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The COSMOS density field: a reconstruction using both weak lensing and galaxy distributions

Amara, A.; Lilly, S.; Kovac, K.; Rhodes, J.; Massey, R.; Zamorani, G.; Carollo, C.M.; Contini, T.; Kneib, J.-P.; Le Fevre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Mignoli, M.; Pello, R.; Peng, Y.; Perez Montero, E.; Presotto, V.; Silverman, J.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Barnes, L.; Bordoloi, R.; Cappi, A.; Cimatti, A.; Coppa, G.; Koekoemoer, A.; Lopez-Sanjuan, C.; McCracken, H.J.; Moresco, M.; Nair, P.; Pozzetti, L.; Welikala, N.

The COSMOS density field: a reconstruction using both weak lensing and galaxy distributions Thumbnail


Authors

A. Amara

S. Lilly

K. Kovac

J. Rhodes

G. Zamorani

C.M. Carollo

T. Contini

J.-P. Kneib

O. Le Fevre

V. Mainieri

A. Renzini

M. Scodeggio

S. Bardelli

M. Bolzonella

A. Bongiorno

K. Caputi

O. Cucciati

S. de la Torre

L. de Ravel

P. Franzetti

B. Garilli

A. Iovino

P. Kampczyk

C. Knobel

F. Lamareille

J.-F. Le Borgne

V. Le Brun

C. Maier

M. Mignoli

R. Pello

Y. Peng

E. Perez Montero

V. Presotto

J. Silverman

M. Tanaka

L. Tasca

L. Tresse

D. Vergani

E. Zucca

L. Barnes

R. Bordoloi

A. Cappi

A. Cimatti

G. Coppa

A. Koekoemoer

C. Lopez-Sanjuan

H.J. McCracken

M. Moresco

P. Nair

L. Pozzetti

N. Welikala



Abstract

The COSMOS field has been the subject of a wide range of observations, with a number of studies focusing on reconstructing the 3D dark matter density field. Typically, these studies have focused on one given method or tracer. In this paper, we reconstruct the distribution of mass in the COSMOS field out to a redshift z= 1 by combining Hubble Space Telescope weak lensing measurements with zCOSMOS spectroscopic measurements of galaxy clustering. The distribution of galaxies traces the distribution of mass with high resolution (particularly in redshift, which is not possible with lensing), and the lensing data empirically calibrates the mass normalization (bypassing the need for theoretical models). Two steps are needed to convert a galaxy survey into a density field. The first step is to create a smooth field from the galaxy positions, which is a point field. We investigate four possible methods for this: (i) Gaussian smoothing, (ii) convolution with truncated isothermal sphere, (iii) fifth nearest neighbour smoothing and (iv) a multiscale entropy method. The second step is to rescale this density field using a bias prescription. We calculate the optimal bias scaling for each method by comparing predictions from the smoothed density field with the measured weak lensing data, on a galaxy-by-galaxy basis. In general, we find scale-independent bias for all the smoothing schemes, to a precision of 10 per cent. For the nearest neighbour smoothing case, we find the bias to be 2.51 ± 0.25. We also find evidence for a strongly evolving bias, increasing by a factor of ∼3.5 between redshifts 0 < z < 0.8. We believe this strong evolution can be explained by the fact that we use a flux limited sample to build the density field.

Citation

Amara, A., Lilly, S., Kovac, K., Rhodes, J., Massey, R., Zamorani, G., …Welikala, N. (2012). The COSMOS density field: a reconstruction using both weak lensing and galaxy distributions. Monthly Notices of the Royal Astronomical Society, 424(1), 553-563. https://doi.org/10.1111/j.1365-2966.2012.21231.x

Journal Article Type Article
Publication Date Jul 21, 2012
Deposit Date Mar 21, 2013
Publicly Available Date Mar 28, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 424
Issue 1
Pages 553-563
DOI https://doi.org/10.1111/j.1365-2966.2012.21231.x
Keywords Dark matter, Large-scale structure of Universe.

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.





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