J/A+A/686/A94 Effects of galaxy environment on merger fraction (Pearson+, 2024)
Effects of galaxy environment on merger fraction.
Pearson W.J., Santos D.J., Goto T., Huang T.-C., Kim S.J., Matsuhara H.,
Pollo A., Ho S.C.-C., Hwang H.S., Malek K., Nakagawa T., Romano M.,
Serjeant S., Suelves L., Shim H., White G.J.
<Astron. Astrophys. 686, A94 (2024)>
=2024A&A...686A..94P 2024A&A...686A..94P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Velocity dispersion
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: groups: general - galaxies: interactions -
galaxies: statistics -
Abstract:
In this work, we intend to examine how environment influences the
merger fraction, from the low density field environment to higher
density groups and clusters. We also aim to study how the properties
of a group or cluster, as well as the position of a galaxy in the
group or cluster, influences the merger fraction.
We identified galaxy groups and clusters in the North Ecliptic Pole
using a friends-of-friends algorithm and the local density. Once
identified, we determined the central galaxies, group radii, velocity
dispersions, and group masses of these groups and clusters. Merging
systems were identified with a neural network as well as visually.
With these, we examined how the merger fraction changes as the local
density changes for all galaxies as well as how the merger fraction
changes as the properties of the groups or clusters change.
We find that the merger fraction increases as local density increases
and decreases as the velocity dispersion increases, as is often found
in literature. A decrease in merger fraction as the group mass
increases is also found. We also find groups with larger radii have
higher merger fractions. The number of galaxies in a group does not
influence the merger fraction.
The decrease in merger fraction as group mass increases is a result of
the link between group mass and velocity dispersion. Hence, this
decrease of merger fraction with increasing mass is a result of the
decrease of merger fraction with velocity dispersion. The increasing
relation between group radii and merger fraction may be a result of
larger groups having smaller velocity dispersion at a larger distance
from the centre or larger groups hosting smaller, infalling groups
with more mergers. However, we do not find evidence smaller groups
having higher merger fractions.
Description:
The merger fraction in different galaxy environments are derived
within NEP, covering an area of 5.4 sq. deg., where the
multiwavelength (ultra violet to sub-mm) data (Kim et al.,
2021MNRAS.500.4078K 2021MNRAS.500.4078K, Cat. J/MNRAS/500/4078) are derived from follow-up
observations based on the AKARI's NEP survey (Kim et al.,
2012A&A...548A..29K 2012A&A...548A..29K, Cat. J/A+A/548/A29) the Hyper Suprime-Cam - NEP
survey is used (HSC-NEP; Goto et al., 2017PKAS...32..225G 2017PKAS...32..225G ; Miyazaki
et al., 2018PASJ...70S...1M 2018PASJ...70S...1M ; Oi et al., 2021MNRAS.500.5024O 2021MNRAS.500.5024O).
In this work, we study how the environment a galaxy lies in and
the physical properties of a group influence the merger fraction of
galaxies in the North Ecliptic Pole. For this, we study the normalised
local density, for group and field galaxies, and the number of
galaxies in a group, the group radius, the velocity dispersion of the
group, and mass of the group and observe how the merger fraction
changes as these properties change.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 34264 Properties of the group a galaxy is a member of
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See also:
J/A+A/661/A52 : North Ecliptic Pole merging galaxy catalogue (Pearson+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 I17 --- HSC HSC ID
19- 21 I3 --- Group [-2/212] Group number (<0 if field galaxy)
23 I1 --- is-center [0/1] If galaxy is central in group
25- 31 F7.1 --- Nfof ?=-9999 Number of friends of friends in host
group (1)
33- 53 F21.15 km/s sigma ?=-9999 Velocity dispersion of host group (1)
55- 75 F21.15 Mpc R50 ?=-9999 Radius of host group (1)
77- 97 F21.15 [Msun] logM50 ?=-9999 Mass of host group (1)
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Note (1): -9999.0 if field galaxy.
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History:
From William Pearson, william.pearson(at)ncbj.gov.pl
Acknowledgements:
W.J.P. has been supported by the Polish National Science Center
project UMO-2020/37/B/ST9/00466.
This research was conducted under the agreement on scientific
cooperation between the Polish Academy of Sciences and the Ministry of
Science and Technology in Taipei and supported by the Polish National
Science Centre grant UMO-2018/30/M/ST9/00757 and by Polish Ministry of
Science and Higher Education grant DIR/WK/2018/12.
SH acknowledges the support of The Australian Research Council Centre
of Excellence for Gravitational Wave Discovery (OzGrav) and the
Australian Research Council Centre of Excellence for All Sky
Astrophysics in 3 Dimensions (ASTRO 3D), through project number
CE17010000 and CE170100013, respectively.
HSH acknowledges the support by the National Research Foundation of
Korea (NRF) grant funded by the Korea government (MSIT) (No.
2021R1A2C1094577).
K. M. has been supported by the Polish National Science Centre project
UMO-2018/30/E/ST9/00082.
TN acknowledges the support by JSPS KAKENHI Grants Number 21H04496 and
23H05441.
M.R. acknowledges support from the Narodowe Centrum Nauki
(UMO-2020/38/E/ST9/00077) and support from the Foundation for Polish
Science (FNP) under the program START 063.2023.
H.S. acknowledges the support from the National Research Foundation of
Korea grant No.2021R1A2C4002725 and No.2022R1A4A3031306, funded by the
Korea government (MSIT).
GJW gratefully acknowledges receipt of an Emeritus Fellowship from The
Leverhulme Trust.
(End) Patricia Vannier [CDS] 19-Mar-2024