RESEARCH
Tools & Datasets
FADO-SDSS spectral synthesis catalogue

The Sloan Digital Sky Survey (SDSS) is one of the most ambitious astronomy projects mapping a quarter of the entire sky in detail. In nearly 20 years of operation, it has acquired spectra for about 2.5 million galaxies with an average redshift of 0.1. These cover an optical spectral range of ~3800-9200 Å with a resolution of R = 1800-2200.

The huge publicly available set of high-quality SDSS data has made possible to produce numerous high-impact studies of galaxies in the local universe and substantially increase our knowledge on their formation and evolution. Here we provide the spectral modeling output for a subset of SDSS spectra with the conceptually novel population synthesis (PS) code FADO www.spectralsynthesis.org and http://www.iastro.pt/research/tools/fado.html (Fitting Analysis using Differential evolution Optimization; Gomes & Papaderos 2017). The reprocessing of SDSS spectra is motivated by the fact that FADO is the sole currently available PS code taking nebular emission into account and ensuring consistency between the best-fitting star-formation history (SFH) and the observed nebular emission characteristics (e.g., hydrogen Balmer-line luminosities and equivalent widths-EWs, shape of the continuum in the region around the Balmer and Paschen jump).

In this release we are providing the PS output for 5k randomly selected galaxy spectra, processed in the framework of an ongoing PS modeling of the entire SDSS spectroscopic data set with FADO and the public release of the results. We are also providing the results with FADO for the 1234 galaxies from the extended VIRGO cluster catalogue from Kim et al. (2014; ApJ Suppl. 215, 22 http://iopscience.iop.org/article/10.1088/0067-0049/215/2/22/pdf). Additional information on this sample is given in https://sites.google.com/site/extendedvcc/ from where ascii tables with various quantities can be downloaded. The Virgo Cluster is a cluster of galaxies whose center is 13.9 +/- 1.0 Mpc (assuming H0 = 73 km/s/Mpc, Ωmatter = 0.27, and Ωvacuum = 0.73) and based on the local velocity field model from Mould et al. (ApJ 529, 786, 2000) that takes into account the correction for Virgo infall, the infall into the Great Attractor, and that from the Shapley Supercluster.

The Virgo cluster comprises ~1300 (and possibly up to 2000) galaxies.

1. Data products: Value-added catalogs
The results for 5000 spectra are in

Ascii format
a) Single ascii file FADO_synt_tables.ascii (XXX Mb) containing 5000 galaxies
b) Single ascii file FADO_em_l_tables.ascii (XXX Mb) containing 5000 galaxies
c) Single ascii file FADO_observedpar.ascii (XXX Mb) containing 5000 galaxies

and the results containing all VIRGO objects processed with FADO are in
d) Single ascii file FADO_synt_tables_VIRGO.ascii (1.9 Mb) containing 1070 galaxies
e) Single ascii file FADO_em_l_tables_VIRGO.ascii (1.6 Mb) containing 1070 galaxies
f) Single ascii file FADO_observedpar_VIRGO.ascii (556 Kb) containing 1070 galaxies

These files are line-by-line matched with the specObj file and PLATEID, FIBERID, MJD values. Furthermore, whenever the file is set to -999, then the parameters are not considered reliable. These files contain measurements of synthesis by-products and emission lines in galaxies. Below there is a description of the content in each of these files.

2. Description of the a) FADO_synt_tables output from FADO
Header with 22 lines containing the following variables:

#TimeStamp: Time stamp
# lst_gals: List of galaxies processed
# gals_dir: Input directory used for the SDSS spectra
# outs_dir: Output directory used for the FADO analysis
# FADO_ver: Version of FADO used
# ODIE_ver: Release version
# OBJ_TYPE: Type of object
# ST__FITS: Statistics
# arq_base: Base file used
# arq_conf: Configuration file
# arq_mask: General mask for spectra
# R_LawOPT: Type of extinction law
# Numparam: Number of parameters used in the fit
# Num_base: Number of SSP elements
# Nindivid: Number of individuals
# Nleffect: Number of effective wavelengths
# IsNEBcOn: Nebular continuum flag
# IsNEBcPL: Power-law flag (currently locked feature)
# IsLeakOn: Leakage of ionizing photons (currently locked feature)
# Self_Con: Self-consistency flag
# lambda_0: Normalization wavelength
# Log Unit: Logarithm of the flux units

Each 122-column file contains:

# 001 spectrum | Spectrum processed with FADO
# 002 ElapsedT | Time elapsed to find the best-fit solution
# 003 chi2_val | Chi2 value
# 004 galsnorm | Normalization at lambda_0, i.e. the normalization wavelength
# 005 L_DisMpc | Luminosity distance in Mpc
# 006 Telectro | Electronic temperature
# 007 Delectro | Electronic density
# 008 Gextinct | Stellar extinction - Best value
# 009 GextBave | Stellar extinction - Mean value
# 010 GextBdev | Stellar extinction - Standard deviation
# 011 Gnebular | Nebular extinction - Best value
# 012 GnebBave | Nebular extinction - Mean value
# 013 GnebBdev | Nebular extinction - Standard deviation
# 014 v0sysgal | Stellar systemic velocity - Best value
# 015 v0sysave | Stellar systemic velocity - Mean value
# 016 v0sysdev | Stellar systemic velocity - Standard deviation
# 017 vdsysgal | Velocity dispersion - Best value
# 018 vdsysave | Velocity dispersion - Mean value
# 019 vdsysdev | Velocity dispersion - Standard deviation
# 020 v0nebgal | Planned for future versions
# 021 v0nebave | Planned for future versions
# 022 v0nebdev | Planned for future versions
# 023 vdnebgal | Planned for future versions
# 024 vdnebave | Planned for future versions
# 025 vdnebdev | Planned for future versions
# 026 bst_Lage | Mean stellar age weighted by light - Best value
# 027 ave_Lage | Mean stellar age weighted by light - Mean value
# 028 dev_Lage | Mean stellar age weighted by light - Standard deviation
# 029 bst_Mage | Mean stellar age weighted by mass - Best value
# 030 ave_Mage | Mean stellar age weighted by mass - Mean value
# 031 dev_Mage | Mean stellar age weighted by mass - Standard deviation
# 032 bstLLage | Mean stellar age logarithmically weighted by light - Best value
# 033 aveLLage | Mean stellar age logarithmically weighted by light - Mean value
# 034 devLLage | Mean stellar age logarithmically weighted by light - Standard deviation
# 035 bstLMage | Mean stellar age logarithmically weighted by mass - Best value
# 036 aveLMage | Mean stellar age logarithmically weighted by mass - Mean value
# 037 devLMage | Mean stellar age logarithmically weighted by mass - Standard deviation
# 038 bst_Lmet | Mean stellar metallicity weighted by light - Best value
# 039 ave_Lmet | Mean stellar metallicity weighted by light - Mean value
# 040 dev_Lmet | Mean stellar metallicity weighted by light - Standard deviation
# 041 bst_Mmet | Mean stellar metallicity weighted by mass - Best value
# 042 ave_Mmet | Mean stellar metallicity weighted by mass - Mean value
# 043 dev_Mmet | Mean stellar metallicity weighted by mass - Standard deviation
# 044 logMEbst | Logarithm of mass ever formed - Best value
# 045 logMEave | Logarithm of mass ever formed - Mean value
# 046 logMEdev | Logarithm of mass ever formed - Standard deviation
# 047 logMCbst | Logarithm of mass currently available - Best value
# 048 logMCave | Logarithm of mass currently available - Mean value
# 049 logMCdev | Logarithm of mass currently available - Standard deviation
# 050 logPEbst | Logarithm of mass ever formed for stellar populations with ages > 1 Myr - Best value
# 051 logPEave | Logarithm of mass ever formed for stellar populations with ages > 1 Myr - Mean value
# 052 logPEdev | Logarithm of mass ever formed for stellar populations with ages > 1 Myr - Standard deviation
# 053 logPCbst | Logarithm of mass currently available for stellar populations with ages > 1 Myr - Best value
# 054 logPCave | Logarithm of mass currently available for stellar populations with ages > 1 Myr - Mean value
# 055 logPCdev | Logarithm of mass currently available for stellar populations with ages > 1 Myr - Standard deviation
# 056 log_Lgal | Luminosity at the normalization wavelength - Best value
# 057 log_Lave | Luminosity at the normalization wavelength - Mean value
# 058 log_Ldev | Luminosity at the normalization wavelength - Standard deviation
# 059 Lbst1Gyr | Luminosity at the normalization wavelength for ages < 1 Gyr - Best value
# 060 Lave1Gyr | Luminosity at the normalization wavelength for ages < 1 Gyr - Mean value
# 061 Ldev1Gyr | Luminosity at the normalization wavelength for ages < 1 Gyr - Standard deviation
# 062 Lbst5Gyr | Luminosity at the normalization wavelength for ages < 5 Gyr - Best value
# 063 Lave5Gyr | Luminosity at the normalization wavelength for ages < 5 Gyr - Mean value
# 064 Ldev5Gyr | Luminosity at the normalization wavelength for ages < 5 Gyr - Standard deviation
# 065 bstlogQH | Logarithm of the number of ionizing photons for Hydrogen - Best value
# 066 avelogQH | Logarithm of the number of ionizing photons for Hydrogen - Mean value
# 067 devlogQH | Logarithm of the number of ionizing photons for Hydrogen - Standard deviation
# 068 Blg_QHeI | Logarithm of the number of ionizing photons for Helium I - Best value
# 069 Alg_QHeI | Logarithm of the number of ionizing photons for Helium I - Mean value
# 070 Dlg_QHeI | Logarithm of the number of ionizing photons for Helium I - Standard deviation
# 071 BlgQHeII | Logarithm of the number of ionizing photons for Helium II - Best value
# 072 AlgQHeII | Logarithm of the number of ionizing photons for Helium II - Mean value
# 073 DlgQHeII | Logarithm of the number of ionizing photons for Helium II - Standard deviation
# 074 Fbst__Ha | Flux of Halpha predicted - Best value (in the flux units of the input spectrum)
# 075 Fave__Ha | Flux of Halpha predicted - Mean value (in the flux units of the input spectrum)
# 076 Fdev__Ha | Flux of Halpha predicted - Standard deviation (in the flux units of the input spectrum)
# 077 EWbst_Ha | Equivalent-width of Halpha predicted - Best value
# 078 EWave_Ha | Equivalent-width of Halpha predicted - Mean value
# 079 EWdev_Ha | Equivalent-width of Halpha predicted - Standard deviation
# 080 Fbst__Hb | Flux of Hbeta predicted - Best value (in the flux units of the input spectrum)
# 081 Fave__Hb | Flux of Hbeta predicted - Mean value (in the flux units of the input spectrum)
# 082 Fdev__Hb | Flux of Hbeta predicted - Standard deviation (in the flux units of the input spectrum)
# 083 EWbst_Hb | Equivalent-width of Hbeta predicted - Best value
# 084 EWave_Hb | Equivalent-width of Hbeta predicted - Mean value
# 085 EWdev_Hb | Equivalent-width of Hbeta predicted - Standard deviation
# 086 FObst_Ha | Flux of Halpha observed - Best value
# 087 FOave_Ha | Flux of Halpha observed - Mean value
# 088 FOdev_Ha | Flux of Halpha observed - Standard deviation
# 089 EObst_Ha | Equivalent-width of Halpha observed - Best value
# 090 EOave_Ha | Equivalent-width of Halpha observed - Mean value
# 091 EOdev_Ha | Equivalent-width of Halpha observed - Standard deviation
# 092 FObst_Hb | Flux of Hbeta observed - Best value
# 093 FOave_Hb | Flux of Hbeta observed - Mean value
# 094 FOdev_Hb | Flux of Hbeta observed - Standard deviation
# 095 EObst_Hb | Equivalent-width of Hbeta observed - Best value
# 096 EOave_Hb | Equivalent-width of Hbeta observed - Mean value
# 097 EOdev_Hb | Equivalent-width of Hbeta observed - Standard deviation
# 098 tau__bst | Best tau-ratio (Predicted/Observed Halpha luminosities)
# 099 tau__ave | Mean tau-ratio (Predicted/Observed Halpha luminosities)
# 100 tau__dev | Standard deviation tau-ratio (Predicted/Observed Halpha luminosities)
# 101 tauRDbst | Best tau-ratio (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 102 tauRDave | Mean tau-ratio (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 103 tauRDdev | Standard deviation tau-ratio (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 104 tauP_bst | Best tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities)
# 105 tauP_ave | Mean tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities)
# 106 tauP_dev | Standard deviation tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities)
# 107 tauPEbst | Best tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 108 tauPEave | Mean tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 109 tauPEdev | Standard deviation tau-ratio for post-AGB stars (Predicted/Observed Halpha luminosities) - Extinction corrected fluxes
# 110 psi__bst | Planned for future versions
# 111 psi__ave | Planned for future versions
# 112 psi__dev | Planned for future versions
# 113 psiRDbst | Planned for future versions
# 114 psiRDave | Planned for future versions
# 115 psiRDdev | Planned for future versions
# 116 zeta_bst | Planned for future versions
# 117 zeta_ave | Planned for future versions
# 118 zeta_dev | Planned for future versions
# 119 zetaEbst | Planned for future versions
# 120 zetaEave | Planned for future versions
# 121 zetaEdev | Planned for future versions
# 122 flag_BPT | Pre-classification

3. Description of the b) FADO_em_l_tables output from FADO

Header with YY lines containing the following variables:

#TimeStamp: Time stamp
# lst_gals: List of galaxies processed
# gals_dir: Input directory used for the SDSS spectra
# outs_dir: Output directory used for the FADO analysis
# FADO_ver: Version of FADO used
# ODIE_ver: FADO version
# OBJ_TYPE: Type of object
# EL__FITS: Emission-lines
# arq_base: Base file used
# arq_conf: Configuration file
# arq_mask: General mask for spectra
# R_LawOPT: Type of exintinction law
# NE_lines: Number of Emission lines
# N_params: Number of parameters
# Totlines: Internal use
# Num_base: Number of SSP elements
# IsNEBcOn: Nebular continuum flag
# IsNEBcPL: Planned for future versions
# IsLeakOn: Planned for future versions
# Self_Con: Self-consistency criterion
# Converge: Convergence
# lambda_0: Normalization wavelength
# Log Unit: Logarithm of the flux units

# Order of each column
# | Flux | EW |
# | 1 | 2 |
# Block__1k
# EL_____1 [NeV] 3425.50000
# EL_____2 [OII] 3727.00000
# EL_____3 [OII] 3729.00000
# EL_____4 H12 3750.20000
# EL_____5 H11 3770.60000
# EL_____6 H10 3797.90000
# EL_____7 H9 3835.40000
# EL_____8 [NeIII] 3869.10000
# EL_____9 H8HeI 3889.00000
# EL____10 [NeIII] 3967.80000
# EL____11 Hepsilon 3970.10000
# EL____12 HeI 4026.20000
# EL____13 [SII] 4068.60000
# EL____14 [SII] 4076.30000
# EL____15 Hdelta 4101.70000
# EL____16 Hgamma 4340.50000
# EL____17 [OIII] 4363.20000
# EL____18 HeI 4471.50000
# EL____19 [FeIII] 4658.00000
# EL____20 HeII 4685.70000
# EL____21 [ArIV] 4711.40000
# EL____22 HeI 4713.20000
# EL____23 [ArIV] 4740.20000
# EL____24 Hbeta 4861.30000
# EL____25 HeI 4921.90000
# EL____26 [OIII] 4958.90000
# EL____27 [FeVII] 4988.60000
# EL____28 [OIII] 5006.80000
# EL____29 HeI 5015.70000
# EL____30 [FeVII] 5158.40000
# EL____31 [NI] 5199.10000
# EL____32 [FeIII] 5270.40000
# EL____33 [ClIII] 5519.20000
# EL____34 [NII] 5754.60000
# EL____35 HeI 5875.60000
# EL____36 [FeVII] 6086.30000
# EL____37 [OI] 6300.30000
# EL____38 [SIII] 6312.10000
# EL____39 [OI] 6363.80000
# EL____40 [NII] 6548.00000
# EL____41 Halpha 6562.80000
# EL____42 [NII] 6583.50000
# EL____43 HeI 6678.20000
# EL____44 [SII] 6716.40000
# EL____45 [SII] 6730.80000
# EL____46 HeI 7065.20000
# EL____47 [ArIII] 7135.80000
# EL____48 [OII] 7319.50000
# EL____49 [OII] 7330.20000
# EL____50 [ArIII] 7751.10000
# EL____51 [FeII] 8617.00000

4. The methods for processing the spectra with FADO are described below

All SDSS spectra were extracted and corrected for Galactic extinction using the attenuation curve from Cardelli, Clayton & Mathis (1989, hereafter CCM) with RV = 3.1 and two-dimensional dust maps from the MilkyWay (Schlafly & Finkbeiner 2011). The spectra were NOT rebinned prior to spectral fitting with FADO (please note that FADO does this automatically with a flux-conserving rebinning routine). The parameters in FADO.config were set such as to compute fits, whenever possible in the full self-consistency mode which has as goal that the best-fitting SFH and intrinsic extinction yields the best possible match to the observed Balmer-line luminosities and equivalent widths. The CCM redenning law was also assumed for the intrinsic extinction in the FADO models. Please note that the 150 base elements used come from Bruzual & Charlot (2003) with the "Padova 1994" tracks and the Chabrier (2003) stellar initial mass function.

This base was chosen due to being largely used in the literature and similar resolution as the SDSS spectra (FWHM~2.3 Å). Note that FADO has the currently unique capability of dealing with SSP bases with up to 2000 elements (no other PS code can effectively cope with SSP bases of that dimension). For almost all star-forming galaxies, FADO has succeeded to model the SDSS spectra in the full-consistency mode and produce high-quality fits.

During the PS fitting, i.e. the computation of the best-fitting stellar population model for the continuum, FADO simultaneously fits all nebular emission lines as Gaussians while taking into account the local continuum level. Note that these measurements have been obtained with FADO after subtraction of the stellar and nebular continuum, which greatly increases the accuracy of line fluxes and equivalent widths.

Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Fundação para a Ciência e a Tecnologia
OUTREACH
Outreach at IA