POLARIZATION DIAGNOSTICS FOR COOL CORE CLUSTER EMISSION LINES

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dc.contributor.authorSparks, W. B.
dc.contributor.authorPringle, J. E.
dc.contributor.authorCarswell, R. F.
dc.contributor.authorVoit, G. M.
dc.contributor.authorDonahue, M.
dc.contributor.authorCracraft, M.
dc.contributor.authorMeyer, E. T.
dc.contributor.authorHough, J. H.
dc.contributor.authorManset, N.
dc.date.accessioned2020-08-24T16:29:52Z
dc.date.available2020-08-24T16:29:52Z
dc.date.issued2013-12-12
dc.description.abstractThe nature of the interaction between low-excitation gas filaments at ~10⁴ K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ~10⁷ K in the centers of galaxy clusters remains a puzzle. The presence of a strong, empirical correlation between the two gas phases is indicative of a fundamental relationship between them, though as yet of undetermined cause. The cooler filaments, originally thought to have condensed from the hot gas, could also arise from a merger or the disturbance of cool circumnuclear gas by nuclear activity. Here, we have searched for intrinsic line emission polarization in cool core galaxy clusters as a diagnostic of fundamental transport processes. Drawing on developments in solar astrophysics, direct energetic particle impact induced polarization holds the promise to definitively determine the role of collisional processes such as thermal conduction in the ISM physics of galaxy clusters, while providing insight into other highly anisotropic excitation mechanisms such as shocks, intense radiation fields, and suprathermal particles. Under certain physical conditions, theoretical calculations predict of the order of 10% polarization. Our observations of the filaments in four nearby cool core clusters place stringent upper limits (lesssim 0.1%) on the presence of emission line polarization, requiring that if thermal conduction is operative, the thermal gradients are not in the saturated regime. This limit is consistent with theoretical models of the thermal structure of filament interfaces.en_US
dc.description.sponsorshipWe acknowledge support from grants HST GO-12271 and GO-11681. STScI/AURA is operated under grant NAS5-26555. JEP thanks the Distinguished Visitor Program at STScI for its continued hospitality.en_US
dc.description.urihttps://iopscience.iop.org/article/10.1088/0004-637X/780/1/66en_US
dc.format.extent49 pagesen_US
dc.genrejournal articles preprintsen_US
dc.identifierdoi:10.13016/m2c0bs-rdyc
dc.identifier.citationW. B. Sparks et al., POLARIZATION DIAGNOSTICS FOR COOL CORE CLUSTER EMISSION LINES, The Astrophysical Journal, Volume 780, Number 1, doi: 10.1088/0004-637x/780/1/66en_US
dc.identifier.uri10.1088/0004-637x/780/1/66
dc.identifier.urihttp://hdl.handle.net/11603/19495
dc.language.isoen_USen_US
dc.publisherIOPen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Physics Department Collection
dc.relation.ispartofUMBC Joint Center for Earth Systems Technology (JCET)
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
dc.rights© 2014. The American Astronomical Society. All rights reserved.
dc.titlePOLARIZATION DIAGNOSTICS FOR COOL CORE CLUSTER EMISSION LINESen_US
dc.typeTexten_US

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