Shapley GALEX Survey

The UV data consist of four contiguous GALEX pointings. The GALEX field of view is circular with diameter 1.2 deg, with pixel scale 1.5 arcsec. Each pointing is simultaneously observed in both the far-UV (FUV) and near-UV (NUV) bands with spatial resolution of 4.3 and 5.3 arcsecs respectively.

The exposure times are in the range 1238-1688 s.

Figure 1. Mosaic of the GALEX NUV images.

Sources were detected and measured using SExtractor (Bertin & Arnouts 1996). As the NUV images are deeper than the FUV images, we used the NUV images for detection. The flux detection limits and completeness of each image were determined by simulations. The resulting completeness levels are shown in Figure 2.

Figure2. Completeness of GALEX NUV and FUV photometric catalogues as function of m_AB. Thick lines show the values averaged over the four GALEX images, while the thin black lines indicate the completeness levels for the individual images.

We expect our UV catalogues to be 90% complete to m_AB(NUV)=22.0 and m_AB(FUV)=22.5. For star-galaxy classification we took profit of the K-band catalogue.

In total, 641 galaxies with both UV and K-band photometry have redshifts, of which 552 are supercluster members.

Details on the Shapley GALEX data are found in Rawle et al. 2008, MNRAS, 385, 209 and Haines et al. (2009 in prep.).

SOS: Shapley Optical Survey

The SOS data, obtained from the ESO Archive (68.A-0084, P.I. Slezak), were acquired with 2.2-m MPG/ESO telescope at La Silla. We analysed B- and R-band photometry of eight contiguous fields covering a 2 sqdeg region centered on the SSC, as shown in Fig. 1.

Figure 1. B-R composite image of a field close to the centre of cluster A 3556.

The observations were carried out with the WFI camera, a mosaic of eight 2046 x 4098 pixels CCDs, mounted on the Cassegrain focus of the telescope. The camera has a field of view of 34′ x 33′, corresponding to 2.0 x 1.9 Mpc^2 (H0=70) at the cluster redshift, and a pixel scale of 0.238 arcsec. The total exposure times for each field
are 1500 s in B band and 1200 s in R band. Landolt (1992) stars were observed in order to perform accurate photometric calibration. The typical accuracy on the zero-point is about 0.03 mag.

We used the ALAMBIC pipeline (version 1.0, Vandame 2004) to reduce and combine the SOS images. The pipeline follows the standard procedures for bias subtraction and flat-field correction; the twilight sky exposures for each band were used to create the master flat.

The photometric calibration was performed into the Johnson-Kron-Cousins photometric system using the Landolt stars.

The photometric catalogues from the SOS images were produced using SExtractor (Bertin & Arnouts, 1996) together with a set of software procedures developed by the authors in order to implement the quality of final catalogues, avoiding spurious detections and misleading results.

The final catalogues consist of 16588 and 28008 galaxies in B and R band, respectively, up to the completeness magnitude limits B=22.5 and R=22.0.

The data reduction and the characteristics of the catalogues are described in full detail in Mercurio et al. 2006 (see ADS).

Shapley K-band Survey

The K-band survey of the Shapley supercluster core was carried out at the United Kingdom Infra-Red telescope (UKIRT) with the Wide Field Infrared Camera (WFCAM) in April 2007. The WFCAM instrument consists of four 2048 x 2048 Rockwell detectors with a pixel scale of 0.4 arcsec.

A single exposure covers an equivalent area of 0.19 sqdeg and four interleaved exposures are required to achieve a filled tile of 0.865 deg on a side (0.78 sqdeg). We observed a mosaic of five complete tiles, covering a 3.043 sqdeg region centred on the SSC of which about 2 sqdeg overlap with the SOS.

The total exposure time for each field is 300 s, reaching K=19.5 mag at 5 sigma, with typical FWHMs of 0.9-1.2 arcsec.

The data was pipeline processed at WSA/CASU, reducing the frames and performing astrometric and photometric calibration with respect to 2MASS (Irwin et al. 2004). Zero-point uncertainty is 0.015 mag and astrometry accuracy is <0.1 arcsec (Irwin et al. 2004).

The completeness function was derived for each detector and turned out to be strongly dependent on the object density.Since in the high density region the completeness is less than 50 % beyond K=18.0 mag, we adopted this conservative limit as the magnitude to which catalogues can be reliably corrected for incompleteness.

The final catalogues consist of 18,534 galaxies with K<18 mag.

Details are found in Merluzzi et al. 2009 (see 2009arXiv0910.3877 ).

Shapley Spitzer Survey

The panoramic Spitzer mid-infrared observations of the Shapley supercluster core consist of five contiguous mosaics observed with MIPS (Rieke et al. 2004) in medium scan mode. the observation strategy allowed a homogeneous coverage across both 24 µm and 70 µm mosaics, with each point covered by two 24 µm scans and one 70 µm scan. The total exposure time is 84 s/pixel in the 24 µm band and 42 s/pixel in the 70µm band.

Figure 1. Mosaic of the Spitzer 24 µm images.

In total, 270 galaxies with 24 µm flux greater than 0.35 mJy (the 90% photometric completeness limit) are supercluster members. Our spectroscopic sample is 40% complete at the above flux limit. The survey covers the range 8E08 – 2E11 of solar luminosities.

The five MIPS mosaics were reduced independently with the MOPEX software. The 70 µm data were processed starting from the BCDs by means of the Germanium Reprocessing Tools to mitigate side lobes around bright sources. Sources were extracted with APEX. In both cases, the completeness and reliability of catalogues was assessed with simulations in which point sources have been added to the source-subtracted backgrounds. The completeness of the data is shown in Figure 2.

Figure 2. Completeness as a function of flux of 24 µm (left) and 70 µm (right) data. The results of simulations on the five individual mosaics are shown with black lines, while orange lines show the average values on the whole fields. Fluxes are aperture-corrected and units are mJy in both cases.