This PAUS Early Data Release (EDR) corresponds to PAUS data obtained in the COSMOS field, described and used in
The PAU Survey: Early demonstration of photometric redshifts (M.Eriksen, A.Alarcon et al. ) 2018, MNRAS 484, 4200–4215 , https://arxiv.org/abs/1809.0437
Please read this paper first before using the data. The EDR release table is in CosmoHub.
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As part of this EDR, we also release, through CosmoHub, the PAU MillGas Lightcone galaxy catalog constructed from the semi-analytic galaxy formation model Galform, which was presented in Stothert et al. (2018). Find more information in the release page of the mock.
The EDR is a JOIN of 3 tables: COSMOS (or reference catalog), PAUDM_FORCED_APERTURE_COADD (this include narrow band fluxes and errors; v821) and BCNZ (this is the photo-z estimation described in Eriksen etal 2018; v866).
Here is a bit more detail about the columns in each table.
COSMOS: is the reference catalog that we use to do forced Narrow Band photometry. Is a join of 3 public catalogs:
- zCOSMOS-30 catalog: Ilbert, Capak, Salvato et al., ApJ, 2008, astro-ph/0809.2101
- Zurich Structure&Morphology catalog – version v1.0 (README_cosmos_morph_zurich_1.0.txt): Scarlata, Carollo, Lilly et al 2007, ApJS, 172, 406, Sargent, Carollo, Lilly et al 2007, ApJS, 172, 434
- zCOSMOS public redshift catalog (ADP.2015-10-15T12_55_10.777_t2.txt)
PAUDM_FORCED_APERTURE_COADD: which adds Narrow Band photometry in 40 bands (each from co-adds of 3-10 exposures). These are the last few columns:
BCNZ photo-z as described in the Eriksen etal paper linked above. These are the first few columns, starting with column ‘zb’, which is the photo-z:
The EDR table contains all the above columns for data with i_auto<22.5 and qz<4 (refer to Eriksen etal 2018 for details). Only good quality photo-z are included in this release as we are still finding the origen of outliers and bad quality data.
You can read here tips to process it as a python panda data frame. There are 6493 separate galaxies with spectra of difference confidence classes. For the Eriksen etal paper we only used 3<= conf < 5. Each galaxy entry has information from 200 (40×5) independent PAUcam exposures.
This plot compares spectroscopic redshifts (column “zspec”) vs photometric redshifts (column “zb”) from the EDR table.
Warning As explained in the above paper, these results are preliminary and we are still working in several points to improve them: - Working on optimal force photometry subtraction. Current flux values in above files correspond to 62.5% apertures (using HST morphological information when available) without weights. Current PSF convolution uses a single PSF value for all the CCD field. Working on GaaP weighted gaussian PSF homogenisation. - Zero-points are being revised to account to variation across FoV. - Improved flat field and scatter light corrections. - Improved background subtraction. - Photo-z estimation is based on template min-Chi2 fit on SED subsets and does not currently account for Bayesian priors in the subset of models. We have noticed that this produces global zero point dependence on wavelength which affect ebv values.