54 citations · 260 across the 17 of their papers we have counts for
17 papers
Parameter-Free Dynamic Regret for Unconstrained Linear Bandits
Alberto Rumi, Andrew Jacobsen, Nicolò Cesa-Bianchi +1
We study dynamic regret minimization in unconstrained adversarial linear bandit problems. In this setting, a learner must minimize the cumulative loss relative to an arbitrary sequ…
The Birth of Be Star Disks II. A High-Resolution Spectroscopic Campaign and TESS Observations of an Outburst of the Classical Be star λ Pavonis
Sola S. Nova, Noel D. Richardson, Jonathan Labadie-Bartz +1
Be stars are rapidly-rotating B stars that have shown emission lines originating in a circumstellar disk. The mechanisms that lead to disk formation and dissipation are not known a…
TESS Light Curve of the Interacting Binary W Serpentis
Douglas R. Gies, Katherine A. Shepard, Aman Kar +1
The unusual light curve of the massive eclipsing binary W Ser was recently observed with high S/N and fast cadence by the NASA TESS mission. The TESS light curve records two eclips…
The birth of Be star disks I. From localized ejection to circularization
J. Labadie-Bartz, A. C. Carciofi, A. C. Rubio +35
Classical Be stars are well known to eject mass, but the details governing the initial distribution and evolution of this matter into a disk are poorly constrained by observations.…
An Investigation into the Variability of Luminous Blue Variable Stars with TESS
Becca Spejcher, Noel D. Richardson, Herbert Pablo +3
Luminous Blue Variables (LBVs) are enigmatic, evolved, massive stars. Their variability has been observed to be episodic with large eruptions, along with variations on time-scales…
Optical Properties and Variability of the Be X-ray binary CPD -29 2176
Clarissa M. Pavao, Noel D. Richardson, Jonathan Labadie-Bartz +2
Be X-ray binaries (Be XRBs) are high-mass X-ray binaries, with a neutron star or black hole orbiting and accreting material from a non-supergiant B-star that is rotating at a near…
Using CHIRON Spectroscopy to Test the Hypothesis of a Precessing Orbit for the WN4 star EZ CMa
Krister DG. Barclay, Sophie Rosu, Noel D. Richardson +4
The bright WN4 star EZ CMa exhibits a 3.77 day periodicity in photometry, spectroscopy, and polarimetry but the variations in the measurements are not strictly phase-locked, exhibi…
A Coordinated X-ray and Optical Campaign on the Nearest Massive Eclipsing Binary, Delta Ori Aa: I. Overview of the X-ray Spectrum
M. F. Corcoran, J. S. Nichols, H. Pablo +22
We present an overview of four phase-constrained Chandra HETGS X-ray observations of Delta Ori A. Delta Ori A is actually a triple system which includes the nearest massive eclipsi…
The relationship between gamma Cassiopeiae's X-ray emission and its circumstellar environment
M. A. Smith, R. Lopes de Oliveira, C. Motch +17
γCas is the prototypical classical Be star and is best known for its variable hard X-ray emission. To elucidate the reasons for this emission, we mounted a multiwavelength campaign…
A Binary Orbit for the Massive, Evolved Star HDE 326823, a WR+O System Progenitor
Noel D. Richardson, Douglas R. Gies, Stephen J. Williams
The hot star HDE 326823 is a candidate transition-phase object that is evolving into a nitrogen-enriched Wolf-Rayet star. It is also a known low-amplitude, photometric variable wit…
Spectroscopy and Interferometry of Luminous Blue Variables
N. D. Richardson, D. R. Gies, N. D. Morrison +4
We report on the preliminary results of a three-year monitoring campaign of Galactic and Magellanic LBVs with both moderate and high resolution spectroscopy. We have collected more…
The H-alpha Variations of the Luminous Blue Variable P Cygni: Discrete Absorption Components and the Short S Doradus Phase
Noel D. Richardson, Nancy D. Morrison, Douglas R. Gies +3
P Cygni is a prototype of the Luminous Blue Variables (or S Doradus variables), and the star displays photometric and emission line variability on a timescale of years (known as th…
A Five-year Spectroscopic and Photometric Campaign on the Prototypical alpha Cygni Variable and A-type Supergiant Star Deneb
N. D. Richardson, N. D. Morrison, E. E. Kryukova +1
Deneb is often considered the prototypical A-type supergiant, and is one of the visually most luminous stars in the Galaxy. A-type supergiants are potential extragalactic distance…
Multi-epoch Near-Infrared Interferometry of the Spatially Resolved Disk Around the Be Star Zeta Tau
G. H. Schaefer, D. R. Gies, J. D. Monnier +14
We present interferometric observations of the Be star Zeta Tau obtained using the MIRC beam combiner at the CHARA Array. We resolved the disk during four epochs in 2007-2009. We f…
Spectral Energy Distributions of Be and Other Massive Stars
Y. Touhami, N. D. Richardson, D. R. Gies +7
We present spectrophotometric data from 0.4 to 4.2 microns for bright, northern sky, Be stars and several other types of massive stars. Our goal is to use these data with ongoing,…
The H-alpha Variations of eta Carinae During the 2009.0 Spectroscopic Event
N. D. Richardson, D. R. Gies, T. J. Henry +2
We report on H-alpha spectroscopy of the 2009.0 spectroscopic event of eta Carinae collected via SMARTS observations using the CTIO 1.5 m telescope and echelle spectrograph. Our ob…
A Spectroscopic Orbit for Regulus
D. R. Gies, S. Dieterich, N. D. Richardson +8
We present a radial velocity study of the rapidly rotating B-star Regulus that indicates the star is a single-lined spectroscopic binary. The orbital period (40.11 d) and probable…