Tidal alignments as a contaminant of redshift space distortions
Identifieur interne : 000118 ( Main/Exploration ); précédent : 000117; suivant : 000119Tidal alignments as a contaminant of redshift space distortions
Auteurs : Christopher M. Hirata [États-Unis]Source :
- Monthly Notices of the Royal Astronomical Society [ 0035-8711 ] ; 2009-10-21.
English descriptors
Abstract
We investigate the effect of orientation‐dependent selection effects on galaxy clustering in redshift space. It is found that if galaxies are aligned by large‐scale tidal fields, then these selection effects give rise to a dependence of the observed galaxy density on the local tidal field, in addition to the well‐known dependences on the matter density and radial velocity gradient. This alters the galaxy power spectrum in a way that is different for Fourier modes parallel to and perpendicular to the line of sight. These tidal galaxy alignments can thus mimic redshift space distortions (RSD), and thus result in a bias in the measurement of the velocity power spectrum. If galaxy orientations are affected only by the local tidal field, then the tidal alignment effect has exactly the same scale and angular dependence as the RSDs in the linear regime, so it cannot be projected out or removed by masking small scales in the analysis. We consider several toy models of tidal alignments and orientation‐dependent selection, normalize their free parameter (an amplitude) to recent observations, and find that they could bias the velocity amplitude f(z)G(z) by 5–10 per cent in some models, although most models give much smaller contamination. We conclude that tidal alignments may be a significant systematic error in RSD measurements that aim to test general relativity via the growth of large‐scale structure. We briefly discuss possible mitigation strategies.
Url:
DOI: 10.1111/j.1365-2966.2009.15353.x
Affiliations:
Links toward previous steps (curation, corpus...)
Le document en format XML
<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title xml:lang="en">Tidal alignments as a contaminant of redshift space distortions</title><author><name sortKey="Hirata, Christopher M" sort="Hirata, Christopher M" uniqKey="Hirata C" first="Christopher M." last="Hirata">Christopher M. Hirata</name></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:2418AC2B104971E8F0CA7C8887BC61B2D483C880</idno><date when="2009" year="2009">2009</date><idno type="doi">10.1111/j.1365-2966.2009.15353.x</idno><idno type="url">https://api.istex.fr/document/2418AC2B104971E8F0CA7C8887BC61B2D483C880/fulltext/pdf</idno><idno type="wicri:Area/Main/Corpus">000138</idno><idno type="wicri:Area/Main/Curation">000138</idno><idno type="wicri:Area/Main/Exploration">000118</idno><idno type="wicri:explorRef" wicri:stream="Main" wicri:step="Exploration">000118</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a" type="main" xml:lang="en">Tidal alignments as a contaminant of redshift space distortions</title><author><name sortKey="Hirata, Christopher M" sort="Hirata, Christopher M" uniqKey="Hirata C" first="Christopher M." last="Hirata">Christopher M. Hirata</name><affiliation wicri:level="1"><country xml:lang="fr">États-Unis</country><wicri:regionArea>Caltech M/C 350‐17, Pasadena, California 91125</wicri:regionArea><wicri:noRegion>California 91125</wicri:noRegion></affiliation></author></analytic><monogr></monogr><series><title level="j">Monthly Notices of the Royal Astronomical Society</title><idno type="ISSN">0035-8711</idno><idno type="eISSN">1365-2966</idno><imprint><publisher>Blackwell Publishing Ltd</publisher><pubPlace>Oxford, UK</pubPlace><date type="published" when="2009-10-21">2009-10-21</date><biblScope unit="volume">399</biblScope><biblScope unit="issue">2</biblScope><biblScope unit="page" from="1074">1074</biblScope><biblScope unit="page" to="1087">1087</biblScope></imprint><idno type="ISSN">0035-8711</idno></series><idno type="istex">2418AC2B104971E8F0CA7C8887BC61B2D483C880</idno><idno type="DOI">10.1111/j.1365-2966.2009.15353.x</idno><idno type="ArticleID">MNR15353</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0035-8711</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>cosmology: theory</term><term>large‐scale structure of Universe</term></keywords></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">We investigate the effect of orientation‐dependent selection effects on galaxy clustering in redshift space. It is found that if galaxies are aligned by large‐scale tidal fields, then these selection effects give rise to a dependence of the observed galaxy density on the local tidal field, in addition to the well‐known dependences on the matter density and radial velocity gradient. This alters the galaxy power spectrum in a way that is different for Fourier modes parallel to and perpendicular to the line of sight. These tidal galaxy alignments can thus mimic redshift space distortions (RSD), and thus result in a bias in the measurement of the velocity power spectrum. If galaxy orientations are affected only by the local tidal field, then the tidal alignment effect has exactly the same scale and angular dependence as the RSDs in the linear regime, so it cannot be projected out or removed by masking small scales in the analysis. We consider several toy models of tidal alignments and orientation‐dependent selection, normalize their free parameter (an amplitude) to recent observations, and find that they could bias the velocity amplitude f(z)G(z) by 5–10 per cent in some models, although most models give much smaller contamination. We conclude that tidal alignments may be a significant systematic error in RSD measurements that aim to test general relativity via the growth of large‐scale structure. We briefly discuss possible mitigation strategies.</div></front></TEI><affiliations><list><country><li>États-Unis</li></country></list><tree><country name="États-Unis"><noRegion><name sortKey="Hirata, Christopher M" sort="Hirata, Christopher M" uniqKey="Hirata C" first="Christopher M." last="Hirata">Christopher M. Hirata</name></noRegion></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Amerique/explor/CaltechV1/Data/Main/Exploration
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 000118 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Main/Exploration/biblio.hfd -nk 000118 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Amerique
|area= CaltechV1
|flux= Main
|étape= Exploration
|type= RBID
|clé= ISTEX:2418AC2B104971E8F0CA7C8887BC61B2D483C880
|texte= Tidal alignments as a contaminant of redshift space distortions
}}
| This area was generated with Dilib version V0.6.32. |  |