scholarly journals ESA study of a wide field imager for supernovae surveys and dark energy characterization

2019 ◽  
Author(s):  
P. Gondoin ◽  
V. Kirschner ◽  
A. Santovincenzo ◽  
A. Lyngvi
Keyword(s):  
Dark Energy ◽  
Wide Field

scholarly journals Dark Energy Survey Year 1 Results: Wide-field mass maps via forward fitting in harmonic space

2020 ◽  
Vol 493 (4) ◽  
pp. 5662-5679 ◽  
Author(s):  
B Mawdsley ◽  
D Bacon ◽  
C Chang ◽  
P Melchior ◽  
E Rozo ◽  
...  
Keyword(s):  
Dark Energy ◽  
Mapping Technique ◽  
Harmonic Space ◽  
Wide Field ◽  
Direct Inversion ◽  
Dark Energy Survey ◽  
Central Regions ◽  
Fitting In ◽  
Energy Survey ◽  
Good Agreement

ABSTRACT We present new wide-field weak lensing mass maps for the Year 1 Dark Energy Survey (DES) data, generated via a forward fitting approach. This method of producing maps does not impose any prior constraints on the mass distribution to be reconstructed. The technique is found to improve the map reconstruction on the edges of the field compared to the conventional Kaiser–Squires method, which applies a direct inversion on the data; our approach is in good agreement with the previous direct approach in the central regions of the footprint. The mapping technique is assessed and verified with tests on simulations; together with the Kaiser–Squires method, the technique is then applied to data from the DES Year 1 data and the differences between the two methods are compared. We also produce the first DES measurements of the convergence Minkowski functionals and compare them to those measured in simulations.

scholarly journals Wide-Field Lensing Mass Maps from Dark Energy Survey Science Verification Data

2015 ◽  
Vol 115 (5) ◽  
Author(s):  
C. Chang ◽  
V. Vikram ◽  
B. Jain ◽  
D. Bacon ◽  
A. Amara ◽  
...  
Keyword(s):  
Dark Energy ◽  
Wide Field ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals The HETDEX Instrumentation: Hobby–Eberly Telescope Wide-field Upgrade and VIRUS

2021 ◽  
Vol 162 (6) ◽  
pp. 298
Author(s):  
Gary J. Hill ◽  
Hanshin Lee ◽  
Phillip J. MacQueen ◽  
Andreas Kelz ◽  
Niv Drory ◽  
...  
Keyword(s):  
Dark Energy ◽  
Large Scale ◽  
Near Infrared ◽  
Cosmological Parameters ◽  
Resolving Power ◽  
Wide Field ◽  
Low Resolution ◽  
Integral Field Spectrograph ◽  
Optical Astronomy ◽  
Integral Field

Abstract The Hobby–Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is undertaking a blind wide-field low-resolution spectroscopic survey of 540 deg2 of sky to identify and derive redshifts for a million Lyα-emitting galaxies in the redshift range 1.9 < z < 3.5. The ultimate goal is to measure the expansion rate of the universe at this epoch, to sharply constrain cosmological parameters and thus the nature of dark energy. A major multiyear Wide-Field Upgrade (WFU) of the HET was completed in 2016 that substantially increased the field of view to 22′ diameter and the pupil to 10 m, by replacing the optical corrector, tracker, and Prime Focus Instrument Package and by developing a new telescope control system. The new, wide-field HET now feeds the Visible Integral-field Replicable Unit Spectrograph (VIRUS), a new low-resolution integral-field spectrograph (LRS2), and the Habitable Zone Planet Finder, a precision near-infrared radial velocity spectrograph. VIRUS consists of 156 identical spectrographs fed by almost 35,000 fibers in 78 integral-field units arrayed at the focus of the upgraded HET. VIRUS operates in a bandpass of 3500−5500 Å with resolving power R ≃ 800. VIRUS is the first example of large-scale replication applied to instrumentation in optical astronomy to achieve spectroscopic surveys of very large areas of sky. This paper presents technical details of the HET WFU and VIRUS, as flowed down from the HETDEX science requirements, along with experience from commissioning this major telescope upgrade and the innovative instrumentation suite for HETDEX.

scholarly journals Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

2015 ◽  
Vol 92 (2) ◽  
Author(s):  
V. Vikram ◽  
C. Chang ◽  
B. Jain ◽  
D. Bacon ◽  
A. Amara ◽  
...  
Keyword(s):  
Dark Energy ◽  
Detailed Analysis ◽  
Wide Field ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals Stellar mass as a galaxy cluster mass proxy: application to the Dark Energy Survey redMaPPer clusters

2020 ◽  
Vol 493 (4) ◽  
pp. 4591-4606 ◽  
Author(s):  
A Palmese ◽  
J Annis ◽  
J Burgad ◽  
A Farahi ◽  
M Soares-Santos ◽  
...  
Keyword(s):  
Dark Energy ◽  
Bayesian Model Averaging ◽  
Galaxy Cluster ◽  
Wide Field ◽  
X Ray ◽  
Mass Scaling ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Stellar Masses ◽  
Energy Survey

Abstract We introduce a galaxy cluster mass observable, μ⋆, based on the stellar masses of cluster members, and we present results for the Dark Energy Survey (DES) Year 1 (Y1) observations. Stellar masses are computed using a Bayesian model averaging method, and are validated for DES data using simulations and COSMOS data. We show that μ⋆ works as a promising mass proxy by comparing our predictions to X-ray measurements. We measure the X-ray temperature–μ⋆ relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 &lt; $z$ &lt; 0.7. For a scaling relation that is linear in logarithmic space, we find a slope of α = 0.488 ± 0.043 and a scatter in the X-ray temperature at fixed μ⋆ of $\sigma _{{\rm ln} T_\mathrm{ X}|\mu _\star }= 0.266^{+0.019}_{-0.020}$ for the joint sample. By using the halo mass scaling relations of the X-ray temperature from the Weighing the Giants program, we further derive the μ⋆-conditioned scatter in mass, finding $\sigma _{{\rm ln} M|\mu _\star }= 0.26^{+ 0.15}_{- 0.10}$. These results are competitive with well-established cluster mass proxies used for cosmological analyses, showing that μ⋆ can be used as a reliable and physically motivated mass proxy to derive cosmological constraints.

scholarly journals Brown dwarf census with the Dark Energy Survey year 3 data and the thin disc scale height of early L types

2019 ◽  
Vol 489 (4) ◽  
pp. 5301-5325 ◽  
Author(s):  
A Carnero Rosell ◽  
B Santiago ◽  
M dal Ponte ◽  
B Burningham ◽  
L N da Costa ◽  
...  
Keyword(s):  
Dark Energy ◽  
Structural Parameters ◽  
Brown Dwarfs ◽  
Scale Height ◽  
Wide Field ◽  
Brown Dwarf ◽  
Thin Disc ◽  
Dark Energy Survey ◽  
Significant Difference ◽  
Energy Survey

ABSTRACT In this paper we present a catalogue of 11 745 brown dwarfs with spectral types ranging from L0 to T9, photometrically classified using data from the Dark Energy Survey (DES) year 3 release matched to the Vista Hemisphere Survey (VHS) DR3 and Wide-field Infrared Survey Explorer (WISE) data, covering ≈2400 deg2 up to iAB = 22. The classification method follows the same phototype method previously applied to SDSS-UKIDSS-WISE data. The most significant difference comes from the use of DES data instead of SDSS, which allow us to classify almost an order of magnitude more brown dwarfs than any previous search and reaching distances beyond 400 pc for the earliest types. Next, we also present and validate the GalmodBD simulation, which produces brown dwarf number counts as a function of structural parameters with realistic photometric properties of a given survey. We use this simulation to estimate the completeness and purity of our photometric LT catalogue down to iAB = 22, as well as to compare to the observed number of LT types. We put constraints on the thin disc scale height for the early L (L0–L3) population to be around 450 pc, in agreement with previous findings. For completeness, we also publish in a separate table a catalogue of 20 863 M dwarfs that passed our colour cut with spectral types greater than M6. Both the LT and the late M catalogues are found at DES release page https://des.ncsa.illinois.edu/releases/other/y3-mlt.

scholarly journals OzDES multi-object fibre spectroscopy for the Dark Energy Survey: results and second data release

2020 ◽  
Vol 496 (1) ◽  
pp. 19-35 ◽  
Author(s):  
C Lidman ◽  
B E Tucker ◽  
T M Davis ◽  
S A Uddin ◽  
J Asorey ◽  
...  
Keyword(s):  
Dark Energy ◽  
Galactic Nuclei ◽  
Wide Field ◽  
Dark Energy Survey ◽  
Data Release ◽  
History Of ◽  
Survey Results ◽  
Deep Fields ◽  
The Masses ◽  
Energy Survey

ABSTRACT We present a description of the Australian Dark Energy Survey (OzDES) and summarize the results from its 6 years of operations. Using the 2dF fibre positioner and AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope, OzDES has monitored 771 active galactic nuclei, classified hundreds of supernovae, and obtained redshifts for thousands of galaxies that hosted a transient within the 10 deep fields of the Dark Energy Survey. We also present the second OzDES data release, containing the redshifts of almost 30 000 sources, some as faint as rAB = 24 mag, and 375 000 individual spectra. These data, in combination with the time-series photometry from the Dark Energy Survey, will be used to measure the expansion history of the Universe out to z ∼ 1.2 and the masses of hundreds of black holes out to z ∼ 4. OzDES is a template for future surveys that combine simultaneous monitoring of targets with wide-field imaging cameras and wide-field multi-object spectrographs.

scholarly journals LSST Data Management: Entering the Era of Petascale Optical Astronomy

2012 ◽  
Vol 10 (H16) ◽  
pp. 675-676 ◽  
Author(s):  
Mario Juric ◽  
Tony Tyson
Keyword(s):  
Dark Energy ◽  
Image Data ◽  
Scaling Up ◽  
Wide Field ◽  
Data Set ◽  
Full Dataset ◽  
Wide Range ◽  
Optical Astronomy ◽  
Annual Scale ◽  
Nature Quality

AbstractThe Large Synoptic Survey Telescope (LSST; Ivezic et al.2008, http://lsst.org) is a planned, large-aperture, wide-field, ground-based telescope that will survey half the sky every few nights in six optical bands from 320 to 1050 nm. It will explore a wide range of astrophysical questions, ranging from discovering killer asteroids, to examining the nature of dark energy. LSST will produce on average 15 terabytes of data per night, yielding an (uncompressed) data set of 200 petabytes at the end of its 10-year mission. Dedicated HPC facilities (with a total of 320 TFLOPS at start, scaling up to 1.7 PFLOPS by the end) will process the image data in near real time, with full-dataset reprocessing on annual scale. The nature, quality, and volume of LSST data will be unprecedented, so the data system design requires petascale storage, terascale computing, and gigascale communications.

scholarly journals ATLAS probe: Breakthrough science of galaxy evolution, cosmology, Milky Way, and the Solar System

2019 ◽  
Vol 36 ◽  
Author(s):  
Yun Wang ◽  
Massimo Robberto ◽  
Mark Dickinson ◽  
Lynne A. Hillenbrand ◽  
Wesley Fraser ◽  
...  
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Solar System ◽  
Galaxy Evolution ◽  
Milky Way ◽  
Space Mission ◽  
Field Of View ◽  
Wide Field ◽  
Large Area

AbstractAstrophysics Telescope for Large Area Spectroscopy Probe is a concept for a National Aeronautics and Space Administration probe-class space mission that will achieve ground-breaking science in the fields of galaxy evolution, cosmology, Milky Way, and the Solar System. It is the follow-up space mission to Wide Field Infrared Survey Telescope (WFIRST), boosting its scientific return by obtaining deep 1–4 μm slit spectroscopy for ∼70% of all galaxies imaged by the ∼2 000 deg2WFIRST High Latitude Survey atz> 0.5. Astrophysics Telescope for Large Area Spectroscopy will measure accurate and precise redshifts for ∼200 M galaxies out toz< 7, and deliver spectra that enable a wide range of diagnostic studies of the physical properties of galaxies over most of cosmic history. Astrophysics Telescope for Large Area Spectroscopy Probe and WFIRST together will produce a 3D map of the Universe over 2 000 deg2, the definitive data sets for studying galaxy evolution, probing dark matter, dark energy and modifications of General Relativity, and quantifying the 3D structure and stellar content of the Milky Way. Astrophysics Telescope for Large Area Spectroscopy Probe science spans four broad categories: (1) Revolutionising galaxy evolution studies by tracing the relation between galaxies and dark matter from galaxy groups to cosmic voids and filaments, from the epoch of reionisation 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 characterising Kuiper Belt Objects. Astrophysics Telescope for Large Area Spectroscopy Probe is a 1.5 m telescope with a field of view of 0.4 deg2, and uses digital micro-mirror devices as slit selectors. It has a spectroscopic resolution ofR= 1 000, and a wavelength range of 1–4 μm. The lack of slit spectroscopy from space over a wide field of view is the obvious gap in current and planned future space missions; Astrophysics Telescope for Large Area Spectroscopy fills this big gap with an unprecedented spectroscopic capability based on digital micro-mirror devices (with an estimated spectroscopic multiplex factor greater than 5 000). Astrophysics Telescope for Large Area Spectroscopy is designed to fit within the National Aeronautics and Space Administration probe-class space mission cost envelope; it has a single instrument, a telescope aperture that allows for a lighter launch vehicle, and mature technology (we have identified a path for digital micro-mirror devices to reach Technology Readiness Level 6 within 2 yr). Astrophysics Telescope for Large Area Spectroscopy 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.

scholarly journals The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections*

2021 ◽  
Vol 923 (2) ◽  
pp. 217
Author(s):  
Karl Gebhardt ◽  
Erin Mentuch Cooper ◽  
Robin Ciardullo ◽  
Viviana Acquaviva ◽  
Ralf Bender ◽  
...  
Keyword(s):  
Dark Energy ◽  
Emission Line ◽  
Survey Design ◽  
Wide Field ◽  
Angular Diameter Distance ◽  
Detection Algorithms ◽  
Hubble Expansion ◽  
Flux Limit ◽  
Deep Survey ◽  
Better Than

Abstract We describe the survey design, calibration, commissioning, and emission-line detection algorithms for the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the redshifts of over a million Lyα emitting galaxies between 1.88 < z < 3.52, in a 540 deg2 area encompassing a comoving volume of 10.9 Gpc3. No preselection of targets is involved; instead the HETDEX measurements are accomplished via a spectroscopic survey using a suite of wide-field integral field units distributed over the focal plane of the telescope. This survey measures the Hubble expansion parameter and angular diameter distance, with a final expected accuracy of better than 1%. We detail the project’s observational strategy, reduction pipeline, source detection, and catalog generation, and present initial results for science verification in the Cosmological Evolution Survey, Extended Groth Strip, and Great Observatories Origins Deep Survey North fields. We demonstrate that our data reach the required specifications in throughput, astrometric accuracy, flux limit, and object detection, with the end products being a catalog of emission-line sources, their object classifications, and flux-calibrated spectra.

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