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1. Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data

Author

Chen, Angela, Huterer, Dragan, Lee, Sujeong, Ferté, Agnès, Weaverdyck, Noah, Alves, Otavio Alonso, Leonard, C. Danielle, MacCrann, Niall, Raveri, Marco, Porredon, Anna, Di Valentino, Eleonora, Muir, Jessica, Lemos, Pablo, Liddle, Andrew, Blazek, Jonathan, Campos, Andresa, Cawthon, Ross, Choi, Ami, Dodelson, Scott, Elvin-Poole, Jack, Gruen, Daniel, Ross, Ashley, Secco, Lucas F., Sevilla, Ignacio, Sheldon, Erin, Troxel, Michael A., Zuntz, Joe, Abbott, Tim, Aguena, Michel, Allam, Sahar, Annis, James, Avila, Santiago, Bertin, Emmanuel, Bhargava, Sunayana, Bridle, Sarah, Brooks, David, Rosell, Aurelio Carnero, Kind, Matias Carrasco, Carretero, Jorge, Costanzi, Matteo, Crocce, Martin, da Costa, Luiz, Pereira, Maria Elidaiana da Silva, Davis, Tamara, Doel, Peter, Eifler, Tim, Ferrero, Ismael, Fosalba, Pablo, Frieman, Josh, Garcia-Bellido, Juan, Gaztanaga, Enrique, Gerdes, David, Gruendl, Robert, Gschwend, Julia, Gutierrez, Gaston, Hinton, Samuel, Hollowood, Devon L., Honscheid, Klaus, Hoyle, Ben, James, David, Jarvis, Mike, Kuehn, Kyler, Lahav, Ofer, Maia, Marcio, Marshall, Jennifer, Menanteau, Felipe, Miquel, Ramon, Morgan, Robert, Palmese, Antonella, Paz-Chinchon, Francisco, Malagón, Andrés Plazas, Roodman, Aaron, Sanchez, Eusebio, Scarpine, Vic, Schubnell, Michael, Serrano, Santiago, Smith, Mathew, Suchyta, Eric, Tarle, Gregory, Thomas, Daniel, To, Chun-Hao, Varga, Tamas Norbert, Weller, Jochen, Wilkinson, Reese, UAM. Departamento de Física Teórica, National Science Foundation (US), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Generalitat de Catalunya, Instituto Nacional de Ciência e Tecnologia (Brasil), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DES, University of Michigan, Duke University, California Institute of Technology, Universidade Estadual Paulista (UNESP), Newcastle Unviersity, Ohio State University, University of Chicago, Institut d'Estudis Espacials de Catalunya (IEEC), Institute of Space Sciences (ICE CSIC), University of Manchester, Stanford University, University College London, Universidade de Lisboa, University of Edinburgh, Perimeter Institute for Theoretical Physics, Observatoire de Sauverny, Carnegie Mellon University, University of Wisconsin-Madison, 382 Via Pueblo Mall, Menlo Park, University of Pennsylvania, Medioambientales y Tecnológicas (CIEMAT), Brookhaven National Laboratory, NSF's National Optical-Infrared Astronomy Research Laboratory, Universidade de São Paulo (USP), LIneA, Fermi National Accelerator Laboratory, Universidad Autonoma de Madrid, Institut d'Astrophysique de Paris, University of Sussex, Instituto de Astrofisica de Canarias, Dpto. Astrofísica, University of Illinois at Urbana-Champaign, National Center for Supercomputing Applications, Barcelona Institute of Science and Technology, INAF-Osservatorio Astronomico di Trieste, Institute for Fundamental Physics of the Universe, Observatório Nacional, University of Queensland, University of Arizona, University of Oslo, Santa Cruz Institute for Particle Physics, Ludwig-Maximilians-Universität, Max Planck Institute for Extraterrestrial Physics, Ludwig-Maximilians Universität München, Center for Astrophysics | Harvard and Smithsonian, Macquarie University, Lowell Observatory, Texas AandM University, Institució Catalana de Recerca i Estudis Avançats, University of Cambridge, Peyton Hall, University of Southampton, Oak Ridge National Laboratory, University of Portsmouth, Chen, Angela, Huterer, Dragan, Lee, Sujeong, Ferté, Agnè, Weaverdyck, Noah, Alonso Alves, Otavio, Leonard, C. Danielle, Maccrann, Niall, Raveri, Marco, Porredon, Anna, Di Valentino, Eleonora, Muir, Jessica, Lemos, Pablo, Liddle, Andrew, Blazek, Jonathan, Campos, Andresa, Cawthon, Ro, Choi, Ami, Dodelson, Scott, Elvin-Poole, Jack, Gruen, Daniel, Ross, Ashley, Secco, Lucas F., Sevilla, Ignacio, Sheldon, Erin, Troxel, Michael A., Zuntz, Joe, Abbott, Tim, Aguena, Michel, Allam, Sahar, Annis, Jame, Avila, Santiago, Bertin, Emmanuel, Bhargava, Sunayana, Bridle, Sarah, Brooks, David, Carnero Rosell, Aurelio, Carrasco Kind, Matia, Carretero, Jorge, Costanzi, Matteo, Crocce, Martin, da Costa, Luiz, Elidaiana da Silva Pereira, Maria, Davis, Tamara, Doel, Peter, Eifler, Tim, Ferrero, Ismael, Fosalba, Pablo, Frieman, Josh, Garcia-Bellido, Juan, Gaztanaga, Enrique, Gerdes, David, Gruendl, Robert, Gschwend, Julia, Gutierrez, Gaston, Hinton, Samuel, Hollowood, Devon L., Honscheid, Klau, Hoyle, Ben, James, David, Jarvis, Mike, Kuehn, Kyler, Lahav, Ofer, Maia, Marcio, Marshall, Jennifer, Menanteau, Felipe, Miquel, Ramon, Morgan, Robert, Palmese, Antonella, Paz-Chinchon, Francisco, Plazas Malagón, André, Roodman, Aaron, Sanchez, Eusebio, Scarpine, Vic, Schubnell, Michael, Serrano, Santiago, Smith, Mathew, Suchyta, Eric, Tarle, Gregory, Thomas, Daniel, Chun-Hao, To, Varga, Tamas Norbert, Weller, Jochen, and Wilkinson, Reese

Subjects
matter: power spectrum, Cosmic microwave background, cosmic background radiation: polarization, Astrophysics, power spectrum, 01 natural sciences, Cosmology, hubble constant, High Energy Physics - Phenomenology (hep-ph), Scale Structure, cosmological model: parameter space, Power Spectrum, Dark energy, Astrophysics - Cosmology and Nongalactic Astrophysic, Large-scale structure of the Universe, 010303 astronomy & astrophysics, media_common, Physics, Energy, massive neutrinos, Hubble Constant, tension, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology, halo-model, statistics, dark energy: density, Dark radiation, symbols, Halo-Model, energy, Cosmology and Nongalactic Astrophysics (astro-ph.CO), media_common.quotation_subject, Dark matter, Cosmological parameters, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, dark matter: density, galaxy formation, Evolution of the Universe, symbols.namesake, scale structure, 0103 physical sciences, supernova, Galaxy formation and evolution, Self-Interactions, Massive Neutrinos, STFC, Sdss, 010308 nuclear & particles physics, RCUK, resolution, Física, self-interactions, inconsistent, Universe, cosmic background radiation: temperature, 13. Climate action, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Galaxy Formation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], sdss, Hubble's law
Abstract

Chen, A., et al. DES Collaboration, We study a phenomenological class of models where dark matter converts to dark radiation in the low redshift epoch. This class of models, dubbed DMDR, characterizes the evolution of comoving dark-matter density with two extra parameters, and may be able to help alleviate the observed discrepancies between early and late-time probes of the Universe. We investigate how the conversion affects key cosmological observables such as the cosmic microwave background (CMB) temperature and matter power spectra. Combining 3x2pt data from Year 1 of the Dark Energy Survey, Planck-2018 CMB temperature and polarization data, supernovae (SN) Type Ia data from Pantheon, and baryon acoustic oscillation (BAO) data from BOSS DR12, MGS and 6dFGS, we place new constraints on the amount of dark matter that has converted to dark radiation and the rate of this conversion. The fraction of the dark matter that has converted since the beginning of the Universe in units of the current amount of dark matter, ζ, is constrained at 68% confidence level to be, he DES data management system is supported by the National Science Foundation under Grants No. AST-1138766 and No. AST-1536171. The DES participants from Spanish institutions are partially supported by MICINN under Grants No. ESP2017-89838, No. PGC2018-094773, No. PGC2018-102021, No. SEV-2016-0588, No. SEV-2016-0597, and No. MDM-2015-0509, some of which include ERDF funds from the European Union. I. F. A. E. is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (Grant No. FP7/2007-2013) including ERC Grants Agreement No. 240672, No. 291329, and No. 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) do e-Universo (CNPq Grant No. 465376/2014-2).

Published
2021

2. Candidate periodically variable quasars from the Dark Energy Survey and the Sloan Digital Sky Survey.

Author

Chen, Yu-Ching, Liu, Xin, Liao, Wei-Ting, Holgado, A Miguel, Guo, Hengxiao, Gruendl, Robert A, Morganson, Eric, Shen, Yue, Zhang, Kaiwen, Abbott, Tim M C, Aguena, Michel, Allam, Sahar, Avila, Santiago, Bertin, Emmanuel, Bhargava, Sunayana, Brooks, David, Burke, David L, Carnero Rosell, Aurelio, Carollo, Daniela, and Carrasco Kind, Matias

Subjects
DARK energy, ASTRONOMICAL surveys, BINARY black holes, SUPERMASSIVE black holes, QUASARS, LIGHT curves
Abstract

Periodically variable quasars have been suggested as close binary supermassive black holes. We present a systematic search for periodic light curves in 625 spectroscopically confirmed quasars with a median redshift of 1.8 in a 4.6 deg2 overlapping region of the Dark Energy Survey Supernova (DES-SN) fields and the Sloan Digital Sky Survey Stripe 82 (SDSS-S82). Our sample has a unique 20-yr long multicolour (griz) light curve enabled by combining DES-SN Y6 observations with archival SDSS-S82 data. The deep imaging allows us to search for periodic light curves in less luminous quasars (down to r ∼23.5 mag) powered by less massive black holes (with masses ≳ 108.5 M ⊙) at high redshift for the first time. We find five candidates with significant (at >99.74 per cent single-frequency significance in at least two bands with a global p-value of ∼7 × 10−4–3 × 10−3 accounting for the look-elsewhere effect) periodicity with observed periods of ∼3–5 yr (i.e. 1–2 yr in rest frame) having ∼4–6 cycles spanned by the observations. If all five candidates are periodically variable quasars, this translates into a detection rate of |${\sim }0.8^{+0.5}_{-0.3}$|  per cent or |${\sim }1.1^{+0.7}_{-0.5}$| quasar per deg2. Our detection rate is 4–80 times larger than those found by previous searches using shallower surveys over larger areas. This discrepancy is likely caused by differences in the quasar populations probed and the survey data qualities. We discuss implications on the future direct detection of low-frequency gravitational waves. Continued photometric monitoring will further assess the robustness and characteristics of these candidate periodic quasars to determine their physical origins. [ABSTRACT FROM AUTHOR]

Published
2020
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3. Dark Energy Survey identification of a low-mass active galactic nucleus at redshift 0.823 from optical variability.

Author

Guo, Hengxiao, Burke, Colin J, Liu, Xin, Phadke, Kedar A, Zhang, Kaiwen, Chen, Yu-Ching, Gruendl, Robert A, Lidman, Christopher, Shen, Yue, Morganson, Eric, Aguena, Michel, Allam, Sahar, Avila, Santiago, Bertin, Emmanuel, Brooks, David, Rosell, Aurelio Carnero, Carollo, Daniela, Kind, Matias Carrasco, Costanzi, Matteo, and da Costa, Luiz N

Subjects
GALACTIC redshift, ACTIVE galactic nuclei, DARK energy, SPECTRAL energy distribution, STELLAR mass, SEYFERT galaxies
Abstract

We report the identification of a low-mass active galactic nucleus (AGN), DES J0218−0430, in a redshift z  = 0.823 galaxy in the Dark Energy Survey (DES) Supernova field. We select DES J0218−0430 as an AGN candidate by characterizing its long-term optical variability alone based on DES optical broad-band light curves spanning over 6 yr. An archival optical spectrum from the fourth phase of the Sloan Digital Sky Survey shows both broad Mg  ii and broad H β lines, confirming its nature as a broad-line AGN. Archival XMM–Newton X-ray observations suggest an intrinsic hard X-ray luminosity of |$L_{{\rm 2-12\, keV}}\approx 7.6\pm 0.4\times 10^{43}$| erg s−1, which exceeds those of the most X-ray luminous starburst galaxies, in support of an AGN driving the optical variability. Based on the broad H β from SDSS spectrum, we estimate a virial black hole (BH) mass of M • ≈ 106.43–106.72 M⊙ (with the error denoting the systematic uncertainty from different calibrations), consistent with the estimation from OzDES, making it the lowest mass AGN with redshift > 0.4 detected in optical. We estimate the host galaxy stellar mass to be M * ≈ 1010.5 ± 0.3 M⊙ based on modelling the multiwavelength spectral energy distribution. DES J0218−0430 extends the M •– M * relation observed in luminous AGNs at z  ∼ 1 to masses lower than being probed by previous work. Our work demonstrates the feasibility of using optical variability to identify low-mass AGNs at higher redshift in deeper synoptic surveys with direct implications for the upcoming Legacy Survey of Space and Time at Vera C. Rubin Observatory. [ABSTRACT FROM AUTHOR]

Published
2020
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4. Spectral variability of a sample of extreme variability quasars and implications for the Mg ii broad-line region.

Author

Yang, Qian, Shen, Yue, Chen, Yu-Ching, Liu, Xin, Annis, James, Avila, Santiago, Bertin, Emmanuel, Brooks, David, Buckley-Geer, Elizabeth, Carnero Rosell, Aurelio, Carrasco Kind, Matias, Carretero, Jorge, da Costa, Luiz, Desai, Shantanu, Thomas Diehl, H, Doel, Peter, Frieman, Josh, Garcia-Bellido, Juan, Gaztanaga, Enrique, and Gerdes, David

Subjects
QUASARS, DARK energy, OPTICAL spectroscopy, ASTRONOMICAL surveys, BLACK holes, STATISTICAL sampling
Abstract

We present new Gemini/GMOS optical spectroscopy of 16 extreme variability quasars (EVQs) that dimmed by more than 1.5 mag in the g band between the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey epochs (separated by a few years in the quasar rest frame). These EVQs are selected from quasars in the SDSS Stripe 82 region, covering a redshift range of 0.5 < z < 2.1. Nearly half of these EVQs brightened significantly (by more than 0.5 mag in the g band) in a few years after reaching their previous faintest state, and some EVQs showed rapid (non-blazar) variations of greater than 1–2 mag on time-scales of only months. To increase sample statistics, we use a supplemental sample of 33 EVQs with multi-epoch spectra from SDSS that cover the broad Mg  ii  λ2798 line. Leveraging on the large dynamic range in continuum variability between the multi-epoch spectra, we explore the associated variations in the broad Mg  ii line, whose variability properties have not been well studied before. The broad Mg  ii flux varies in the same direction as the continuum flux, albeit with a smaller amplitude, which indicates at least some portion of Mg  ii is reverberating to continuum changes. However, the full width at half-maximum (FWHM) of Mg  ii does not vary accordingly as continuum changes for most objects in the sample, in contrast to the case of the broad Balmer lines. Using the width of broad Mg  ii to estimate the black hole mass with single epoch spectra therefore introduces a luminosity-dependent bias. [ABSTRACT FROM AUTHOR]

Published
2020
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5. Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

Author

Bonnett, Christopher, Troxel, Michael, Hartley, William, Amara, Adam, Leistedt, Boris, Becker, Matthew R., Bernstein, Gary M., Bridle, Sarah Louise, Bruderer, Claudio, Busha, M. T., Carrasco Kind, Matías, Childress, Michael, Castander Serentill, Francisco Javier, Chang, Chihway, Crocce, Martin, Davis, Tamara M., Eifler, Tim, Frieman, Joshua A., Gangkofner, C., Gaztañaga, Enrique, Glazebrook, Karl, Gruen, Daniel, Kacprzak, Tomasz, King, Anthea L., Kwan, Juliana, Lahav, Ofer, Lewis, Geraint F., Lidman, Chris, Lin, H., MacCrann, Niall, Miquel, Ramon, O'Neill, C. R., Palmese, A., Peiris, Hiranya V., Refregier, Alexandre, Rozo, Eduardo, Rykoff, Eli, Sadeh, Iftach, Sánchez Alonso, Carles, Sheldon, Erin, Uddin, Syed, Wechsler, Risa H., Zuntz, J., Abbott, Timothy M. C., Abdalla, Filipe B., Allam, Sahar S., Armstrong, Robert, Banerji, M., Bauer, Anne Hollister, Benoit-Lévy, Aurélien, Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Capozzi, Diego, Carnero Rosell, Aurelio, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Dietrich, Jörg P., Doel, Peter, Fausti Neto, Angelo, Fernandez, Enrique, Flaugher, Brenna, Fosalba Vela, Pablo, Gerdes, David W., Gruendl, Robert A., Honscheid, K., Jain, Bhuvnesh, James, David J., Jarvis, Michael, Kim, A. G., Kuehn, Kyler, Kuropatkin, Nikolay P., Li, T. S., Lima, Marcos Vinicius Borges Teixeira, Maia, Marcio Antonio Geimba, March, Marisa Cristina, Marshall, Jennifer L., Martini, Paul, Melchior, Peter M., Miller, Christopher J., Neilsen, Eric H., Nichol, Robert C., Nord, Brian Dennis, Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Reil, Kevin, Romer, Anita K., Roodman, Aaron, Sako, Masao, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thaler, Jon J., Thomas, D., Vikram, Vinu, Walker, Alistair, and DES Collaboration

Subjects
Lentes gravitacionais, DATA RELEASE, SURVEY REQUIREMENTS, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, SHAPE MEASUREMENT, 01 natural sciences, Cosmology, Physics, Particles & Fields, PRECISION COSMOLOGY, LARGE-SCALE STRUCTURE, 0103 physical sciences, STAR-FORMING GALAXIES, PHOTO-Z PERFORMANCE, Deslocamento para o vermelho, Galáxias, PHOTOMETRIC REDSHIFTS, 010303 astronomy & astrophysics, Weak gravitational lensing, Astrophysics::Galaxy Astrophysics, QB, Photometric redshift, Physics, Science & Technology, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Sigma, VLT DEEP SURVEY, Redshift survey, Galaxy, Redshift, Fotometria astronômica, Physical Sciences, astro-ph.CO, Dark energy, NEURAL-NETWORKS
Abstract

We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model-or machine learning-based photometric redshift methods-ANNZ2, BPZ calibrated against BCC-Ufig simulations, SKYNET, and TPZ-are analyzed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-z's. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 +/- 0.01 over the range 0.3 < z < 1.3, we construct three tomographic bins with means of z = {0.45;0.67;1.00}. These bins each have systematic uncertainties delta z

Published
2016

6. Star/galaxy separation at faint magnitudes : application to a simulated Dark Energy Survey

Author

Soumagnac, Maayane Tamar, Abdalla, Filipe B., Lahav, Ofer, Kirk, Donnacha, Sevilla Noarbe, Ignacio, Bertin, Emmanuel, Rowe, Barnaby T. P., Annis, James T., Busha, M. T., Costa, Luiz N. da, Frieman, Joshua A., Gaztañaga, Enrique, Jarvis, Michael, Lin, H., Percival, Will J., Santiago, Basilio Xavier, Sabiu, Cristiano Giovanni, Wechsler, Risa H., Wolz, Laura, and Yanny, Brian

Subjects
Mapeamentos astronômicos, Cosmologia, Lentes gravitacionais, Scale structure of universe, Dark energy, Energia escura, Large, Surveys, Galáxias, weak [Gravitational lensing], data analysis [Methods], observations [Cosmology]
Abstract

We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper.We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information.We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SEXTRACTOR), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23.

Published
2015

7. The Dark Energy Survey Data Processing and Calibration System

Author

Mohr, Joseph J., Armstrong, Robert, Bertin, Emmanuel, Daues, Gregory E., Desai, Shantanu, Gower, Michelle, Gruendl, Robert, Hanlon, William, Kuropatkin, Nikolay, Lin, Huan, Marriner, John, Petravick, Don, Sevilla, Ignacio, Swanson, Molly, Tomashek, Todd, Tucker, Douglas, Yanny, Brian, and Collaboration, the Dark Energy Survey

Subjects
Computer science, FOS: Physical sciences, law.invention, Photometry (optics), Telescope, Photometric calibration, law, Data quality, Calibration, Dark energy, Survey data collection, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Remote sensing
Abstract

The Dark Energy Survey (DES) is a 5000 deg2 grizY survey reaching characteristic photometric depths of 24th magnitude (10 sigma) and enabling accurate photometry and morphology of objects ten times fainter than in SDSS. Preparations for DES have included building a dedicated 3 deg2 CCD camera (DECam), upgrading the existing CTIO Blanco 4m telescope and developing a new high performance computing (HPC) enabled data management system (DESDM). The DESDM system will be used for processing, calibrating and serving the DES data. The total data volumes are high (~2PB), and so considerable effort has gone into designing an automated processing and quality control system. Special purpose image detrending and photometric calibration codes have been developed to meet the data quality requirements, while survey astrometric calibration, coaddition and cataloging rely on new extensions of the AstrOmatic codes which now include tools for PSF modeling, PSF homogenization, PSF corrected model fitting cataloging and joint model fitting across multiple input images. The DESDM system has been deployed on dedicated development clusters and HPC systems in the US and Germany. An extensive program of testing with small rapid turn-around and larger campaign simulated datasets has been carried out. The system has also been tested on large real datasets, including Blanco Cosmology Survey data from the Mosaic2 camera. In Fall 2012 the DESDM system will be used for DECam commissioning, and, thereafter, the system will go into full science operations., Comment: 12 pages, submitted for publication in SPIE Proceeding 8451-12

Published
2012
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8. Crowded Cluster Cores: An Algorithm for Deblending in Dark Energy Survey Images.

Author

YUANYUAN ZHANG, MCKAY, TIMOTHY A., BERTIN, EMMANUEL, JELTEMA, TESLA, MILLER, CHRISTOPHER J., RYKOFF, ELI, and JEESEON SONG

Subjects
DARK energy, OPTICAL images, GALAXY clusters, DIGITAL image processing software, IMAGING systems in astronomy, ASTRONOMICAL photometry
Abstract

Deep optical images are often crowded with overlapping objects. This is especially tine in the cores of galaxy clusters, where images of dozens of galaxies may lie atop one another. Accurate measurements of cluster properties require deblending algorithms designed to automatically extract a list of individual objects and decide what fraction of the light in each pixel comes from each object. In this article, we introduce a new software tool called the Gradient And Interpolation based (GAIN) deblender. GAIN is used as a secondary deblender to improve the separation of overlapping objects in galaxy cluster cores in Dark Energy Survey images. It uses image intensity gradients and an interpolation technique originally developed to correct flawed digital images. This paper is dedicated to describing the algorithm of the GAIN deblender and its applications, but we additionally include modest tests of the software based on real Dark Energy Survey co-add images. GAIN helps to extract an unbiased photometry measurement for blended sources and improve detection completeness, while introducing few spurious detections. When applied to processed Dark Energy Survey data, GAIN serves as a useful quick fix when a high level of deblending is desired. [ABSTRACT FROM AUTHOR]

Published
2015
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9. Candidate periodically variable quasars from the Dark Energy Survey and the Sloan Digital Sky Survey

Author

J. Carretero, Tamara M. Davis, Matias Carrasco Kind, Samuel Hinton, M. March, S. Everett, Timothy M. C. Abbott, E. Suchyta, G. Gutierrez, H. Thomas Diehl, Luiz N. da Costa, Juan Garcia-Bellido, Marcos Lima, Yu-Ching Chen, Antonella Palmese, Xin Liu, Aurelio Carnero Rosell, Alistair R. Walker, M. Costanzi, Sunayana Bhargava, Jennifer L. Marshall, Brad E. Tucker, Kaiwen Zhang, David J. James, Michel Aguena, Ramon Miquel, Wei-Ting Liao, A. A. Plazas, A. Miguel Holgado, Felipe Menanteau, C. Lidman, Geraint F. Lewis, B. Flaugher, Gregory Tarle, Nikolay Kuropatkin, Michael Schubnell, Karl Glazebrook, Peter Doel, David J. Brooks, Hengxiao Guo, Enrique Gaztanaga, Emmanuel Bertin, Santiago Avila, Shantanu Desai, Devon L. Hollowood, Marcio A. G. Maia, Mathew Smith, D. L. Burke, Yue Shen, S. Allam, Robert A. Gruendl, E. J. Sanchez, F. Paz-Chinchón, Daniel Gruen, Daniela Carollo, Alex G. Kim, Santiago Serrano, Molly E. C. Swanson, Eric Morganson, Juan de Vicente, I. Sevilla-Noarbe, T. N. Varga, Joshua A. Frieman, Douglas Friedel, Kyler Kuehn, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DES, National Science Foundation (US), European Commission, European Research Council, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Chen, Yu-Ching, Liu, Xin, Liao, Wei-Ting, Holgado, A Miguel, Guo, Hengxiao, Gruendl, Robert A, Morganson, Eric, Shen, Yue, Zhang, Kaiwen, Abbott, Tim M C, Aguena, Michel, Allam, Sahar, Avila, Santiago, Bertin, Emmanuel, Bhargava, Sunayana, Brooks, David, Burke, David L, Rosell, Aurelio Carnero, Carollo, Daniela, Kind, Matias Carrasco, Carretero, Jorge, Costanzi, Matteo, da Costa, Luiz N, Davis, Tamara M, De Vicente, Juan, Desai, Shantanu, Diehl, H Thoma, Doel, Peter, Everett, Spencer, Flaugher, Brenna, Friedel, Dougla, Frieman, Joshua, García-Bellido, Juan, Gaztanaga, Enrique, Glazebrook, Karl, Gruen, Daniel, Gutierrez, Gaston, Hinton, Samuel R, Hollowood, Devon L, James, David J, Kim, Alex G, Kuehn, Kyler, Kuropatkin, Nikolay, Lewis, Geraint F, Lidman, Christopher, Lima, Marco, Maia, Marcio A G, March, Marisa, Marshall, Jennifer L, Menanteau, Felipe, Miquel, Ramon, Palmese, Antonella, Paz-Chinchón, Francisco, Plazas, Andrés A, Sanchez, Eusebio, Schubnell, Michael, Serrano, Santiago, Sevilla-Noarbe, Ignacio, Smith, Mathew, Suchyta, Eric, Swanson, Molly E C, Tarle, Gregory, Tucker, Brad E, Varga, Tamas Norbert, and Walker, Alistair R

Subjects
Software_OPERATINGSYSTEMS, ComputingMethodologies_SIMULATIONANDMODELING, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, black hole physics, galaxies: active, nuclei [galaxies], FOS: Physical sciences, Astrophysics, Data_CODINGANDINFORMATIONTHEORY, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 01 natural sciences, surveys, galaxies: high-redshift, quasars: general, 0103 physical sciences, Hardware_INTEGRATEDCIRCUITS, galaxies: nuclei, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, survey, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common, ONDAS GRAVITACIONAIS, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, general [quasars], 010308 nuclear & particles physics, Gravitational wave, Astronomy and Astrophysics, Quasar, ComputerSystemsOrganization_PROCESSORARCHITECTURES, Light curve, black hole physic, Redshift, Supernova, 13. Climate action, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), active [galaxies], Dark energy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], high-redshift [galaxies], Astronomical and Space Sciences
Abstract

DES Collaboration: et al., Periodically variable quasars have been suggested as close binary supermassive black holes. We present a systematic search for periodic light curves in 625 spectroscopically confirmed quasars with a median redshift of 1.8 in a 4.6 deg2 overlapping region of the Dark Energy Survey Supernova (DES-SN) fields and the Sloan Digital Sky Survey Stripe 82 (SDSS-S82). Our sample has a unique 20-yr long multicolour (griz) light curve enabled by combining DES-SN Y6 observations with archival SDSS-S82 data. The deep imaging allows us to search for periodic light curves in less luminous quasars (down to r ∼23.5 mag) powered by less massive black holes (with masses ≳ 108.5M⊙) at high redshift for the first time. We find five candidates with significant (at >99.74 per cent single-frequency significance in at least two bands with a global p-value of ∼7 × 10−4–3 × 10−3 accounting for the look-elsewhere effect) periodicity with observed periods of ∼3–5 yr (i.e. 1–2 yr in rest frame) having ∼4–6 cycles spanned by the observations. If all five candidates are periodically variable quasars, this translates into a detection rate of ∼0.8+0.5−0.3 per cent or ∼1.1+0.7−0.5 quasar per deg2. Our detection rate is 4–80 times larger than those found by previous searches using shallower surveys over larger areas. This discrepancy is likely caused by differences in the quasar populations probed and the survey data qualities. We discuss implications on the future direct detection of low-frequency gravitational waves. Continued photometric monitoring will further assess the robustness and characteristics of these candidate periodic quasars to determine their physical origins., The DES data management system is supported by the National Science Foundation under grants AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grants 240672, 291329, and 306478.

Published
2020

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