TY - JOUR
T1 - Fingers-of-God effect of infalling satellite galaxies
AU - Hikage, Chiaki
AU - Yamamoto, Kazuhiro
N1 - Funding Information:
This work was supported by MEXT/JSPS KAKENHI Grant Numbers 24740160 and 15H05895.
Publisher Copyright:
© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2016
Y1 - 2016
N2 - Non-linear redshift-space distortion known as the Fingers-of-God (FoG) effect is a major systematic uncertainty in redshift-space distortion studies conducted to test gravity models. The FoG effect has been usually attributed to the random motion of galaxies inside their clusters. When the internal galaxy motion is not well virialized, however, the coherent infalling motion towards the cluster centre generates the FoG effect. Here, we derive an analytical model of the satellite velocity distribution due to the infall motion combined with the random motion. We show that the velocity distribution becomes far from Maxwellian when the infalling motion is dominant. We use simulated subhalo catalogues to find that the contribution of infall motion is important to massive subhaloes and that the velocity distribution has a top-hat like shape as expected from our analytic model. We also study the FoG effect due to infall motion on the redshift-space power spectrum. Using simulated mock samples of luminous red galaxies constructed from haloes and massive subhaloes in N-body simulations, we show that the redshift-space power spectra can differ from expectations when the infall motion is ignored.
AB - Non-linear redshift-space distortion known as the Fingers-of-God (FoG) effect is a major systematic uncertainty in redshift-space distortion studies conducted to test gravity models. The FoG effect has been usually attributed to the random motion of galaxies inside their clusters. When the internal galaxy motion is not well virialized, however, the coherent infalling motion towards the cluster centre generates the FoG effect. Here, we derive an analytical model of the satellite velocity distribution due to the infall motion combined with the random motion. We show that the velocity distribution becomes far from Maxwellian when the infalling motion is dominant. We use simulated subhalo catalogues to find that the contribution of infall motion is important to massive subhaloes and that the velocity distribution has a top-hat like shape as expected from our analytic model. We also study the FoG effect due to infall motion on the redshift-space power spectrum. Using simulated mock samples of luminous red galaxies constructed from haloes and massive subhaloes in N-body simulations, we show that the redshift-space power spectra can differ from expectations when the infall motion is ignored.
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U2 - 10.1093/mnrasl/slv153
DO - 10.1093/mnrasl/slv153
M3 - Article
AN - SCOPUS:85045972945
VL - 455
SP - L77-L81
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
SN - 1745-3925
IS - 1
ER -