S. Drew Chojnowski
A5083371948- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Spectroscopy and Laser Applications
- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Advanced Frequency and Time Standards
- Water Quality Monitoring and Analysis
- Advanced X-ray Imaging Techniques
- Species Distribution and Climate Change
- Nuclear Physics and Applications
- Chemical Thermodynamics and Molecular Structure
- Space Exploration and Technology
- Air Quality Monitoring and Forecasting
Ames Research Center
2024
New Mexico State University
2014-2023
Montana State University
2021-2023
University of Virginia
2012-2017
McCormick (United States)
2014
Texas Christian University
2011
Kitt Peak National Observatory
2011
Florida Institute of Technology
2011
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...
The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. data release includes first spectroscopic Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with Baryon Oscillation Spectroscopic (BOSS) taken through 2012 July. APOGEE instrument is a near-infrared R ∼ 22,500 300 fiber spectrograph covering 1.514–1.696 μm. survey studying chemical abundances and radial...
This paper documents the seventeenth data release (DR17) from Sloan Digital Sky Surveys; fifth and final fourth phase (SDSS-IV). DR17 contains complete of Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal surveying over 10,000 nearby galaxies. The MaNGA Stellar Library (MaStar) accompanies this data, providing observations almost 30,000 stars through instrument during bright time. also Galactic Evolution Experiment 2 (APOGEE-2) survey publicly...
The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations Milky Way. After a three year observing campaign on 2.5-m Telescope, APOGEE collected half million high resolution (R~22,500), S/N (>100), infrared (1.51-1.70 microns) spectra for 146,000 stars, with time series information via repeat visits to most these stars....
This paper documents the sixteenth data release (DR16) from Sloan Digital Sky Surveys; fourth and penultimate phase (SDSS-IV). is first of southern hemisphere survey Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new APOGEE-2 North are also included. DR16 notable as final for main cosmological program Extended Baryon Oscillation Spectroscopic Survey (eBOSS), all raw reduced spectra that project released here. includes Time Domain (TDSS) SPectroscopic IDentification...
The SDSS-III/APOGEE survey operated from 2011-2014 using the APOGEE spectrograph, which collects high-resolution (R~22,500), near-IR (1.51-1.70 microns) spectra with a multiplexing (300 fiber-fed objects) capability. We describe data products that are publicly available, include catalogs radial velocity, stellar parameters, and 15 elemental abundances for over 150,000 stars, as well more than 500,000 these quantities derived. Calibration relations parameters (Teff, log g, [M/H], [alpha/M])...
Abstract The data and analysis methodology used for the SDSS/APOGEE Data Releases 13 14 are described, highlighting differences from DR12 presented in Holtzman et al. Some improvement handling of telluric absorption persistence is demonstrated. derivation calibration stellar parameters, chemical abundances, respective uncertainties along with ranges over which was performed. known issues public related to effective temperatures (DR13), surface gravity (DR13 DR14), C N abundances dwarfs DR14)...
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all environments (i.e., bulge, disk, and halo), with the principal goal of constraining dynamical chemical evolution models Milky Way. APOGEE takes advantage reduced effects extinction at wavelengths to observe inner Galaxy bulge an unprecedented level detail. survey's broad spatial wavelength coverage enables users data address numerous structure stellar...
Abstract APOGEE-2 is a high-resolution, near-infrared spectroscopic survey observing ∼3 × 10 5 stars across the entire sky. It successor to APOGEE and part of Sloan Digital Sky Survey IV (SDSS-IV). expanding on APOGEE’s goals addressing critical questions stellar astrophysics, populations, Galactic chemodynamical evolution using (1) an enhanced set target types (2) second spectrograph at Las Campanas Observatory in Chile. targeting red giant branch clump stars, RR Lyrae, low-mass dwarf young...
Formation of globular clusters (GCs), the Galactic bulge, or galaxy bulges in general, are important unsolved problems astronomy. Homogeneous infrared observations large samples stars belonging to GCs and bulge field one best ways study these problems. We report discovery by APOGEE a population inner Galaxy with abundances N, C, Al that typically found GC stars. The newly discovered have high [N/Fe], which is correlated [Al/Fe] anti-correlated [C/Fe]. They homogeneously distributed across,...
The Sloan Digital Sky Survey III's Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution near-infrared spectroscopic survey covering all of the major components Galaxy, including dust-obscured regions inner Milky Way disk and bulge. Here we present sample 10,341 likely red-clump stars (RC) from first two years APOGEE operations, selected based on their position in color–metallicity–surface-gravity–effective-temperature space using new method calibrated stellar...
The Sloan Digital Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three-year survey that collecting 105 high-resolution spectra in the near-IR across multiple populations. To derive stellar parameters and chemical compositions from this massive data set, APOGEE Stellar Parameters Chemical Abundances Pipeline (ASPCAP) has been developed. Here, we describe empirical calibrations of presented first SDSS-III release (DR10). These were enabled by...
The initial velocity dispersion of newborn stars is a major unconstrained aspect star formation theory. Using near-infrared spectra obtained with the APOGEE spectrograph, we show that young (1-2 Myr) in NGC 1333 0.92+/-0.12 km/s after correcting for measurement uncertainties and effect binaries. This consistent virial region diffuse gas dispersion, but significantly larger than dense, star-forming cores, which have sub-virial 0.5 km/s. Since cluster dynamically deeply embedded, this provides...
The B-emission line stars are rapid rotators that were probably spun up by mass and angular momentum accretion through transfer in an interacting binary. Mass will strip the donor star of its envelope to create a small hot subdwarf remnant. Here we report on Hubble Space Telescope/STIS far-ultraviolet spectroscopy sample Be reveals presence sdO companion calculation cross-correlation functions observed model spectra. We clearly detect spectral signature 10 13 sample, signals indicate hot,...
Abstract The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing chemodynamical mapping Milky Way. targeting for APOGEE-2 complex and has evolved time. In this paper, we present updates additions to initial strategy APOGEE-2N presented in Zasowski et al. (2017). These modifications come two implementation modes: (i) “Ancillary Science Programs” competitively awarded Sloan Digital Sky...
APOGEE is a high-resolution (R sim 22,000), near-infrared, multi-epoch, spectroscopic survey of the Milky Way. The second generation project, APOGEE-2, includes an expansion to Southern Hemisphere called APOGEE-2S. This enabled perform fully panoramic mapping all main regions Way; in particular, by operating H-band, uniquely able probe dust-hidden inner Way that are best accessed from Hemisphere. In this paper we present targeting strategy APOGEE-2S, with special attention documenting...
Some active galactic nuclei (AGN) are surrounded by extended emission-line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over light travel time from AGN to gas. From a new set such EELRs, we present evidence that in many Seyfert galaxies undergo luminous episodes 0.2–2 years duration. Motivated discovery spectacular nebula known as Hanny's Voorwerp, ionized powerful has apparently faded dramatically within years, Galaxy Zoo volunteers have...
Over two years 8,859 high-resolution H-band spectra of 3,493 young (1 - 10 Myr) stars were gathered by the multi-object spectrograph APOGEE project as part IN-SYNC ancillary program that SDSS-III survey. Here we present forward modeling approach used to derive effective temperatures, surface gravities, radial velocities, rotational and veiling from these near-infrared spectra. We discuss in detail statistical systematic uncertainties stellar parameters. In addition accurate extinctions...
We present narrow- and medium-band Hubble Space Telescope imaging, with additional supporting ground-based spectrophotometry, Fabry–Perot interferometric data, for eight galaxies identified as hosting a fading active galactic nucleus (AGN). These are selected to have AGN-ionized gas projected kpc from the energy budgets significant shortfall of ionizing radiation between requirement ionize distant AGN observed directly, indicating on ≈50,000 yr timescales. This paper focuses host-galaxy...
Abstract We consider the energy budgets and radiative history of eight fading active galactic nuclei (AGNs), identified from an shortfall between requirements to ionize very extended (radius > 10 kpc) ionized clouds luminosity nucleus as we view it directly. All show evidence significant on timescales ≈50,000 yr. explore use minimum ionizing Q ion derived photoionization balance in brightest pixels H α at each projected radius. Tests using presumably constant Palomar–Green QSOs, one our...
We present the results of SDSS APOGEE INfrared Spectroscopy Young Nebulous Clusters program (IN-SYNC) survey Orion A molecular cloud. This obtained high resolution near infrared (NIR) spectroscopy about 2700 young pre-main sequence stars throughout region, acquired across five distinct fields spanning 6deg field view (FOV). With these spectra, we have measured accurate stellar parameters (T_eff, log g, v sin i) and extinctions, placed sources in Hertzsprung-Russel Diagram (HRD). also...
We present an overview of the distributions 11 elemental abundances in Milky Way's inner regions, as traced by APOGEE stars released part SDSS Data Release 14/15 (DR14/DR15), including O, Mg, Si, Ca, Cr, Mn, Co, Ni, Na, Al, and K. This sample spans ~4000 with R_GC<4 kpc, enabling most comprehensive study to date these their variations within innermost few kiloparsecs Way. describe observed abundance patterns ([X/Fe]-[Fe/H]), compare previous literature results at solar Galactic radius,...
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band near-infrared (1.51-1.7 μm), high resolution (R~22,500) spectrograph to survey approximately 100,000 giant stars across the Milky Way. This three-year survey, in operation since late-summer 2011 as part of Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding kinematical and chemical enrichment histories all stellar populations. We present performance instrument...
Most field stars will have encountered the highest stellar density and hence largest number of interactions in their birth environment. Yet dynamics during this crucial phase are poorly understood. Here we analyze radial velocities measured for 152 out 380 observed 2–6 Myr old star cluster IC 348 as part SDSS-III APOGEE. The velocity distribution these is fitted with one or two Gaussians, convolved measurement uncertainties including binary orbital motions. Including a second Gaussian...
We present Hubble Space Telescope imaging and spectroscopy for the extended high-ionization cloud known as Hanny's Voorwerp, near spiral galaxy IC 2497. WFC3 images show complex dust absorption nucleus of STIS spectra a type 2 Seyfert AGN rather low luminosity. The ionization parameter log U = -3.5 is in accord with its weak X-ray emission. find no gas nucleus, adding to evidence that currently at radiative output (perhaps now dominated by kinetic energy). accompanied an expanding ring...