Star Formation Activity in CLASH Brightest Cluster Galaxies

摘要: The CLASH X-ray selected sample of 20 galaxy clusters contains ten brightest cluster galaxies (BCGs) that exhibit significant ($>$5 $\sigma$) extinction-corrected star formation rates (SFRs). Star activity is inferred from photometric estimates UV and H$\alpha$+[\ion{N}{2}] emission in knots filaments detected HST ACS WFC3 observations. UV-derived SFRs these BCGs span two orders magnitude, including with a SFR $\gtrsim$ 100 M$_{\odot}$ yr$^{-1}$. These measurements are supplemented [\ion{O}{2}], [\ion{O}{3}], H$\beta$ fluxes measured spectra obtained the SOAR telescope. We confirm photoionization ongoing powers line nebulae BCGs, although many there also evidence LINER-like contribution to emission. Coupling data Chandra measurements, we infer occurs exclusively low-entropy cores exhibits correlation gas properties related cooling. perform an in-depth study starburst history BCG RXJ1532.9+3021, create 2D maps stellar on scales down $\sim$350 pc. reveal for burst occurring elongated filaments, generally $\sim$ 0.5-1.0 Gyr timescales, some consistent much younger ($\lesssim$ Myr) timescales may be correlated recent AGN. relationship between surrounding ICM provide new support process feedback-regulated cooling theoretical predictions.