Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Extinction Towards the GRB970228 Field   We determine the local galactic extinction towards the field of gamma-ray
burst GRB970228 using a variety of methods. We develop a maximum likelihood
method for measuring the extinction by comparing galaxy counts in the field of
interest to those in a field of known extinction, and apply this method to the
GRB970228 field. We also measure the extinction by comparing the observed
stellar spectral energy distributions of stars in the GRB970228 field to the
spectral energy distribution of library spectra of the same spectral type.
Finally we estimate the extinction using the Balmer emission line ratios of a
galaxy in the GRB970228 field, and the neutral hydrogen column density and
amount of infrared dust emission toward this field. Combining the results of
these methods, we find a best-fit galactic extinction in the optical of
$A_V=1.19^{+0.10}_{-0.17}$, which implies a a substantial dimming and change of
the spectral slope of the intrinsic GRB970228 afterglow.

3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org