MACS J0417.5-1154 is a remarkable merger of a very massive cluster and a smaller subcluster. A previous 11 ksec Chandra exposure shows the hot gas distribution to appear distinctly comet-like: the peak is centered on the cD galaxy of the main cluster; the tail, however, extends several hundred kpc and encompasses a pair of giant ellipticals. Optical imaging reveals a bridge of intra-cluster light between the three galaxies, strengthening the hypothesis that this is a merger system with a low impact parameter, seen after pericentric passage. The proposed 80 ksec Chandra observation will allow us to map the detailed thermodynamic state of the system, to study how the merging process affects the cluster cores, and investigate the origin and state of the stripped gas in the tail.

This is an imaging program of the galaxy cluster MACS J0417.5-1154, with the aim to reconstruct the mass distribution at the core from gravitational lensing. The primary aim is a weak lensing mass reconstruction. For the weak lensing analysis, we will observe the target for 3 orbits with WFC3 in F606W. Each orbit is split into 4 exposures of 596s each. All exposures are dithered along a LINE pattern, aiming to close the chip gap, and achieve 1/2 pixel resolution. Since we effectively have 12 exposures, we observe with CR-SPLIT=NO. MACS J0417.5-1154 is a strong lensing cluster, and in order to identify further multiple image systems, we plan to observe it with a second filter, F814W. Because of its higher throughput, we use ACS for this single-orbit observation. We take 5 exposures along a LINE pattern, again closing the chip gap and aiming for 1/2 pixel resolution. For a high S/N weak lensing mass map and the search for multiple image systems we need the highest depth reachable within the given observing time. Hence we require the LOW-SKY special requirement for the whole program. The orientation constraints and the POS TARG of the ACS observation are chosen to avoid the bright stars in the field. 12 false 0.0 0.0 false false false false SUPPORTED CLUSTER OF GALAXIES GRAVITATIONAL LENS RICH CLUSTER J2000 04 17 33.1832 -11 54 2.75 J2000 WFC3/UVIS Imaging No No F606W POS-TARG DITHER 1.4163 LINE false true 12 93.9 LINE 5 false POS-TARG DITHER 3.011 LINE false true 5 85.28 ACS-WFC-DITHER-LINE 10 false POS-TARG DITHER 1.4163 LINE false false 3 93.9 LINE 11 false The scheduling data was generated by CASM 19.0. CASM was run in Phase II mode. 1295505983000 60.80174952883121 (Tic-Visit :proposal-id 12009 :visit-id "01" :proposal-version -1 :trans-version "20090702" :date "18-Nov-2009 18:15:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 40.0 :data-volume 3465008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12009 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12009 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2776 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) (Tic-Orbit :proposal-id 12009 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2776 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) (Tic-Orbit :proposal-id 12009 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2776 :al-overhead-at-end 116 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) true 3 0 HOPR repeat of the first three exposures from visit 1. (Tic-Visit :proposal-id 12009 :visit-id "51" :proposal-version -1 :trans-version "20100902" :date "08-Feb-2011 10:37:36.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 40.0 :data-volume 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12009 :visit-id "51" :obset-id "51" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12009 :visit-id "51" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2052 :al-overhead-at-end 116 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) false 1 0 The scheduling data was generated by CASM 19.0. CASM was run in Phase II mode. HOPR repeat of the first three exposures from visit 1. (Tic-Visit :proposal-id 12009 :visit-id "52" :proposal-version -1 :trans-version "20100902" :date "10-Feb-2011 06:51:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 40.0 :data-volume 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12009 :visit-id "52" :obset-id "52" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12009 :visit-id "52" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2052 :al-overhead-at-end 116 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. 1291957167000 7.95093330217901 (Tic-Visit :proposal-id 12009 :visit-id "03" :proposal-version -1 :trans-version "20090702" :date "18-Nov-2009 18:15:13.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 40.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12009 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12009 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2778 :al-overhead-at-end 0 :internal-dur-at-end 349 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3178 :pcs-gap 400 ) true 1 0