Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The impact of a major cluster merger on galaxy evolution in
  MACS\,J0025.4-1225   We present results of an extensive morphological, spectroscopic, and
photometric study of the galaxy population of MACS J0025.4$-$1225 (z=0.586), a
major cluster merger with clear segregation of dark and luminous matter, to
examine the impact of mergers on galaxy evolution. Based on 436 galaxy spectra
obtained with Keck DEIMOS, we identified 212 cluster members within 4 Mpc of
the cluster centre, and classified them using three spectroscopic types; we
find 111 absorption-line, 90 emission-line (including 23 e(a) and 11 e(b)), and
6 E+A galaxies. The fraction of absorption(emission)-line galaxies is a
monotonically increasing(decreasing) function of both projected galaxy density
and radial distance to the cluster center. More importantly, the 6 observed E+A
cluster members are all located between the dark-matter peaks of the cluster
and within ~0.3Mpc radius of the X-ray flux peak, unlike the E+A galaxies in
other intermediate-redshift clusters which are usually found to avoid the core
region. In addition, we use Hubble Space Telescope imaging to classify cluster
members according to morphological type. We find the global fraction of spiral
and lenticular galaxies in MACS J0025 to be among the highest observed to date
in clusters at z>0.5. The observed E+A galaxies are found to be of lenticular
type with Sersic indices of ~2, boosting the local fraction of S0 to 70 per
cent between the dark-matter peaks. Combing the results of our analysis of the
spatial distribution, morphology, and spectroscopic features of the galaxy
population, we propose that the starburst phase of these E+A galaxies was both
initiated and terminated during the first core-passage about 0.5--1Gyr ago, and
that their morphology has already been transformed into S0 due to ram pressure
and/or tidal forces near the cluster core. By contrast, ongoing starbursts are
observed predominantly in infalling galaxies, and thus appears to be unrelated
to the cluster merger.

13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics