James R. A. Davenport
A5090455120- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Space Science and Extraterrestrial Life
- History and Developments in Astronomy
- Space Exploration and Technology
- Conferences and Exhibitions Management
- Astrophysics and Cosmic Phenomena
- Genetic and Kidney Cyst Diseases
- Time Series Analysis and Forecasting
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Climate Change Communication and Perception
- Oil, Gas, and Environmental Issues
- Planetary Science and Exploration
- Inertial Sensor and Navigation
- Pulsars and Gravitational Waves Research
- Renal and related cancers
University of Washington
2016-2025
City University of Seattle
2022-2024
Seattle University
2019-2023
Western Washington University
2015-2019
Vanderbilt University
2015-2016
Vanderbilt University Medical Center
2011
Université de Montréal
2010
Cerro Tololo Inter-American Observatory
2010
San Diego State University
2008-2009
University of Alabama at Birmingham
2004-2007
This paper describes the Seventh Data Release of Sloan Digital Sky Survey (SDSS), marking completion original goals SDSS and end phase known as SDSS-II. It includes 11,663 deg2 imaging data, with most ∼2000 increment over previous data release lying in regions low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. survey also repeat on a 120° long, 25 wide stripe along celestial equator Southern Cap, some covered by many 90 individual runs. We...
Building on the legacy of Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program four spectroscopic surveys three scientific themes: dark energy cosmological parameters, history structure Milky Way, population giant planets around other stars. In keeping with SDSS tradition, will provide regular public releases all its data, beginning Data Release 8 (DR8), which was made in 2011 January includes SDSS-I SDSS-II images spectra reprocessed latest pipelines calibrations produced for...
The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using original SDSS wide-field imager, and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution novel interferometer. All SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all acquired through 2013 July, 12 (DR12) adding July (including included in previous releases), marking end observing. Relative our public...
ABSTRACT The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from Baryon Oscillation Spectroscopic (BOSS). This ninth release (DR9) of SDSS project includes 535,995 new galaxy spectra (median z ∼ 0.52), 102,100 quasar 2.32), and 90,897 stellar spectra, along with presented in previous releases. These were obtained BOSS spectrograph taken between 2009 December 2011 July. In addition, parameters pipeline, which determines radial velocities, surface temperatures,...
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with instrumentation and surveys focused on Galactic structure chemical evolution, measurements of the baryon oscillation feature clustering galaxies quasar Ly alpha forest, radial velocity search for planets around ~8000 stars. This paper describes first data release SDSS-III (and eighth counting from beginning SDSS). includes five-band imaging roughly 5200 deg^2 Southern Cap, bringing total footprint SDSS to 14,555...
The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in clustering matter over a larger volume than combined efforts all previous spectroscopic surveys large-scale structure. BOSS uses 1.5 million luminous galaxies as faint i = 19.9 10,000 deg2 BAO redshifts z < 0.7. Observations neutral hydrogen Lyα forest more 150,000 quasar spectra (g 22) will constrain redshift range 2.15 3.5. Early results from include first detection...
This paper describes the Sixth Data Release of Sloan Digital Sky Survey. With this data release, imaging northern Galactic cap is now complete. The survey contains images and parameters roughly 287 million objects over 9583 deg2, including scans a large range latitudes longitudes. also includes 1.27 spectra stars, galaxies, quasars, blank sky (for subtraction) selected 7425 deg2. release much more stellar spectroscopy than was available in previous releases detailed estimates temperatures,...
We present the design and performance of multi-object fiber spectrographs for Sloan Digital Sky Survey (SDSS) their upgrade Baryon Oscillation Spectroscopic (BOSS). Originally commissioned in Fall 1999 on 2.5-m aperture Telescope at Apache Point Observatory, produced more than 1.5 million spectra SDSS SDSS-II surveys, enabling a wide variety Galactic extra-galactic science including first observation baryon acoustic oscillations 2005. The were upgraded 2009 are currently use BOSS, flagship...
Ground- and space-based planet searches employing radial velocity techniques transit photometry have detected thousands of planet-hosting stars in the Milky Way. The chemistry these atmospheres is controlled by shape absolute flux stellar spectral energy distribution, however, distributions relatively inactive low-mass are poorly known at present. To better understand exoplanets orbiting stars, we executed a panchromatic (X-ray to mid-IR) study 11 nearby hosting {\it Measurements Ultraviolet...
ABSTRACT A homogeneous search for stellar flares has been performed using every available Kepler light curve. An iterative curve de-trending approach was used to filter out both astrophysical and systematic variability detect flares. The flare recovery completeness also computed throughout each artificial injection tests, the tools this work have made publicly available. final sample contains 851,168 candidate events recovered above 68% threshold, which were detected from 4041 stars, or 1.9%...
We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release Sloan Digital Sky Survey. For each spectrum, we provide measurements spectral type, number molecular band heads, and Hα, Hβ, Hγ, Hδ, Ca ii K emission lines. In addition, calculate metallicity-sensitive parameter ζ identify relationship between g − r z colors dwarfs. assess precision our types (which were assigned by individual examination), review bulk attributes sample, examine magnetic...
Abstract We report the latest view of Kepler solar-type (G-type main-sequence) superflare stars, including recent updates with Apache Point Observatory (APO) 3.5 m telescope spectroscopic observations and Gaia -DR2 data. First, we newly conducted APO 18 stars found from 1-minute time-cadence More than half (43 stars) are confirmed to be “single” among 64 in total that have been spectroscopically investigated so far this our previous Subaru/HDS observations. The measurements v sin i...
Abstract Study Analysis Group 21 (SAG21) of NASA’s Exoplanet Exploration Program was organized to study the effect stellar contamination on space-based transmission spectroscopy, a method for studying exoplanetary atmospheres by measuring wavelength-dependent radius planet as it transits its star. Transmission spectroscopy relies precise understanding spectrum star being occulted. However, stars are not homogeneous, constant light sources but have temporally evolving photospheres and...
Abstract We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, AD Leo. Spectroscopic were obtained using Apache Point Observatory 3.5 m Small Moderate Aperture Research Telescope System 1.5 telescopes during 31 nights. Among 41 detected flares, seven flares showed clear blue wing asymmetries in H α line, with various correspondences properties. The duration range from 20 minutes to 2.5 hr, including a showing...
Although human congenital cerebellar malformations are common, their molecular and developmental basis is still poorly understood. Recently, cilia-related gene deficiencies have been implicated in several disorders that exhibit abnormalities such as Joubert syndrome, Meckel-Gruber Bardet-Biedl Orofaciodigital syndrome. The association of cilia mutations with these syndromes suggests may be important for development, but the nature involvement has not elucidated. To assess importance proteins...
We analyzed Kepler short-cadence M dwarf observations. Spectra from the ARC 3.5m telescope identify magnetically active (H$α$ in emission) stars. The stars are of mid-M spectral type, have numerous flares, and well-defined rotational modulation due to starspots. inactive early-M exhibit less starspot signature, fewer flares. A U-band energy scaling allows comparison flare frequency distributions with previous ground-based data. dwarfs span a large range energy, blurring distinction between...
We present the results of a blind exercise to test recoverability stellar rotation and differential in Kepler light curves. The simulated curves lasted 1000 days included activity cycles, Sun-like butterfly patterns, spot evolution. range periods, levels lifetime were chosen be representative data solar like stars. Of curves, 770 injected into actual quiescent simulate noise. also five 1000-day segments Sun's total irradiance variations at different points cycle. Five teams took part...
We present the largest sample of flares ever compiled for a single M dwarf, active M4 star GJ 1243. Over 6100 individual flare events, with energies ranging from $10^{29}$ to $10^{33}$ erg, are found in 11 months 1-minute cadence data Kepler. This is unique its completeness and dynamic range. have developed automated tools finding short-cadence Kepler light curves, performed extensive validation classification by eye. From this pristine we generate median template. template shows that two...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
We present a study of white light flares from the active M5.5 dwarf Proxima Centauri using Canadian microsatellite MOST. Using 37.6 days monitoring data 2014 and 2015, we have detected 66 individual flare events, largest number observed to date on Cen. Flare energies in our sample range $10^{29}$-$10^{31.5}$ erg. The rate is lower than that other classic stars similar spectral type, such as UV Ceti, which may indicate Cen had higher its youth. does an unusually high given slow rotation...
We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra photometry covering near-ultraviolet optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light components at bluer redder than Balmer jump. Our goals break degeneracy between mechanisms that have been fit broadband colors flares provide constraints radiative-hydrodynamic (RHD) flare models seek reproduce emission. The main results are following: (1)...
Few observational constraints exist for the tidal synchronization rate of late-type stars, despite its fundamental role in binary evolution. We visually inspected light curves 2278 eclipsing binaries (EBs) from Kepler Eclipsing Binary Catalog to identify those with starspot modulations, as well other types out-of-eclipse variability. report rotation periods 816 EBs and find that 79% orbital less than ten days are synchronized. However, a population short period exists typically 13% slower...
Understanding the impact of active M-dwarf stars on atmospheric equilibrium and surface conditions a habitable zone Earth-like planet is key to assessing M dwarf habitability. Previous modeling electromagnetic (EM) radiation protons from single large flare an atmosphere indicated that significant long-term reductions in ozone were possible, but recovered. These more realistically exhibit frequent flaring with power-law distribution energies. Here we use coupled 1D photochemical...