Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of gamma-ray lines from interstellar 60Fe by the high
  resolution spectrometer SPI   It is believed that core-collapse supernovae (CCSN), occurring at a rate
about once per century, have seeded the interstellar medium with long-lived
radioisotopes such as 60Fe (half-life 1.5 Myr), which can be detected by the
gamma rays emitted when they beta-decay. Here we report the detection of the
60Fe decay lines at 1173 keV and 1333 keV with fluxes 3.7 +/- 1.1 x 10(-5) ph
cm(-2) s(-1) per line, in spectra taken by the SPI spectrometer on board
INTEGRAL during its first year. The same analysis applied to the 1809 keV line
of 26Al yielded a line flux ratio 60Fe/26Al = 0.11 +/- 0.03. This supports the
hypothesis that there is an extra source of 26Al in addition to CCSN.

7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat