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Euclid preparation: XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography

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Euclid preparation : XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography. / Euclid Collaboration; Ilbert, O.; Amara, A.; Markovic, K.

In: Astronomy and Astrophysics, Vol. 647, A117, 01.03.2021, p. 1-21.

Research output: Contribution to journalArticlepeer-review

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Euclid Collaboration ; Ilbert, O. ; Amara, A. ; Markovic, K. / Euclid preparation : XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography. In: Astronomy and Astrophysics. 2021 ; Vol. 647. pp. 1-21.

Bibtex

@article{255bfbf4c3344e3c95f5195e30deccc0,
title = "Euclid preparation: XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography",
abstract = "The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy equation of state relies on an accurate knowledge of the galaxy mean redshift ⟨z⟩. We investigate the possibility of measuring ⟨z⟩ with an accuracy better than 0.002(1  +  z) in ten tomographic bins spanning the redshift interval 0.2  <  z  <  2.2, the requirements for the cosmic shear analysis of Euclid. We implement a sufficiently realistic simulation in order to understand the advantages and complementarity, as well as the shortcomings, of two standard approaches: the direct calibration of ⟨z⟩ with a dedicated spectroscopic sample and the combination of the photometric redshift probability distribution functions (zPDFs) of individual galaxies. We base our study on the Horizon-AGN hydrodynamical simulation, which we analyse with a standard galaxy spectral energy distribution template-fitting code. Such a procedure produces photometric redshifts with realistic biases, precisions, and failure rates. We find that the current Euclid design for direct calibration is sufficiently robust to reach the requirement on the mean redshift, provided that the purity level of the spectroscopic sample is maintained at an extremely high level of > 99.8%. The zPDF approach can also be successful if the zPDF is de-biased using a spectroscopic training sample. This approach requires deep imaging data but is weakly sensitive to spectroscopic redshift failures in the training sample. We improve the de-biasing method and confirm our finding by applying it to real-world weak-lensing datasets (COSMOS and KiDS+VIKING-450).",
keywords = "Dark energy, Galaxies: distances and redshifts, Methods: statistical",
author = "{Euclid Collaboration} and O. Ilbert and {De La Torre}, S. and N. Martinet and Wright, {A. H.} and S. Paltani and C. Laigle and I. Davidzon and E. Jullo and H. Hildebrandt and Masters, {D. C.} and A. Amara and Conselice, {C. J.} and S. Andreon and N. Auricchio and R. Azzollini and C. Baccigalupi and A. Balaguera-Antolinez and M. Baldi and A. Balestra and S. Bardelli and R. Bender and A. Biviano and C. Bodendorf and D. Bonino and S. Borgani and A. Boucaud and E. Bozzo and E. Branchini and M. Brescia and C. Burigana and R. Cabanac and S. Camera and V. Capobianco and A. Cappi and C. Carbone and J. Carretero and Carvalho, {C. S.} and S. Casas and Castander, {F. J.} and M. Castellano and G. Castignani and S. Cavuoti and A. Cimatti and R. Cledassou and C. Colodro-Conde and G. Congedo and L. Conversi and Y. Copin and L. Corcione and K. Markovic",
year = "2021",
month = mar,
day = "1",
doi = "10.1051/0004-6361/202040237",
language = "English",
volume = "647",
pages = "1--21",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

RIS

TY - JOUR

T1 - Euclid preparation

T2 - XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography

AU - Euclid Collaboration

AU - Ilbert, O.

AU - De La Torre, S.

AU - Martinet, N.

AU - Wright, A. H.

AU - Paltani, S.

AU - Laigle, C.

AU - Davidzon, I.

AU - Jullo, E.

AU - Hildebrandt, H.

AU - Masters, D. C.

AU - Amara, A.

AU - Conselice, C. J.

AU - Andreon, S.

AU - Auricchio, N.

AU - Azzollini, R.

AU - Baccigalupi, C.

AU - Balaguera-Antolinez, A.

AU - Baldi, M.

AU - Balestra, A.

AU - Bardelli, S.

AU - Bender, R.

AU - Biviano, A.

AU - Bodendorf, C.

AU - Bonino, D.

AU - Borgani, S.

AU - Boucaud, A.

AU - Bozzo, E.

AU - Branchini, E.

AU - Brescia, M.

AU - Burigana, C.

AU - Cabanac, R.

AU - Camera, S.

AU - Capobianco, V.

AU - Cappi, A.

AU - Carbone, C.

AU - Carretero, J.

AU - Carvalho, C. S.

AU - Casas, S.

AU - Castander, F. J.

AU - Castellano, M.

AU - Castignani, G.

AU - Cavuoti, S.

AU - Cimatti, A.

AU - Cledassou, R.

AU - Colodro-Conde, C.

AU - Congedo, G.

AU - Conversi, L.

AU - Copin, Y.

AU - Corcione, L.

AU - Markovic, K.

PY - 2021/3/1

Y1 - 2021/3/1

N2 - The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy equation of state relies on an accurate knowledge of the galaxy mean redshift ⟨z⟩. We investigate the possibility of measuring ⟨z⟩ with an accuracy better than 0.002(1  +  z) in ten tomographic bins spanning the redshift interval 0.2  <  z  <  2.2, the requirements for the cosmic shear analysis of Euclid. We implement a sufficiently realistic simulation in order to understand the advantages and complementarity, as well as the shortcomings, of two standard approaches: the direct calibration of ⟨z⟩ with a dedicated spectroscopic sample and the combination of the photometric redshift probability distribution functions (zPDFs) of individual galaxies. We base our study on the Horizon-AGN hydrodynamical simulation, which we analyse with a standard galaxy spectral energy distribution template-fitting code. Such a procedure produces photometric redshifts with realistic biases, precisions, and failure rates. We find that the current Euclid design for direct calibration is sufficiently robust to reach the requirement on the mean redshift, provided that the purity level of the spectroscopic sample is maintained at an extremely high level of > 99.8%. The zPDF approach can also be successful if the zPDF is de-biased using a spectroscopic training sample. This approach requires deep imaging data but is weakly sensitive to spectroscopic redshift failures in the training sample. We improve the de-biasing method and confirm our finding by applying it to real-world weak-lensing datasets (COSMOS and KiDS+VIKING-450).

AB - The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy equation of state relies on an accurate knowledge of the galaxy mean redshift ⟨z⟩. We investigate the possibility of measuring ⟨z⟩ with an accuracy better than 0.002(1  +  z) in ten tomographic bins spanning the redshift interval 0.2  <  z  <  2.2, the requirements for the cosmic shear analysis of Euclid. We implement a sufficiently realistic simulation in order to understand the advantages and complementarity, as well as the shortcomings, of two standard approaches: the direct calibration of ⟨z⟩ with a dedicated spectroscopic sample and the combination of the photometric redshift probability distribution functions (zPDFs) of individual galaxies. We base our study on the Horizon-AGN hydrodynamical simulation, which we analyse with a standard galaxy spectral energy distribution template-fitting code. Such a procedure produces photometric redshifts with realistic biases, precisions, and failure rates. We find that the current Euclid design for direct calibration is sufficiently robust to reach the requirement on the mean redshift, provided that the purity level of the spectroscopic sample is maintained at an extremely high level of > 99.8%. The zPDF approach can also be successful if the zPDF is de-biased using a spectroscopic training sample. This approach requires deep imaging data but is weakly sensitive to spectroscopic redshift failures in the training sample. We improve the de-biasing method and confirm our finding by applying it to real-world weak-lensing datasets (COSMOS and KiDS+VIKING-450).

KW - Dark energy

KW - Galaxies: distances and redshifts

KW - Methods: statistical

UR - http://www.scopus.com/inward/record.url?scp=85103132302&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/202040237

DO - 10.1051/0004-6361/202040237

M3 - Article

AN - SCOPUS:85103132302

VL - 647

SP - 1

EP - 21

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A117

ER -

ID: 27056469