We have deduced the cosmic microwave background temperature in the Coma Cluster (A1656, z = 0.0231) and in A2163 (z = 0.203) from spectral measurements of the Sunyaev-Zeldovich (SZ) effect over four passbands at radio and microwave frequencies. The resulting temperatures at these redshifts are T Coma = 2.789 -0.065 +0.080 K and T A2163 = 3.377 -0.102 +0.101 K, respectively. These values confirm the expected relation T(z) - T 0(1 + z), where T 0 = 2.725 ± 0.002 K is the value measured by the COBE Far Infrared Absolute Spectrometer experiment. Alternative scaling relations that are conjectured in nonstandard cosmologies can be constrained by the data; for example, if T(z) = T 0(1 + z) 1-a or T(z) = T 0[1 + (1 + d)z], then a = -0.16 -0.32 +0.34 and d = 0.17 ± 0.36 (at 95% confidence). We briefly discuss future prospects for more precise SZ measurements of T(z) at higher redshifts.
Cosmic Microwave Background temperature at Galaxy Cluster / Battistelli, Elia Stefano; DE PETRIS, Marco; Lamagna, Luca; Melchiorri, F; Palladino, E; Savini, G; Cooray, A; Melchiorri, Alessandro; REPHAELI Y., And; Shimon, M.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 580:(2002), pp. 101-104. [10.1086/345589]
Cosmic Microwave Background temperature at Galaxy Cluster
BATTISTELLI, Elia Stefano
;DE PETRIS, Marco;LAMAGNA, Luca;MELCHIORRI, Alessandro;
2002
Abstract
We have deduced the cosmic microwave background temperature in the Coma Cluster (A1656, z = 0.0231) and in A2163 (z = 0.203) from spectral measurements of the Sunyaev-Zeldovich (SZ) effect over four passbands at radio and microwave frequencies. The resulting temperatures at these redshifts are T Coma = 2.789 -0.065 +0.080 K and T A2163 = 3.377 -0.102 +0.101 K, respectively. These values confirm the expected relation T(z) - T 0(1 + z), where T 0 = 2.725 ± 0.002 K is the value measured by the COBE Far Infrared Absolute Spectrometer experiment. Alternative scaling relations that are conjectured in nonstandard cosmologies can be constrained by the data; for example, if T(z) = T 0(1 + z) 1-a or T(z) = T 0[1 + (1 + d)z], then a = -0.16 -0.32 +0.34 and d = 0.17 ± 0.36 (at 95% confidence). We briefly discuss future prospects for more precise SZ measurements of T(z) at higher redshifts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.