Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: You Can't Get There From Here: Hubble Relaxation in the Local Volume   A beginning end-point for galaxy motions within the 10-Mpc Local Volume is
constructed by requiring a smooth distribution of (luminous) mass at the time
of recombination, which is shown to be equivalent to a smooth Hubble flow at
early times. It is found, by this purely kinematical method, that present
peculiar motions are too small by a factor of at least several (and largely in
the wrong direction) to have produced the observed structures within the age of
the universe. Known dynamical effects are inadequate to remove the discrepancy.
This result is different in origin from previously known ``cold flow''
problems. The simple dynamical picture often used within the Local Volume (for
instance, in deriving masses through calculation of a zero-velocity surface) is
thus called into question. The most straightforward explanation (though not the
only possible) is that there exists a large quantity of baryonic matter in this
region so far undetected, and unassociated with galaxies or groups.

2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con