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We present a multi-wavelength analysis of the core of the massive galaxy cluster MACS,J0417.5-1154 ($z = 0.441$; MACS;J0417). Our analysis takes advantage of VLT/MUSE observations which allow the spectroscopic confirmation of three strongly-lensed systems. One of these, nick-named emph{The Doughnut}, consists of three complete images of a complex ring galaxy at $z = 0.8718$ and a fourth, partial and radial image close to the Brightest Cluster Galaxy (BCG) only discernible thanks to its strong [OII] line emission. The best-fit mass model (rms of 0.38arcsec) yields a two-dimensional enclosed mass of $M({rm R < 200,kpc}) = (1.77pm0.03)times10^{14},msun$ and almost perfect alignment between the peaks of the BCG light and the dark matter of ($0.5pm0.5$)arcsec . Our finding that a significant misalignment results when the radial image of emph{The Doughnut} is omitted serves as an important caveat for studies of BCG-dark matter offsets in galaxy clusters. Using emph{Chandra} data to map the intra-cluster gas, we observe an offset between the gas and dark-matter peaks of ($1.7pm0.5$)arcsec, and excellent alignment of the X-ray peak with the location of optical emission line associated with the BCG. We interpret all observational evidence in the framework of on-going merger activity, noting specifically that the coincidence between the gas peak and the peak of blue light from the BCG may be evidence of dense, cold gas leading to direct star formation. We use the surface area $sigma_{mu}$ above a given magnification factor $mu$ as a metric to estimate the lensing power of MACS,J0417. We obtain $sigma(mu > 3) = 0.22$,arcmin$^2$ confirming MACS,J0417 as an efficient gravitational lens. Finally, we discuss the differences between our mass model and Mahler et al. (2018).
We reveal the importance of ongoing in-situ star formation in the Brightest Cluster Galaxy in the massive cool-core CLASH cluster MACS 1931.8-2635 at z=0.35. Using a multi-wavelength approach, we assess the stellar and warm ionized medium components,
Strong gravitational lensing by clusters of galaxies probes the mass distribution at the core of each cluster and magnifies the universe behind it. MACS J0417.5-1154 at z=0.443 is one of the most massive clusters known based on weak lensing, X-ray, a
Clusters of galaxies are outstanding laboratories for understanding the physics of supermassive black hole feedback. Here, we present the first textit{Chandra}, Karl G. Janksy Very Large Array and textit{Hubble Space Telescope} analysis of MACS J1447
Observations of massive stars in young open clusters (< ~8 Myr) have shown that a majority of them are in binary systems, most of which will interact during their life. Populations of massive stars older than ~20 Myr allow us to probe the outcome of
A majority of massive stars are part of binary systems, a large fraction of which will inevitably interact during their lives. Binary-interaction products (BiPs), i.e. stars affected by such interaction, are expected to be commonly present in stellar