MG15 - Talk detail

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 Participant

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Session

Accepted

Yes

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Time

Talk

Title

Abstract

Ordered non-thermal motions (e.g. rotation) of the intra-cluster medium (ICM) in galaxy clusters can play an important role in estimating cluster masses accurately. We propose an update on the characterization of possible ICM rotation through the temperature distortion of the cosmic microwave backgroud (CMB) produced by the kinetic Sunyaev--Zel'dovich effect (kSZ). We apply this study to data from the high-resolution MUSIC simulations (Sembolini et al., 2013), selecting the most massive and relaxed galaxy clusters, having spin parameter of the gas larger than 0.07. We produce maps of the the kSZ effect and fit them to a suitable theoretical map, which we construct using a radial profile for the rotational velocity proposed in a companion paper, named vp2b model. We treat both a simplified case, accounting only for the rotational component, and a more realistic one which includes also the cluster bulk motion. We find that it is possible to reconstruct the expected radial profile of the tangential velocity of the gas within two standard deviations at most in both the aforementioned cases, averaging over different lines of sight. We can also recover the projected bulk velocity of the cluster within few tens of per cent with respect to the true values from the simulations. From the comparison between the amplitude of the dipole -- which is consistent with previous estimates from the literature -- and the maximum kSZ signal obtained when accounting for the cluster bulk, the contribution from rotation is found to be of the order of 23 per cent, at the best observational conditions. This confirms that a high sensitivity is needed for the detection of ICM rotation from kSZ maps.

Pdf file

Session

Accepted

Yes

Order

Time

Talk

Title

Abstract

Ordered non-thermal motions (e.g. rotation) of the intra-cluster medium (ICM) in galaxy clusters can play an important role in estimating cluster masses accurately. We propose an update on the characterization of possible ICM rotation through the temperature distortion of the cosmic microwave backgroud (CMB) produced by the kinetic Sunyaev--Zel'dovich effect (kSZ). We apply this study to data from the high-resolution MUSIC simulations (Sembolini et al., 2013), selecting the most massive and relaxed galaxy clusters, having spin parameter of the gas larger than 0.07. We produce maps of the the kSZ effect and fit them to a suitable theoretical map, which we construct using a radial profile for the rotational velocity proposed in a companion paper, named vp2b model. We treat both a simplified case, accounting only for the rotational component, and a more realistic one which includes also the cluster bulk motion. We find that it is possible to reconstruct the expected radial profile of the tangential velocity of the gas within two standard deviations at most in both the aforementioned cases, averaging over different lines of sight. We can also recover the projected bulk velocity of the cluster within few tens of per cent with respect to the true values from the simulations. From the comparison between the amplitude of the dipole -- which is consistent with previous estimates from the literature -- and the maximum kSZ signal obtained when accounting for the cluster bulk, the contribution from rotation is found to be of the order of 23 per cent, at the best observational conditions. This confirms that a high sensitivity is needed for the detection of ICM rotation from kSZ maps.

Pdf file

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