J/MNRAS/443/1549 MACSJ0416.1-2403 strong-lensing analysis (Jauzac+, 2014)
Hubble Frontier Fields: a high-precision strong-lensing analysis of galaxy
cluster MACSJ0416.1-2403 using ∼200 multiple images.
Jauzac M., Clement B., Limousin M., Richard J., Jullo E., Ebeling H.,
Atek H., Kneib J.-P., Knowles K., Natarajan P., Eckert D., Egami E.,
Massey R., Rexroth M.
<Mon. Not. R. Astron. Soc., 443, 1549-1554 (2014)>
=2014MNRAS.443.1549J 2014MNRAS.443.1549J
ADC_Keywords: Clusters, galaxy ; Gravitational lensing
Keywords: gravitational lensing: strong -
galaxies: clusters: individual: MACSJ0416.1-2403 -
cosmology: observations
Abstract:
We present a high-precision mass model of the galaxy cluster
MACSJ0416.1-2403, based on a strong-gravitational-lensing analysis of
the recently acquired Hubble Space Telescope Frontier Fields (HFF)
imaging data. Taking advantage of the unprecedented depth provided by
HST/Advanced Camera for Survey observations in three passbands, we
identify 51 new multiply imaged galaxies, quadrupling the previous
census and bringing the grand total to 68, comprising 194 individual
lensed images. Having selected a subset of the 57 most securely
identified multiply imaged galaxies, we use the lenstool software
package to constrain a lens model comprised of two cluster-scale
dark-matter haloes and 98 galaxy-scale haloes. Our best-fitting model
predicts image positions with an rms error of 0.68-arcsec, which
constitutes an improvement of almost a factor of 2 over previous,
pre-HFF models of this cluster. We find the total projected mass
inside a 200kpc aperture to be (1.60±0.01)x1014M☉, a
measurement that offers a three-fold improvement in precision,
reaching the per cent level for the first time in any cluster.
Finally, we quantify the increase in precision of the derived
gravitational magnification of high-redshift galaxies and find an
improvement by a factor of ∼2.5 in the statistical uncertainty. Our
findings impressively confirm that HFF imaging has indeed opened the
domain of high-precision mass measurements for massive clusters of
galaxies.
Description:
The HFF observations of MACSJ0416 (ID: 13496) were obtained with ACS
between 2014 January 5 and February 9, in the three filters F435W,
F606W, and F814W, for total integration times corresponding to 20, 12,
and 48 orbits, respectively. We applied basic data-reduction
procedures using HSTCAL and the most recent calibration files.
Individual frames were co-added using Astrodrizzle after registration
to a common ACS reference image using Tweakreg. After an iterative
process, we achieve an alignment accuracy of 0.1-pixel. Our final
stacked images have a pixel size of 0.03-arcsec.
Objects:
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RA (2000) DE Designation(s)
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04 16 10.0 -24 03 58 CSJ 04161-2403 = MCS J0416.1-2403
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 55 194 Multiply imaged systems considered in this work
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_ID [+*] Note on system (1)
2- 5 F4.1 --- ID [1.1/73.2] Identification number
7- 15 F9.6 deg RAdeg Right ascension (J2000)
17- 26 F10.6 deg DEdeg Right ascension (J2000)
28- 33 F6.4 --- zsp [1.8/3.3]?=- Spectroscopic redshift
35- 38 F4.2 --- zmod [1/6]?=- Model redshift
40- 43 F4.1 mag F814W [22.1/29.3]?=- F814W magnitude (2)
45 A1 --- l_mu Limit flag on mu
46- 49 F4.1 --- mu [1.4/30] Flux magnification factor (3)
51- 55 F5.2 --- e_mu [0.03/11.8]? rms uncertainty on mu (3)
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Note (1): Note as follows:
* = image identifications in which we are less confident
+ = even though we have not confirmed system 4 spectroscopically,
we assume that systems 3 and 4 correspond to different
sub-structures of the same background source.
Note (2): Some of the magnitudes are not quoted because we were facing
deblending issues that did not allow us to get reliable measurements.
Note (3): The flux magnification factors come from our best-fit mass model,
with errors derived from MCMC (Markov Chain Monte Carlo) sampling.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Apr-2015