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Title: Brightest Cluster Galaxy Offsets in Cold Dark Matter

The distribution of offsets between the brightest cluster galaxies of galaxy clusters and the centroid of their dark matter distributions is a promising probe of the underlying dark matter physics. In particular, since this distribution is sensitive to the shape of the potential in galaxy cluster cores, it constitutes a test of dark matter self-interaction on the largest mass scales in the universe. We examine these offsets in three suites of modern cosmological simulations; IllustrisTNG, MillenniumTNG and BAHAMAS. For clusters above , we examine the dependence of the offset distribution on gravitational softening length, the method used to identify centroids, redshift, mass, baryonic physics, and establish the stability of our results with respect to various nuisance parameter choices. We find that offsets are overwhelmingly measured to be smaller than the minimum converged length scale in each simulation, with a median offset of in the highest resolution simulation considered, TNG300-1, which uses a gravitational softening length of . We also find that centroids identified via source extraction on smoothed dark matter and stellar particle data are consistent with the potential minimum, but that observationally relevant methods sensitive to cluster strong gravitational lensing scales, or those using the the “light traces mass” approach, in this context meaning gas is used as a tracer for the potential, can overestimate offsets by factors of10and30, respectively. This has the potential to reduce tensions with existing offset measurements which have served as evidence for a nonzero dark matter self-interaction cross section.

 
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Award ID(s):
1751096
PAR ID:
10537824
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
Maynooth Academic Publishing
Date Published:
Journal Name:
The Open Journal of Astrophysics
Volume:
7
ISSN:
2565-6120
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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Retrieved from https://par.nsf.gov/biblio/10537824. <em>The Open Journal of Astrophysics</em> 7. Web. doi:10.33232/001c.122309. </div> <div class="modal-footer"> <button class="btn btn-sm btn-default" data-dismiss="modal" aria-hidden="true">Close</button> </div> </div> </div> </div></li> <li class="links-format"><a href="#cite-apa" data-toggle="modal">APA</a> <div id="cite-apa" class="modal" tabindex="-1" role="dialog" aria-labelledby="cite-apa_label" aria-hidden="true"> <div class="modal-dialog"> <div class="modal-content"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> <strong id="cite-apa_label">Cite: APA Format</strong> </div> <div class="modal-body">Roche, Cian, McDonald, Michael, Borrow, Josh, Vogelsberger, Mark, Shen, Xuejian, Springel, Volker, Hernquist, Lars, Pakmor, Ruediger, Bose, Sownak, & Kannan, Rahul. <em>Brightest Cluster Galaxy Offsets in Cold Dark Matter</em>. <em>The Open Journal of Astrophysics</em>, <em>7</em> (). Retrieved from https://par.nsf.gov/biblio/10537824. <a href="https://doi.org/10.33232/001c.122309">https://doi.org/10.33232/001c.122309</a> </div> <div class="modal-footer"> <button class="btn btn-sm btn-default" data-dismiss="modal" aria-hidden="true">Close</button> </div> </div> </div> </div></li> <li class="links-format"><a href="#cite-chi" data-toggle="modal">Chicago</a> <div id="cite-chi" class="modal" tabindex="-1" role="dialog" aria-labelledby="cite-chi_label" aria-hidden="true"> <div class="modal-dialog"> <div class="modal-content"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> <strong id="cite-chi_label">Cite: Chicago Format</strong> </div> <div class="modal-body">Roche, Cian, McDonald, Michael, Borrow, Josh, Vogelsberger, Mark, Shen, Xuejian, Springel, Volker, Hernquist, Lars, Pakmor, Ruediger, Bose, Sownak, and Kannan, Rahul. "Brightest Cluster Galaxy Offsets in Cold Dark Matter". <em>The Open Journal of Astrophysics</em> 7 (). Country unknown/Code not available: Maynooth Academic Publishing. <a href="https://doi.org/10.33232/001c.122309">https://doi.org/10.33232/001c.122309.</a> <a href="https://par.nsf.gov/biblio/10537824">https://par.nsf.gov/biblio/10537824</a>. </div> <div class="modal-footer"> <button class="btn btn-sm btn-default" data-dismiss="modal" aria-hidden="true">Close</button> </div> </div> </div> </div></li> <li class="links-format"><a href="#cite-bib" data-toggle="modal">BibTeX</a> <div id="cite-bib" class="modal" tabindex="-1" role="dialog" aria-labelledby="cite-bib_label" aria-hidden="true"> <div class="modal-dialog"> <div class="modal-content"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> <strong id="cite-bib_label">Cite: BibTeX Format</strong> </div> <div class="modal-body"> @article{osti_10537824,<br/> place = {Country unknown/Code not available}, title = {Brightest Cluster Galaxy Offsets in Cold Dark Matter}, url = {https://par.nsf.gov/biblio/10537824}, DOI = {10.33232/001c.122309}, abstractNote = {The distribution of offsets between the brightest cluster galaxies of galaxy clusters and the centroid of their dark matter distributions is a promising probe of the underlying dark matter physics. In particular, since this distribution is sensitive to the shape of the potential in galaxy cluster cores, it constitutes a test of dark matter self-interaction on the largest mass scales in the universe. We examine these offsets in three suites of modern cosmological simulations; IllustrisTNG, MillenniumTNG and BAHAMAS. For clusters above , we examine the dependence of the offset distribution on gravitational softening length, the method used to identify centroids, redshift, mass, baryonic physics, and establish the stability of our results with respect to various nuisance parameter choices. We find that offsets are overwhelmingly measured to be smaller than the minimum converged length scale in each simulation, with a median offset of in the highest resolution simulation considered, TNG300-1, which uses a gravitational softening length of . We also find that centroids identified via source extraction on smoothed dark matter and stellar particle data are consistent with the potential minimum, but that observationally relevant methods sensitive to cluster strong gravitational lensing scales, or those using the the “light traces mass” approach, in this context meaning gas is used as a tracer for the potential, can overestimate offsets by factors of∼10and∼30, respectively. This has the potential to reduce tensions with existing offset measurements which have served as evidence for a nonzero dark matter self-interaction cross section.}, journal = {The Open Journal of Astrophysics}, volume = {7}, publisher = {Maynooth Academic Publishing}, author = {Roche, Cian and McDonald, Michael and Borrow, Josh and Vogelsberger, Mark and Shen, Xuejian and Springel, Volker and Hernquist, Lars and Pakmor, Ruediger and Bose, Sownak and Kannan, Rahul}, }</div> <div class="modal-footer"> <button class="btn btn-sm btn-default" data-dismiss="modal" aria-hidden="true">Close</button> </div> </div> </div> </div></li> <li class="divider"></li> </ul> <ul class="nav nav-list" style="font-size: 14px; font-family: Arial Regular;"> <li class="nav-header header-format">Export Metadata</li> <li class="links-format"><a href="https://par.nsf.gov/endnote?osti_id=10537824">EndNote</a></li> <li class="links-format"><a href="https://par.nsf.gov/export/format:excel/osti-id:10537824">Excel</a></li> <li class="links-format"><a href="https://par.nsf.gov/export/format:csv/osti-id:10537824">CSV</a></li> <li class="links-format"><a href="https://par.nsf.gov/export/format:xml/osti-id:10537824">XML</a></li> <li class="divider"></li> </ul> <ul class="nav nav-list" style="font-size: 14px; 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