Search Publications
Radial Velocity Photon Limits for the Dwarf Stars of Spectral Classes F-M
Reiners, Ansgar; Zechmeister, Mathias
The determination of extrasolar planet masses with the radial velocity (RV) technique requires spectroscopic Doppler information from the planet's host star, which varies with stellar brightness and temperature. We analyze the Doppler information in spectra from dwarfs of spectral types F-M utilizing empirical information from HARPS and CARMENES d…
Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe
Krimigis, S. M.; Mitchell, D. G.; McComas, D. J. +33 more
A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (IS⊙IS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly…
Classifying Single Stars and Spectroscopic Binaries Using Optical Stellar Templates
Roulston, Benjamin R.; Green, Paul J.; Kesseli, Aurora Y.
Stellar spectral classification is a fundamental tool of modern astronomy, providing insight into physical characteristics such as effective temperature, surface gravity, and metallicity. Accurate and fast spectral typing is an integral need for large all-sky spectroscopic surveys like the Sloan Digital Sky Survey (SDSS) and the Large Sky Area Mul…
Microlensing Optical Depth and Event Rate in the OGLE-IV Galactic Plane Fields
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +10 more
Searches for gravitational microlensing events are traditionally concentrated on the central regions of the Galactic bulge but many microlensing events are expected to occur in the Galactic plane, far from the Galactic Center. Owing to the difficulty in conducting high-cadence observations of the Galactic plane over its vast area, which are necess…
X-Ray Binary Luminosity Function Scaling Relations in Elliptical Galaxies: Evidence for Globular Cluster Seeding of Low-mass X-Ray Binaries in Galactic Fields
Brandt, William N.; Tzanavaris, Panayiotis; Basu-Zych, Antara +10 more
We investigate X-ray binary (XRB) luminosity function (XLF) scaling relations for Chandra-detected populations of low-mass XRBs (LMXBs) within the footprints of 24 early-type galaxies. Our sample includes Chandra and Hubble Space Telescope observed galaxies at $D\lesssim 25$ Mpc that have estimates of the globular cluster (GC) specific frequency (…
Gaia RR Lyrae Stars in Nearby Ultra-faint Dwarf Satellite Galaxies
Walker, Alistair R.; Vivas, A. Katherina; Martínez-Vázquez, Clara
We search for RR Lyrae stars (RRLs) in 27 nearby (<100 kpc) ultra-faint dwarf satellite galaxies using the Gaia DR2 catalog of RRLs. Based on proper motions, magnitudes, and location on the sky, we associate 47 Gaia RRLs with 14 different satellites. Distances based on RRLs are provided for those galaxies. We have identified RRLs for the first …
The Next Generation Virgo Cluster Survey. XXXIV. Ultracompact Dwarf Galaxies in the Virgo Cluster
Zhang, Hongxin; Liu, Chengze; Gwyn, Stephen +26 more
We present a study of ultracompact dwarf (UCD) galaxies in the Virgo cluster based mainly on imaging from the Next Generation Virgo Cluster Survey (NGVS). Using ∼100 deg2 of u*giz imaging, we have identified more than 600 candidate UCDs, from the core of Virgo out to its virial radius. Candidates have been selected through a combination…
Update of the Solar Lyα Profile Line Model
Bzowski, Maciej; Kubiak, Marzena A.; Sokół, Justyna M. +1 more
We present a modification of a model of solar cycle evolution of the solar Lyα line profile, along with a sensitivity study of interstellar neutral hydrogen to uncertainties in radiation pressure level. The line profile model, originally developed by Kowalska-Leszczynska et al., is parameterized by the composite solar Lyα flux, which recently was …
The K2 Galactic Archaeology Program Data Release 2: Asteroseismic Results from Campaigns 4, 6, and 7
Chaplin, William J.; Davies, Guy R.; Huber, Daniel +18 more
Studies of Galactic structure and evolution have benefited enormously from Gaia kinematic information, though additional, intrinsic stellar parameters like age are required to best constrain Galactic models. Asteroseismology is the most precise method of providing such information for field star populations en masse, but existing samples for the m…
Search for Nearby Earth Analogs .III. Detection of 10 New Planets, 3 Planet Candidates, and Confirmation of 3 Planets around 11 Nearby M Dwarfs
Butler, R. Paul; Vogt, Steven S.; Holden, Bradford +10 more
Earth-sized planets in the habitable zones of M dwarfs are good candidates for the study of habitability and detection of biosignatures. To search for these planets, we analyze all available radial velocity data and apply four signal detection criteria to select the optimal candidates. We find 10 strong candidates satisfying these criteria and thr…