24/11/2008 STAGES Data Release contact: Meghan.Gray [at] nottingham.ac.uk 1. INTRODUCTION ----------------------------------------------------------------------------- STAGES (Space Telescope A901/902 Galaxy Evolution Survey) is a large area (~0.5x0.5 degree) survey of the Abell 901(a,b)/902 multiple-cluster system at z=0.165. An 80-tile imaging mosaic in F606W was conducted in Cycle 13 under GO program 10395 (PI: Gray). Parallel observations with WFPC2 and NIC3 were also taken but are not included in this data release. This README documents the data products available at MAST for the STAGES. The contents include reduced HST/ACS images for each of the 80 tiles in the F606W ACS mosaic, as well as postage stamps for all objects in the field and the complete output of GALFIT profile fitting. The STAGES ACS data are located in the anonymous ftp area on archive.stsci.edu in the directory /pub/hlsp/stages/. To retrieve all data, ftp to archive.stsci.edu, login as anonymous and cd /pub/hlsp/stages. For all details regarding the survey construction, data reduction, and catalogue creation see: M. Gray et al. "STAGES: The Space Telescope A901/902 Galaxy Evolution Survey" MNRAS, 2008 (accepted) To download the associated STAGES master catalogue (including SExtractor and GALFIT parameters; COMBO-17 photometry, photometric redshifts and stellar masses; and UV and 24 micron derived star formation rates) or additional multiwavelength data, visit the STAGES homepage: http://www.nottingham.ac.uk/astronomy/stages 2. IMAGING DATA FOR DOWNLOAD FROM MAST: ----------------------------------------------------------------------------- A note about naming convention: Full images are referred to by tile number (XX), and postage stamps of individual objects by tile number and object number (NNNN) within that tile. For the STAGES master catalogue, the relevant columns are XX = ST_TILE [1,80] NNNN = ST_NUMBER [1,9999] * For each tile, there exists: hlsp_stages_hst_acs-wfc_XX_f606w_v1_sci.fits <- original science image (sky subtracted, units=counts/s) hlsp_stages_hst_acs-wfc_XX_f606w_v1_flx.fits <- science image converted to flux units (sky added in, units=counts) hlsp_stages_hst_acs-wfc_XX_f606w_v1_wht.fits <- weight image hlsp_stages_hst_acs-wfc_XX_f606w_v1.jpg <- colour jpeg of tile stages_galfit_XX.tgz <- gzipped tar file of GALFIT fitting results (including postage stamps) stages_galfit_XX/ <- browseable directory of GALFIT output For tiles 44, 78, and 79, bright stars in the field were removed prior to profile fitting. The original *flx.fits images without this correction are available and named hlsp_stages_hst_acs-wfc_44_f606w_v1_flx_orig.fits hlsp_stages_hst_acs-wfc_78_f606w_v1_flx_orig.fits hlsp_stages_hst_acs-wfc_79_f606w_v1_flx_orig.fits * For each tile, the output from GALFIT is contained within stages_galfit_XX (browsable) or stages_galfit_XX.tgz (downloadable). The data were processed with the data pipeline GALAPAGOS (Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SExtractor; Barden et al in prep.). The algorithm includes running SExtractor in dual dynamic range mode ("hot" and "cold"; described in detail in Gray et al 2008). aXX.check.cold.fits <- check image with SExtractor apertures (cold run) aXX.check.hot.fits <- same for hot run aXX.coldcat <- SExtractor ascii detections catalogue (cold run) aXX.hotcat <- same for hot run aXX.outcat <- combined catalogue (using GALAPAGOS) aXX.outparam <- SExtractor parameter file (i.e. column headers for the aforementioned catalogues) aXX.coldseg.fits <- SExtractor segmentation map (cold run) aXX.hotseg.fits <- same for hot run aXX.skymap.fits <- map with enlarged SExtractor apertures; pixel values changed to 0,1,2,3,... depending on number of overlapping sources at that pixel based on aperture (definition in GALAPAGOS paper) aXX.stamps <- postage stamps definition file aXX.vNNNN.fits <- postage stamp image aXX.NNNN.fits <- colour jpeg postage stamp aXX.v_gfNNNN.fits <- GALFIT output file aXX.objNNNN <- GALFIT startup file aXX.constrNNN <- GALFIT constraint file aXX_maskNNNN.fits <- GALFIT object mask aXX.outskyNNNN <- GALAPAGOS estimated sky 3. FOR FURTHER REFERENCE: -------------------------------------------------------------------- STAGES: Gray et al. 2008, MNRAS (accepted) GALFIT: Peng et al 2002, AJ, 124, 266 GALAPAGOS: Barden et al 2008 (in prep)