J/A+A/527/A109 Dust and PAH emission SEDs of disk galaxies (Popescu+, 2011)
Modelling the spectral energy distribution of galaxies.
V. The dust and PAH emission SEDs of disk galaxies.
Popescu C.C., Tuffs R.J., Dopita M.A., Fischera J., Kylafis N.D.,
Madore B.F.
<Astron. Astrophys. 527, A109 (2011)>
=2011A&A...527A.109P 2011A&A...527A.109P
ADC_Keywords: Models ; Galaxies, photometry ; Energy distributions
Keywords: radiative transfer - dust, extinction -
galaxies: spiral - galaxies: individual: NGC 891 -
infrared: galaxies - ultraviolet: galaxies
Abstract:
We present a self-consistent model of the spectral energy
distributions (SEDs) of spiral galaxies from the ultraviolet (UV) to
the mid-infrared (MIR)/far-infrared (FIR)/submillimeter (submm) based
on a full radiative transfer calculation of the propagation of
starlight in galaxy disks. This model predicts not only the total
integrated energy absorbed in the UV/optical and re-emitted in the
infrared/submm, but also the colours of the dust emission based on an
explicit calculation of the strength and colour of the UV/optical
radiation fields heating the dust, and incorporating a full
calculation of the stochastic heating of small dust grains and PAH
molecules.
The geometry of the translucent components of the model is empirically
constrained using the results from the radiation transfer analysis of
Xilouris et al. on spirals in the middle range of the Hubble sequence,
while the geometry of the optically thick components is constrained
from physical considerations with a posteriori checks of the model
predictions with observational data.
These geometrical constraints enable the dust emission to be predicted
in terms of a minimum set of free parameters: the central face-on dust
opacity in the B-band τfB, a clumpiness factor F for the
star-forming regions, the star-formation rate SFR, the normalised
luminosity of the old stellar population old and the bulge-to-disk
ratio B/D.
The results of the calculations are made available in the form of a
large library of simulated dust emission SEDs spanning the whole
parameter space of our model, together with the corresponding library
of dust attenuation calculated using the same model.
Description:
Simulated dust/PAH emission SEDs for the diffuse component of our model,
for the parameter space sampled by the calculations:
--------------------------------------------------
| tau^f._B | SFR' | Old | B/D
| | Msolar/yr | |
--------------------------------------------------
1 | 0.1 | 0.0 | 0.0 | 0.00
2 | 0.3 | 0.1 | 0.1 | 0.25
3 | 0.5 | 0.2 | 0.2 | 0.50
4 | 1.0 | 0.5 | 0.5 | 1.00
5 | 2.0 | 1.0 | 1.0 | 2.00
6 | 4.0 | 2.0 | 2.0 |
7 | 8.0 | 5.0 | 5.0 |
8 | | 10.0 | 10.0 |
9 | | 20.0 | 20.0 |
--------------------------------------------------
where SFR' = SFR x (1-F)
In total there are 2835 combinations, however those with SFR=0 and
old=0 (no stellar luminosity at all) cannot exist, therefore the
library contain only 2800 simulated SEDs. (the cases SFR'=0.0, Old=0.0
not simulated).
The second set of simulated data needed to fit the panchromatic SEDs
is the library of attenuations in the UV/optical/NIR as a function of
τfB and inclination i. The description of the general
characteristics of the attenuation curves can be found in Tuffs et al.
(2004A&A...419..821T 2004A&A...419..821T, Paper III), while the updated version of the
calculations (due to the change in the dust model) is described in
Appendix B and C of this present paper (Paper V).
To facilitate access to the information and to allow the attenuation to
be calculated for any inclination, the attenuation curves are
presented in form of polynomial function fits to the simulated data.
The fitted function is given by Eq. 6 in Paper III. The values of the
fitted coefficients are tabulated below for the old stellar disk
(disk), young stellar disk (sdisk) and bulge. These are updates of
Tables 4-6 from Paper III. The format is kept the same but
calculations at two new UV wavelength (1500 and 3650Å) are
added to the tables, to increase the sampling in the UV spectral
region.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
models.dat 20 2800 List of models for SED
sed.dat 48 1761200 Models spectral energy distribution (SED)
for 2800 combinations (merged contents of
the files in "luminosity.tar")
luminosity.tar 611 1797600 Tar file of all SEDs
coeff.dat 63 168 Attenuation coefficients for
14 wavelengths x 3 morphological components,
where the disk and the bulge is only sampled at
optical/NIR wavelengths (5 wavelengths)
attenuation.tar 651 240 Tar file of all attenuation coefficients
--------------------------------------------------------------------------------
Byte-by-byte Description of file: models.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 F3.1 --- tau [0.1/8.0] Face-on central opacity in B band
model parameter (1)
5- 9 F5.2 solMass/yr SFR [0/20] SFR model parameter (2)
11- 15 F5.2 solMass/yr Old [0/20] Old model parameter(2)
17- 20 F4.2 --- B/D [0/2] B/D model parameter (3)
--------------------------------------------------------------------------------
Note (1): tau values are 0.1, 0.3, 0.5, 1.0, 2.0, 4.0 and 8.0.
Note (2): SFR and Old values are 0, 0.1, 0.2, 0.5, 1, 2, 5, 10 and 20.
Note (3): B/D values are 0, 0.25, 0.5, 1 and 2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sed.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 F3.1 --- tau [0.1/8.0] Face-on central opacity in B band
model parameter (1)
5- 9 F5.2 solMass/yr SFR [0/20] SFR model parameter (2)
11- 15 F5.2 solMass/yr Old [0/20] Old model parameter(2)
17- 20 F4.2 --- B/D [0/2] B/D model parameter (3)
23- 34 F12.3 0.1nm lambda [10131/5e7] Wavelength
36- 48 E13.8 W/Hz Lum Luminosity
--------------------------------------------------------------------------------
Note (1): tau values are 0.1, 0.3, 0.5, 1.0, 2.0, 4.0 and 8.0.
Note (2): SFR and Old values are 0, 0.1, 0.2, 0.5, 1, 2, 5, 10 and 20.
Note (3): B/D values are 0, 0.25, 0.5, 1 and 2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: coeff.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Mcomp Morphological component (disk, sdisk, bulge)
7- 11 A5 --- Band Wavelength/waveband (1)
13- 15 F3.1 --- tau Face-on central opacity in B band (taufB)
18- 23 F6.3 --- a0 a0 attenuation coefficient (2)
26- 31 F6.3 --- a1 a1 attenuation coefficient (2)
34- 39 F6.3 --- a2 a2 attenuation coefficient (2)
42- 47 F6.3 --- a3 a3 attenuation coefficient (2)
49- 55 F7.3 --- a4 a4 attenuation coefficient (2)
58- 63 F6.3 --- a5 ? a5 attenuation coefficient (2)
--------------------------------------------------------------------------------
Note (1): Wavelength/waveband are
BVIJK, UV09, UV13, UV15 ,UV16, UV20, UV22, UV25, UV28 and UV36
Note (2): To facilitate access to this information and to allow attenuation
to be calculated for any inclination, we fit the attenuation curves
(Δm vs. i) with polynomial functions of the form:
{Delat}m = ∑{J=0,n}aj(l-cosi)j for l-cosi≤0.90, where n=5 for
the disk and thin disk and n=4 for the bulge.
--------------------------------------------------------------------------------
Acknowledgements:
Cristina Popescu, cpopescu(at)uclan.ac.uk
References:
Popescu et al., Paper I 2000A&A...362..138P 2000A&A...362..138P
Misiriotis et al., Paper II 2001A&A...372..775M 2001A&A...372..775M
Tuffs et al., Paper III 2004A&A...419..821T 2004A&A...419..821T
Moellenhoff et al., Paper IV 2006A&A...456..941M 2006A&A...456..941M
(End) Patricia Vannier [CDS] 22-Nov-2010