Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraints on intergalactic dust from quasar colours   Colour measurements of quasars are used to constrain the abundance and
properties of intergalactic dust and the related extinction effects on high-z
sources. For Type Ia supernovae at z = 1, we derive an upper limit on the
possible dimming from intergalactic dust of dm=0.2, ruling out the ``grey''
dust scenario as being solely responsible for the observed faintness of high-z
SNIa.

12
The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
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The categories of this paper are: stat
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex