Query : 2005A&A...440..799M

2005A&A...440..799M - Astronomy and Astrophysics, volume 440, 799-808 (2005/9-4)

Tracing large-scale structure at high redshift with Lyman-α emitters: the effect of peculiar velocities.


Abstract (from CDS):

We investigate the effect of peculiar velocities on the redshift space distribution of z>2 galaxies, and we focus in particular on Lyα emitters. We generate catalogues of dark matter (DM) halos and identify emitters with halos of the same co-moving space density (M(Lyαemitters)≃3x1011M). We decompose the peculiar velocity field of halos into streaming, gradient and random components, and compute and analyse these as a function of scale. Streaming velocities are determined by fluctuations on very large scales, strongly affected by sample variance, but have a modest impact on the interpretation of observations. Gradient velocities are the most important as they distort structures in redshift space, changing the thickness and orientation of sheets and filaments. Random velocities are typically below or of the same order as the typical observational uncertainty on the redshift. We discuss the importance of these effects for the interpretation of data on the large-scale structure as traced by Lyα emitters (or similar kinds of astrophysical high-redshift objects), focusing on the induced errors in the viewing angles of filaments. We compare our predictions of velocity patterns for Lyα emitters to observations and find that redshift clumping of Lyα emitters, as reported for instance in the fields of high-redshift radio galaxies, does not allow to infer whether an observed field is sampling an early galaxy overdensity.

Abstract Copyright:

Journal keyword(s): cosmology: theory - cosmological parameters

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 QSO B1346-033 QSO 13 49 16.6595971512 -03 37 15.649009140   21.23 19.91     ~ 40 0
2 LBQS 2138-4427 QSO 21 41 59.5007724552 -44 13 25.930211268   19.17 18.20     ~ 67 1

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