21 research outputs found

    Qrlew: Rewriting SQL into Differentially Private SQL

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    This paper introduces Qrlew, an open source library that can parse SQL queries into Relations -- an intermediate representation -- that keeps track of rich data types, value ranges, and row ownership; so that they can easily be rewritten into differentially-private equivalent and turned back into SQL queries for execution in a variety of standard data stores. With Qrlew, a data practitioner can express their data queries in standard SQL; the data owner can run the rewritten query without any technical integration and with strong privacy guarantees on the output; and the query rewriting can be operated by a privacy-expert who must be trusted by the owner, but may belong to a separate organization

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

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    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

    The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library

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    Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July–2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA—we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020–2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment

    Get PDF
    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014–2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V

    The fifteenth data release of the Sloan Digital Sky Surveys : first release of MaNGA derived quantities, data visualization tools and stellar library

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    Twenty years have passed since first light for the Sloan Digital SkySurvey (SDSS). Here, we release data taken by the fourth phase of SDSS(SDSS-IV) across its first three years of operation (July 2014-July2017). This is the third data release for SDSS-IV, and the fifteenth from SDSS (Data Release Fifteen; DR15). New data come from MaNGA - we release 4824 datacubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g. stellar and gas kinematics, emission line, andother maps) from the MaNGA Data Analysis Pipeline (DAP), and a new data visualisation and access tool we call "Marvin". The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials and examples of data use. While SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V(2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.Publisher PDFPeer reviewe

    Mesure de la position du pic d'oscillations acoustiques baryoniques dans les forêts Lyα et Lyβ des spectres des quasars du relevé eBOSS-SDSS IV

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    The propagation of the baryonic acoustic oscillations has been unprinted in the matter distribution in the Universe as a probability excess for two objets to be separated by the acoustic scale. Measuring the acoustic scale in the matter 2 point correlation function at redshift z, along and transversally to the line-of-sight, gives access to the DH(z)/rd et DM(z)/rd ratios, with DH the Hubble distance, DM the comoving angular distance and rd the acoustic horizon. We are able to trace the matter in the Universe by using the Lyman-alpha absorptions which shape the spectra of the high redshift quasars. Since each spectrum contain hundreds of absorption, this allow us to measure the acoustic scale even if the observed quasar density is low. In this thesis, I describe the analysis of about 200,000 spectra from the eBOSS-SDSS IV survey which conducts to the measurements DH(2.34)/rd = 8.86 0.29 et DM(2.34)/rd = 37.41 1.86. By combining these results with measurements of the acoustic scale at other redshifts, I obtain the strongest current constraints at low redshift on the Omega-m and Omega-Lambda Lambda-CDM parameters.La propagation des oscillations acoustiques baryoniques a laissé une empreinte dans la répartition de la matière de l’univers, visible sous la forme d’un excès de probabilité pour deux objets d’être séparés par une distance égale à l’échelle acoustique. La mesure de l’échelle acoustique dans la fonction de corrélation à deux points de la matière au redshift z, parallèlement et perpendiculairement à la ligne de visée donne accès, respectivement, aux rapports DH(z)/rd et DM(z)/rd où DH est la distance de Hubble, DM la distance angulaire comobile et rd l’horizon acoustique. On peut suivre la répartition de la matière en utilisant les absorptions Lyman-alpha visibles, sous la forme de forêts, dans les spectres des quasars à haut redshift. Puisque chaque spectre donne accès une centaine d’absorptions, cela permet de mesurer l’échelle acoustique même quand la densité de quasars observés est faible. Dans cette thèse, je décris le processus d’analyse qui, en utilisant environ 200 000 spectres de quasars du relevé eBOSS-SDSS IV, aboutit aux mesures DH(2.34)/rd = 8.86+/-0.29 et DM(2.34)/rd = 37.41+/-1.86. En combinant ces résultats avec les mesures de l’échelle acoustique à d’autres redshifts, j’obtiens la plus forte contrainte actuelle, à bas redshift, sur les paramètres Omega-m et Omega-Lambda dans le cadre du modèle Lambda-CDM

    Measuring the position of the baryonic acoustic oscillation peak with the Lyα and Lyβ forests of the eBOSS-SDSS IV quasar spectra

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    La propagation des oscillations acoustiques baryoniques a laissé une empreinte dans la répartition de la matière de l’univers, visible sous la forme d’un excès de probabilité pour deux objets d’être séparés par une distance égale à l’échelle acoustique. La mesure de l’échelle acoustique dans la fonction de corrélation à deux points de la matière au redshift z, parallèlement et perpendiculairement à la ligne de visée donne accès, respectivement, aux rapports DH(z)/rd et DM(z)/rd où DH est la distance de Hubble, DM la distance angulaire comobile et rd l’horizon acoustique. On peut suivre la répartition de la matière en utilisant les absorptions Lyman-alpha visibles, sous la forme de forêts, dans les spectres des quasars à haut redshift. Puisque chaque spectre donne accès une centaine d’absorptions, cela permet de mesurer l’échelle acoustique même quand la densité de quasars observés est faible. Dans cette thèse, je décris le processus d’analyse qui, en utilisant environ 200 000 spectres de quasars du relevé eBOSS-SDSS IV, aboutit aux mesures DH(2.34)/rd = 8.86+/-0.29 et DM(2.34)/rd = 37.41+/-1.86. En combinant ces résultats avec les mesures de l’échelle acoustique à d’autres redshifts, j’obtiens la plus forte contrainte actuelle, à bas redshift, sur les paramètres Omega-m et Omega-Lambda dans le cadre du modèle Lambda-CDM.The propagation of the baryonic acoustic oscillations has been unprinted in the matter distribution in the Universe as a probability excess for two objets to be separated by the acoustic scale. Measuring the acoustic scale in the matter 2 point correlation function at redshift z, along and transversally to the line-of-sight, gives access to the DH(z)/rd et DM(z)/rd ratios, with DH the Hubble distance, DM the comoving angular distance and rd the acoustic horizon. We are able to trace the matter in the Universe by using the Lyman-alpha absorptions which shape the spectra of the high redshift quasars. Since each spectrum contain hundreds of absorption, this allow us to measure the acoustic scale even if the observed quasar density is low. In this thesis, I describe the analysis of about 200,000 spectra from the eBOSS-SDSS IV survey which conducts to the measurements DH(2.34)/rd = 8.86 0.29 et DM(2.34)/rd = 37.41 1.86. By combining these results with measurements of the acoustic scale at other redshifts, I obtain the strongest current constraints at low redshift on the Omega-m and Omega-Lambda Lambda-CDM parameters

    The triply-ionized carbon forest from eBOSS: cosmological correlations with quasars in SDSS-IV DR14

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    International audienceWe present measurements of the cross-correlation of the triply-ionized carbon (CIV) forest with quasars using Sloan Digital Sky Survey Data Release 14. The study exploits a large sample of new quasars from the first two years of observations by the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The CIV forest is a weaker tracer of large-scale structure than the Lyα forest, but benefits from being accessible at redshifts z<2 where the quasar number density from eBOSS is high. Our data sample consists of 287,651 CIV forest quasars in the redshift range 1.4<z<3.5 and 387,315 tracer quasars with 1.2<z<3.5. We measure large-scale correlations from CIV absorption occuring in three distinct quasar rest-frame wavelength bands of the spectra referred to as the CIV forest, the SiIV forest and the Lyα forest. From the combined fit to the quasar-CIV cross-correlations for the CIV forest and the SiIV forest, the CIV redshift-space distortion parameter is βCIV=0.27 −0.14 −0.26 +0.16 +0.34 and its combination with the CIV linear transmission bias parameter is bCIV(1+βCIV)=−0.0183 −0.0014 −0.0029 +0.0013 +0.0025 (1σ and 2σ statistical errors) at the mean redshift z=2.00. Splitting the sample at z=2.2 to constrain the bias evolution with redshift yields the power-law exponent γ=0.60±0.63, indicating a significantly weaker redshift-evolution than for the Lyα forest linear transmission bias. Additionally, we demonstrate that CIV absorption has the potential to be used as a probe of baryon acoustic oscillations (BAO). While the current data set is insufficient for a detection of the BAO peak feature, the final quasar samples for redshifts 1.4<z<2.2 from eBOSS and the Dark Energy Spectroscopic Instrument (DESI) are expected to provide measurements of the isotropic BAO scale to ~7% and ~3% precision, respectively, at z1.6
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