ELAIS SEDs Update ------------------------------- Mark Allen (CDS), Dec 22, 2004 This is an update to the example files and scripts for generating SEDs from the ELAIS catalogue. The IDL procedure for generating the SEDs has been updated so that the aperture corrections are applied to the optical magnitudes. This solves the issue of reproducing the SEDs as displyed in the Rowan-Robinson paper. Minor changes have also been made to the JHK central wavelengths, and the K band zero point. Concurrently, Noel Winstanley is translating the original IDL scripts into 'groovy' scripts so that these steps can be done in the AstroGrid workflow. The updates described here should be only minor changes to the groovy script, and I suggest they be implemented after Noel has made his first cut of the translation. RED, BLUE and ERO subsets -------------------------- The subsets of objects in the catalogue have been better defined into 3 groups. - A low redshift (z<0.5) RED sample (5 objects) [ detected in all optical bands, r-i > 0.8 AND g-r > 1.2 ] - A low redshift (z<0.5) BLUE sample (83 objects_ [ detected in all optical bands, r-i < 0.8 AND g-r < 1.2 ] - An Extremely Red Objects (ERO) sample (4 objects) [ r' - K > 3.5, detected in all optical and NIR bands ] Tables of RED, BLUE and ERO subsets ----------------------------------- Tables including the converted fluxes have been generated for all the ELAIS sources, and the subsets elaiscat_21a_mga3.vot - All ELAIS sources (VOTable) elaiscat_21a_mga3_fluxes.vot - All ELAIS sources flux cols only (VOTable) elaiscat_21a_mga3_fluxes.txt - " (ascii) ELAIS_RED_fluxes.vot - RED sources (VOTable) ELAIS_RED_fluxes.txt - " (ascii) ELAIS_BLUE_fluxes.vot - BLUE sources (VOTable) ELAIS_BLUE_fluxes.txt - " (ascii) ELAIS_ERO_fluxes.vot - ERO sources (VOTable) ELAIS_ERO_fluxes.txt - " (ascii) SEDs of RED, BLUE and ERO subsets ---------------------------------- The SEDs of all the sources have been generated in both 'original measurements', and 'normalized+redshifted' form. The specview compatible txt files of these SEDs are available in the tar files: SEDs_21dec04.tar SEDs_norm_21dec04.tar SSA files describing URL available SEDs ---------------------------------------- These same files are also available via URL, and are described in the following SSA files. These SSA files can be loaded into the AVO prototype (locally), which then provides direct access to the SED files from my URL. ELAIS_RED_norm_sed_ssa.txt - normalized RED source SEDs ELAIS_RED_sed_ssa.txt - RED source SEDs ELAIS_BLUE_norm_sed_ssa.txt - normalized BLUE source SEDs ELAIS_BLUE_sed_ssa.txt - BLUE source SEDs ELAIS_ERO_norm_sed_ssa.txt - normalized ERO source SEDs ELAIS_ERO_sed_ssa.txt - ERO source SEDs These files, the SSA access mechanism, and the interop with the original catalogues in the prototype is starting to make it easy to use and visualise these SEDs. For example, ELAISC15_J161302.4+542846_orig+norm.png is a specview screen shot where the original and normalized SEDs of an example object are shown in specview. This is done by loading the various SSA files, making catalog planes of the catalog subsets by the "create catalog plane of spectra" feature, and selecting one objects and loading all the SEDs of that object into specview using the coplot feature. When SSA files of the models are created, this same process can be used to easily plot the models over the SEDs, which is the whole point. Combining ELAIS with SWIRE --------------------------- Ideally we would also like to combine the ELAIS catalogue with the new, high quality data from the SWIRE catalogue (Vizier II/255/iraccat). This has been tested for a small set of objects. Tests by Piero Rosati brought up a few scientific issues relating again to aperture corrections etc. These can probably be overcome, but I note that the combining of catalogs to make SEDs is an additional layer of complexity to the process. I plan to : - Combine the catalogues and generate SEDs similar to what I've done here for the ELAIS catalogue. (this could be a little bit tricky because it requires careful matching of the catalogues, and taking aperture corrections into account) - Generate a set of SWIRE (only) SEDs, that could in principle be ploted with the ELAIS ones. This is easy, and involves very minor changes to my current IDL scripts. Porting all these processes into groovy scripts to be integral to the demo would again require Noel's help. I suggest we see how he handles the first step of translating the current IDL scripts for the ELAIS SEDs before we burden him with this extra complexity.