[seminar] Astro Journal Club on 20 April

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm (sharp) in the
seminar room F-201 of the Physics Department. This time we will discuss
about the Sunyaev-Zel'dovich effect in galaxy clusters.

Presenter: Mario Petricevic
Paper title: Simulations of the Pairwise Kinematic Sunyaev-Zel'dovich Signal
Authors: Flender, S., Bleem, L., Finkel, H., et al.

Summary:
The pairwise kinematic Sunyaev-Zel'dovich (kSZ) signal from galaxy
clusters is a probe of their line-of-sight momenta, and thus a potentially
valuable source of cosmological information. In addition to the momenta,
the amplitude of the measured signal depends on the properties of the
intra-cluster gas and observational limitations such as errors in
determining cluster centers and redshifts. In this work we simulate the
pairwise kSZ signal of clusters at z<1, using the output from a
cosmological N-body simulation and including the properties of the
intra-cluster gas via a model that can be varied in post-processing. We
find that modifications to the gas profile due to star formation and
feedback reduce the pairwise kSZ amplitude of clusters by 50%, relative to
the naive 'gas traces mass' assumption. We further demonstrate that
offsets between the true and observer-selected centers of clusters can
reduce the overall amplitude of the pairwise kSZ signal by up to 10%,
while errors in the redshifts can lead to an almost complete suppression
of the signal at small separations. Using realistic parameters in the
model for the intra-cluster gas, we confirm that a high-significance
detection of the pairwise kSZ signal is expected from the combination of
data from current-generation, high-resolution CMB experiments and cluster
samples from optical photometric surveys such as those conducted by the
South Pole Telescope and Dark Energy Survey, respectively. Furthermore, we
forecast that future experiments such as Advanced ACTPol in conjunction
with data from the Dark Energy Spectroscopic Instrument will yield
detection significances of at least 20sigma, and up to 57sigma in an
optimistic scenario. To aid in future explorations of the kSZ signal, we
are releasing our simulated maps and halo catalog with this work; the
datasets are publicly available at
http://www.hep.anl.gov/cosmology/ksz.html.

Link to the paper: http://adsabs.harvard.edu/abs/2015arXiv151102843F

Hope to see you all on Wednesday!

Cheers,
Oskari