Search Publications
Multiwavelength Investigation of Pulsar Wind Nebula DA 495 with HAWC, VERITAS, and NuSTAR
Zhang, H.; Li, H.; Gotthelf, E. V. +10 more
Pulsar wind nebula DA 495 (G65.7+1.2) was detected in TeV gamma-rays by the High Altitude Water Cerenkov Observatory in 2017 (2HWC J1953+294). Follow-up observations by the Very Energetic Radiation Imaging Telescope Array System confirmed the association between 2HWC J1953+294 and DA 495 and found the TeV emission to be spatially coincident with t…
Nonthermal Emission from the Interaction of Magnetized Exoplanets with the Wind of Their Host Star
Loeb, Abraham; Wang, Xiawei
We study the nonthermal emission from the interaction between magnetized Jupiter-like exoplanets and the wind from their host star. The supersonic motion of planets through the wind forms a bow shock that accelerates electrons that produce nonthermal radiation across a broad wavelength range. We discuss three wind mass-loss rates: {\dot{M}}{{…
Cross-correlation of CMB Polarization Lensing with High-z Submillimeter Herschel-ATLAS Galaxies
Baccigalupi, C.; Borrill, J.; Stompor, R. +46 more
We report a 4.8σ measurement of the cross-correlation signal between the cosmic microwave background (CMB) lensing convergence reconstructed from measurements of the CMB polarization made by the POLARBEAR experiment and the infrared-selected galaxies of the Herschel-ATLAS survey. This is the first measurement of its kind. We infer a best-fit galax…
Ultralow-amplitude RR Lyrae Stars in M4
Wallace, Joshua J.; Hartman, Joel D.; Bakos, Gáspár Á. +1 more
We report evidence for a new class of variable star, which we dub millimagnitude RR Lyrae (mmRR). From K2 observations of the globular cluster M4, we find that out of 24 horizontal branch stars not previously known to be RR Lyrae variables, two show photometric variability with periods and shapes consistent with those of first-overtone RR Lyrae va…
Dependence of Galactic Halo Kinematics on the Adopted Galactic Potential
Beers, Timothy C.; Lee, Young Sun; Kim, Young Kwang
We explore differences in Galactic halo kinematic properties derived from two commonly employed Galactic potentials: the Stäckel potential and the default Milky Way-like potential used in the “Galpy” package (MWPotential2014), making use of stars with available metallicities, radial velocities, and proper motions from Sloan Digital Sky Survey Data…
The Two Most Recent Thermonuclear Supernovae in the Local Group: Radio Constraints on their Progenitors and Evolution
Chomiuk, Laura; Badenes, Carles; Tremou, Evangelia +3 more
Young supernova remnants (SNRs) provide a unique perspective on supernova (SN) progenitors and connect the late evolution of SNe with the onset of the SNR phase. Here we study SN 1885A and G1.9+0.3, the most recent thermonuclear SNe in the Local Group (with ages ∼100 yr) with radio data, which provide a sensitive probe of the SN environment and en…
New Spatially Resolved Imaging of the SR 21 Transition Disk and Constraints on the Small-grain Disk Geometry
van der Marel, N.; Ireland, M. J.; Puglisi, A. +9 more
We present new 0.6-4 µm imaging of the SR 21 transition disk from Keck/NIRC2 and Magellan/MagAO. The protoplanetary disk around SR 21 has a large (∼30-40 au) clearing first inferred from its spectral energy distribution and later detected in submillimeter imaging. Both the gas and small dust grains are known to have a different morphology, w…
Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy
Frebel, Anna; Chiti, Anirudh
We present the metallicities and carbon abundances of four newly discovered metal-poor stars with -2.2 < [Fe/H] < -1.6 in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a combination of public photometry from the SkyMapper Southern Sky Survey and proper-motion data from the second dat…
Modeling the Protoplanetary Disks of Two Brown Dwarfs in the Taurus Molecular Cloud
Espaillat, Catherine C.; Macías, Enrique; Rilinger, Anneliese M.
Measuring the properties of protoplanetary disks around brown dwarfs (BDs) is central to understanding the formation of BDs and their planetary companions. We present modeling of CFHT Tau 4 and 2M0444, two BDs with protoplanetary disks in the Taurus Molecular Cloud. By combining modeling of the spectral energy distributions and Atacama Large Milli…
Photometry and Spectroscopy of Faint Candidate Spectrophotometric Standard DA White Dwarfs
Rest, Armin; Matheson, Thomas; Points, Sean +14 more
We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equator, and are all fainter than r ∼ 16.5 mag. This network of stars, when established as standards and together with the three Hubble Space Telescope prim…