J/MNRAS/528/2790ivo://CDS.VizieR/J/MNRAS/528/2790doi:10.26093/cds/vizier.75282790CDSZibetti S.Rossi E.Gallazzi A.R.2024-11-06T20:35:11Z2024-02-07T12:21:31ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiesspectroscopyvisible-astronomystellar-populationsstellar-agesAs the reconstruction of the star-formation histories (SFH) of galaxies from spectroscopic data becomes increasingly popular, we explore the best age resolution achievable with stellar population synthesis (SPS) models, relying on different constraints: broad-band colours, absorption indices, a combination of the two, and the full spectrum. We perform idealized experiments on SPS models and show that the minimum resolvable relative duration of a star-formation episode (time difference between 10% and 90% of the stellar mass formed divided by the median age) is never better than 0.4, even when using spectra with signal-to-noise ratio (SNR) larger than 100 per {AA}. Typically, the best relative age resolution ranges between 0.4 and 0.7 over most of the age-metallicity plane, corresponding to minimum bin sizes for SFH sampling between 0.15 and 0.25dex. This resolution makes the spectroscopic exploration of distant galaxies mandatory in order to reconstruct the early phases of galaxies' SFHs. We show that spectroscopy with SNR>~20{AA}^-1^ is essential for good age resolution. Remarkably, using the full spectrum does not prove significantly more effective than relying on absorption indices, especially at SNR<~20{AA}^-1^. We discuss the physical origins of the age resolution trends as a function of age and metallicity, and identify the presence of maxima in age resolution (i.e. minima in measurable relative time duration) at the characteristic ages that correspond to quick time variations in spectral absorption features. We connect these maxima to bumps commonly observed in reconstructed SFHs.2024MNRAS.528.2790Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/528/2790CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/528/2790https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/528/2790http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/528/2790https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/528/2790https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/528/2790http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/528/2790GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/MNRAS/528/2790/fig2Fig.2 min dagen(age50,Z), different constraintsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col-Z002? Minimum dagen, colours only, Z=0.02 Zsuntime.agefloatnullablelogdagen-col-Z020? Minimum dagen, colours only, Z=0.20 Zsuntime.agefloatnullablelogdagen-col-Z040? Minimum dagen, colours only, Z=0.40 Zsuntime.agefloatnullablelogdagen-col-Z100? Minimum dagen, colours only, Z=1.00 Zsuntime.agefloatnullablelogdagen-col-Z250? Minimum dagen, colours only, Z=2.50 Zsuntime.agefloatnullablelogdagen-idx-Z002? Minimum dagen, indices only, Z=0.02 Zsuntime.agefloatnullablelogdagen-idx-Z020? Minimum dagen, indices only, Z=0.20 Zsuntime.agefloatnullablelogdagen-idx-Z040? Minimum dagen, indices only, Z=0.40 Zsuntime.agefloatnullablelogdagen-idx-Z100? Minimum dagen, indices only, Z=1.00 Zsuntime.agefloatnullablelogdagen-idx-Z250? Minimum dagen, indices only, Z=2.50 Zsuntime.agefloatnullablelogdagen-all-Z002? Minimum dagen, colours+indx, Z=0.02 Zsuntime.agefloatnullablelogdagen-all-Z020? Minimum dagen, colours+indx, Z=0.20 Zsuntime.agefloatnullablelogdagen-all-Z040? Minimum dagen, colours+indx, Z=0.40 Zsuntime.agefloatnullablelogdagen-all-Z100? Minimum dagen, colours+indx, Z=1.00 Zsuntime.agefloatnullablelogdagen-all-Z250? Minimum dagen, colours+indx, Z=2.50 Zsuntime.agefloatnullableJ/MNRAS/528/2790/fig3z002Fig.3.1 min dagen(age50), Z=0.02 Zsun for different spectroscopic SNR (indices)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col? Minimum dagen, colours onlytime.agefloatnullablelogdagen-SNR5? Minimum dagen, colours+indices SNR=5time.agefloatnullablelogdagen-SNR10? Minimum dagen, colours+indices SNR=10time.agefloatnullablelogdagen-SNR20? Minimum dagen, colours+indices SNR=20time.agefloatnullablelogdagen-SNR50? Minimum dagen, colours+indices SNR=50time.agefloatnullablelogdagen-SNR100? Minimum dagen, colours+indices SNR=100time.agefloatnullablelogdagen-SNR200? Minimum dagen, colours+indices SNR=200time.agefloatnullablelogdagen-SNR500? Minimum dagen, colours+indices SNR=500time.agefloatnullableJ/MNRAS/528/2790/fig3z020Fig.3.2 min dagen(age50), Z=0.20 Zsun for different spectroscopic SNR (indices)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col? Minimum dagen, colours onlytime.agefloatnullablelogdagen-SNR5? Minimum dagen, colours+indices SNR=5time.agefloatnullablelogdagen-SNR10? Minimum dagen, colours+indices SNR=10time.agefloatnullablelogdagen-SNR20? Minimum dagen, colours+indices SNR=20time.agefloatnullablelogdagen-SNR50? Minimum dagen, colours+indices SNR=50time.agefloatnullablelogdagen-SNR100? Minimum dagen, colours+indices SNR=100time.agefloatnullablelogdagen-SNR200? Minimum dagen, colours+indices SNR=200time.agefloatnullablelogdagen-SNR500? Minimum dagen, colours+indices SNR=500time.agefloatnullableJ/MNRAS/528/2790/fig3z040Fig.3.3 min dagen(age50), Z=0.40 Zsun for different spectroscopic SNR (indices)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col? Minimum dagen, colours onlytime.agefloatnullablelogdagen-SNR5? Minimum dagen, colours+indices SNR=5time.agefloatnullablelogdagen-SNR10? Minimum dagen, colours+indices SNR=10time.agefloatnullablelogdagen-SNR20? Minimum dagen, colours+indices SNR=20time.agefloatnullablelogdagen-SNR50? Minimum dagen, colours+indices SNR=50time.agefloatnullablelogdagen-SNR100? Minimum dagen, colours+indices SNR=100time.agefloatnullablelogdagen-SNR200? Minimum dagen, colours+indices SNR=200time.agefloatnullablelogdagen-SNR500? Minimum dagen, colours+indices SNR=500time.agefloatnullableJ/MNRAS/528/2790/fig3z100Fig.3.4 min dagen(age50), Z=1.00 Zsun for different spectroscopic SNR (indices)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col? Minimum dagen, colours onlytime.agefloatnullablelogdagen-SNR5? Minimum dagen, colours+indices SNR=5time.agefloatnullablelogdagen-SNR10? Minimum dagen, colours+indices SNR=10time.agefloatnullablelogdagen-SNR20? Minimum dagen, colours+indices SNR=20time.agefloatnullablelogdagen-SNR50? Minimum dagen, colours+indices SNR=50time.agefloatnullablelogdagen-SNR100? Minimum dagen, colours+indices SNR=100time.agefloatnullablelogdagen-SNR200? Minimum dagen, colours+indices SNR=200time.agefloatnullablelogdagen-SNR500? Minimum dagen, colours+indices SNR=500time.agefloatnullableJ/MNRAS/528/2790/fig3z250Fig.3.5 min dagen(age50), Z=2.50 Zsun for different spectroscopic SNR (indices)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagen-col? Minimum dagen, colours onlytime.agefloatnullablelogdagen-SNR5? Minimum dagen, colours+indices SNR=5time.agefloatnullablelogdagen-SNR10? Minimum dagen, colours+indices SNR=10time.agefloatnullablelogdagen-SNR20? Minimum dagen, colours+indices SNR=20time.agefloatnullablelogdagen-SNR50? Minimum dagen, colours+indices SNR=50time.agefloatnullablelogdagen-SNR100? Minimum dagen, colours+indices SNR=100time.agefloatnullablelogdagen-SNR200? Minimum dagen, colours+indices SNR=200time.agefloatnullablelogdagen-SNR500? Minimum dagen, colours+indices SNR=500time.agefloatnullableJ/MNRAS/528/2790/fig4Fig.4 min dagen(age50), Z=1.00 Zsun for different spectroscopic constraints at different SNR (different panels)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagenIdxcol-5? Minimum dagen, SNR=5 colours+indices (logdagen-idxcol-SNR5)time.agefloatnullablelogdagen-FS-n-5? Minimum dagen, SNR=5 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR5)time.agefloatnullablelogdagenFS-w-5? Minimum dagen, SNR=5 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR5)time.agefloatnullablelogdagenFS-r-n-5? Minimum dagen, SNR=5 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR5)time.agefloatnullablelogdagenFS-r-w-5? Minimum dagen, SNR=5 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR5)time.agefloatnullablelogdagenIdxcol-10? Minimum dagen, SNR=10 colours+indices (logdagen-idxcol-SNR10)time.agefloatnullablelogdagenFS-n-10? Minimum dagen, SNR=10 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR10)time.agefloatnullablelogdagenFS-w-10? Minimum dagen, SNR=10 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR10)time.agefloatnullablelogdagenFS-r-n-10? Minimum dagen, SNR=10 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR10)time.agefloatnullablelogdagenFS-r-w-10? Minimum dagen, SNR=10 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR10)time.agefloatnullablelogdagenIdxcol-20? Minimum dagen, SNR=20 colours+indices (logdagen-idxcol-SNR20)time.agefloatnullablelogdagenFS-n-20? Minimum dagen, SNR=20 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR20)time.agefloatnullablelogdagenFS-w-20? Minimum dagen, SNR=20 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR20)time.agefloatnullablelogdagenFS-r-n-20? Minimum dagen, SNR=20 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR20)time.agefloatnullablelogdagenFS-r-w-20? Minimum dagen, SNR=20 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR20)time.agefloatnullablelogdagenIdxcol-100? Minimum dagen, SNR=100 colours+indices (logdagen-idxcol-SNR100)time.agefloatnullablelogdagenFS-n-100? Minimum dagen, SNR=100 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR100)time.agefloatnullablelogdagenFS-w-100? Minimum dagen, SNR=100 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR100)time.agefloatnullablelogdagenFS-r-n-100? Minimum dagen, SNR=100 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR100)time.agefloatnullablelogdagenFS-r-w-100? Minimum dagen, SNR=100 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR100)time.agefloatnullableJ/MNRAS/528/2790/figa1Fig.A1 min dagen(age50), Z=0.20 Zsun for different spectroscopic constraints at different SNR (different panels)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogage50Median age of the stellar populationlog(yr)time.age;stat.medianfloatlogdagenIdxcol-5? Minimum dagen, SNR=5 colours+indices (logdagen-idxcol-SNR5)time.agefloatnullablelogdagen-FS-n-5? Minimum dagen, SNR=5 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR5)time.agefloatnullablelogdagenFS-w-5? Minimum dagen, SNR=5 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR5)time.agefloatnullablelogdagenFS-r-n-5? Minimum dagen, SNR=5 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR5)time.agefloatnullablelogdagenFS-r-w-5? Minimum dagen, SNR=5 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR5)time.agefloatnullablelogdagenIdxcol-10? Minimum dagen, SNR=10 colours+indices (logdagen-idxcol-SNR10)time.agefloatnullablelogdagenFS-n-10? Minimum dagen, SNR=10 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR10)time.agefloatnullablelogdagenFS-w-10? Minimum dagen, SNR=10 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR10)time.agefloatnullablelogdagenFS-r-n-10? Minimum dagen, SNR=10 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR10)time.agefloatnullablelogdagenFS-r-w-10? Minimum dagen, SNR=10 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR10)time.agefloatnullablelogdagenIdxcol-20? Minimum dagen, SNR=20 colours+indices (logdagen-idxcol-SNR20)time.agefloatnullablelogdagenFS-n-20? Minimum dagen, SNR=20 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR20)time.agefloatnullablelogdagenFS-w-20? Minimum dagen, SNR=20 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR20)time.agefloatnullablelogdagenFS-r-n-20? Minimum dagen, SNR=20 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR20)time.agefloatnullablelogdagenFS-r-w-20? Minimum dagen, SNR=20 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR20)time.agefloatnullablelogdagenIdxcol-100? Minimum dagen, SNR=100 colours+indices (logdagen-idxcol-SNR100)time.agefloatnullablelogdagenFS-n-100? Minimum dagen, SNR=100 full spectrum [3800-5600{AA}] (logdagen-FS-narrow-SNR100)time.agefloatnullablelogdagenFS-w-100? Minimum dagen, SNR=100 full spectrum [3500-7000{AA}] (logdagen-FS-wide-SNR100)time.agefloatnullablelogdagenFS-r-n-100? Minimum dagen, SNR=100 full spectrum rectified [3800-5600{AA}] (logdagen-FS-rect-narrow-SNR100)time.agefloatnullablelogdagenFS-r-w-100? Minimum dagen, SNR=100 full spectrum rectified [3500-7000{AA}] (logdagen-FS-rect-wide-SNR100)time.agefloatnullable