Eric H. Neilsen
A5065466786- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- CCD and CMOS Imaging Sensors
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Calibration and Measurement Techniques
- Management and Organizational Studies
- Impact of Light on Environment and Health
- Distributed and Parallel Computing Systems
- Big Data Technologies and Applications
- Dark Matter and Cosmic Phenomena
- Organizational Learning and Leadership
- History and Developments in Astronomy
- Scientific Computing and Data Management
- Infrared Target Detection Methodologies
- Radio Astronomy Observations and Technology
- Business Strategy and Innovation
Centre National de la Recherche Scientifique
2024
Aix-Marseille Université
2024
Austin Peay State University
2024
American Public University System
2024
Stanford University
2024
Oak Ridge National Laboratory
2024
Ludwig-Maximilians-Universität München
2024
Lancaster University
2024
University of Zurich
2024
Fermi National Accelerator Laboratory
2014-2023
The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of distribution luminous and nonluminous matter in universe: a photometrically astrometrically calibrated digital imaging survey π sr above about Galactic latitude 30° five broad optical bands depth g' ∼ 23 mag, spectroscopic approximately 106 brightest galaxies 105 quasars found photometric object catalog produced by survey. This paper summarizes observational parameters products SDSS serves as an...
We describe the design, construction, and performance of Sloan Digital Sky Survey Telescope located at Apache Point Observatory. The telescope is a modified two-corrector Ritchey-Chretien design which has 2.5-m, f/2.25 primary, 1.08-m secondary, Gascoigne astigmatism corrector, one pair interchangeable highly aspheric correctors near focal plane, for imaging other spectroscopy. final ratio f/5. instrumented by wide-area, multiband CCD camera fiber-fed double spectrographs. Novel features...
Abridged: We estimate the distances to ~48 million stars detected by Sloan Digital Sky Survey and map their 3D number density distribution in 100 < D 20 kpc range over 6,500 deg^2 of sky. The data show strong evidence for a Galaxy consisting an oblate halo, disk component, localized overdensities with exponential parameters (bias-corrected assumed 35% binary fraction) H_1 = 300 pc, L_1 2600 H_2 900 L_2 3600 local normalization 12%. find halo be oblate, best-fit axis ratio c/a 0.64, r^{-2.8}...
The Sloan Digital Sky Survey (SDSS) has validated and made publicly available its Second Data Release. This data release consists of 3324 deg2 five-band (ugriz) imaging with photometry for over 88 million unique objects, 367,360 spectra galaxies, quasars, stars, calibrating blank sky patches selected 2627 this area, tables measured parameters from these data. reach a depth r ≈ 22.2 (95% completeness limit point sources) are photometrically astrometrically calibrated to 2% rms 100 mas per...
This paper describes the Fourth Data Release of Sloan Digital Sky Survey (SDSS), including all survey-quality data taken through 2004 June. The release includes five-band photometric for 180 million objects selected over 6670 deg2 and 673,280 spectra galaxies, quasars, stars from 4783 those imaging using standard SDSS target selection algorithms. These numbers represent a roughly 27% increment Third Release; previous releases are included in present release. also an additional 131,840...
The Sloan Extension for Galactic Understanding and Exploration (SEGUE) Survey obtained ≈240,000 moderate-resolution (R ∼ 1800) spectra from 3900 Å to 9000 of fainter Milky Way stars (14.0 < g 20.3) a wide variety spectral types, both main-sequence evolved objects, with the goal studying kinematics populations our Galaxy its halo. are clustered in 212 regions spaced over three quarters sky. Radial velocity accuracies at 18, degrading 20. For signal-to-noise ratio >10 per resolution element,...
We present UV, optical, and NIR photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced LIGO/Virgo, binary neutron star merger GW170817. Our data set extends discovery optical at $0.47$ days $18.5$ post-merger, includes observations with Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), {\it Hubble Space Telescope} ({\it HST}). The spectral energy distribution (SED) inferred this $0.6$ is well described by blackbody model $T\approx 8300$...
This overview paper describes the legacy prospect and discovery potential of Dark Energy Survey (DES) beyond cosmological studies, illustrating it with examples from DES early data.DES is using a wide-field camera (DECam) on 4 m Blanco Telescope in Chile to image 5000 sq deg sky five filters (grizY).
We determine the number counts and z = 0-5 luminosity function for a well-defined, homogeneous sample of quasars from Sloan Digital Sky Survey (SDSS). conservatively define most uniform statistical possible, consisting 15,343 within an effective area 1622 deg2 that was derived parent 46,420 spectroscopically confirmed broad-line in 5282 imaging data SDSS Data Release 3. The extends i 15 to 19.1 at ≲ 3 20.2 ≳ agree well with results Two Degree Field QSO Redshift (2QZ) redshifts luminosities...
This paper describes the Third Data Release of Sloan Digital Sky Survey (SDSS). release, containing data taken up through 2003 June, includes imaging in five bands over 5282 deg2, photometric and astrometric catalogs 141 million objects detected these data, spectra 528,640 selected 4188 deg2. The pipelines analyzing both images spectroscopy are unchanged from those used our Second Release.
This paper describes the Fifth Data Release (DR5) of Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and represents completion SDSS-I project (whose successor, SDSS-II will continue mid-2008). It five-band photometric for 217 million objects selected over 8000 square degrees, 1,048,960 spectra galaxies, quasars, stars from 5713 degrees that imaging data. These numbers represent a roughly 20% increment those Fourth Release; previous releases are...
The Dark Energy Camera is a new imager with 22 diameter field of view mounted at the prime focus Victor M. Blanco 4 m telescope on Cerro Tololo near La Serena, Chile. camera was designed and constructed by Survey Collaboration meets or exceeds stringent requirements for wide-field supernova surveys which collaboration uses it. consists five-element optical corrector, seven filters, shutter 60 cm aperture, charge-coupled device (CCD) focal plane 250 μm thick fully depleted CCDs cooled inside...
Abstract We present the Dark Energy Camera (DECam) discovery of optical counterpart first binary neutron star merger detected through gravitational-wave emission, GW170817. Our observations commenced 10.5 hr post-merger, as soon localization region became accessible from Chile. imaged 70 deg 2 in i and z bands, covering 93% initial integrated probability, to a depth necessary identify likely counterparts (e.g., kilonova). At 11.4 post-merger we bright transient located nucleus NGC 4993 at...
We present an algorithm to photometrically calibrate wide-field optical imaging surveys, which simultaneously solves for the calibration parameters and relative stellar fluxes using overlapping observations. The decouples problem of "relative" calibrations from that "absolute" calibrations; absolute is reduced determining a few numbers entire survey. pay special attention spatial structure errors, allowing one isolate particular error modes in downstream analyses. Applying this SDSS data, we...
We present the discovery of seven quasars at z > 5.7, selected from ∼2000 deg2 multicolor imaging data Sloan Digital Sky Survey. The new have redshifts 5.79 to 6.13. Five are as part a complete flux-limited sample in SDSS northern Galactic cap; two larger photometric errors and not sample. One quasars, J1335+3533 (z = 5.93), exhibits no emission lines; 3 σ limit on rest-frame equivalent width Lyα+N V line is 5 Å. It highest redshift lineless quasar known could be gravitational lensed galaxy,...
In this Letter, we report the discovery of a new dwarf satellite to Milky Way, located at (α2000, δ2000) = (15872, 5192) in constellation Ursa Major. This object was detected as an overdensity red, resolved stars Sloan Digital Sky Survey data. The color-magnitude diagram Major looks remarkably similar that Sextans, lowest surface brightness Way companion known, but with approximately order magnitude fewer stars. Deeper follow-up imaging confirms has old and metal-poor stellar population is...
An extensive sample of M, L and T dwarfs identified in the Sloan Digital Sky Survey (SDSS) has been compiled. The 718 includes 677 new objects (629 M dwarfs, 48 dwarfs) together with 41 that have previously published. All some published ones optical spectra obtained either SDSS spectrographs or Apache Point Observatory 3.5m ARC telescope. Spectral types colors are available for all objects; approximately 35% also near-infrared magnitudes measured by 2MASS on Mauna Kea system. We use this to...
We report the discovery of eight new Milky Way companions in optical imaging data collected during first year Dark Energy Survey (DES). Each system is identified as a statistically significant over-density individual stars consistent with expected isochrone and luminosity function an old metal-poor stellar population. The objects span wide range absolute magnitudes (MV from to ), physical sizes (), heliocentric distances (). Based on low surface brightnesses, large sizes, and/or...
We present a catalog of 9316 spectroscopically confirmed white dwarfs from the Sloan Digital Sky Survey Data Release 4. have selected stars through photometric cuts and spectroscopic modeling, backed up by set visual inspections. Roughly 6000 are new discoveries, roughly doubling number dwarfs. analyze performing temperature surface gravity fits to grids pure hydrogen helium atmospheres. Among rare outliers presumed helium-core DA with estimated masses below 0.3 Msun, including two...
We describe the creation, content, and validation of Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support upcoming cosmological analyses. The GOLD set is assembled from multiple epochs DES imaging consists calibrated photometric zeropoints, object catalogs, ancillary products - e.g., maps survey depth observing conditions, star-galaxy classification, redshift estimates that are necessary for accurate wide-area catalog ~137 million objects detected coadded...
We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 square degrees with a median redshift of $0.59$. The cover main fields: Stripe 82, and an area overlapping South Pole Telescope survey region. describe our analysis process in particular measurement using independent shear pipelines, METACALIBRATION IM3SHAPE. catalogue uses Gaussian model innovative internal calibration scheme, was applied to $riz$-bands, yielding 34.8M objects. IM3SHAPE...
We present the first constraints on cosmology from Dark Energy Survey (DES), using weak lensing measurements preliminary Science Verification (SV) data. use 139 square degrees of SV data, which is less than 3% full DES survey area. Using cosmic shear 2-point over three redshift bins we find ${\ensuremath{\sigma}}_{8}({\mathrm{\ensuremath{\Omega}}}_{\mathrm{m}}/0.3{)}^{0.5}=0.81\ifmmode\pm\else\textpm\fi{}0.06$ (68% confidence), after marginalizing 7 systematics parameters and 3 other...
We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time new Dark Energy Camera (DECam) being used Survey (DES). describe our object selection, point spread function estimation and measurement procedures using two independent pipelines, im3shape ngmix, which produce 2.12 million 3.44 galaxies, respectively. detail a set null tests measurements find that they pass requirements systematic errors at level necessary science...
We describe the Dark Energy Survey (DES) photometric data set assembled from first three years of science operations to support DES Year 3 cosmology analyses, and provide usage notes aimed at broad astrophysics community. Y3 Gold improves on previous releases DES, Y1 Data Release 1 (DES DR1), presenting an expanded curated that incorporates algorithmic developments in image detrending processing, calibration, object classification. comprises nearly 5000 square degrees grizY imaging south...