arXiv subjects

Stephen Smee

Publications and source records attributed to Stephen Smee.

6 recordsLinked to original sources

arXiv2019

ATLAS Probe: Breakthrough Science of Galaxy Evolution, Cosmology, Milky Way, and the Solar System

ATLAS (Astrophysics Telescope for Large Area Spectroscopy) is a concept for a NASA probe-class space mission. It is the spectroscopic follow-up mission to WFIRST, boosting its scientific return by obtaining deep NIR & MIR slit spectroscopy for most of the galaxies imaged by the WFIRST High Latitude Survey at z>0.5. ATLAS will measure accurate and precise redshifts for ~200M galaxies out to z=7 and beyond, and deliver spectra that enable a wide range of diagnostic studies of the physical properties of galaxies over most of cosmic history. ATLAS and WFIRST together will produce a definitive 3D map of the Universe over 2000 sq deg. ATLAS Science Goals are: (1) Discover how galaxies have evolved in the cosmic web of dark matter from cosmic dawn through the peak era of galaxy assembly. (2) Discover the nature of cosmic acceleration. (3) Probe the Milky Way's dust-enshrouded regions, reaching the far side of our Galaxy. (4) Discover the bulk compositional building blocks of planetesimals formed in the outer Solar System. These flow down to the ATLAS Scientific Objectives: (1A) Trace the relation between galaxies and dark matter with less than 10% shot noise on relevant scales at 1<z<7. (1B) Probe the physics of galaxy evolution at 1<z<7. (2) Obtain definitive measurements of dark energy and tests of General Relativity. (3) Measure the 3D structure and stellar content of the inner Milky Way to a distance of 25 kpc. (4) Detect and quantify the composition of 3,000 planetesimals in the outer Solar System. ATLAS is a 1.5m telescope with a FoV of 0.4 sq deg, and uses Digital Micro-mirror Devices (DMDs) as slit selectors. It has a spectroscopic resolution of R = 1000, and a wavelength range of 1-4 microns. ATLAS has an unprecedented spectroscopic capability based on DMDs, with a spectroscopic multiplex factor ~6,000. ATLAS is designed to fit within the NASA probe-class space mission cost envelope.

astro-ph.IM↗

arXiv2019

ATLAS Probe: Breakthrough Science of Galaxy Evolution, Cosmology, Milky Way, and the Solar System

ATLAS (Astrophysics Telescope for Large Area Spectroscopy) Probe is a concept for a NASA probe-class space mission. It is the follow-up space mission to WFIRST, boosting its scientific return by obtaining deep IR slit spectroscopy for 70% of all galaxies imaged by a 2000 sq deg WFIRST High Latitude Survey at z>0.5. ATLAS will measure accurate and precise redshifts for 200M galaxies out to z < 7, and deliver spectra that enable a wide range of diagnostic studies of the physical properties of galaxies over most of cosmic history. ATLAS Probe science spans four broad categories: (1) Revolutionizing galaxy evolution studies by tracing the relation between galaxies and dark matter from galaxy groups to cosmic voids and filaments, from the epoch of reionization through the peak era of galaxy assembly; (2) Opening a new window into the dark Universe by weighing the dark matter filaments using 3D weak lensing with spectroscopic redshifts, and obtaining definitive measurements of dark energy and modification of General Relativity using galaxy clustering; (3) Probing the Milky Way's dust-enshrouded regions, reaching the far side of our Galaxy; and (4) Exploring the formation history of the outer Solar System by characterizing Kuiper Belt Objects. ATLAS Probe is a 1.5m telescope with a field of view of 0.4 sq deg, and uses Digital Micro-mirror Devices (DMDs) as slit selectors. It has a spectroscopic resolution of R = 1000 over 1-4 microns, and a spectroscopic multiplex factor >5,000. ATLAS is designed to fit within the NASA probe-class space mission cost envelope; it has a single instrument, a telescope aperture that allows for a lighter launch vehicle, and mature technology. ATLAS Probe will lead to transformative science over the entire range of astrophysics: from galaxy evolution to the dark Universe, from Solar System objects to the dusty regions of the Milky Way.

astro-ph.IM↗

arXiv2015

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three year observing campaign on the Sloan 2.5-m Telescope, APOGEE has collected a half million high resolution (R~22,500), high S/N (>100), infrared (1.51-1.70 microns) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design---hardware, field placement, target selection, operations---and gives an overview of these aspects as well as the data reduction, analysis and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12, all of the APOGEE data products are now publicly available.

astro-ph.IM↗

arXiv2013

The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near ultraviolet to the near infrared, with a resolving power R = λ/FWHM ~ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 < λ< 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.

astro-ph.IM↗

arXiv2012

A spectrograph instrument concept for the Prime Focus Spectrograph (PFS) on Subaru Telescope

We describe the conceptual design of the spectrograph opto-mechanical concept for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the SUBARU telescope. The SuMIRe PFS will consist of four identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering in total, a wavelength range from 380 nm to 1300 nm. The requirements for the instrument are summarized in Section 1. We present the optical design and the optical performance and analysis in Section 2. Section 3 introduces the mechanical design, its requirements and the proposed concepts. Finally, the AIT phases for the Spectrograph System are described in Section 5.

astro-ph.IM↗

arXiv2008

The FourStar Infrared Camera

The FourStar infrared camera is a 1.0-2.5 micron (JHKs) near infrared camera for the Magellan Baade 6.5m telescope at Las Campanas Observatory (Chile). It is being built by Carnegie Observatories and the Instrument Development Group at Johns Hopkins and is scheduled for completion in 2009. The instrument uses four Teledyne HAWAII-2RG arrays that produce a 10.9 x 10.9 arcmin field of view. The outstanding seeing at the Las Campanas site coupled with FourStar's high sensitivity and large field of view will enable many new survey and targeted science programs.

astro-ph↗