Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First measurement of the correlation between cosmic voids and the
  Lyman-$\alpha$ forest   We report the first detection of large-scale matter flows around cosmic voids
at a median redshift z = 2.49. Voids are identified within a tomographic map of
the large-scale matter density built from eBOSS Lyman-$\alpha$ (Lya) forests in
SDSS Stripe 82. We measure the imprint of flows around voids, known as
redshift-space distortions (RSD), with a statistical significance of 10
$\sigma$. The observed quadrupole of the void-forest cross-correlation is
described by a linear RSD model. The derived RSD parameter is $\beta = 0.52 \pm
0.05$. Our model accounts for the tomographic effect induced by the Lya data
being located along parallel quasar lines of sight. This work paves the way
towards growth-rate measurements at redshifts currently inaccessible to galaxy
surveys.

15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph