Search Publications
The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
Lazio, T. J. W.; Ransom, S. M.; Chatterjee, S. +21 more
The precise localization of the repeating fast radio burst (FRB 121102) has provided the first unambiguous association (chance coincidence probability p ≲ 3 × 10-4) of an FRB with an optical and persistent radio counterpart. We report on optical imaging and spectroscopy of the counterpart and find that it is an extended (0.″6-0.″8) obje…
Dust in the Reionization Era: ALMA Observations of a z = 8.38 Gravitationally Lensed Galaxy
Pérez-Fournon, I.; Laporte, N.; Bauer, F. E. +6 more
We report on the detailed analysis of a gravitationally lensed Y-band dropout, A2744_YD4, selected from deep Hubble Space Telescope imaging in the Frontier Field cluster Abell 2744. Band 7 observations with the Atacama Large Millimeter/submillimeter Array (ALMA) indicate the proximate detection of a significant 1 mm continuum flux suggesting the p…
Standing on the Shoulders of Dwarfs: the Kepler Asteroseismic LEGACY Sample. II.Radii, Masses, and Ages
Chaplin, William J.; Davies, Guy R.; Latham, David W. +21 more
We use asteroseismic data from the Kepler satellite to determine fundamental stellar properties of the 66 main-sequence targets observed for at least one full year by the mission. We distributed tens of individual oscillation frequencies extracted from the time series of each star among seven modeling teams who applied different methods to determi…
Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
Petigura, Erik A.; von Braun, Kaspar; Yee, Samuel W.
Classification of stars, by comparing their optical spectra to a few dozen spectral standards, has been a workhorse of observational astronomy for more than a century. Here, we extend this technique by compiling a library of optical spectra of 404 touchstone stars observed with Keck/HIRES by the California Planet Search. The spectra have high reso…
Asteroseismology and Gaia: Testing Scaling Relations Using 2200 Kepler Stars with TGAS Parallaxes
Chaplin, William J.; Davies, Guy R.; Latham, David W. +17 more
We present a comparison of parallaxes and radii from asteroseismology and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red-giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived from asteroseismology and eclipsing binaries have likely been overestimated for parallaxes …
A millimeter Continuum Size-Luminosity Relationship for Protoplanetary Disks
Wilner, David J.; Andrews, Sean M.; Birnstiel, Tilman +1 more
We present a survey at subarcsecond resolution of the 340 GHz dust continuum emission from 50 nearby protoplanetary disks, based on new and archival observations with the Submillimeter Array. The observed visibility data were modeled with a simple prescription for the radial surface brightness profile. The results were used to extract intuitive, e…
Three Radial Gaps in the Disk of TW Hydrae Imaged with SPHERE
Quanz, S. P.; Avenhaus, H.; Dominik, C. +24 more
We present scattered light images of the TW Hya disk performed with the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument in Polarimetric Differential Imaging mode at 0.63, 0.79, 1.24, and 1.62 µm. We also present H2/H3-band angular differential imaging (ADI) observations. Three distinct radial depressions in the polarized int…
Gaia Reveals a Metal-rich, in situ Component of the Local Stellar Halo
Conroy, Charlie; Bonaca, Ana; Hopkins, Philip F. +2 more
We use the first Gaia data release, combined with the RAVE and APOGEE spectroscopic surveys, to investigate the origin of halo stars within ≲ 3 kpc from the Sun. We identify halo stars kinematically as moving at a relative speed of at least 220 km s-1 with respect to the local standard of rest. These stars are generally less metal-rich …
FRB 121102 Is Coincident with a Star-forming Region in Its Host Galaxy
Ransom, S. M.; Chatterjee, S.; Cordes, J. M. +16 more
We present optical, near-infrared, and mid-infrared imaging of the host galaxy of FRB 121102 with the Gemini North telescope, the Hubble Space Telescope, and the Spitzer Space Telescope. The FRB 121102 host galaxy is resolved, revealing a bright star-forming region located in the outskirts of the irregular, low-metallicity dwarf galaxy. The star-f…
Placing the Spotted T Tauri Star LkCa 4 on an HR Diagram
Herczeg, Gregory J.; Jose, Jessy; Liu, Chun-Fan +12 more
Ages and masses of young stars are often estimated by comparing their luminosities and effective temperatures to pre-main-sequence stellar evolution tracks, but magnetic fields and starspots complicate both the observations and evolution. To understand their influence, we study the heavily spotted weak-lined T-Tauri star LkCa 4 by searching for sp…