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Title: The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations

Abstract

We report Chandra X-ray observations and optical weak-lensing measurements from Subaru/Suprime-Cam images of the double galaxy cluster A2465 ( z = 0.245). The X-ray brightness data are fit to a β model to obtain the radial gas density profiles of the northeast (NE) and southwest (SW) subcomponents, which are seen to differ in structure. We determine core radii, central temperatures, the gas masses within r {sub 500c}, and the total masses for the broader NE and sharper SW components assuming hydrostatic equilibrium. There is no large X-ray excess between the two components. The central entropy of the NE subcluster is about two times higher than the SW. Along with its structural properties and an apparent radio halo that is a sign of a merger, this suggests that the NE component has undergone merging on its own. The weak-lensing analysis gives virial masses for each substructure, which compare well with earlier dynamical results. The derived outer mass contours of the SW sub-component from weak lensing are more irregular and extended than those of the NE. Although there is a weak enhancement and small offsets between X-ray gas and mass centers from weak lensing, the lack of large amounts of gas betweenmore » the two subclusters indicates that A2465 is in a pre-merger state. We discuss star formation enhancement in this system resulting from its dynamics and shock-induced star formation scenarios. A dynamical model that is consistent with the observed cluster data, based on the FLASH program and the radial infall model, is constructed, where the subclusters currently separated by ∼1.2 Mpc are approaching each other at ∼2000 km s{sup −1} and will meet in ∼0.4 Gyr.« less

Authors:
 [1]; ;  [2];  [3];  [4]; ; ; ; ;  [5]
  1. Department of Physics and Astronomy, 6127 Wilder Laboratory, Hanover, NH 03745 (United States)
  2. Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)
  3. INAF/Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste (Italy)
  4. Department of Astrophysical Sciences, 4 Ivy Lane, Princeton, NJ 08544 (United States)
  5. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22663353
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 844; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; DENSITY; ENTROPY; EQUILIBRIUM; GALAXY CLUSTERS; GRAVITATIONAL LENSES; HYDROSTATICS; MASS; NONLUMINOUS MATTER; STARS; X RADIATION; X-RAY GALAXIES

Citation Formats

Wegner, Gary A., Umetsu, Keiichi, Molnar, Sandor M., Nonino, Mario, Medezinski, Elinor, Andrade-Santos, Felipe, Bogdan, Akos, Lovisari, Lorenzo, Forman, William R., and Jones, Christine, E-mail: gary.wegner@dartmouth.edu. The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA784A.
Wegner, Gary A., Umetsu, Keiichi, Molnar, Sandor M., Nonino, Mario, Medezinski, Elinor, Andrade-Santos, Felipe, Bogdan, Akos, Lovisari, Lorenzo, Forman, William R., & Jones, Christine, E-mail: gary.wegner@dartmouth.edu. The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations. United States. doi:10.3847/1538-4357/AA784A.
Wegner, Gary A., Umetsu, Keiichi, Molnar, Sandor M., Nonino, Mario, Medezinski, Elinor, Andrade-Santos, Felipe, Bogdan, Akos, Lovisari, Lorenzo, Forman, William R., and Jones, Christine, E-mail: gary.wegner@dartmouth.edu. Thu . "The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations". United States. doi:10.3847/1538-4357/AA784A.
@article{osti_22663353,
title = {The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations},
author = {Wegner, Gary A. and Umetsu, Keiichi and Molnar, Sandor M. and Nonino, Mario and Medezinski, Elinor and Andrade-Santos, Felipe and Bogdan, Akos and Lovisari, Lorenzo and Forman, William R. and Jones, Christine, E-mail: gary.wegner@dartmouth.edu},
abstractNote = {We report Chandra X-ray observations and optical weak-lensing measurements from Subaru/Suprime-Cam images of the double galaxy cluster A2465 ( z = 0.245). The X-ray brightness data are fit to a β model to obtain the radial gas density profiles of the northeast (NE) and southwest (SW) subcomponents, which are seen to differ in structure. We determine core radii, central temperatures, the gas masses within r {sub 500c}, and the total masses for the broader NE and sharper SW components assuming hydrostatic equilibrium. There is no large X-ray excess between the two components. The central entropy of the NE subcluster is about two times higher than the SW. Along with its structural properties and an apparent radio halo that is a sign of a merger, this suggests that the NE component has undergone merging on its own. The weak-lensing analysis gives virial masses for each substructure, which compare well with earlier dynamical results. The derived outer mass contours of the SW sub-component from weak lensing are more irregular and extended than those of the NE. Although there is a weak enhancement and small offsets between X-ray gas and mass centers from weak lensing, the lack of large amounts of gas between the two subclusters indicates that A2465 is in a pre-merger state. We discuss star formation enhancement in this system resulting from its dynamics and shock-induced star formation scenarios. A dynamical model that is consistent with the observed cluster data, based on the FLASH program and the radial infall model, is constructed, where the subclusters currently separated by ∼1.2 Mpc are approaching each other at ∼2000 km s{sup −1} and will meet in ∼0.4 Gyr.},
doi = {10.3847/1538-4357/AA784A},
journal = {Astrophysical Journal},
number = 1,
volume = 844,
place = {United States},
year = {Thu Jul 20 00:00:00 EDT 2017},
month = {Thu Jul 20 00:00:00 EDT 2017}
}