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The Dark Energy Survey supernova program: cosmological analysis and systematic uncertainties

The Dark Energy Survey supernova program: cosmological analysis and systematic uncertainties
The Dark Energy Survey supernova program: cosmological analysis and systematic uncertainties
We present the full Hubble diagram of photometrically-classified Type Ia supernovae (SNe Ia) from the Dark Energy Survey supernova program (DES-SN). DES-SN discovered more than 20,000 SN candidates and obtained spectroscopic redshifts of 7,000 host galaxies. Based on the light-curve quality, we select 1635 photometrically-identified SNe Ia with spectroscopic redshift 0.10$< z 0.5$ supernovae by a factor of five. In a companion paper, we present cosmological results of the DES-SN sample combined with 194 spectroscopically-classified SNe Ia at low redshift as an anchor for cosmological fits. Here we present extensive modeling of this combined sample and validate the entire analysis pipeline used to derive distances. We show that the statistical and systematic uncertainties on cosmological parameters are $\sigma_{\Omega_M,{\rm stat+sys}}^{\Lambda{\rm CDM}}=$0.017 in a flat $\Lambda$CDM model, and $(\sigma_{\Omega_M},\sigma_w)_{\rm stat+sys}^{w{\rm CDM}}=$(0.082, 0.152) in a flat $w$CDM model. Combining the DES SN data with the highly complementary CMB measurements by Planck Collaboration (2020) reduces uncertainties on cosmological parameters by a factor of 4. In all cases, statistical uncertainties dominate over systematics. We show that uncertainties due to photometric classification make up less than 10% of the total systematic uncertainty budget. This result sets the stage for the next generation of SN cosmology surveys such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time.
astro-ph.CO
Vincenzi, M.
a15a3563-56f2-4692-b192-36b745e67d0b
Brout, D.
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Armstrong, P.
3a76ed23-d82e-439a-a1ff-ee299ed953de
Kelsey, L.
e468815b-9246-4e0f-a6d5-b037765590e4
Smith, M.
8bdc74e1-a37b-434d-ae75-82763109bf7a
Sullivan, M.
2f31f9fa-8e79-4b35-98e2-0cb38f503850
Wiseman, P.
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Frohmaier, C.
e752dabb-bbdc-430d-ac86-861ea58d0e1b
Toy, M.
5ef48181-2bd7-4207-9215-9764f4184aba
et al.
Vincenzi, M.
a15a3563-56f2-4692-b192-36b745e67d0b
Brout, D.
2e6c15c6-38ee-4593-b3b6-3c3f406b4fb1
Armstrong, P.
3a76ed23-d82e-439a-a1ff-ee299ed953de
Kelsey, L.
e468815b-9246-4e0f-a6d5-b037765590e4
Smith, M.
8bdc74e1-a37b-434d-ae75-82763109bf7a
Sullivan, M.
2f31f9fa-8e79-4b35-98e2-0cb38f503850
Wiseman, P.
865f95f8-2200-46a8-bd5e-3ee30bb44072
Frohmaier, C.
e752dabb-bbdc-430d-ac86-861ea58d0e1b
Toy, M.
5ef48181-2bd7-4207-9215-9764f4184aba

[Unknown type: UNSPECIFIED]

Record type: UNSPECIFIED

Abstract

We present the full Hubble diagram of photometrically-classified Type Ia supernovae (SNe Ia) from the Dark Energy Survey supernova program (DES-SN). DES-SN discovered more than 20,000 SN candidates and obtained spectroscopic redshifts of 7,000 host galaxies. Based on the light-curve quality, we select 1635 photometrically-identified SNe Ia with spectroscopic redshift 0.10$< z 0.5$ supernovae by a factor of five. In a companion paper, we present cosmological results of the DES-SN sample combined with 194 spectroscopically-classified SNe Ia at low redshift as an anchor for cosmological fits. Here we present extensive modeling of this combined sample and validate the entire analysis pipeline used to derive distances. We show that the statistical and systematic uncertainties on cosmological parameters are $\sigma_{\Omega_M,{\rm stat+sys}}^{\Lambda{\rm CDM}}=$0.017 in a flat $\Lambda$CDM model, and $(\sigma_{\Omega_M},\sigma_w)_{\rm stat+sys}^{w{\rm CDM}}=$(0.082, 0.152) in a flat $w$CDM model. Combining the DES SN data with the highly complementary CMB measurements by Planck Collaboration (2020) reduces uncertainties on cosmological parameters by a factor of 4. In all cases, statistical uncertainties dominate over systematics. We show that uncertainties due to photometric classification make up less than 10% of the total systematic uncertainty budget. This result sets the stage for the next generation of SN cosmology surveys such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time.

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2401.02945v2 - Author's Original
Available under License Other.
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Accepted/In Press date: 5 January 2024
Additional Information: 39 pages, 19 figures; Submitted to ApJ; companion paper Dark Energy Collaboration et al. on consecutive arxiv number 2401.02929
Keywords: astro-ph.CO

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Local EPrints ID: 487413
URI: http://eprints.soton.ac.uk/id/eprint/487413
PURE UUID: 81e7c211-f6fb-47c4-b184-615144a1b023
ORCID for M. Smith: ORCID iD orcid.org/0000-0002-3321-1432
ORCID for M. Sullivan: ORCID iD orcid.org/0000-0001-9053-4820
ORCID for P. Wiseman: ORCID iD orcid.org/0000-0002-3073-1512
ORCID for C. Frohmaier: ORCID iD orcid.org/0000-0001-9553-4723

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Date deposited: 20 Feb 2024 12:47
Last modified: 18 Mar 2024 04:00

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Contributors

Author: M. Vincenzi
Author: D. Brout
Author: P. Armstrong
Author: L. Kelsey
Author: M. Smith ORCID iD
Author: M. Sullivan ORCID iD
Author: P. Wiseman ORCID iD
Author: C. Frohmaier ORCID iD
Author: M. Toy
Corporate Author: et al.

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