Search Publications
Effective Opacity of the Intergalactic Medium from Galaxy Spectra Analysis
Chisholm, John; Prochaska, J. Xavier; Lee, Khee-Gan +1 more
We measure the effective opacity ( ${\tau }_{\mathrm{eff}}$ ) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2 ≲ z ≲ 3. Our spectra are taken from the COSMOS Lyα Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We…
The Hubble Space Telescope Advanced Camera for Surveys Emission Line Survey of Andromeda. I. Classical Be Stars
Dalcanton, J. J.; Choi, Y.; Johnson, L. C. +9 more
We present results from a two epoch Hubble Space Telescope Hα emission line survey of the Andromeda galaxy that overlaps the footprint of the Panchromatic Hubble Andromeda Treasury (PHAT) survey. We found 552 (542) classical Be stars and 8429 (8556) normal B-type stars in epoch # 1 (epoch # 2), yielding an overall fractional Be content of 6.15% ± …
Early High-contrast Imaging Results with Keck/NIRC2-PWFS: The SR 21 Disk
Baranec, Christoph; Jensen-Clem, Rebecca; Uyama, Taichi +22 more
High-contrast imaging of exoplanets and protoplanetary disks depends on wave front sensing and correction made by adaptive optics instruments. Classically, wave front sensing has been conducted at optical wavelengths, which made high-contrast imaging of red targets such as M-type stars or extincted T Tauri stars challenging. Keck/NIRC2 has combine…
Low-mass Group Environments Have No Substantial Impact on the Circumgalactic Medium Metallicity
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
We explore how environment affects the metallicity of the circumgalactic medium (CGM) using 13 low-mass galaxy groups (two to five galaxies) at $\langle {z}_{\mathrm{abs}}\rangle =0.25 identified near background quasars. Using quasar spectra from the Hubble Space Telescope/COS and from Keck/HIRES or the Very Large Telescope/UVES, we measure column…
Learning Spectral Templates for Photometric Redshift Estimation from Broadband Photometry
Connolly, Andrew J.; Crenshaw, John Franklin
Estimating redshifts from broadband photometry is often limited by how accurately we can map the colors of galaxies to an underlying spectral template. Current techniques utilize spectrophotometric samples of galaxies or spectra derived from spectral synthesis models. Both of these approaches have their limitations: either the sample sizes are sma…
An Asymmetric Eclipse Seen toward the Pre-main-sequence Binary System V928 Tau
Schlieder, Joshua E.; Howard, Andrew W.; Stauffer, John R. +21 more
K2 observations of the weak-lined T Tauri binary V928 Tau A and B show the detection of a single, asymmetric eclipse, which may be due to a previously unknown substellar companion eclipsing one component of the binary with an orbital period >66 days. Over an interval of about 9 hr, one component of the binary dims by around 60%, returning to it…
Variability in Proto-planetary Nebulae. VI. Multitelescope Light Curve Studies of Several Medium-bright (V = 13-15), Carbon-rich Objects
Lu, Wenxian; Hrivnak, Bruce J.; Henson, Gary +3 more
We present 10 years of new photometric monitoring of the light variability of five evolved stars with strong mid-infrared emission from surrounding dust. Three are known carbon-rich proto-planetary nebulae (PPNe) with F-G spectral types; the nature of the other two was previously unknown. For the three PPNe, we determine or refine the pulsation pe…
Light-curve Evolution due to Secular Dynamics and the Vanishing Transits of KOI 120.01
Aharonson, Oded; Judkovsky, Yair; Ofir, Aviv
Non-Keplerian dynamics of planetary orbits manifest in the transit light curve as variations of different types. In addition to transit timing variations, the shape of the transits contains additional information on variations in the geometry of the orbit. This study presents an analytic approach to light-curve fitting: dynamical variations in the…
Spectroscopic Orbits of Subsystems in Multiple Stars. VII.
Tokovinin, Andrei
Spectroscopic orbits of main-sequence stars HIP 3150A, 6873B, 11537A, 22531A, 22534B, 31089B, 49336A, 104833C, and 107731A belonging to eight multiple systems are determined from high-resolution spectra taken with CHIRON. Two of those are twins with mass ratios above 0.95. HIP 11537 is a young three-tier quadruple system with inner periods of 22.3…
A Search for Transiting Planets in the Globular Cluster M4 with K2: Candidates and Occurrence Limits
Wallace, Joshua J.; Hartman, Joel D.; Bakos, Gáspár Á.
We perform a search for transiting planets in the NASA K2 observations of the globular cluster (GC) M4. This search is sensitive to larger orbital periods (P ≲ 35 days, compared to the previous best of P ≲ 16 days), and at the shortest periods, smaller planet radii (Rp ≳ 0.3 RJ, compared to the previous best of Rp …