Search Publications
Constraining the multiplicity statistics of the coolest brown dwarfs: binary fraction continues to decrease with spectral type
Allers, Katelyn; Bonavita, Mariangela; Fontanive, Clémence +1 more
Binary statistics of the latest-type T and Y brown dwarfs are sparse and it is unclear whether the trends seen in the multiplicity properties of their more massive counterparts hold for the very coolest brown dwarfs. We present results from a search for substellar and planetary-mass companions to a sample of 12 ultracool T8-Y0 field brown dwarfs w…
Searching for outflows in ultraluminous X-ray sources through high-resolution X-ray spectroscopy
Fabian, A. C.; Pinto, C.; Walton, D. J. +1 more
Ultraluminous X-ray sources (ULXs) are non-nuclear point sources exceeding the Eddington luminosity of a 10 M⊙ black hole. Modern consensus for a majority of the ULX population is that they are powered by stellar-mass black holes or neutron stars accreting well above the Eddington limit. Theoretical models of super-Eddington accretion p…
The unusual late-time evolution of the tidal disruption event ASASSN-15oi
Kochanek, C. S.; Shappee, B. J.; Brown, J. S. +4 more
We present late-time optical spectroscopy and X-ray, UV, and optical photometry of the nearby (d = 214 Mpc, z = 0.0479) tidal disruption event (TDE) ASASSN-15oi. The optical spectra span 450 days after discovery and show little remaining transient emission or evolution after roughly three months. In contrast, the Swift and XMM-Newton observations …
A collection of model stellar spectra for spectral types B to early-M
Allende Prieto, C.; Koesterke, L.; Barklem, P. S. +3 more
Context. Models of stellar spectra are necessary for interpreting light from individual stars, planets, integrated stellar populations, nebulae, and the interstellar medium.
Aims: We provide a comprehensive and homogeneous collection of synthetic spectra for a wide range of atmospheric parameters and chemical compositions.
Methods: We co…
Old, Metal-poor Extreme Velocity Stars in the Solar Neighborhood
Bell, Eric F.; Hattori, Kohei; Roederer, Ian U. +1 more
We report the discovery of 30 stars with extreme space velocities (≳480 {km} {{{s}}}-1) in the Gaia-DR2 archive. These stars are a subset of 1743 stars with high-precision parallax, large tangential velocity (v tan > 300 {km} {{{s}}}-1), and measured line-of-sight velocity in DR2. By tracing the orbits of the st…
MAHALO Deep Cluster Survey II. Characterizing massive forming galaxies in the Spiderweb protocluster at z = 2.2
Cai, Zheng; Suzuki, Tomoko L.; Koyama, Yusei +10 more
This paper is the second in a series presenting the results of our deep H α-line survey towards protoclusters at z > 2, based on narrow-band imaging with the Subaru Telescope. This work investigates massive galaxies in a protocluster region associated with a radio galaxy (PKS 1138 - 262), the Spiderweb galaxy, at z = 2.2. Our 0.5 mag deeper nar…
Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +192 more
Thanks to its high spectral resolution (∼5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallic…
The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MegaSaura). I. The Sample and the Spectra
Dahle, H.; Rigby, J. R.; Bayliss, M. B. +7 more
We introduce Project MEGaSaURA: the Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas. MEGaSaURA comprises medium-resolution, rest-frame ultraviolet spectroscopy of N = 15 bright gravitationally lensed galaxies at redshifts of 1.68 < z < 3.6, obtained with the MagE spectrograph on the Magellan telescopes. The spect…
Streamer-blowout Coronal Mass Ejections: Their Properties and Relation to the Coronal Magnetic Field Structure
Vourlidas, Angelos; Webb, David F.
We present a comprehensive analysis of a particular class of coronal mass ejection (CME) event called streamer-blowout CMEs (SBOs). The events are characterized by a gradual swelling of the overlying streamer, lasting hours to days, followed by a slow, wide CME, generally exhibiting a three-part structure, which leaves the streamer significantly d…
The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
Kuzuhara, M.; Tamura, M.; Rouan, D. +79 more
Context. The G-type star GJ504A is known to host a 3-35 MJup companion whose temperature, mass, and projected separation all contribute to making it a test case for planet formation theories and atmospheric models of giant planets and light brown dwarfs.
Aims: We aim at revisiting the system age, architecture, and companion physica…