S-COSMOS IRAC GO2 Delivery 27May2007 O. Ilbert + M.Salvato + S-COSMOS team I. Basic Information Telescope: Spitzer Instrument: IRAC PI: David B. Sanders Program Title: SCOSMOS Program ID: 20070 IRAC Bands: 3.6, 4.5, 5.8 amd 8 um SSC Software Version: S14.0.0 See SSC website for S14.0 data issues and Calibration. II. Products READme (this file) IRAC_0407_IRSA.tbl catalog for sources having total flux in 3.6um >1uJ [uJ] irac_ch1_gO2_sci.fits 3.6um image [MJ/sr] irac_ch1_g02_cov.fits 3.6um coverage map [MJ/sr] irac_ch1_g02_unc.fits 3.6um uncertainty map irac_ch2_gO2_sci.fits 4.5um image [MJ/sr] irac_ch2_g02_cov.fits 4.5um coverage map[MJ/sr] irac_ch2_g02_unc.fits 4.5um uncertainty map irac_ch3_gO2_sci.fits 5.8um image [MJ/sr] irac_ch3_g02_cov.fits 5.8um coverage map[MJ/sr] irac_ch3_g02_unc.fits 5.8um uncertainty map irac_ch4_gO2_sci.fits 8.0um image [MJ/sr] irac_ch4_g02_cov.fits 8.0um coverage map[MJ/sr] irac_ch4_g02_unc.fits 8.0um uncertainty map Columns of the catalog: 1 ID unique IRAC 3.6um ID number null 2 Xcoo X coordinates in pixels on IRAC 3.6um mosaic pix 3 Ycoo Y coordinates in pixels on IRAC 3.6um mosaic pix 4 BKG Background at centroid position uJ 5 Thresh Detection threshold above background uJ 6 flux_max Peak flux above background uJ 7 RA_2000 Right ascension of barycenter (J2000) deg 8 DEC_2000 Declination of barycenter (J2000) deg 9 CXX Cxx object ellipse parameter x^(-2) 10 CYY Cyy object ellipse parameter x^(-2) 11 CXY Cxy object ellipse parameter x^(-2) 12 A Profile RMS along major axis pix 13 B Profile RMS along minor axis pix 14 Theta Position angle (CCW/x) deg 15 FLAG SExtractor flag null 16 flux_c1_1 Flux in 3.6um in 1.4" aperture uJ 17 err_c1_1 error uJ 18 flux_c1_2 Flux in 3.6um in 1.9" aperture uJ 19 err_c1_2 error uJ 20 flux_c1_3 Flux in 3.6um in 2.9" aperture uJ 21 err_c1_3 error uJ 22 flux_c1_4 Flux in 3.6um in 4.1" aperture uJ 23 err_c1_4 error uJ 24 fl_c1 data quality flag in 3.6um image null 25 flux_c2_1 Flux in 4.5um in 1.4" aperture uJ 26 err_c2_1 error uJ 27 flux_c2_2 Flux in 4.5um in 1.9" aperture uJ 28 err_c2_2 error uJ 29 flux_c2_3 Flux in 4.5um in 2.9" aperture uJ 30 err_c2_3 error uJ 31 flux_c2_4 Flux in 4.5um in 4.1" aperture uJ 32 err_c2_4 error uJ 33 fl_c2 data qiality flag in 4.5um image null 34 flux_c3_1 Flux in 5.8um in 1.4" aperture uJ 35 err_c3_1 error uJ 36 flux_c3_2 Flux in 5.8um in 1.9" aperture uJ 37 err_c3_2 error uJ 38 flux_c3_3 Flux in 5.8um in 2.9" aperture uJ 39 err_c3_3 error uJ 40 flux_c3_4 Flux in 5.8um in 4.1" aperture uJ 41 err_c3_4 error uJ 42 fl_c3 data quality flag in 5.8um image null 43 flux_c4_1 Flux in 8.0um in 1.4" aperture uJ 44 err_c4_1 error uJ 45 flux_c4_2 Flux in 8.0um in 1.9" aperture uJ 46 err_c4_2 error uJ 47 flux_c4_3 Flux in 8.0um in 2.9" aperture uJ 48 err_c4_3 error uJ 49 flux_c4_4 Flux in 8.0um in 4.1" aperture uJ 50 err_c4_4 error on uJ 51 fl_c4 quality flag in 8.0um image null Notes on the images (1) Images are color corrected (2) images are in MJ/sr, pixel scale of 0.6"/px: they are dithered with a factor of 0.65 (3) The astrometry has as an accuracy of 0.5" (2MASS catalog used as reference) (4) To transform the images in uJ/pix the conversion factor 8.4616 has been used. Notes on the catalog (1) The catalog includes photometry in the 4 IRAC channels for all those sources that have a measured flux in IRAC Channel 1 above 1 uJy [micro-Jansky]. In the catalog, this flux is listed in column #16, "flux_c1_1". (2) The first 15 columns are standard outputs (Astrometric and geometric parameters) of SExstractor (http://terapix.iap.fr/IMG/pdf/sextractor.pdf) (3) The following corrections (flux_catalog/correction) should be applied to each channel/aperture, in order to obtain the total flux: 1.4'' 1.9'' 2.9'' 4.1'' ch1 0.610 0.765 0.900 0.950 ch2 0.590 0.740 0.900 0.940 ch3 0.490 0.625 0.840 0.940 ch4 0.450 0.580 0.730 0.910 (4) For very faint sources (roughly 4% of the catalog), measured fluxes in the larger apertures will be reported with a negative number or have lower fluxes than those measured in the smaller apertures. These are objects lying near much brighter objects that compromise measurement of the background. Despite the poorer flux measures, these sources have been retained in the catalog since their infrared detections are nonetheless real. For accurate photometry we advise that flux_c#_2 be used whenever it is larger than flux_c#_3 and flux_c#_4 (where #=1,2,3,4 is the IRAC channel number). (5) Objects close to bright stars or close to the border of the images, do not have reliable measured flux. Values in flag columns #24 (fl_c1), #33 (fl_c2), #42 (fl_c3) and #51 (fl_c4) indicate whether a source is close to a bright star (1 and 2) or not (0). All sources with flag=0 in all the 4 channels are reliable. Note on Flags: To improve the detection of blended objects, an agressive detection method using a Mexican hat filter was employed. A drawback of this technique is that it produces many false sources at the borders of bright stars. In order to label these spurious detections, masks have been created at the locations of 2MASS point sources brighter than K=14. IRAC detections that are in a non-masked region are assigned flag=0. An IRAC detection falling into the masked area of a 2MASS object brighter than K=14 is considered a true detection and replaced with its detection using a Gaussian filter instead. Such sources are flagged with 1 or 2; flag=1 for 10