Search Publications
The Luminosity Function of Red Supergiants in M31
Drout, Maria R.; Massey, Philip; Levesque, Emily M. +5 more
The mass-loss rates of red supergiant stars (RSGs) are poorly constrained by direct measurements, and yet the subsequent evolution of these stars depends critically on how much mass is lost during the RSG phase. In 2012 the Geneva evolutionary group updated their mass-loss prescription for RSGs with the result that a 20 M⊙ star now lose…
Narrowband Large Amplitude Whistler-mode Waves in the Solar Wind and Their Association with Electrons: STEREO Waveform Capture Observations
Breneman, A. W.; Cattell, C. A.; Short, B. +1 more
Large amplitude (up to 70 mV m-1) whistler-mode waves at frequencies of ∼0.2-0.4 fce (electron cyclotron frequency) are frequently observed in the solar wind. The waves are obliquely propagating at angles close to the resonance cone, resulting in significant electric fields parallel to the background magnetic field, enabling …
Supernovae in Orion: The Missing Link in the Star-forming History of the Region
Kounkel, Marina
The Orion Complex is a notable star-forming region fragmented into several different populations with substantial differences in their phase space. I propose a model that attempts to explain the how the Complex has evolved into this current configuration. In the model presented here, the large-scale expansion can be attributable to a supernova tha…
The Morphology-Density Relationship in 1 < z < 2 Clusters
Rodriguez-Gomez, Vicente; Snyder, Gregory F.; Brodwin, Mark +8 more
The morphology-density relationship states that dense cosmic environments such as galaxy clusters have an overabundance of quiescent elliptical galaxies, but it is unclear at which redshift this relationship is first established. We study the morphology of four clusters with 1.2 < z < 1.8 using Hubble Space Telescope imaging and the morpholo…
An Isolated White Dwarf with 317 s Rotation and Magnetic Emission
Hermes, J. J.; Clemens, J. C.; Vanderbosch, Z. +5 more
We report the discovery of short-period photometric variability and modulated Zeeman-split hydrogen emission in SDSSJ125230.93-023417.72 (EPIC 228939929), a variable white dwarf star observed at long cadence in K2 Campaign 10. The behavior is associated with a magnetic (B = 5.0 MG) spot on the stellar surface, making the 317.278 s period a direct …
Blazars at the Cosmic Dawn
Ajello, M.; Giroletti, M.; Madejski, Greg +5 more
The uncharted territory of the high-redshift (z ≳ 3) universe holds the key to understanding the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, that is, blazars, we have carried out a multiwavelength study of a large sample of radio-loud quasars beyond z = 3. Our sample consists of nine γ-ray-det…
A Kinematic View of NGC 1261: Structural Parameters, Internal Dispersion, Absolute Proper Motion, and Blue Straggler Stars
Anderson, Jay; Cadelano, Mario; Pallanca, Cristina +8 more
We constructed a Hubble Space Telescope (HST) astrophotometric catalog of the central region of the Galactic globular cluster NGC 1261. This catalog, complemented with Gaia DR2 data sampling the external regions, has been used to estimate the structural parameters of the system (I.e., core, half-mass, tidal radii, and concentration) from its resol…
Infrared Excesses around Bright White Dwarfs from Gaia and unWISE. I.
Lai, Samuel; Xu, Siyi; Dennihy, Erik
Studies of excess infrared radiation around white dwarfs provide important constraints on the evolution of planetary systems and low-mass companions beyond the main-sequence stage. In this paper series, we focus on identifying and characterizing bright white dwarfs with an infrared excess. Here, we present 188 infrared excess candidates from Gaia …
Direct Radio Discovery of a Cold Brown Dwarf
Callingham, J. R.; Shimwell, T. W.; Vedantham, H. K. +9 more
Magnetospheric processes seen in gas giants such as aurorae and circularly polarized cyclotron maser radio emission have been detected from some brown dwarfs. However, previous radio observations targeted known brown dwarfs discovered via their infrared emission. Here we report the discovery of BDR J1750+3809, a circularly polarized radio source d…
The Angular Momentum of the Circumgalactic Medium in the TNG100 Simulation
Genel, Shy; Pillepich, Annalisa; Nelson, Dylan +3 more
We present an analysis of the angular momentum content of the circumgalactic medium (CGM) using TNG100, one of the flagship runs of the IllustrisTNG project. We focus on Milky Way-mass halos (∼1012 M⊙) at z = 0 but also analyze other masses and redshifts up to z = 5. We find that the CGM angular momentum properties are strong…