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Golovich, Nathan,Weeren, Reinout J. van,Dawson, William A.,Jee, M. James,Wittman, David American Astronomical Society 2017 The Astrophysical journal Vol.838 No.2
<P>We present and analyze a rich data set including Subaru/SuprimeCam, HST/Advanced Camera for Surveys and Wide Field Camera 3, Keck/DEIMOS, Chandra/ACIS-I, and JVLA/C and D array for the merging cluster of galaxies ZwCl 0008.8+ 5215. With a joint Subaru+ HST weak gravitational lensing analysis, we identify two dominant subclusters and estimate the masses to be M-200 = 5.8(-1.8)(+2.8) x 10(14) M-circle dot. We estimate the projected separation between the two subclusters to be 924(-206)(+243) kpc. We perform a clustering analysis of spectroscopically confirmed cluster member galaxies and estimate the line-of-sight velocity difference between the two subclusters to be 92 +/- 164 km s(-1). We further motivate, discuss, and analyze the merger scenario through an analysis of the 42 ks of Chandra/ACIS-I and JVLA/C and D array polarization data. The X-ray surface brightness profile reveals a merging gas-core reminiscent of the Bullet Cluster. The global X-ray luminosity in the 0.5-7.0 keV band is 1.7. +/- 0.1 x 10(44) erg s(-1) and the global X-ray temperature is 4.90 +/- 0.13 keV. The radio relics are polarized up to 40%,. and along with the masses, velocities, and positions of the two subclusters, we input these quantities into a Monte Carlo dynamical analysis and estimate the merger velocity at pericenter to be 1800(-300)(+400) km s(-1). This is a lower-mass version of the Bullet Cluster and therefore may prove useful in testing alternative models of dark matter (DM). We do not find significant offsets between DM and galaxies, but the uncertainties are large with the current lensing data. Furthermore, in the east, the BCG is offset from other luminous cluster galaxies, which poses a puzzle for defining DM-galaxy offsets.</P>
Deep VLA Observations of the Cluster 1RXS J0603.3+4214 in the Frequency Range of 1-2 GHz
Rajpurohit, K.,Hoeft, M.,van Weeren, R. J.,Rudnick, L.,Rö,ttgering, H. J. A.,Forman, W. R.,Brü,ggen, M.,Croston, J. H.,Andrade-Santos, F.,Dawson, W. A.,Intema, H. T.,Kraft, R. P.,Jones, C.,Jee American Astronomical Society 2018 The Astrophysical Journal Vol.852 No.2
<P>We report L-band VLA observations of 1RXS J0603.3+4214, a cluster that hosts a bright radio relic, known as the Toothbrush, and an elongated giant radio halo. These new observations allow us to study the surface brightness distribution down to 1 arcsec resolution with very high sensitivity. Our images provide an unprecedented detailed view of the Toothbrush, revealing enigmatic filamentary structures. To study the spectral index distribution, we complement our analysis with published LOFAR and GMRT observations. The bright 'brush' of the Toothbrush shows a prominent narrow ridge to its north with a sharp outer edge. The spectral index at the ridge is in the range -0.70 <= alpha <= -0.80. We suggest that the ridge is caused by projection along the line of sight. With a simple toy model for the smallest region of the ridge, we conclude that the magnetic field is below 5 mu G and varies significantly across the shock front. Our model indicates that the actual Mach number is higher than that obtained from the injection index and agrees well with the one derived from the overall spectrum, namely M = 3.78(-0.2)(+0.3). The radio halo shows an average spectral index of alpha = -1.16 +/- 0.05 and a slight gradient from north to south. The southernmost part of the halo is steeper and possibly related to a shock front. Excluding the southernmost part, the halo morphology agrees very well with the X-ray morphology. A power-law correlation is found between the radio and X-ray surface brightness.</P>
Jee, M. James,Dawson, William A.,Stroe, Andra,Wittman, David,van Weeren, Reinout J.,Brü,ggen, Marcus,Bradač,, Maruš,a,Rö,ttgering, Huub American Astronomical Society 2016 The Astrophysical journal Vol.817 No.2
<P>The galaxy cluster RX J0603.3+4214. at z-0.225 is one of the rarest clusters boasting an extremely large (similar to 2 Mpc) radio. relic. Because of the remarkable morphology of the relic, the cluster is nicknamed the. 'Toothbrush Cluster.' Although the cluster's underlying mass distribution is one of the critical pieces of information needed to reconstruct the merger scenario responsible for the puzzling radio. relic morphology, its proximity to the Galactic plane b similar to 10 degrees has imposed significant observational challenges. We present a high-resolution weak-lensing study of the cluster with Subaru/Suprime Cam and Hubble Space Telescope imaging data. Our mass reconstruction reveals that the cluster is composed of complicated dark matter substructures closely tracing the galaxy distribution, in contrast, however, with the relatively simple binary X-ray morphology. Nevertheless, we find that the cluster mass is still dominated by the two most massive clumps aligned north-south with a similar to 3: 1 mass ratio (M-200 = 6.29(-1.62)(+2.24) x 10(14) M-circle dot and 1.98(-0.74)(+1.24) x 10(14) M-circle dot for the northern and southern clumps, respectively). The southern mass peak is similar to 2' offset toward the south with respect to the corresponding X-ray peak, which has a 'bullet'-like morphology pointing south. Comparison of the current weak-lensing result with the X-ray, galaxy, and radio. relic suggests that perhaps the dominant mechanism responsible for the observed relic may be a highspeed collision of the two most massive subclusters, although the peculiarity of the morphology necessitates involvement of additional subclusters. Careful numerical simulations should follow in order to obtain more complete understanding of the merger scenario utilizing all existing observations.</P>
Benson, B.,Wittman, D. M.,Golovich, N.,Jee, M. James,van Weeren, R. J.,Dawson, W. A. American Astronomical Society 2017 The Astrophysical Journal Vol.841 No.1
<P>ZwCl 2341.1+0000, a merging galaxy cluster with disturbed X-ray morphology and widely separated (similar to 3 Mpc) double radio relics, was thought to be an extremely massive (10-30 x 10(14) M-circle dot) and complex system, with little known about its merger history. We present JVLA 2-4 GHz observations of the cluster, along with new spectroscopy from our Keck/DEIMOS survey, and apply Gaussian Mixture Modeling to the three-dimensional distribution of 227 confirmed cluster galaxies. After adopting the Bayesian Information Criterion to avoid overfitting, which we discover can bias high the total dynamical mass estimates, we find that a three-substructure model with a total dynamical mass estimate of 9.39 +/- 0.81 x 10(14) M-circle dot is favored. We also present deep Subaru imaging and perform the first weak lensing analysis on this system, obtaining a weak lensing mass estimate of 5.57 +/- 2.47 x 10(14) M-circle dot. This is a more robust estimate because it does not depend on the dynamical state of the system, which is disturbed due to the merger. Our results indicate that ZwCl 2341.1+0000 is a multiple merger system comprised of at least three substructures, with the main merger that produced the radio relics occurring near the plane of the sky, and a younger merger in the north occurring closer to the line of sight. Dynamical modeling of the main merger reproduces observed quantities (relic positions and polarizations, subcluster separation and radial velocity difference), if the merger axis angle of similar to 10(-6)(+34) degrees and the collision speed at pericenter is similar to 1900(-200)(+300) km s(-1).</P>