Mapping the hot gas temperature in galaxy clusters using X-ray and Sunyaev-Zel'dovich imaging
Adam, R.; Arnaud, M.; Benoît, A.; Catalano, A.; Désert, F. -X.; Lagache, G.; Pajot, F.; Perotto, L.; Pointecouteau, E.; Pratt, G. W.; Rodriguez, L.; Bartalucci, I.; Bourdin, H.; Billot, N.; Romero, C.; Maurogordato, S.; Kramer, C.; André, P.; Beelen, A.; Ade, P.; Bourrion, O.; Calvo, M.; Doyle, S.; Goupy, J.; Leclercq, S.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Pisano, G.; Ponthieu, N.; Revéret, V.; Ritacco, A.; Ruppin, F.; Schuster, K.; Sievers, A.; Tucker, C.; Zylka, R.; Bideaud, A.; Coiffard, G.; Comis, B.; D'Addabbo, A.; Ferrari, C.; Pascale, E.; Triqueneaux, S.; Macías-Pérez, J. -F.
France, United Kingdom, Spain, Italy, United States
Abstract
We propose a method to map the temperature distribution of the hot gas in galaxy clusters that uses resolved images of the thermal Sunyaev-Zel'dovich (tSZ) effect in combination with X-ray data. Application to images from the New IRAM KIDs Array (NIKA) and XMM-Newton allows us to measure and determine the spatial distribution of the gas temperature in the merging cluster MACS J0717.5+3745, at z = 0.55. Despite the complexity of the target object, we find a good morphological agreement between the temperature maps derived from X-ray spectroscopy only - using XMM-Newton (TXMM) and Chandra (TCXO) - and the new gas-mass-weighted tSZ+X-ray imaging method (TSZX). We correlate the temperatures from tSZ+X-ray imaging and those from X-ray spectroscopy alone and find that TSZX is higher than TXMM and lower than TCXO by ~ 10% in both cases. Our results are limited by uncertainties in the geometry of the cluster gas, contamination from kinetic SZ (~10%), and the absolute calibration of the tSZ map (7%). Investigation using a larger sample of clusters would help minimise these effects.