VI/157 Full-spectrum fitting of simple stellar pop. (Goudfrooij+, 2021)
On the precision of full-spectrum fitting of simple stellar populations.
II. The dependence on star cluster mass in the wavelength range 0.3-5.0um.
Goudfrooij P., Asa'd R.
<Mon. Not. R. Astron. Soc., 501, 440-466>
=2021MNRAS.501..440G 2021MNRAS.501..440G
=2021yCat.6157....0G 2021yCat.6157....0G
ADC_Keywords: Models ; Populations, stellar ; Spectroscopy
Keywords: stars: abundances - stars: luminosity function, mass function -
galaxies: star clusters: general
Abstract:
In this second paper of a series on the accuracy and precision of the
determination of age and metallicity of simple stellar populations
(SSPs) by means of the full spectrum fitting technique, we study the
influence of star cluster mass through stochastic fluctuations of the
number of stars near the top of the stellar mass function, which
dominate the flux in certain wavelength regimes depending on the
age.We consider SSP models based on the Padova isochrones, spanning
the age range 7.0≤log(age/yr)≤10.1. Simulated spectra of star
clusters in the mass range 104≤M/M☉<106 are compared with
SSP model spectra to determine best-fit ages and metallicities using a
full-spectrum fitting routine in four wavelength regimes: the blue
optical (0.35-0.70um), the red optical (0.6-1.0um), the near-IR
(1.0-2.5um), and the mid-IR (2.5-5.0um). We compare the power of each
wavelength regime in terms of both the overall precision of age and
metallicity determination, and of its dependence on cluster mass. We
also study the relevance of spectral resolution in this context by
utilizing two different spectral libraries (BaSeL and BT-Settl). We
highlight the power of the mid-IR regime in terms of identifying young
massive clusters in dusty star forming regions in distant galaxies.
The spectra of the simulated star clusters and SSPs are made available
online to enable follow-up studies by the community.
Description:
The cluster spectra:
The integrated-light spectra of the simulated clusters are provided in
the following 9 gzipped tar files, with file sizes listed in in the
first column:
456K clustersBTSettl1e4
44K clustersBTSettl1e5
152K clustersBTSettl3e4
16K clustersBTSettl3e5
388K clustersBaSeL1e4
76K clustersBaSeL1e5
4K clustersBaSeL1e6
132K clustersBaSeL3e4
28K clustersBaSeL3e5
where "BaSeL" and "BTSettl" indicate the spectral library used to
create the integrated-light spectra (see paper for more details on
that), and "1e4", "3e4", etc., indicates the mass of the clusters in
the tar file in question (in solar masses).
Every cluster spectrum in these tar files is named as follows:
clus_p_..spec.dat
where:
- metallicity code is the fractional part of Z
(example: 'p008' means Z = 0.008).
- age code is log(age/yr) in f5.2 format times hundred
(example: '0980' means log(age/yr) = 9.80)
The spectra consist of ASCII files with two columns: Wavelength (in
Angstroms) and surface Flux density (in F_lambda units).
The SSP spectra:
the integrated-light spectra of the simulated SSPs are provided in the
following two gzipped tar files, with file sizes listed in the first
column:
12K SSP_BTSettl
12K SSP_BaSeL
The naming and format of the SSP spectra are the same as those for the
cluster spectra described above. Note however that the cluster spectra
used in this paper were only created for Z = 0.008 while the SSP
spectra were created for Z = 0.002, 0.003, 0.005, 0.008, 0.012, 0.019,
and 0.025.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 158 29901 List of individual spectra
SSP_BTSettl/* . 238 Spectrum with BTSettl library
SSP_BaSeL/* . 238 Spectrum with BaSeL library
clustersBTSettl1e4/* . 9601 Integrated-light spectrum, BTSettl library
clustersBTSettl1e5/* . 897 Integrated-light spectrum, BTSettl library
clustersBTSettl3e4/* . 3201 Integrated-light spectrum, BTSettl library
clustersBTSettl3e5/* . 321 Integrated-light spectrum, BTSettl library
clustersBaSeL1e4/* . 9601 Integrated-light spectrum, BTSettl library
clustersBaSeL1e5/* . 1887 Integrated-light spectrum, BaSeL library
clustersBaSeL1e6/* . 71 Integrated-light spectrum, BaSeL library
clustersBaSeL3e4/* . 3201 Integrated-light spectrum, BaSeL library
clustersBaSeL3e5/* . 654 Integrated-light spectrum, BaSeL library
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 51 A51 --- FileName Name of the spectrum file with localisation
53-158 A106 --- Title Title of the file
--------------------------------------------------------------------------------
Acknowledgements:
Paul Goudfrooij, goudfroo(at)stsci.edu
(End) Patricia Vannier [CDS] 01-Dec-2020