10 results on '"Ellie Kitanidis"'
Search Results
2. Avalon: A Benchmark for RL Generalization Using Procedurally Generated Worlds.
- Author
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Joshua Albrecht, Abraham J. Fetterman, Bryden Fogelman, Ellie Kitanidis, Bartosz Wróblewski, Nicole Seo, Michael Rosenthal, Maksis Knutins, Zack Polizzi, James Simon, and Kanjun Qiu
- Published
- 2022
3. Preliminary clustering properties of the DESI BGS bright targets using DR9 Legacy Imaging Surveys
- Author
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Pauline Zarrouk, Omar Ruiz-Macias, Shaun Cole, Peder Norberg, Carlton Baugh, David Brooks, Enrique Gaztañaga, Ellie Kitanidis, Robert Kehoe, Martin Landriau, John Moustakas, Francisco Prada, and Gregory Tarlé
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- 2021
- Full Text
- View/download PDF
4. Despite 'super-human' performance, current LLMs are unsuited for decisions about ethics and safety.
- Author
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Joshua Albrecht, Ellie Kitanidis, and Abraham J. Fetterman
- Published
- 2022
- Full Text
- View/download PDF
5. Preliminary clustering properties of the DESI BGS bright targets using DR9 Legacy Imaging Surveys
- Author
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Robert Kehoe, David Brooks, Martin Landriau, Carlton M. Baugh, Peder Norberg, Shaun Cole, Gregory Tarle, Francisco Prada, Enrique Gaztanaga, Omar Ruiz-Macias, John Moustakas, Pauline Zarrouk, Ellie Kitanidis, European Commission, Ministerio de Ciencia e Innovación (España), Science and Technology Facilities Council (UK), National Science Foundation (US), Consejo Nacional de Ciencia y Tecnología (México), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Large-scale structure of Universe ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astronomy & Astrophysics ,7. Clean energy ,01 natural sciences ,Astronomical data bases: miscellaneous ,Apparent magnitude ,0103 physical sciences ,miscellaneous [Astronomical data bases] ,observations [Cosmology] ,Cluster analysis ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Selection (genetic algorithm) ,Physics ,010308 nuclear & particles physics ,Cosmology: observations ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,3. Good health ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Dark energy ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Data release ,Astronomical and Space Sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We characterize the selection cuts and clustering properties of a magnitude-limited sample of bright galaxies that is part of the Bright Galaxy Survey (BGS) of the Dark Energy Spectroscopic Instrument (DESI) using the ninth data release of the Legacy Imaging Surveys (DR9). We describe changes in the DR9 selection compared to the DR8 one and we also compare the DR9 selection in three distinct regions: BASS/MzLS in the north Galactic Cap (NGC), DECaLS in the NGC, and DECaLS in the south Galactic Cap (SGC). We investigate the systematics associated with the selection and assess its completeness by matching the BGS targets with the Galaxy and Mass Assembly (GAMA) survey. We measure the angular clustering for the overall bright sample (rmag ≤ 19.5) and as function of apparent magnitude and colour. This enables to determine the clustering strength r0 and slope γ by fitting a power-law model that can be used to generate accurate mock catalogues for this tracer. We use a counts-in-cells technique to explore higher order statistics and cross-correlations with external spectroscopic data sets in order to check the evolution of the clustering with redshift and the redshift distribution of the BGS targets using clustering redshifts. While this work validates the properties of the BGS bright targets, the final target selection pipeline and clustering properties of the entire DESI BGS will be fully characterized and validated with the spectroscopic data of Survey Validation. © 2021 The Author(s)., PZ, OR-M, SC, PN, and CB acknowledge support from the Science Technology Facilities Council through ST/P000541/1 andST/T000244/1. OR-M is supported by the Mexican National Council of Science and Technology (CONACyT) through grant No. 297228/440775 and funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement No 734374. JM gratefully acknowledges support from the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DESC0020086 and from the National Science Foundation under grant AST-1616414. Authors want to thank the GAMA collaboration for early access to GAMA DR4 data for this work. Some of the results in this paper have been derived using the healpy and HEALPIX package. We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).This work also made extensive use of the NASA Astrophysics Data System and of the astro-ph preprint archive at arXiv.org. This work used the DiRAC@Durham facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K00042X/1, ST/P002293/1, and ST/R002371/1, Durham University and STFC operations grant ST/R000832/1. DiRAC is part of the National e-Infrastructure. This research used resources of the National Energy Research Scientific Computing Center (NERSC). NERSC is a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under Contract No. DE-AC02-05CH1123, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract; additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under Contract No. AST-0950945 to the NSF’s National Optical-Infrared Astronomy Research Laboratory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico; the Ministry of Economy of Spain, and by the DESI Member Institutions. The authors are honored to be permitted to conduct astronomical research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.
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- 2021
6. Characterizing the target selection pipeline for the Dark Energy Spectroscopic Instrument Bright Galaxy Survey
- Author
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Michael Schubnell, Carlton M. Baugh, D. Lang, Francisco Prada, Peter Doel, John Moustakas, John R. Lucey, Shaun Cole, Daniel J. Eisenstein, Omar Ruiz-Macias, Peder Norberg, Enrique Gaztanaga, M. J. Wilson, Pauline Zarrouk, David H. Weinberg, Robert Kehoe, Martin Landriau, Adam D. Myers, ChangHoon Hahn, Ellie Kitanidis, Arjun Dey, Consejo Nacional de Ciencia y Tecnología (México), European Commission, Science and Technology Facilities Council (UK), Department of Energy (US), National Science Foundation (US), and Ministerio de Economía y Competitividad (España)
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Large-scale structure of Universe ,media_common.quotation_subject ,astro-ph.GA ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Surveys ,Astronomy & Astrophysics ,01 natural sciences ,7. Clean energy ,Photometry (optics) ,surveys ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,010303 astronomy & astrophysics ,Stellar density ,Astrophysics::Galaxy Astrophysics ,catalogues ,media_common ,Physics ,010308 nuclear & particles physics ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy and Astrophysics ,Catalogues ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Stars ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Dark energy ,large-scale structure of Universe ,Astronomical and Space Sciences - Abstract
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., We present the steps taken to produce a reliable and complete input galaxy catalogue for the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey (BGS) using the photometric Legacy Survey DR8 DECam. We analyse some of the main issues faced in the selection of targets for the DESI BGS, such as star–galaxy separation, contamination by fragmented stars and bright galaxies. Our pipeline utilizes a new way to select BGS galaxies using Gaia photometry and we implement geometrical and photometric masks that reduce the number of spurious objects. The resulting catalogue is cross-matched with the Galaxy And Mass Assembly (GAMA) survey to assess the completeness of the galaxy catalogue and the performance of the target selection. We also validate the clustering of the sources in our BGS catalogue by comparing with mock catalogues and the Sloan Digital Sky Survey (SDSS) data. Finally, the robustness of the BGS selection criteria is assessed by quantifying the dependence of the target galaxy density on imaging and other properties. The largest systematic correlation we find is a 7 per cent suppression of the target density in regions of high stellar density. © 2021 The Author(s)., OR-M is supported by the Mexican National Council of Science and Technology (CONACYT) through grant no. 297228/440775 and funding from the European Union’s Horizon 2020 Framework Programme under the Marie Sklodowska-Curie grant agreement no. 734374. SC, PN, PZ, CMB, and JL acknowledge support from the Science and Technology Facilities Council through ST/P000541/1 and ST/T000244/1. ADM was supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Number DE-SC0019022. JM gratefully acknowledges support from the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC002008 and from the National Science Foundation under grant AST-1616414. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under contract no. DEAC02-05CH11231. This work also made extensive use of the NASA Astrophysics Data System and of the astro-ph preprint archive at arXiv.org. Authors want to thank the GAMA Collaboration for early access to GAMA DR4 data for this work. Some of the results in this paper have been derived using the HEALPY and HEALPIX package. We acknowledge the usage of the HyperLeda data base (http://leda.univ-lyon1.fr). The Siena Galaxy Atlas was made possible by funding support from the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC002008 and from the National Science Foundation under grant AST-1616414. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work used the DiRAC@Durham facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K00042X/1, ST/P002293/1, and ST/R002371/1, Durham University, and STFC operations grant ST/R000832/1. DiRAC is part of the National e-Infrastructure. This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under contract no. DE-AC02-05CH1123, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract; additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under contract no. AST-0950945 to the NSF’s National Optical-Infrared Astronomy Research Laboratory, the Science and Technology Facilities Council of the United Kingdom, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, the French Alternative Energies and Atomic Energy Commission (CEA), the National Council of Science and Technology, Mexico, the Ministry of Economy of Spain, and by the DESI Member Institutions. The authors are honoured to be permitted to conduct astronomical research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.
- Published
- 2021
7. Cross-Correlation of Planck CMB Lensing with DESI-Like LRGs
- Author
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Martin White and Ellie Kitanidis
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Dark matter ,Cosmic microwave background ,Cosmic background radiation ,FOS: Physical sciences ,cosmic background radiation ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astronomy & Astrophysics ,01 natural sciences ,Cosmology ,symbols.namesake ,0103 physical sciences ,Planck ,010303 astronomy & astrophysics ,Physics ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Galaxy ,Redshift ,Space and Planetary Science ,astro-ph.CO ,symbols ,Dark energy ,large-scale structure of Universe ,Astronomical and Space Sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Cross-correlations between the lensing of the cosmic microwave background (CMB) and other tracers of large-scale structure provide a unique way to reconstruct the growth of dark matter, break degeneracies between cosmology and galaxy physics, and test theories of modified gravity. We detect a cross-correlation between DESI-like luminous red galaxies (LRGs) selected from DECaLS imaging and CMB lensing maps reconstructed with the Planck satellite at a significance of $S/N = 27.2$ over scales $\ell_{\rm min} = 30$, $\ell_{\rm max} = 1000$. To correct for magnification bias, we determine the slope of the LRG cumulative magnitude function at the faint limit as $s = 0.999 \pm 0.015$, and find corresponding corrections on the order of a few percent for $C^{\kappa g}_{\ell}, C^{gg}_{\ell}$ across the scales of interest. We fit the large-scale galaxy bias at the effective redshift of the cross-correlation $z_{\rm eff} \approx 0.68$ using two different bias evolution agnostic models: a HaloFit times linear bias model where the bias evolution is folded into the clustering-based estimation of the redshift kernel, and a Lagrangian perturbation theory model of the clustering evaluated at $z_{\rm eff}$. We also determine the error on the bias from uncertainty in the redshift distribution; within this error, the two methods show excellent agreement with each other and with DESI survey expectations., Comment: 18 pages, 14 figures, 6 tables; final version accepted for publication
- Published
- 2020
8. Imaging Systematics and Clustering of DESI Main Targets
- Author
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Julien Guy, Ellie Kitanidis, John Moustakas, David J. Schlegel, Francisco Prada, Martin Landriau, David J. Brooks, Gregory Tarle, Arjun Dey, Yu Feng, Benjamin A. Weaver, Martin White, Michael Levi, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Energy (US), National Energy Research Scientific Computing Center (US), National Science Foundation (US), Science and Technology Facilities Council (UK), Gordon and Betty Moore Foundation, Heising Simons Foundation, and Consejo Nacional de Ciencia y Tecnología (México)
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Large-scale structure of Universe ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astronomy & Astrophysics ,01 natural sciences ,Luminosity ,Sky brightness ,0103 physical sciences ,Cluster analysis ,010303 astronomy & astrophysics ,Stellar density ,Astrophysics::Galaxy Astrophysics ,Physics ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Quasar ,Galaxy ,13. Climate action ,Space and Planetary Science ,Magnitude (astronomy) ,Dark energy ,astro-ph.CO ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Astronomical and Space Sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We evaluate the impact of imaging systematics on the clustering of luminous red galaxies (LRG), emission-line galaxies (ELG), and quasars (QSO) targeted for the upcoming Dark Energy Spectroscopic Instrument (DESI) survey. Using Data Release 7 of the DECam Legacy Survey, we study the effects of astrophysical foregrounds, stellar contamination, differences between north galactic cap and south galactic cap measurements, and variations in imaging depth, stellar density, galactic extinction, seeing, airmass, sky brightness, and exposure time before presenting survey masks and weights to mitigate these effects. With our sanitized samples in hand, we conduct a preliminary analysis of the clustering amplitude and evolution of the DESI main targets. From measurements of the angular correlation functions, we determine power law fits r(0) = 7.78 +/- 0.26 h(-1) Mpc, gamma = 1.98 +/- 0.02 for LRGs and r(0) = 5.45 +/- 0.1 h(-1) Mpc, gamma = 1.54 +/- 0.01 for ELGs. Additionally, from the angular power spectra, we measure the linear biases and model the scale-dependent biases in the weakly non-linear regime. Both sets of clustering measurements show good agreement with survey requirements for LRGs and ELGs, attesting that these samples will enable DESI to achieve precise cosmological constraints. We also present clustering as a function of magnitude, use cross-correlations with external spectroscopy to infer dN/dz and measure clustering as a function of luminosity, and probe higher order clustering statistics through counts-in-cells moments.© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society, The authors thank Stephen Bailey, Daniel Eisenstein, Shirley Ho, Dustin Lang, Jeffrey Newman, Anand Raichoor, Ashley Ross, HeeJong Seo, Mike Wilson, Christophe Y`eche, and Pauline Zarrouk for many useful discussions. E. K. and M. W. are supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award No. DE-SC0017860. D. S., J. G., M. L., and J. M. are supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under contract no. DE-AC02-05CH11231, and by the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility under the same contract. This work also made extensive use of the NASA Astrophysics Data System and of the astro-ph preprint archive at arXiv.org. Additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under contract no. AST-0950945 to the National Optical Astronomy Observatory; the Science and Technologies Facilities Council of theUnitedKingdom; theGordon and Betty Moore Foundation; the Heising-Simons Foundation; the National Council of Science and Technology of Mexico; and by the DESI Member Institutions. The authors are honored to be permitted to conduct astronomical research on Iolkam Duag (Kitt Peak), a mountain with particular significance to the Tohono O'odham Nation.
- Published
- 2020
9. Cosmological Evolution of Long Gamma-ray Bursts and Star Formation Rate
- Author
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Ellie Kitanidis, Daniel Kocevski, and Vahé Petrosian
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Star formation ,media_common.quotation_subject ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Universe ,Cosmology ,Luminosity ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Gamma-ray burst ,Astrophysics - High Energy Astrophysical Phenomena ,Stellar evolution ,Luminosity function (astronomy) ,media_common ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Gamma-ray bursts (GRBs) by virtue of their high luminosities can be detected up to very high redshifts and therefore can be excellent probes of the early universe. This task is hampered by the fact that most of their characteristics have a broad range so that we first need to obtain an accurate description of the distribution of these characteristics, and specially, their cosmological evolution. We use a sample of about 200 \swift long GRBs with known redshift to determine the luminosity and formation rate evolutions and the general shape of the luminosity function. In contrast to most other forward fitting methods of treating this problem we use the Efron Petrosian methods which allow a non-parametric determination of above quantities. We find a relatively strong luminosity evolution, a luminosity function that can be fitted to a broken power law, and an unusually high rate of formation rate at low redshifts, a rate more than one order of magnitude higher than the star formation rate (SFR). On the other hand, our results seem to agree with the almost constant SFR in redshifts 1 to 3 and the decline above this redshift., 12 pages, six figures, accepted for publication in ApJ
- Published
- 2015
10. COSMOLOGICAL EVOLUTION OF LONG GAMMA-RAY BURSTS AND THE STAR FORMATION RATE.
- Author
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Vahé Petrosian, Ellie Kitanidis, and Daniel Kocevski
- Subjects
- *
GAMMA ray bursts , *LUMINOSITY , *REDSHIFT , *STELLAR evolution , *X-ray bursts - Abstract
Gamma-ray bursts (GRBs), by virtue of their high luminosities, can be detected up to very high redshifts and therefore can be excellent probes of the early universe. This task is hampered by the fact that most of their characteristics have a broad range, so we first need to obtain an accurate description of the distribution of these characteristics and, especially, their cosmological evolution. We use a sample of about 200 Swift long GRBs with known redshifts to determine the evolution of the luminosity, formation rate, and the general shape of the luminosity function (LF). In contrast to most other forward-fitting methods of treating this problem, we use the Efron–Petrosian methods, which allow a non-parametric determination of the above quantities. We find a relatively strong luminosity evolution, an LF that can be fitted to a broken power law, and an unusually high formation rate at low redshifts, a rate more than one order of magnitude higher than the star formation rate (SFR). On the other hand, our results seem to agree with the almost constant SFR in redshifts 1–3 and the decline above this redshift. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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