J/MNRAS/432/2746 POPSTAR models. III. Young star clusters (Garcia-Vargas+, 2013)
POPSTAR evolutionary synthesis models.
III. Photometric properties of young star clusters and mixed populations.
Garcia-Vargas M.L., Molla M., Martin-Manjon M.L.
<Mon. Not. R. Astron. Soc., 432, 2746-2772 (2013)>
=2013MNRAS.432.2746G 2013MNRAS.432.2746G
ADC_Keywords: Models, evolutionary ; Photometry ; Colors
Keywords: H II regions - galaxies: abundances - galaxies: evolution -
galaxies: starburst - galaxies: star clusters: general -
galaxies: stellar content
Abstract:
This is the third paper of a series reporting the results from the
POPSTAR evolutionary synthesis models. The main goal of this work is
to present and discuss the synthetic photometric properties of single
stellar populations resulting from our POPSTAR code. Colours in the
Johnson and Sloan Digital Sky Survey (SDSS) systems, Hα and
Hβ luminosities and equivalent widths, and ionizing region size,
have been computed for a wide range of metallicity (Z=0.0001-0.05) and
age (0.1Myr to 20Gyr). We calculate the evolution of the cluster and
the region geometry in a consistent manner. We demonstrate the
importance of the contribution of emission lines to broader band
photometry when characterizing stellar populations, through the
presentation of both contaminated and non-contaminated colours (in
both the Johnson and SDSS systems). The tabulated colours include
stellar and nebular components, in addition to line emission. The main
application of these models is the determination of physical
properties of a given young ionizing cluster, when only photometric
observations are available; for an isolated star-forming region, the
young star cluster models can be used, free from the contamination of
any underlying background stellar population. In most cases, however,
the ionizing population is usually embedded in a large and complex
system, and the observed photometric properties result from the
combination of a young star-forming burst and the underlying older
population of the host. Therefore, the second objective of this paper
is to provide a grid of models useful in the interpretation of mixed
regions where the separation of young and old populations is not
sufficiently reliable. We describe the set of popstar spectral energy
distributions (SEDs), and the derived colours for mixed populations
where an underlying host population is combined in different
mass-ratios with a recent ionizing burst. These colours, together with
other common photometric parameters, such as the Hα radius of
the ionized region, and Balmer line equivalent widths and
luminosities, allow one to infer the physical properties of
star-forming regions even in the absence of spectroscopic information.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 56 4116 Computed radii for the modelled stellar clusters of
all ages and metallicities, for ne=10 and 100cm-3
table4.dat 110 6216 Johnson colours evolution results for the modelled
stellar clusters of all ages and metallicities,
for ne=10 and 100cm-3
table5.dat 114 6216 SDSS colour evolution results for the modelled
stellar clusters of all ages and metallicities,
for ne=10 and 100cm-3
list.dat 43 198 List of tables in subdirectory "models" giving the
evolution of clusters with 2 populations
models/* . 198 Individual files for each combination of 6
metallicities and 33 ages for the old stellar
population (table 6)
table6.zip 512 225425 All tables included in the subdirectory "models"
and listed in list.dat
--------------------------------------------------------------------------------
Description of file: table6.zip
table6.zip includes all the files listed in list.dat and available
individually in the subdirectory "models".
We have calculated the colours of a system composed of two
populations: one older than 100Myr (logτ(yr)≥8.00) and one
younger than this same limit (logτ<8.00). The stellar mass of the
young population in this model grid takes the same values as in the
SSP models: 0.12, 0.20, 0.40, 0.60, 1.0, 1.5 and 2.0 x105M☉.
For each model or composite system, we assume an old stellar
population with a mass on the zero time main sequence defined by a
factor F=Mold/Myoung. We have taken 6 possible values for
this grid, F=0, 1, 10, 100, 1000 and 5000. Colours are computed by
using the total luminosity emitted by both the old population and the
young stellar population, including the emission lines contribution
and the nebular continuum.
We have obtained a table for each old stellar population defined by
its age and metallicity, where all possible combinations with the
young stellar population (scanning the grid in mass, age and
metallicity of the young cluster) are included. table6.zip is a zip
file with all these tables (198 files, 33 ages for each of the six
metallicities).
See section 4 for further explanations.
See also:
J/MNRAS/403/2012 : PopStar II. Giant HII regions models (Martin-Manjon+, 2010)
J/MNRAS/398/451 : PopStar I: Evolutionary synthesis models (Molla+, 2009)
J/A+A/471/795 : Population ages & metallicities from colors (Li+, 2007)
J/A+A/428/837 : HII regions in minor mergers of galaxies (Ferreiro+, 2004)
J/AJ/108/1276 : Clusters in GEHRs (Mayya, 1994)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 cm-3 ne [10/100] Electron density of the stellar cluster
ISM used for CLOUDY models (10 or 100)
6- 11 F6.4 --- Z [0.0001/0.05] Total abundance of the stellar
cluster
13- 17 F5.2 [yr] logt [5/8] Log of age of the stellar cluster
19- 22 F4.1 10+4Msun Mass [1.2/20] Initial total cluster mass
24- 33 F10.5 pc Rin [4.7/445.3] Inner radius of the HII region
35- 45 E11.5 pc deltaR Shell thickness of the HII region
47- 56 F10.5 pc Rout [6/8597] External radius (observed) of
the HII region
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 cm-3 ne [10/100] Electron density of the stellar
cluster ISM used for CLOUDY models
7- 12 F6.4 --- Z [0.0001/0.05] Total abundance of the
stellar cluster
14- 18 F5.2 [yr] logt [5/8] Log of the age of the stellar cluster
20- 25 I6 Msun Mass [12000/200000] Initial total mass in stars
in the cluster
28- 32 F5.2 [10-7W] logLHb [31/40] Log of luminosity of the Hβ line
in erg/s
34- 38 F5.2 [10-7W] logLHa [31/41] Log of luminosity of the Hα line
in erg/s
40- 46 F7.3 mag VMagc [-14.192/-6.948] Absolute V-band magnitude
including emission lines
48- 53 F6.3 mag U-Bc U-B color index including emission lines
55- 60 F6.3 mag B-Vc B-V color index including emission lines
62- 67 F6.3 mag V-Rc V-R color index including emission lines
69- 74 F6.3 mag R-Ic R-I color index including emission lines
76- 82 F7.3 mag VMag [-14.093/-6.948] V-band absolute magnitude
(uncontaminated)
84- 89 F6.3 mag U-B [-1.413/-0.241] Johnson U-B color index
91- 96 F6.3 mag B-V [-0.255/0.466] Johnson B-V color index
98-103 F6.3 mag V-R [-0.093/0.523] Johnson V-R color index
105-110 F6.3 mag R-I [-0.147/1.051] Johnson R-I color index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 cm-3 ne [10/100] Electron density of the stellar
cluster ISM used for CLOUDY
7- 12 F6.4 --- Z [0.0001/0.05] Total abundance of the
stellar cluster
14- 18 F5.2 [yr] logt [5/8] Log of the stellar cluster age
20- 25 I6 Msun Mass [12000/200000] Initial total mass in stars
in the cluster
28- 34 F7.1 0.1nm EWHb [-10.6/500.4] Equivalent width of the Hβ
line in Å
36- 42 F7.1 0.1nm EWHa [-67.6/3412] Equivalent width of the Hα
line in Å
44- 50 F7.3 mag gMagc [-13.921/-6.569] Absolute magnitude in g-band
including emission lines
52- 57 F6.3 mag (u-g)c u-g color index including emission lines
59- 64 F6.3 mag (g-r)c g-r color index including emission lines
66- 71 F6.3 mag (r-i)c r-i color index including emission lines
73- 78 F6.3 mag (i-z)c i-z color index including emission lines
80- 86 F7.3 mag gMag [-13.535/-6.569] Uncontaminated absolute
g-band magnitude
88- 93 F6.3 mag u-g [-0.731/0.751] SDSS u-g color index
95-100 F6.3 mag g-r [-0.431/0.345] SDSS g-r color index
102-107 F6.3 mag r-i [-0.366/0.437] SDSS r-i color index
109-114 F6.3 mag i-z [-0.652/0.678] SDSS i-z color index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.4 --- Z [0.0001/0.05] Metallicity
8- 12 F5.2 [yr] logt [8/11] Age of the old stellar population (log)
14- 43 A30 --- FileName Name of the table in subdirectory models
--------------------------------------------------------------------------------
Byte-by-byte Description of file (#): models/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 7 F6.4 --- Z.o Old stellar population metallicity
9- 13 F5.2 [yr] logt.o Age (logarithmic scale) of the
old stellar population (τ)
15- 20 F6.4 --- Z.y Young stellar population metallicity
22- 26 F5.2 [yr] logt.y Age (logarithmic scale) of the young
stellar population
28- 31 I4 --- F Ratio Mold/Myoung
33- 40 E8.2 Msun M.y Mass of the young stellar population
42- 48 F7.2 pc Rout The HII region outer (or photometric) radius
50- 54 F5.2 [10-7W] LHa Logarithm of the luminosity of Hα line
56- 62 F7.2 0.1nm EWHa The equivalent width of Hα in Å
64- 70 F7.3 mag Vc Magnitude V in the Johnson system corrected
by the emission line contribution
72- 78 F7.3 mag (U-B)c Colour U-B in the Johnson system corrected
by the emission line contribution
80- 86 F7.3 mag (B-V)c Colour B-V in the Johnson system corrected
by the emission line contribution
88- 94 F7.3 mag (V-R)c Colour V-R in the Johnson system corrected
by the emission line contribution
96-102 F7.3 mag (R-I)c Colour R-I in the Johnson system corrected
by the emission line contribution
104-110 F7.3 mag V Magnitude V in the Johnson system without
the emission line contribution
112-118 F7.3 mag U-B Colour U-B in the Johnson system without
the emission line contribution
120-126 F7.3 mag B-V Colour B-V in the Johnson system without
the emission line contribution
128-134 F7.3 mag V-R Colour V-R in the Johnson system without
the emission line contribution
136-142 F7.3 mag R-I Colour R-I in the Johnson system without
the emission line contribution
144-150 F7.3 mag gc Magnitude V in the SDSS system corrected
by the emission line contribution
152-158 F7.3 mag (u-g)c Colour U-B in the SDSS system corrected
by the emission line contribution
160-166 F7.3 mag (g-r)c Colour B-V in the SDSS system corrected
by the emission line contribution
168-174 F7.3 mag (r-i)c Colour V-R in the SDSS system corrected
by the emission line contribution
176-182 F7.3 mag (i-z)c Colour R-I in the SDSS system corrected
by the emission line contribution
184-190 F7.3 mag g Magnitude V in the SDSS system without
the emission line contribution
192-198 F7.3 mag u-g Colour U-B in the SDSS system without
the emission line contribution
200-206 F7.3 mag g-r Colour B-V in the SDSS system without
the emission line contribution
208-214 F7.3 mag r-i Colour V-R in the SDSS system without
the emission line contribution
216-222 F7.3 mag i-z Colour R-I in the SDSS system without
the emission line contribution
-------------------------------------------------------------------------------
Acknowledgements:
Mercedes Molla, <mercedes.molla( at )ciemat.es>
References:
Molla et al. Paper I. 2009MNRAS.398..451M 2009MNRAS.398..451M Cat. J/MNRAS/398/451
Martin-Majon et al. Paper II. 2010MNRAS.403.2012M 2010MNRAS.403.2012M Cat. J/MNRAS/403/2012
(End) Mercedes Molla [CIEMAT], Emmanuelle Perret [CDS] 30-Jul-2013