Science Highlight




Science Verification: RXCJ1347-1145


RXCJ1347-1145 is one of the most X-ray luminous galaxy clusters and exhibits a very centrally-compact Sunyaev-Zeldovich (SZ) source.

Example references: Schindler et al. 1997, A&A 317, 646; Mason et al. 2010, ApJ 716, 739

Capabilities to be verified

With this target we will demonstrate the Cycle 1 imaging extended structure capabilities. Observations will use the 12-m array plus the 7-m array (ACA), in Band 3 continuum. We need to demonstrate that ALMA can image weak extended structures accurately and SZ observations are one of the more important cases of this type. For cycle 1 we will not have single-dish continuum capability but, for relatively compact SZ sources, the 7-m array should be able to obtain good images. The combination of the 7-m and 12-m arrays is particularly important because of the need to subtract accurately the emission from individual sources in the field. Correlator modes to be used are: low spectral resolution.


Because the SZ deviation is deep and relatively compact this is the easiest object on which to demonstrate ALMA's ability to make SZ measurements. The declination of -12 means that we can get good overlap between the 12-m and 7-m arrays despite the limitations on the number of 7-m antennas available at present.


Initial observations carried out. If data of suitable quality for release is obtained, an announcement will appear here prior to the Science Verification data being publicly released via the ALMA Science Portal.