학술논문
Planck intermediate results
Document Type
article
Author
Ade, PAR; Aghanim, N; Arnaud, M; Ashdown, M; Aubourg, E; Aumont, J; Baccigalupi, C; Banday, AJ; Barreiro, RB; Bartolo, N; Battaner, E; Benabed, K; Benoit-Lévy, A; Bersanelli, M; Bielewicz, P; Bock, JJ; Bonaldi, A; Bonavera, L; Bond, JR; Borrill, J; Bouchet, FR; Burigana, C; Calabrese, E; Cardoso, J-F; Catalano, A; Chamballu, A; Chiang, HC; Christensen, PR; Clements, DL; Colombo, LPL; Combet, C; Crill, BP; Curto, A; Cuttaia, F; Danese, L; Davies, RD; Davis, RJ; de Bernardis, P; de Zotti, G; Delabrouille, J; Dickinson, C; Diego, JM; Dolag, K; Donzelli, S; Doré, O; Douspis, M; Ducout, A; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, TA; Eriksen, HK; Finelli, F; Forni, O; Frailis, M; Fraisse, AA; Franceschi, E; Frejsel, A; Galeotta, S; Galli, S; Ganga, K; Génova-Santos, RT; Giard, M; Gjerløw, E; González-Nuevo, J; Górski, KM; Gregorio, A; Gruppuso, A; Hansen, FK; Harrison, DL; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, SR; Hivon, E; Hobson, M; Hornstrup, A; Huffenberger, KM; Hurier, G; Jaffe, AH; Jaffe, TR; Jones, WC; Juvela, M; Keihänen, E; Keskitalo, R; Kitaura, F; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J-M; Lasenby, A; Lattanzi, M; Lawrence, CR; Leonardi, R; León-Tavares, J; Levrier, F; Liguori, M; Lilje, PB
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Subject
Language
Abstract
By looking at the kinetic Sunyaev-Zeldovich effect (kSZ) in Planck nominal mission data, we present a significant detection of baryons participating in large-scale bulk flows around central galaxies (CGs) at redshift z ≈ 0.1. We estimate the pairwise momentum of the kSZ temperature fluctuations at the positions of the Central Galaxy Catalogue (CGC) samples extracted from Sloan Digital Sky Survey (SDSS-DR7) data. For the foreground-cleaned SEVEM, SMICA, NILC, and COMMANDER maps, we find 1.8-2.5σ detections of the kSZ signal, which are consistent with the kSZ evidence found in individual Planck raw frequency maps, although lower than found in the WMAP-9yr W-band (3.3σ). We further reconstruct the peculiar velocity field from the CG density field, and compute for the first time the cross-correlation function between kSZ temperature fluctuations and estimates of CG radial peculiar velocities. This correlation function yields a 3.0-3.7σ detection of the peculiar motion of extended gas on Mpc scales in flows correlated up to distances of 80-100 h-1 Mpc. Both the pairwise momentum estimates and the kSZ temperature-velocity field correlation find evidence for kSZ signatures out to apertures of 8 arcmin and beyond, corresponding to a physical radius of >1 Mpc, more than twice the mean virial radius of halos. This is consistent with the predictions from hydrodynamical simulations that most of the baryons are outside the virialized halos. We fit a simple model, in which the temperature-velocity cross-correlation is proportional to the signal seen in a semi-analytic model built upon N-body simulations, and interpret the proportionality constant as an effective optical depth to Thomson scattering. We find τT = (1.4 ± 0.5) × 10-4; the simplest interpretation of this measurement is that much of the gas is in a diffuse phase, which contributes little signal to X-ray or thermal Sunyaev-Zeldovich observations.