Multiwavelength Analysis of A1240, the Double Radio-relic Merging Galaxy Cluster Embedded in an 80 Mpc-long Cosmic Filament

January 2022 • 2022ApJ...925...68C

Authors • Cho, Hyejeon • James Jee, M. • Smith, Rory • Finner, Kyle • Lee, Wonki

Abstract • We present a multiwavelength study of the double radio-relic cluster A1240 at z = 0.195. Our Subaru-based weak-lensing analysis detects three mass clumps forming an ~4 Mpc filamentary structure elongated in a north-south orientation. The northern ( ${M}_{200}={2.61}_{-0.60}^{+0.51}\times {10}^{14}{M}_{\odot }$ ) and middle ( ${M}_{200}={1.09}_{-0.43}^{+0.34}\times {10}^{14}{M}_{\odot }$ ) mass clumps separated by ~1.3 Mpc are associated with A1240 and colocated with the X-ray peaks and cluster galaxy overdensities revealed by Chandra and MMT/Hectospec observations, respectively. The southern mass clump ( ${M}_{200}={1.78}_{-0.55}^{+0.44}\times {10}^{14}{M}_{\odot }$ ), ~1.5 Mpc to the south of the middle clump, coincides with the galaxy overdensity in A1237, the A1240 companion cluster at z = 0.194. Considering the positions, orientations, and polarization fractions of the double radio relics measured by the LOFAR study, we suggest that A1240 is a postmerger binary system in the returning phase with a time since collision of ~1.7 Gyr. With the SDSS DR16 data analysis, we also find that A1240 is embedded in the much larger scale (~80 Mpc) filamentary structure whose orientation is in remarkable agreement with the hypothesized merger axis of A1240.

Links

• PREPRINT http://arxiv.org/abs/2109.06879
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2022ApJ...925...68C
• ELECTR https://doi.org/10.3847%2F1538-4357%2Fac36c8
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2022ApJ...925...68C
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ac36c8/pdf
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/925/68
• DATA https://cda.harvard.edu/chaser?obsid=4961