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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The Dark Energy Survey supernova program
T2 - cosmological biases from supernova photometric classification
AU - Dark Energy Survey Collaboration
AU - Vincenzi, M.
AU - Sullivan, M.
AU - Möller, A.
AU - Armstrong, P.
AU - Bassett, B. A.
AU - Brout, D.
AU - Carollo, D.
AU - Carr, A.
AU - Davis, T. M.
AU - Frohmaier, C.
AU - Galbany, L.
AU - Glazebrook, K.
AU - Graur, O.
AU - Kelsey, L.
AU - Kessler, R.
AU - Kovacs, E.
AU - Lewis, G. F.
AU - Lidman, C.
AU - Malik, U.
AU - Nichol, R. C.
AU - Popovic, B.
AU - Sako, M.
AU - Scolnic, D.
AU - Smith, M.
AU - Taylor, G.
AU - Tucker, B. E.
AU - Wiseman, P.
AU - Aguena, M.
AU - Allam, S.
AU - Annis, J.
AU - Asorey, J.
AU - Bacon, D.
AU - Bertin, E.
AU - Brooks, D.
AU - Burke, D. L.
AU - Carnero Rosell, A.
AU - Carretero, J.
AU - Castander, F. J.
AU - Costanzi, M.
AU - da Costa, L. N.
AU - Pereira, M. E. S.
AU - De Vicente, J.
AU - Desai, S.
AU - Diehl, H. T.
AU - Doel, P.
AU - Everett, S.
AU - Ferrero, I.
AU - Flaugher, B.
AU - Fosalba, P.
AU - Frieman, J.
PY - 2023/1/31
Y1 - 2023/1/31
N2 - Cosmological analyses of samples of photometrically identified type Ia supernovae (SNe Ia) depend on understanding the effects of 'contamination' from core-collapse and peculiar SN Ia events. We employ a rigorous analysis using the photometric classifier SuperNNova on state-of-the-art simulations of SN samples to determine cosmological biases due to such 'non-Ia' contamination in the Dark Energy Survey (DES) 5-yr SN sample. Depending on the non-Ia SN models used in the SuperNNova training and testing samples, contamination ranges from 0.8 to 3.5 per cent, with a classification efficiency of 97.7-99.5 per cent. Using the Bayesian Estimation Applied to Multiple Species (BEAMS) framework and its extension BBC ('BEAMS with Bias Correction'), we produce a redshift-binned Hubble diagram marginalized over contamination and corrected for selection effects, and use it to constrain the dark energy equation-of-state, w. Assuming a flat universe with Gaussian ΩM prior of 0.311 ± 0.010, we show that biases on w are <0.008 when using SuperNNova, with systematic uncertainties associated with contamination around 10 per cent of the statistical uncertainty on w for the DES-SN sample. An alternative approach of discarding contaminants using outlier rejection techniques (e.g. Chauvenet's criterion) in place of SuperNNova leads to biases on w that are larger but still modest (0.015-0.03). Finally, we measure biases due to contamination on w0 and wa (assuming a flat universe), and find these to be <0.009 in w0 and <0.108 in wa, 5 to 10 times smaller than the statistical uncertainties for the DES-SN sample.
AB - Cosmological analyses of samples of photometrically identified type Ia supernovae (SNe Ia) depend on understanding the effects of 'contamination' from core-collapse and peculiar SN Ia events. We employ a rigorous analysis using the photometric classifier SuperNNova on state-of-the-art simulations of SN samples to determine cosmological biases due to such 'non-Ia' contamination in the Dark Energy Survey (DES) 5-yr SN sample. Depending on the non-Ia SN models used in the SuperNNova training and testing samples, contamination ranges from 0.8 to 3.5 per cent, with a classification efficiency of 97.7-99.5 per cent. Using the Bayesian Estimation Applied to Multiple Species (BEAMS) framework and its extension BBC ('BEAMS with Bias Correction'), we produce a redshift-binned Hubble diagram marginalized over contamination and corrected for selection effects, and use it to constrain the dark energy equation-of-state, w. Assuming a flat universe with Gaussian ΩM prior of 0.311 ± 0.010, we show that biases on w are <0.008 when using SuperNNova, with systematic uncertainties associated with contamination around 10 per cent of the statistical uncertainty on w for the DES-SN sample. An alternative approach of discarding contaminants using outlier rejection techniques (e.g. Chauvenet's criterion) in place of SuperNNova leads to biases on w that are larger but still modest (0.015-0.03). Finally, we measure biases due to contamination on w0 and wa (assuming a flat universe), and find these to be <0.009 in w0 and <0.108 in wa, 5 to 10 times smaller than the statistical uncertainties for the DES-SN sample.
U2 - 10.1093/mnras/stac1404
DO - 10.1093/mnras/stac1404
M3 - Journal article
VL - 518
SP - 1106
EP - 1127
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -