Chandra observations of ten galaxy clusters
In the present study the X-ray properties of 10 galaxy clusters (CL0024+17, RXJ1347.5+1145, A223, A521, A611, A697, A907, A1204, A1413 and A2744) are analysed using the archival X-ray data of the Chandra observatory. The average temperature of each cluster is estimated to be ∼ 4 − 10 keV, and the ra...
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Головна астрономічна обсерваторія НАН України
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| Цитувати: | Chandra observations of ten galaxy clusters / Iu. Babyk, O. Melnyk, A. Elyiv // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 188-190. — Бібліогр.: 9 назв. — англ. |
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Babyk, Iu. Melnyk, O. Elyiv, A. 2017-06-06T18:28:14Z 2017-06-06T18:28:14Z 2012 Chandra observations of ten galaxy clusters / Iu. Babyk, O. Melnyk, A. Elyiv // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 188-190. — Бібліогр.: 9 назв. — англ. 2227-1481 https://nasplib.isofts.kiev.ua/handle/123456789/119398 In the present study the X-ray properties of 10 galaxy clusters (CL0024+17, RXJ1347.5+1145, A223, A521, A611, A697, A907, A1204, A1413 and A2744) are analysed using the archival X-ray data of the Chandra observatory. The average temperature of each cluster is estimated to be ∼ 4 − 10 keV, and the radial temperature profiles are reconstructed. Using the Navarro-Frenk-White (NFW) density pro le of the dark matter the density and mass profiles for the dark matter and the hot diffuse gas, and also the total mass profiles are derived. The typical size of galaxy clusters and the density of the dark matter halo are estimated to be ∼ 0.1−2 Mpc and ∼ 10⁻²²−10⁻²⁴ kg/m³, respectively. The fraction of each component in the total cluster mass for the whole sample is found to be ∼ 80-90% for dark matter and ∼ 10 − 20% for intracluster gas, respectively. en Головна астрономічна обсерваторія НАН України Advances in Astronomy and Space Physics Chandra observations of ten galaxy clusters Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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Chandra observations of ten galaxy clusters |
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Chandra observations of ten galaxy clusters Babyk, Iu. Melnyk, O. Elyiv, A. |
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Chandra observations of ten galaxy clusters |
| title_full |
Chandra observations of ten galaxy clusters |
| title_fullStr |
Chandra observations of ten galaxy clusters |
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Chandra observations of ten galaxy clusters |
| title_sort |
chandra observations of ten galaxy clusters |
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Babyk, Iu. Melnyk, O. Elyiv, A. |
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Babyk, Iu. Melnyk, O. Elyiv, A. |
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2012 |
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Advances in Astronomy and Space Physics |
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Головна астрономічна обсерваторія НАН України |
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Article |
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In the present study the X-ray properties of 10 galaxy clusters (CL0024+17, RXJ1347.5+1145, A223, A521, A611, A697, A907, A1204, A1413 and A2744) are analysed using the archival X-ray data of the Chandra observatory. The average temperature of each cluster is estimated to be ∼ 4 − 10 keV, and the radial temperature profiles are reconstructed. Using the Navarro-Frenk-White (NFW) density pro le of the dark matter the density and mass
profiles for the dark matter and the hot diffuse gas, and also the total mass profiles are derived. The typical size of galaxy clusters and the density of the dark matter halo are estimated to be ∼ 0.1−2 Mpc and ∼ 10⁻²²−10⁻²⁴ kg/m³, respectively. The fraction of each component in the total cluster mass for the whole sample is found to be ∼ 80-90% for dark matter and ∼ 10 − 20% for intracluster gas, respectively.
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2227-1481 |
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https://nasplib.isofts.kiev.ua/handle/123456789/119398 |
| citation_txt |
Chandra observations of ten galaxy clusters / Iu. Babyk, O. Melnyk, A. Elyiv // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 188-190. — Бібліогр.: 9 назв. — англ. |
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AT babykiu chandraobservationsoftengalaxyclusters AT melnyko chandraobservationsoftengalaxyclusters AT elyiva chandraobservationsoftengalaxyclusters |
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2025-11-25T22:43:38Z |
| last_indexed |
2025-11-25T22:43:38Z |
| _version_ |
1850570022192152576 |
| fulltext |
Chandra observations of ten galaxy clusters
Iu. Babyk1∗, O.Melnyk2,3, A. Elyiv1,3
Advances in Astronomy and Space Physics, 2, 188-190 (2012)
© Iu. Babyk, O.Melnyk, A. Elyiv, 2012
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Zabolotnoho 27, 03680, Kyiv, Ukraine
2Astronomical Observatory, Taras Shevchenko National University of Kyiv, Observatorna str., 4, 04053, Kyiv, Ukraine
3 Institut d'Astrophysique et de Géophysique, Université de Liège, 4000, Belgium
In the present study the X-ray properties of 10 galaxy clusters (CL0024+17, RXJ1347.5+1145, A223, A521,
A611, A697, A907, A1204, A1413 and A2744) are analysed using the archival X-ray data of the Chandra observatory.
The average temperature of each cluster is estimated to be ∼ 4 − 10 keV, and the radial temperature pro�les are
reconstructed. Using the Navarro-Frenk-White (NFW) density pro�le of the dark matter the density and mass
pro�les for the dark matter and the hot di�use gas, and also the total mass pro�les are derived. The typical size of
galaxy clusters and the density of the dark matter halo are estimated to be∼ 0.1−2Mpc and ∼ 10−22−10−24 kg/m3,
respectively. The fraction of each component in the total cluster mass for the whole sample is found to be ∼ 80-90%
for dark matter and ∼ 10− 20% for intracluster gas, respectively.
Key words: galaxies: clusters: general � intergalactic medium � X-rays
introduction
The galaxy clusters are the largest gravitationally
bound systems in the Universe. The main targets
of their study are the cluster evolution, the struc-
ture formation and the cluster population [1]. The
mass of the cluster is an important characteristic for
de�ning the cosmological parameters. The observa-
tions of the hot gas in X-rays are very useful and
e�ective tool for the precise estimation of the total
mass [2, 9]. The present generation of satellites such
as the XMM-Newton and Chandra represent a giant
step forward in terms of resolution and sensitivity of
X-ray observations. So using the assumption of the
hydrostatic equilibrium one can precisely reconstruct
the total mass distribution in clusters [6]. Therefore
the main aim of the present study is to derive the
total mass pro�les of 10 galaxy clusters and to check
the correspondence of their shapes. We also report
about the estimations of temperature, density and
mass of these galaxy clusters. Throughout the pa-
per we assume H0 = 73 km/s/Mpc, Ωm = 0.27 and
ΩΛ = 0.73.
data processing
Our sample contains ten galaxy clusters with
z < 0.5. The main characteristics of the clusters
are presented in Table 1. The �rst step of the data
reduction was done with the CIAO software package
version 4.2. We split the image of each cluster on
the concentric rings toward from the centre, gener-
ated ARF and RMF �les using the SPECEXTRACT sub-
routine, and derived the spectrum in each ring for
each cluster. Then we used the Xspec software pack-
age version 12.6 for the spectra �tting. We applied
the WABS*MEKAL model, where WABS is the Galactic
absorption parameter for the cluster [3] and MEKAL is
a model which describes a di�use emission from the
hot plasma.
We extracted the temperature in each region and
parameter Norm from the MEKAL model, which is pro-
portional to the electron and proton concentrations,
within the energy range 0.4 − 7.0 keV [7]. All other
parameters of the model, for example, metallicity
(we used the solar value Z = 0.3), redshift and WABS
were frozen. The average values of the temperature
are shown in Table 1. We also estimated the �ux of
each cluster.
method
We assume that the gas temperature is constant
along the radius and is in hydrostatic equilibrium
with cluster potential [5, 8]. We run numerical sim-
ulations using the NFW density pro�le of the dark
matter [4] for reconstruction of the parameters of the
dark matter distribution in each cluster. The NFW
pro�le can be presented as:
ρDM (r) =
ρ0
(r/rs)(1 + r/rs)2
, (1)
where rs is the characteristic scale radius of the halo
and ρ0 is the typical density. The integrated mass of
the dark matter inside the radius r is:
M(< r) =
∫ r
0
4πr2ρ(r)dr =
= 4πρ0r
3
s
[
ln(
rs + r
rs
) +
r
rs + r
]
. (2)
∗babikyura@gmail.com
188
Advances in Astronomy and Space Physics Iu. Babyk, O.Melnyk, A. Elyiv
Table 1: The main characteristics of the sample.
Cluster ObsID z Detector Exp.time NH , T, Flux,
(ks) 1020cm2 keV 10−13 erg/cm2/s
A223 4967 0.21 ACIS-I 45.6 2.2 5.01+0.85
−0.91 2.83
A521 430 0.25 ACIS-S 39.6 5.81 10.21+1.85
−1.91 4.25
A611 3194 0.28 ACIS-S 36.6 4.99 6.24+0.78
−0.67 1.13
A697 4217 0.28 ACIS-I 19.7 3.42 10.22+1.24
−1.55 6.6
A907 3205 0.15 ACIS-I 47.7 5.4 5.81+0.75
−0.66 7.59
A1204 2205 0.17 ACIS-I 23.9 1.4 4.84+1.93
−1.34 2.28
A1413 537 0.14 ACIS-I 9.34 2.19 8.07+2.28
−2.02 4.96
A2744 2212 0.31 ACIS-S 25.14 1.62 9.82+0.43
−0.41 6.14
CL0024 929 0.39 ACIS-S 40.34 4.22 4.35+0.51
−0.44 0.22
RXJ1347 2222 0.45 ACIS-S 93.9 4.85 11.81+1.89
−2.04 8.05
Massive dark matter halo possesses the �eld of grav-
itational potential which forms the shape of the hot
gas halo. Gravitational potential ϕ can be found
from the following relation:
dϕ
dr
= G
M(< r)
r2
. (3)
Using the hydrostatic equilibrium of the X-ray emit-
ting gas with the cluster potential and NFW dark
matter pro�le, we derived and solved equation for
unknown gas density distribution:
∇ρg
ρg
= −∇ϕ(r)
µmp
kTg
. (4)
surface brightness profile
Using rs and ρ0 parameters we determined the
cluster potential and the hot gas distribution pro�le.
We also used these parameters to derive the surface
brightness pro�les (see Fig. 1), which were then com-
pared to the observed ones.
In Fig. 1 the surface brightness pro�le for
CL0024+17 cluster is present as an example. The
surface brightness pro�les for other clusters from our
sample have similar shapes but di�erent values of rs
and ρ0. These values vary from 0.1 to 2Mpc for
parameters rs and 10−22-10−24 kg/m3 for ρ0.
results of the modelling
The integrated total mass pro�les for the whole
sample of the galaxy clusters as well as the scaled
mass pro�les for these clusters are shown in Fig. 2.
The masses are scaled to M200 and the radii to R200
(R200 is the radius where the density is equal to
200ρcr at the cluster redshift and M200 is the mass
within this radius, ρcr is the critical density of the
Universe). In Table 2 the cluster parameters ob-
tained from the modelling are presented.
conclusions
We reconstructed the total mass density pro�les
of ten galaxy clusters using the Chandra observa-
tions. Our sample has the temperature within the
range from 4 to 10 keV and covers an order of mag-
nitude range in mass from M200 = 3.1 × 1014M�
to 2.2× 1015M�. We con�rm that the NFW pro�le
represents the observed mass pro�les quite well. The
dark matter fraction in the total mass of the clusters
is found to be 71-91%.
references
[1] ArnaudM., PrattG.W. & PointecouteauE. 2004, Mem-
orie della Società Astronomica Italiana, 75, 529
[2] CoiaD., McBreenB., Metcalfe L. et al. 2005, A&A, 431,
433
[3] Dickey J.M. & LockmanF. J. 1990, ARA&A, 28, 215
[4] Navarro J. F., FrenkC. S. & White SD.M. 1996, ApJ,
462, 563
[5] PointecouteauE., ArnaudM. & PrattG.W. 2005, Ad-
vances in Space Research, 36, 659
[6] PrattG.W. & ArnaudM. 2005, A&A, 429, 791
[7] VikhlininA., FormanW. & JonesC. 1999, ApJ, 525, 47
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A&A, 413, 49
189
Advances in Astronomy and Space Physics Iu. Babyk, O.Melnyk, A. Elyiv
Table 2: The cluster parameters obtained from the modelling.
Cluster R200 Mtot,200 MDM,200 Mg,200 MDM,200/Mtot,200
Mpc 1014M� 1014M� 1013M�
A223 1.44+0.26
−0.21 4.44+0.45
−0.61 3.79+0.51
−0.34 6.26+0.81
−0.45 0.85
A521 1.67+0.16
−0.12 3.14+0.83
−0.73 2.87+0.27
−0.16 2.61+0.36
−0.45 0.91
A611 1.44+0.19
−0.15 4.98+0.12
−0.23 3.57+0.09
−0.12 1.41+0.06
−0.07 0.72
A697 2.04+0.19
−0.22 13.71+1.46
−1.34 10.66+0.54
−0.43 30.45+1.73
−1.61 0.77
A907 1.67+0.15
−0.21 6.67+0.54
−0.65 5.95+0.20
−0.25 7.56+0.42
−0.32 0.89
A1204 1.28+0.44
−0.26 3.05+0.33
−0.23 2.54+0.15
−0.12 5.01+0.74
−0.70 0.83
A1413 1.83+0.66
−0.57 8.61+0.46
−0.49 7.23+0.65
−0.71 14.811.10
−0.91 0.84
A2744 2.38+0.36
−0.31 22.26+1.30
−1.20 18.81+1.80
−2.10 33.11+1.72
−2.51 0.84
CL0024 1.24+0.12
−0.17 3.51+0.38
−0.47 3.09+0.37
−0.33 4.56+0.86
−0.49 0.88
RXJ1347 1.85+0.16
−0.18 12.22+1.93
−1.75 8.75+0.24
−0.24 34.91+1.08
−1.23 0.71
Fig. 1: Left: The observed (points with bars) and simulated surface brightness pro�le (solid line) of CL0024+17. The
bars represent the 2σ deviation. Right: The area values of rs and ρ0 with 90% probability. The lowest value of χ2 is
marked by the cross (the best-�t of observational surface pro�le).
Fig. 2: Left: The total mass pro�les. The solid lines is the best-�t of the NFW model. Right: The scaled mass pro�les.
The solid line represents the mean scaled NFW pro�le.
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