Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: GRB 140102A: Insight into Prompt Spectral Evolution and Early Optical
  Afterglow Emission   We present and perform a detailed analysis of multi-wavelength observations
of \thisgrb, an optical bright GRB with an observed reverse shock (RS)
signature. Observations of this GRB were acquired with the BOOTES-4 robotic
telescope, the \fermi, and the \swift missions. Time-resolved spectroscopy of
the prompt emission shows that changes to the peak energy (\Ep) tracks
intensity and the low-energy spectral index seems to follow the intensity for
the first episode, whereas this tracking behavior is less clear during the
second episode. The fit to the afterglow light curves shows that the early
optical afterglow can be described with RS emission and is consistent with the
thin shell scenario of the constant ambient medium. The late time afterglow
decay is also consistent with the prediction of the external forward shock (FS)
model. We determine the properties of the shocks, Lorentz factor, magnetization
parameters, and ambient density of \thisgrb, and compare these parameters with
another 12 GRBs, consistent with having RS produced by thin shells in an
ISM-like medium. The value of the magnetization parameter ($R_{\rm B} \approx
18$) indicates a moderately magnetized baryonic dominant jet composition for
\thisgrb. We also report the host galaxy photometric observations of \thisgrb
obtained with 10.4m GTC, 3.5m CAHA, and 3.6m DOT telescopes and find the host
(photo $z$ = $2.8^{+0.7}_{-0.9}$) to be a high mass, star-forming galaxy with a
star formation rate of $20 \pm 10 \msun$ $\rm yr^{-1}$.

12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom