Search Publications
Selection of Massive Evolved Galaxies at 3 ≤ z ≤ 4.5 in the CANDELS Fields
Papovich, Casey; Finkelstein, Steven L.; Dickinson, Mark +14 more
Using the CANDELS photometric catalogs for the Hubble Space Telescope/ACS and WFC3, we identified massive evolved galaxies at 3 < z < 4.5 employing three different selection methods. We find the comoving number density of these objects to be ∼2 × 10-5 and 8 × 10-6 Mpc-3 after correction for completeness for t…
Hard X-Ray Excess from the Magnificent Seven Neutron Stars
Safdi, Benjamin R.; Foster, Joshua W.; Dessert, Christopher
We report significant hard X-ray excesses in the energy range 2-8 keV for two nearby isolated neutron stars: RX J1856.6-3754 and RX J0420.0-5022. These neutron stars have previously been observed in soft X-rays to have nearly thermal spectra at temperatures ∼100 eV, which are thought to arise from the warm neutron star surfaces. We find nontrivial…
Whistler Waves and Electron Properties in the Inner Heliosphere: Helios Observations
Alexandrova, Olga; de Wit, Thierry Dudok; Maksimovic, Milan +4 more
We present the analysis of narrowband whistler wave signatures observed in the inner heliosphere (0.3-1 au). These signatures are bumps in the spectral density in the 10-200 Hz frequency range of the AC magnetic field as measured by the search coil magnetometer on board the Helios 1 spacecraft. We show that the majority of whistler signatures are …
Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra
Zhao, Gang; Németh, Péter; Zhao, Jingkun +1 more
182 single-lined hot subdwarf stars are identified by using spectra from the sixth and seventh data releases (DR6 and DR7) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope survey. We classified all the hot subdwarf stars using a canonical classification scheme, and got 89 sdB, 37 sdOB, 26 sdO, 24 He-sdOB, 3 He-sdO, and 3 He-sdB sta…
An Exact, Generalized Laplace Resonance in the HR 8799 Planetary System
Goździewski, Krzysztof; Migaszewski, Cezary
A system of four super-Jupiter planets around HR 8799 is the first multiplanet configuration discovered via the direct imaging technique. Despite over a decade of research, the system's architecture is still not fully resolved. The main difficulty comes from a still narrow observing window of ∼20 yr that covers small arcs of orbits with periods fr…
Mapping the Escape Fraction of Ionizing Photons Using Resolved Stars: A Much Higher Escape Fraction for NGC 4214
Skillman, Evan D.; Williams, Benjamin F.; Gordon, Karl D. +6 more
We demonstrate a new method for measuring the escape fraction of ionizing photons using Hubble Space Telescope imaging of resolved stars in NGC 4214, a local analog of high-redshift starburst galaxies that are thought to be responsible for cosmic reionization. Specifically, we forward model the UV through near-IR spectral energy distributions of ∼…
Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event
Feliz, Dax L.; Zang, Weicheng; Gould, Andrew +26 more
We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector ${{\boldsymbol{\pi }}}_{{\rm{E}}}$ using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interf…
Hunting for Runaways from the Orion Nebula Cluster
Tan, Jonathan C.; Eyer, Laurent; Farias, Juan P.
We use Gaia DR2 to hunt for runaway stars from the Orion Nebula Cluster (ONC). We search a region extending 45° around the ONC and out to 1 kpc to find sources that have overlapped in angular position with the cluster in the last ∼10 Myr. We find ∼17,000 runaway/walkaway candidates that satisfy this 2D traceback condition. Most of these are expect…
Characterization of Temporarily Captured Minimoon 2020 CD3 by Keck Time-resolved Spectrophotometry
Duev, Dmitry A.; Riddle, Reed; Ip, Wing-Huen +42 more
We present time-resolved visible spectrophotometry of 2020 CD3, the second known minimoon. The spectrophotometry was taken with the Keck I/Low Resolution Imaging Spectrometer between wavelengths 434 and 912 nm in the B, g, V, R, I, and RG850 filters as it was leaving the Earth-Moon system on 2020 March 23 UTC. The spectrum of 2020 CD
The Hidden Past of M92: Detection and Characterization of a Newly Formed 17° Long Stellar Stream Using the Canada-France Imaging Survey
Jensen, Jaclyn; Navarro, Julio F.; Cuillandre, Jean-Charles +17 more
We present an analysis of the structure, kinematics, and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a "color-color-magnitude" diagram, created using photometry from the Canada-France Imaging Survey and the Pan-S…