J/A+A/678/A3 ACT-CL J0 102-15 MUSE view (Caminha+, 2023)
A MUSE view of the massive merging galaxy cluster ACT-CL J0 102-15 (El Gordo)
at z = 0.87. Robust strong lensing model and data release.
Caminha G., Grillo C., Rosati P., Liu A., Acebron A., Bergamini P.,
Caputi K.I., Mercurio A., Tozzi P., Vanzella E., Demarco R., Frye B.,
Rosani G., Sharon K.
<Astron. Astrophys. 678, A3 (2023)>
=2023A&A...678A...3C 2023A&A...678A...3C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Gravitational lensing ; Redshifts
Keywords: galaxies: clusters: individual: ACT-CL J0102-4915 -
gravitational lensing: strong - dark matter
Abstract:
We present a detailed strong lensing analysis of the massive and
distant (z=0.870) galaxy cluster ACT-CL J0102-4915 (ACT0102, also
known as El Gordo), taking advantage of new spectroscopic data from
the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large
Telescope and archival imaging from the Hubble Space Telescope. Thanks
to the MUSE data, we were able to measure secure redshifts for 374
single objects, including 23 multiply lensed galaxies, and 167 cluster
members of ACT0102. We used the observed positions of 56 multiple
images, along with their new spectroscopic redshift measurements, as
constraints for our strong lensing model. Remarkably, some multiple
images are detected out to a large projected distance of ∼1Mpc from
the brightest cluster galaxy, allowing us to estimate a projected
total mass value of 1.84-0.04+0.03x1015M☉ within that
radius. We find that we need two extended cluster mass components, the
mass contributions from the cluster members and the additional lensing
effect of a foreground (z=0.633) group of galaxies, to predict the
positions of all multiple images with a root mean square offset of
0.75". The main cluster-scale mass component is centred very close to
the brightest cluster galaxy, and the other extended mass component is
located in the north-west region of the cluster. These two mass
components have very similar values of mass projected within 300kpc of
their centres, namely 2.29-0.10+0.09x1014M☉ and
2.10-0.09+0.08x1014M☉, in agreement with the major merging
scenario of ACT0102. We make publicly available the lens model,
including the magnification maps and posterior distributions of the
model parameter values, as well as the full spectroscopic catalogue
containing all redshift measurements obtained with MUSE.
Description:
We make publicly available the lens model of ACT-CL J0102-4915 (aka El
Gordo) and the MUSE redshift catalogue presented in the paper.
If you use the information in these files please cite the paper, and
for any further question contact the author via the e-mail
gbcaminha(at)gmail.com
Subdirectory files contains the files used by the software lenstool
(https://projets.lam.fr/projects/lenstool/wiki) are described below:
best_fit.par : input best fit file for the lenstool software
to_sample.par : input file for the sampling mode of lenstool
bayes.dat : 10000 random points from the full lenstool MCMC sampling
output. This file can be used to compute the model parameter
confidence levels and the statistical error of lensing related
quantities, such as magnification factors
(see https://projets.lam.fr/projects/lenstool/wiki for more information).
members_all.dat : file containing the list of cluster members, used as
input to the lenstool software. The columns follow the format described
on https://projets.lam.fr/projects/lenstool/wiki/PotFile.
The columns are 1) ID; 2),3) RA and Dec in degrees;
4),5),6) semi major and minor axes and orientation (in our case we adopt
circularly symmetric profiles); 7) magnitude measured on the
HST/WFC F160W filter. The last columns is not used by lenstool but
must be included so that the software can read this file.
obsarcsv1newIDs.dat : file containing the list of multiple images,
used as input to the lenstool software.
The columns are 1) ID; 2),3) RA and Dec in degrees;
4),5) re-scaled positional error on x and y directions in arcseconds;
6) image orientation (not used in this work);
7) spectroscopic redshift; 8) reference magnitude (not used in this work)
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
catalog.dat 65 402 MUSE redshift catalogue (table 1)
list.dat 137 9 List of fits maps
fits/* . 9 Individual fits maps
files/* . 5 Files used by the software lenstool
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Byte-by-byte Description of file: catalog.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 28 A28 --- Name ID build from the cluster name and object RA
and Dec (ACT0102-JHHMMSS.ss+DDMMSS.ss)
30- 39 F10.7 deg RAdeg Observed right ascension (J2000) (1)
41- 51 F11.7 deg DEdeg Observed declination (J2000) (1)
53- 58 F6.4 --- zsp Spectroscopic redshift
61 I1 --- q_zsp [2/9] Redshift quality flag (2)
65 I1 --- Nmult [1/3] Number of entries of the same object in
this catalogue used to indicate multiply
lensed sources
--------------------------------------------------------------------------------
Note (1): The coordinates are with respect to the HST/RELICS public images.
See https://archive.stsci.edu/prepds/relics/
Note (2): Redshift quality flag as follows:
2 = likely
3 = secure measurement
9 = single line measurement
4 = field stars
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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- 33 I4 Kibyte size Size of FITS file
35- 65 A31 --- FileName Name of FITS file, in subdirectory fits
67-137 A71 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Gabriel Caminha, gbcaminha(at)gmail.com
(End) Patricia Vannier [CDS] 08-Aug-2023