Cluster Merger Shock Constraints On Particle Acceleration And Nonthermal Pressure In The Intracluster Medium

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dc.contributor.utaustinauthorMilosavljevic, Milosen_US
dc.creatorNakar, Ehuden_US
dc.creatorMilosavljevic, Milosen_US
dc.creatorNagai, Daisukeen_US
dc.date.accessioned2016-04-28T19:42:17Z
dc.date.available2016-04-28T19:42:17Z
dc.date.issued2008-03en
dc.description.abstractX-ray observations of galaxy cluster merger shocks can be used to constrain nonthermal processes in the intracluster medium (ICM). The presence of nonthermal pressure components in the ICM, as well as the shock acceleration of particles and their escape, all affect shock jump conditions in distinct ways. Therefore, these processes can be constrained using X-ray surface brightness and temperature maps of merger shock fronts. Here we use these observations to place constraints on particle acceleration efficiency in intermediate Mach number ( M approximate to 2-3) shocks and explore the potential to constrain the contribution of nonthermal components ( e. g., cosmic rays, magnetic field, and turbulence) to ICM pressure in cluster outskirts. We model the hydrodynamic jump conditions in merger shocks discovered in the galaxy clusters A520 ( M approximate to 2) and 1E 0657-56 ( M approximate to 3) using a multifluid model comprising a thermal plasma, a nonthermal plasma, and a magnetic field. Based on the published X-ray spectroscopic data alone, we find that the fractional contribution of cosmic rays accelerated in these shocks is less than or similar to 10% of the shock downstream pressure. Current observations do not constrain the fractional contribution of nonthermal components to the pressure of the undisturbed shock upstream. Future X-ray observations, however, have the potential to either detect particle acceleration in these shocks through its effect on the shock dynamics, or place a lower limit on the nonthermal pressure contributions in the undisturbed ICM. We briefly discuss implications formodels of particle acceleration in collisionless shocks and the estimates of galaxy cluster masses derived from X-ray and Sunyaev-Zel'dovich effect observations.en_US
dc.description.departmentAstronomyen_US
dc.description.sponsorshipen_US
dc.identifierdoi:10.15781/T24R65
dc.identifier.Filename2008_03_clustermerger.pdfen_US
dc.identifier.citationNakar, Ehud, Miloﾚ Milosavljevi?, and Daisuke Nagai. "Cluster merger shock constraints on particle acceleration and nonthermal pressure in the intracluster medium." The Astrophysical Journal, Vol. 675, No. 1 (Mar., 2008): 126.en_US
dc.identifier.doi10.1086/526409en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/35135
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectcosmic raysen_US
dc.subjectgalaxies : clusters : generalen_US
dc.subjectgalaxies : clusters :en_US
dc.subjectindividual (a520, 1e 0657-06)en_US
dc.subjectintergalactic mediumen_US
dc.subjectshock wavesen_US
dc.subjectturbulenceen_US
dc.subjectx-rays : galaxies : clustersen_US
dc.subjectlarge-scale structureen_US
dc.subjectcosmic-ray protonsen_US
dc.subjectmagnetic-fielden_US
dc.subjectgalaxyen_US
dc.subjectclustersen_US
dc.subjectgamma-rayen_US
dc.subjectnonlinear amplificationen_US
dc.subjectisotropic turbulenceen_US
dc.subjectsupernova-remnanten_US
dc.subjecthigh-energyen_US
dc.subjectbow shocken_US
dc.subjectastronomy & astrophysicsen_US
dc.titleCluster Merger Shock Constraints On Particle Acceleration And Nonthermal Pressure In The Intracluster Mediumen_US
dc.typeArticleen_US

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