Stephen J. Turnbull, Michael J. Hudson, Hume A. Feldman, Malcolm Hicken, Robert P. Kirshner, Richard Watkin
Peculiar velocities are one of the only probes of very large-scale mass
density fluctuations in the nearby Universe. We present new "minimal variance"
bulk flow measurements based upon the "First Amendment" compilation of 245 Type
Ia supernovae (SNe) peculiar velocities and find a bulk flow of 249 +/- 76 km/s
in the direction l= 319 +/- 18 deg, b = 7 +/- 14 deg. The SNe bulk flow is
consistent with the expectations of \Lambda CDM. However, it is also marginally
consistent with the bulk flow of a larger compilation of non-SNe peculiar
velocities (Watkins, Feldman, & Hudson 2009). By comparing the SNe peculiar
velocities to predictions of the IRAS Point Source Catalog Redshift survey
(PSCz) galaxy density field, we find \Omega_{m}^{0.55} \sigma_{8,lin} = 0.40
+/- 0.07, which is in agreement with \Lambda CDM. However, we also show that
the PSCz density field fails to account for 150 +/- 43 km/s of the SNe bulk
motion.
View original:
http://arxiv.org/abs/1111.0631
No comments:
Post a Comment