Probing galaxy evolution in massive clusters using ACT and DES: splashback as a cosmic clock
Creators: name: Adhikari, Susmita
name: Shin, Tae-hyeon
name: Jain, Bhuvnesh
name: Hilton, Matt
name: Baxter, Eric
name: Chang, Chihway
name: Wechsler, Risa H.
name: Battaglia, Nick
name: Bond, J. Richard
name: Bocquet, Sebastian
name: DeRose, Joseph
name: Choi, Steve K.
name: Devlin, Mark
name: Dunkley, Jo
name: Evrard, August E.
name: Ferraro, Simone
name: Hill, J. Colin
name: Hughes, John P.
name: Gallardo, Patricio A.
name: Lokken, Martine
name: MacInnis, Amanda
name: McMahon, Jeffrey
name: Madhavacheril, Mathew S.
name: Nati, Frederico
name: Newburgh, Laura B.
name: Niemack, Michael D.
name: Page, Lyman A.
name: Palmese, Antonella
name: Partridge, Bruce
name: Rozo, Eduardo
name: Rykoff, Eli
name: Salatino, Maria
name: Schillaci, Alessandro
name: Sehgal, Neelima
name: Sifón, Cristóbal
name: To, Chun-Hao
name: Wollack, Ed
name: Wu, Hao-Yi
name: Xu, Zhilei
name: Aguena, Michel
name: Allam, Sahar
name: Amon, Alexandra
name: Annis, James
name: Avila, Santiago
name: Bacon, David
name: Bertin, Emmanuel
name: Bhargava, Sunayana
name: Brooks, David
name: Burke, David L.
name: Rosell, Aurelio C.
name: Kind, Matias Carrasco
name: Carretero, Jorge
name: Castander, Francisco Javier
name: Choi, Ami
name: Costanzi, Matteo
name: da Costa, Luiz N.
name: De Vicente, Juan
name: Desai, Shantanu
name: Diehl, Thomas H.
name: Doel, Peter
name: Everett, Spencer
name: Ferrero, Ismael
name: Ferté, Agnès
name: Flaugher, Brenna
name: Fosalba, Pablo
name: Frieman, Josh
name: García-Bellido, Juan
name: Gaztanaga, Enrique
name: Gruen, Daniel
name: Gruendl, Robert A.
name: Gschwend, Julia
name: Gutierrez, Gaston
name: Hartley, Will G.
name: Hinton, Samuel R.
name: Hollowood, Devon L.
name: Honscheid, Klaus
name: James, David J.
name: Jeltema, Tesla
name: Kuehn, Kyler
name: Kuropatkin, Nikolay
name: Lahav, Ofer
name: Lima, Marcos
name: Maia, Marcio A. G.
name: Marshall, Jennifer L.
name: Martini, Paul
name: Melchior, Peter
name: Menanteau, Felipe
name: Miquel, Ramon
name: Morgan, Robert
name: Ogando, Ricardo L. C.
name: Paz-Chinchón, Francisco
name: Malagón, Andrés Plazas
name: Sanchez, Eusebio
name: Santiago, Basilio
name: Scarpine, Vic
name: Serrano, Santiago
name: Sevilla-Noarbe, Ignacio
name: Smith, Mathew
name: Soares-Santos, Marcelle
name: Suchyta, Eric
name: Swanson, Molly E. C.
name: Varga, Tamas N.
name: Wilkinson, Reese D.
name: Zhang, Yuanyuan
name: Austermann, Jason E.
name: Beall, James A.
name: Becker, Daniel T.
name: Denison, Edward V.
name: Duff, Shannon M.
name: Hilton, Gene C.
name: Hubmayr, Johannes
name: Ullom, Joel N.
name: Van Lanen, Jeff
name: Vale, Leila R.
name: Collaboration, DES
name: Collaboration, ACT
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We measure the projected number density profiles of galaxies and the splashback feature in clusters selected by the Sunyaev--Zeldovich (SZ) effect from the Advanced Atacama Cosmology Telescope (AdvACT) survey using galaxies observed by the Dark Energy Survey (DES). The splashback radius for the complete galaxy sample is consistent with theoretical measurements from CDM-only simulations, and is located at $2.4^{+0.3}_{-0.4}$ Mpc $h^{-1}$. We split the sample based on galaxy color and find significant differences in the profile shapes. Red galaxies and those in the green valley show a splashback-like minimum in their slope profile consistent with theoretical predictions, while the bluest galaxies show a weak feature that appears at a smaller radius. We develop a mapping of galaxies to subhalos in $N$-body simulations by splitting subhalos based on infall time onto the cluster halos. We find that the location of the steepest slope and differences in the shapes of the profiles can be mapped to differences in the average time of infall of galaxies of different colors. The minima of the slope in the galaxy profiles trace a discontinuity in the phase space of dark matter halos. By relating spatial profiles to infall time for galaxies of different colours, we can use splashback as a clock to understand galaxy quenching. We find that red galaxies have on average been in their clusters for over $3.2 ~\rm Gyrs$, green galaxies about $2.2 ~\rm Gyrs$, while blue galaxies have been accreted most recently and have not reached apocenter. Using the information from the complete radial profiles, we fit a simple quenching model and find that the onset of galaxy quenching in clusters occurs after a delay of about a gigayear, and that galaxies quench rapidly thereafter with an exponential timescale of $0.6$ Gyr.
description: 23 pages, 10 figures, to be submitted to ApJ