J/A+A/670/A96 SMACS J0723.3-7327 eROSITA and Chandra images (Liu+, 2023)
X-ray analysis of JWST's first galaxy cluster lens SMACS J0723.3-7327.
Liu A., Bulbul E., Ramos-Ceja M.E., Sanders J.S., Ghirardini V., Bahar Y.E.,
Yeung M., Gatuzz E., Freyberg M., Garrel C., Zhang X., Merloni A., Nandra K.
<Astron. Astrophys. 670, A96 (2023)>
=2023A&A...670A..96L 2023A&A...670A..96L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Radio sources
Keywords: galaxies: clusters: intracluster medium -
galaxies: clusters: individual: SMACS J0723.3-7327 -
X-rays: galaxies: clusters
Abstract:
SMACS J0723.3-7327 is the first galaxy cluster lens observed by James
Webb Space Telescope (JWST). Based on its early release observation
data, several groups have reported the results on strong lensing
analysis and mass distribution of this cluster. The new lens model
dramatically improves upon previous results, thanks to JWST's
unprecedented sensitivity and angular resolution. However, limited by
the angular coverage of the JWST data, the strong lensing models only
cover the central region. Conducting an X-ray analysis on the hot
intracluster medium (ICM) is necessary to obtain a more complete
constraint on the mass distribution in this very massive cluster. In
this work, we perform a comprehensive X-ray analysis of SMACS
J0723.3-7327 with an aim to obtain accurate ICM hydrostatic mass
measurements, using the X-ray data from Spectrum Roentgen Gamma
(SRG)/eROSITA and Chandra X-ray observatories. By comparing the
hydrostatic mass profile with the strong lensing model, we aim to
provide the most reliable constraint on the distribution of mass up to
R500. Thanks to the eROSITA all-sky survey and Chandra, which
provide high signal-to-noise ratio (S/N) and high angular resolution
data, respectively, we were able to constrain the ICM gas density
profile and temperature profile with good accuracy both in the core
and to the outskirts. With the density and temperature profiles, we
computed the hydrostatic mass profile, which was then projected along
the line of sight to compare with the mass distribution obtained from
the recent strong lensing analysis based on JWST data. We also
deprojected the strong lensing mass distribution using the hydrostatic
mass profile obtained in this work. The X-ray results obtained from
eROSITA and Chandra are in very good agreement. The hydrostatic mass
profiles we measured in this work, both projected and deprojected, are
in good agreement with recent strong lensing results based on JWST
data, at all radii. The projected hydrostatic mass within 128kpc (the
estimated Einstein radius) is 8.0±0.7x1013M☉, consistent
with the strong lensing mass reported in recent literature. With the
hydrostatic mass profile, we measured R2500=0.54±0.04Mpc and
M2500=(3.5±0.8)x1014M☉, while the R500 and M500 are
1.32±0.23Mpc and (9.8±5.1)x1014M_☉, with a relatively larger
error bar due to the rapidly decreasing S/N in the outskirts. We also
find that the radial acceleration relation in SMACS J0723.3-7327 is
inconsistent with the RAR for spiral galaxies, implying that the
latter is not a universal property of gravity across all mass scales.
Description:
The eROSITA data are obtained during the all-sky survey (eRASS) from
December 2019 to February 2022. SMACS J0723.3-7327 was scanned five
times in the first five all-sky surveys (eRASS:5). The total effective
exposure after correcting for vignetting effect is ∼4.4ks. We note
that the exposure on SMACS J0723.3-7327 is significantly larger than
the average depth of eRASS, because it lies close to the south
ecliptic pole of the survey. The Chandra observation (ObsID: 15296,
PI: S. Murray) was performed in April 2014, with a cleaned exposure
time of 16.5ks.
The reduction of Chandra data is performed using the software CIAO
v4.14, with the latest release of the Chandra Calibration Database at
the time of writing (CALDB v4.9). Time intervals with a high
background level are filtered out by performing a 2 clipping of the
light curve in the 2.3-7.3keV band source-free image. The total
cleaned exposure time after deflare is 16.5ks. Point sources within
the field of view (FOV) were identified with wavdetect on the Chandra
0.5-7keV band image, checked visually, and eventually masked. Gaps
between the CCD chips are also masked.
Objects:
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RA (2000) DE Designation(s)
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07 23 19.20 -73 27 22.5 SMACS J0723.3-7327 = PLCKESZ G284.99-23.70
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 172 2 List of fits images
fits/* . 2 Individual fits images
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See also:
J/A+A/666/L9 : SMACS J0723.3-7327 first JWST observations (Caminha+, 2022)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 34 I5 Kibyte size Size of FITS file
36- 56 A21 --- FileName Name of FITS file, in subdirectory fits
58-172 A115 --- Title Title of the FITS file
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Acknowledgements:
Ang Liu, liuang.ou(at)gmail.com
(End) Patricia Vannier [CDS] 07-Dec-2022