Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Black Hole Mass - Galaxy Age Relation   We present evidence that there is a significant correlation between the
fraction of a galaxy's mass that lies in its central black hole and the age of
the galaxy's stellar population. Since the absorption line indices that are
used to estimate the age are luminosity weighted, they essentially measure the
time since the last significant episode of star formation in the galaxy. The
existence of this correlation is consistent with several theories of galaxy
formation, including the currently-favoured hierarchical picture of galaxy
evolution, which predicts just such a relation between black hole mass and the
time since the last burst of merger-induced star formation. It is not
consistent with models in which the massive black hole is primordial, and hence
uncoupled from the stellar properties of the galaxy.

31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin