96 research outputs found
The first Hubble diagram and cosmological constraints using superluminous supernovae
This paper has gone through internal review by the DES collaboration.
It has Fermilab preprint number 19-115-AE and DES
publication number 13387. We acknowledge support from EU/FP7-
ERC grant 615929. RCN would like to acknowledge support from
STFC grant ST/N000688/1 and the Faculty of Technology at the
University of Portsmouth. LG was funded by the European Unionâs
Horizon 2020 Framework Programme under the Marie SkĆodowska-
Curie grant agreement no. 839090. This work has been partially
supported by the Spanish grant PGC2018-095317-B-C21 within
the European Funds for Regional Development (FEDER). Funding
for the DES Projects has been provided by the U.S. Department
of Energy, the U.S. National Science Foundation, the Ministry
of Science and Education of Spain, the Science and Technology
Facilities Council of the United Kingdom, the Higher Education
Funding Council for England, the National Center for Supercomputing
Applications at the University of Illinois at Urbana-Champaign,
the Kavli Institute of Cosmological Physics at the University of
Chicago, the Center for Cosmology and Astro-Particle Physics at
the Ohio State University, the Mitchell Institute for Fundamental
Physics and Astronomy at Texas A&M University, Financiadora
de Estudos e Projetos, Fundacž Ëao Carlos Chagas Filho de Amparo
`a Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de
Desenvolvimento CientŽıfico e TecnolŽogico and the MinistŽerio da
CiËencia, Tecnologia e Inovacž Ëao, the Deutsche Forschungsgemeinschaft,
and the Collaborating Institutions in the Dark Energy Survey.
The Collaborating Institutions are Argonne National Laboratory, the
University of California at Santa Cruz, the University of Cambridge,
Centro de Investigaciones EnergÂŽeticas, Medioambientales y Tecnol
ÂŽogicas-Madrid, the University of Chicago, University College
London, the DES-Brazil Consortium, the University of Edinburgh,
the Eidgenšossische Technische Hochschule (ETH) Zšurich, Fermi
NationalAccelerator Laboratory, theUniversity of Illinois atUrbana-
Champaign, the Institut de Ci`encies de lâEspai (IEEC/CSIC), the
Institut de FŽısica dâAltes Energies, Lawrence Berkeley National
Laboratory, the Ludwig-Maximilians Universitšat Mšunchen and the
associated Excellence Cluster Universe, the University of Michigan,
the National Optical Astronomy Observatory, the University of
Nottingham, The Ohio State University, the University of Pennsylvania,
the University of Portsmouth, SLAC National Accelerator
Laboratory, Stanford University, the University of Sussex, Texas
A&M University, and the OzDES Membership Consortium. Based
in part on observations at Cerro Tololo Inter-American Observatory,
National Optical Astronomy Observatory, which is operated by the
Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
The DES data management system is supported by the
National Science Foundation under grant numbers AST-1138766
and AST-1536171. The DES participants from Spanish institutions
are partially supported by MINECO under grants AYA2015-
71825, ESP2015-66861, FPA2015-68048, 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 Seventh Framework Programme
(FP7/2007-2013) including ERC grant agreements 240672, 291329,
and 306478.We acknowledge support from the Australian Research
Council Centre of Excellence for All-skyAstrophysics (CAASTRO),
through project number CE110001020, and the Brazilian Instituto
Nacional de CiËencia e Tecnologia (INCT) e-Universe (CNPq grant
465376/2014-2).
This paper has been authored by Fermi Research Alliance, LLC
under Contract No.DE-AC02-07CH11359 with theU.S.Department
of Energy, Office of Science, Office of High Energy Physics. The
United States Government retains and the publisher, by accepting
the paper for publication, acknowledges that the United States
Government retains a non-exclusive, paid-up, irrevocable, worldwide
license to publish or reproduce the published form of this paper,
or allow others to do so, for United States Government purposes.We present the first Hubble diagram of superluminous supernovae (SLSNe) out to a redshift of two, together with constraints
on the matter density, M, and the dark energy equation-of-state parameter, w(âĄp/Ï). We build a sample of 20 cosmologically
useful SLSNe I based on light curve and spectroscopy quality cuts. We confirm the robustness of the peakâdecline SLSN I
standardization relation with a larger data set and improved fitting techniques than previous works. We then solve the SLSN
model based on the above standardization via minimization of the Ï2 computed from a covariance matrix that includes statistical
and systematic uncertainties. For a spatially flat cold dark matter ( CDM) cosmological model, we find M = 0.38+0.24
â0.19,
with an rms of 0.27 mag for the residuals of the distance moduli. For a w0waCDM cosmological model, the addition of SLSNe I
to a âbaselineâ measurement consisting of Planck temperature together with Type Ia supernovae, results in a small improvement
in the constraints of w0 and wa of 4 per cent.We present simulations of future surveys with 868 and 492 SLSNe I (depending on
the configuration used) and show that such a sample can deliver cosmological constraints in a flat CDM model with the same
precision (considering only statistical uncertainties) as current surveys that use Type Ia supernovae, while providing a factor of
2â3 improvement in the precision of the constraints on the time variation of dark energy, w0 and wa. This paper represents the
proof of concept for superluminous supernova cosmology, and demonstrates they can provide an independent test of cosmology
in the high-redshift (z > 1) universe.EU/FP7-ERC grant 615929STFC grant ST/N000688/1Faculty of Technology at the
University of PortsmouthEuropean Unionâs
Horizon 2020 Framework Programme under the Marie SkĆodowska-
Curie grant agreement no. 839090Spanish grant PGC2018-095317-B-C21 within
the European Funds for Regional Development (FEDER)U.S. Department
of EnergyU.S. National Science FoundationMinistry
of Science and Education of SpainScience and Technology
Facilities Council of the United KingdomHigher Education
Funding Council for EnglandNational Center for Supercomputing
Applications at the University of Illinois at Urbana-Champaign,Kavli Institute of Cosmological Physics at the University of
ChicagoCenter for Cosmology and Astro-Particle Physics at
the Ohio State UniversityMitchell Institute for Fundamental
Physics and Astronomy at Texas A&M University, Financiadora
de Estudos e Projetos, FundacĂŁo Carlos Chagas Filho de Amparo
`a Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de
Desenvolvimento CientĂfico e TecnolĂłgico and the MinistĂ©rio da
Ciencia, Tecnologia e InovacĂŁoDeutsche ForschungsgemeinschaftCollaborating Institutions in the Dark Energy Survey.National Science Foundation under grant numbers AST-1138766
and AST-1536171.T MINECO under grants AYA2015-
71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-
2016-0597, and MDM-2015-0509, some of which include ERDF
funds from the European Union.CERCA program of the Generalitat de Catalunya.European Research
Council under the European Union Seventh Framework Programme
(FP7/2007-2013) including ERC grant agreements 240672, 291329,
and 306478.Australian Research
Council Centre of Excellence for All-skyAstrophysics (CAASTRO),
through project number CE110001020Brazilian Instituto
Nacional de CiËencia e Tecnologia (INCT) e-Universe (CNPq grant
465376/2014-2)Fermi Research Alliance, LLC
under Contract No.DE-AC02-07CH11359 with theU.S.Department
of Energy, Office of Science, Office of High Energy Physic
DES Y3 + KiDS-1000: Consistent cosmology combining cosmic shear surveys
We present a joint cosmic shear analysis of the Dark Energy Survey (DES Y3)
and the Kilo-Degree Survey (KiDS-1000) in a collaborative effort between the
two survey teams. We find consistent cosmological parameter constraints between
DES Y3 and KiDS-1000 which, when combined in a joint-survey analysis, constrain
the parameter with a mean value of
. The mean marginal is lower than the maximum a
posteriori estimate, , owing to skewness in the marginal
distribution and projection effects in the multi-dimensional parameter space.
Our results are consistent with constraints from observations of the
cosmic microwave background by Planck, with agreement at the level.
We use a Hybrid analysis pipeline, defined from a mock survey study quantifying
the impact of the different analysis choices originally adopted by each survey
team. We review intrinsic alignment models, baryon feedback mitigation
strategies, priors, samplers and models of the non-linear matter power
spectrum.Comment: 38 pages, 21 figures, 15 tables, submitted to the Open Journal of
Astrophysics. Watch the core team discuss this analysis at
https://cosmologytalks.com/2023/05/26/des-kid
The first Hubble diagram and cosmological constraints using superluminous supernovae
We present the first Hubble diagram of superluminous supernovae (SLSNe) out to a redshift of two, together with constraints on the matter density, ΩM, and the dark energy equation-of-state parameter, w(âĄp/Ï). We build a sample of 20 cosmologically useful SLSNe I based on light curve and spectroscopy quality cuts. We confirm the robustness of the peakâdecline SLSN I standardization relation with a larger data set and improved fitting techniques than previous works. We then solve the SLSN model based on the above standardization via minimization of the Ï2 computed from a covariance matrix that includes statistical and systematic uncertainties. For a spatially flat Î cold dark matter (ÎCDM) cosmological model, we find ΩM=0.38+0.24â0.19â , with an rms of 0.27 mag for the residuals of the distance moduli. For a w0waCDM cosmological model, the addition of SLSNe I to a âbaselineâ measurement consisting of Planck temperature together with Type Ia supernovae, results in a small improvement in the constraints of w0 and wa of 4 per cent. We present simulations of future surveys with 868 and 492 SLSNe I (depending on the configuration used) and show that such a sample can deliver cosmological constraints in a flat ÎCDM model with the same precision (considering only statistical uncertainties) as current surveys that use Type Ia supernovae, while providing a factor of 2â3 improvement in the precision of the constraints on the time variation of dark energy, w0 and wa. This paper represents the proof of concept for superluminous supernova cosmology, and demonstrates they can provide an independent test of cosmology in the high-redshift (z > 1) universe.</p
Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck . I. Construction of CMB lensing maps and modeling choices
Joint analyses of cross-correlations between measurements of galaxy positions, galaxy lensing, and lensing of the cosmic microwave background (CMB) offer powerful constraints on the large-scale structure of the Universe. In a forthcoming analysis, we will present cosmological constraints from the analysis of such cross-correlations measured using Year 3 data from the Dark Energy Survey (DES), and CMB data from the South Pole Telescope (SPT) and Planck. Here we present two key ingredients of this analysis: (1) an improved CMB lensing map in the SPT-SZ survey footprint and (2) the analysis methodology that will be used to extract cosmological information from the cross-correlation measurements. Relative to previous lensing maps made from the same CMB observations, we have implemented techniques to remove contamination from the thermal Sunyaev Zelâdovich effect, enabling the extraction of cosmological information from smaller angular scales of the cross-correlation measurements than in previous analyses with DES Year 1 data. We describe our model for the cross-correlations between these maps and DES data, and validate our modeling choices to demonstrate the robustness of our analysis. We then forecast the expected cosmological constraints from the galaxy survey-CMB lensing auto and cross-correlations. We find that the galaxy-CMB lensing and galaxy shear-CMB lensing correlations will on their own provide a constraint on
S
8
=
Ï
8
â
Ω
m
/
0.3
at the few percent level, providing a powerful consistency check for the DES-only constraints. We explore scenarios where external priors on shear calibration are removed, finding that the joint analysis of CMB lensing cross-correlations can provide constraints on the shear calibration amplitude at the 5% to 10% level
Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck . II. Cross-correlation measurements and cosmological constraints
Cross-correlations of galaxy positions and galaxy shears with maps of gravitational lensing of the cosmic microwave background (CMB) are sensitive to the distribution of large-scale structure in the Universe. Such cross-correlations are also expected to be immune to some of the systematic effects that complicate correlation measurements internal to galaxy surveys. We present measurements and modeling of the cross-correlations between galaxy positions and galaxy lensing measured in the first three years of data from the Dark Energy Survey with CMB lensing maps derived from a combination of data from the
2500
â
â
deg
2
SPT-SZ survey conducted with the South Pole Telescope and full-sky data from the Planck satellite. The CMB lensing maps used in this analysis have been constructed in a way that minimizes biases from the thermal Sunyaev Zelâdovich effect, making them well suited for cross-correlation studies. The total signal-to-noise of the cross-correlation measurements is 23.9 (25.7) when using a choice of angular scales optimized for a linear (nonlinear) galaxy bias model. We use the cross-correlation measurements to obtain constraints on cosmological parameters. For our fiducial galaxy sample, which consist of four bins of magnitude-selected galaxies, we find constraints of
Ω
m
=
0.272
+
0.032
â
0.052
and
S
8
âĄ
Ï
8
â
Ω
m
/
0.3
=
0.736
+
0.032
â
0.028
(
Ω
m
=
0.245
+
0.026
â
0.044
and
S
8
=
0.734
+
0.035
â
0.028
) when assuming linear (nonlinear) galaxy bias in our modeling. Considering only the cross-correlation of galaxy shear with CMB lensing, we find
Ω
m
=
0.270
+
0.043
â
0.061
and
S
8
=
0.740
+
0.034
â
0.029
. Our constraints on
S
8
are consistent with recent cosmic shear measurements, but lower than the values preferred by primary CMB measurements from Planck
Chemical Analysis of the Brightest Star of the Cetus II Ultra-Faint Dwarf Galaxy Candidate
International audienceWe present a detailed chemical abundance analysis of the brightest star in the ultra-faint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra. For this star, DES J011740.53-173053, abundances or upper limits of 18 elements from Carbon to Europium are derived. Its chemical abundances generally follow those of other UFD galaxy stars, with a slight enhancement of the alpha-elements (Mg, Si, and Ca) and low neutron-capture element (Sr, Ba, Eu) abundances supporting the classification of Cetus II as a likely UFD. The star exhibits lower Sc, Ti, and V abundances than Milky Way (MW) halo stars with similar metallicity. This signature is consistent with yields from a supernova (SN) originating from a star with a mass of ~11.2 solar masses. In addition, the star has a Potassium abundance of [K/Fe] = 0.81 which is somewhat higher than the K abundances of MW halo stars with similar metallicity, a signature which is also present in a number of UFD galaxies. A comparison including globular clusters (GC) and stellar stream stars suggests that high K is a specific characteristic for some UFD galaxy stars and can thus be used to help classify objects as UFD galaxies
Environmental Quenching of Low Surface Brightness Galaxies near Milky Way mass Hosts
International audienceLow Surface Brightness Galaxies (LSBGs) are excellent probes of quenching and other environmental processes near massive galaxies. We study an extensive sample of LSBGs near massive hosts in the local universe that are distributed across a diverse range of environments. The LSBGs with surface-brightness 24.2 mag arcsec are drawn from the Dark Energy Survey Year 3 catalog while the hosts with masses comparable to the Milky Way and the Large Magellanic Cloud are selected from the z0MGS sample. We study the projected radial density profiles of LSBGs as a function of their color and surface brightness around hosts in both the rich Fornax-Eridanus cluster environment and the low-density field. We detect an overdensity with respect to the background density, out to 2.5 times the virial radius for both hosts in the cluster environment and the isolated field galaxies. When the LSBG sample is split by color or surface brightness , we find the LSBGs closer to their hosts are significantly redder and brighter, like their high surface-brightness counterparts. The LSBGs form a clear 'red sequence' in both the cluster and isolated environments that is visible beyond the virial radius of the hosts. This suggests a pre-processing of infalling LSBGs and a quenched backsplash population around both host samples. However, the relative prominence of the 'blue cloud' feature implies that pre-processing is ongoing near the isolated hosts compared to the cluster hosts
OzDES Reverberation Mapping Program: Mg II Lags and R-L relation
The correlation between the broad line region radius and continuum luminosity ( relation) of active galactic nuclei (AGN) is critical for single-epoch mass estimates of supermassive black holes (SMBHs). At , where AGN activity peaks, the relation is constrained by the reverberation mapping (RM) lags of the Mg II line. We present 25 Mg II lags from the Australian Dark Energy Survey (OzDES) RM project based on six years of monitoring. We define quantitative criteria to select good lag measurements and verify their reliability with simulations based on both the damped random walk stochastic model and the re-scaled, re-sampled versions of the observed lightcurves of local, well-measured AGN. Our sample significantly increases the number of Mg II lags and extends the relation to higher redshifts and luminosities. The relative iron line strength has little impact on the relation. The best-fit Mg II relation has a slope with an intrinsic scatter . The slope is consistent with previous measurements and shallower than the H relation. The intrinsic scatter of the new relation is substantially smaller than previous studies and comparable to the intrinsic scatter of the H relation. Our new relation will enable more precise single-epoch mass estimates and SMBH demographic studies at cosmic noon
OzDES Reverberation Mapping Program: Mg II Lags and R-L relation
The correlation between the broad line region radius and continuum luminosity ( relation) of active galactic nuclei (AGN) is critical for single-epoch mass estimates of supermassive black holes (SMBHs). At , where AGN activity peaks, the relation is constrained by the reverberation mapping (RM) lags of the Mg II line. We present 25 Mg II lags from the Australian Dark Energy Survey (OzDES) RM project based on six years of monitoring. We define quantitative criteria to select good lag measurements and verify their reliability with simulations based on both the damped random walk stochastic model and the re-scaled, re-sampled versions of the observed lightcurves of local, well-measured AGN. Our sample significantly increases the number of Mg II lags and extends the relation to higher redshifts and luminosities. The relative iron line strength has little impact on the relation. The best-fit Mg II relation has a slope with an intrinsic scatter . The slope is consistent with previous measurements and shallower than the H relation. The intrinsic scatter of the new relation is substantially smaller than previous studies and comparable to the intrinsic scatter of the H relation. Our new relation will enable more precise single-epoch mass estimates and SMBH demographic studies at cosmic noon
Dark Energy Survey Deep Field photometric redshift performance and training incompleteness assessment
International audienceContext. The determination of accurate photometric redshifts (photo-zs) in large imaging galaxy surveys is key for cosmological studies. One of the most common approaches are machine learning techniques. These methods require a spectroscopic or reference sample to train the algorithms. Attention has to be paid to the quality and properties of these samples since they are key factors in the estimation of reliable photo-zs. Aims. The goal of this work is to calculate the photo-zs for the Y3 DES Deep Fields catalogue using the DNF machine learning algorithm. Moreover, we want to develop techniques to assess the incompleteness of the training sample and metrics to study how incompleteness affects the quality of photometric redshifts. Finally, we are interested in comparing the performance obtained with respect to the EAzY template fitting approach on Y3 DES Deep Fields catalogue. Methods. We have emulated -- at brighter magnitude -- the training incompleteness with a spectroscopic sample whose redshifts are known to have a measurable view of the problem. We have used a principal component analysis to graphically assess incompleteness and to relate it with the performance parameters provided by DNF. Finally, we have applied the results about the incompleteness to the photo-z computation on Y3 DES Deep Fields with DNF and estimated its performance. Results. The photo-zs for the galaxies on DES Deep Fields have been computed with the DNF algorithm and added to the Y3 DES Deep Fields catalogue. They are available at https://des.ncsa.illinois.edu/releases/y3a2/Y3deepfields. Some techniques have been developed to evaluate the performance in the absence of "true" redshift and to assess completeness. We have studied... (Partial abstract
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