3D and NLTE analysis for large stellar surveys

Report
3D and NLTE analysis for
large stellar surveys
Karin Lind
Uppsala University, Sweden
Martin Asplund, Paul Barklem, Andrey Belyaev, Maria Bergemann,
Remo Collet, Zazralt Magic, Anna Marino, Jorge Meléndez, Yeisson Osorio
Outline
- Introduction
- 1D LTE/NLTE
- Worst-case scenarios
- Recent progress
- Calibration techniques
- Practical implementation
- Applications
- 3D LTE/NLTE
- Worst-case scenarios
- Observational tests
- Mg : 1D/<3D>/LTE/NLTE
- Ca : 1D/<3D>/3D/LTE/NLTE
- Applications
Motivation
Galactic archaeology by chemical tagging of FGK stars
- Statistics : Soon > 106 stars
- Precision (S/N, wavelength range) :
σ[X/H] < 0.1dex, σTeff<150K, σlog(g)<0.3dex
- Accuracy (assumptions: 1D, LTE, atomic data) :
σ [X/H]< 0.5 dex, σTeff<400K, σlog(g)< 1 dex
Methods
Model atmosphere
1D/<3D>/3D LTE
R. Collet
Detailed rad. Transfer
1D/3D LTE/NLTE
NLTE line formation
(1D) NIs it really
necessary?
Is it safe?
Worst-case scenario I
NaD lines in metal-poor horisontal branch stars
568.8nm
B−I
1.5
0.0
0.5
1.0
1.0
588.9nm
589.5nm
[Na/ Fe]
DNLTE
2.0
2.5
588.9nm
DNLTE
589.5nm
3.0
Lind et al. 2011, Marino et al. 2011
B-I
Worst-case scenario II
OI 777nm triplet at very low metallicities
LTE trend
Fabbian et al. 2009
Input data for NLTE analysis
Energy levels + oscillator strengths + photo-ionization cross sections
Red boxes : have sufficient(?) data
Blue boxes : missing e.g. QM photo-ionisation, but NLTE still attempted
Input data for NLTE analysis
Blue boxes : QM hydrogen collisions exist or will exist
Input data for NLTE analysis
Most important free parameter in NLTE
modelling of Fe is FeI+HI collisional cross-section
Black – LTE
Blue – NLTE with no hydrogen collisions
Solar neighborhood MDF
Halo MDF
[X/Fe] vs [Fe/H]
Calibration techniques: ionisation balance
Korn et al. 2003
FeI/FeII ionisation
equilibrium
calibrated using
Hipparcos gravities
 S(H)=3
Calibration techniques: excitation balance
Bergemann & Gehren
2008
“Thus, NLTE can solve the
discrepancy between the
abundances derived from
the MnI resonance triplet
at 403 nm and excited
lines, which is found in
analyses of metal-poor
subdwarfs and subgiants”
 S(H)=0.05
Calibration techniques: CLV
Allende Prieto et al. (2004)
Solar centre-to-limb variation of OI lines
Practical implementation I
“Curves-ofgrowth” from
UV-NIR:
Teff=6500K
log(g)=4.0
ξ=2km/s
3200 FeI lines
107 FeII lines
ΔNLTE
Lind et al. (2012)
Practical implementation II
Pre-computed departure coefficients  NLTE synthesis
T. Nordlander
FeI NLTE grid
Lind et al. (2012)
Application : metal-poor stars
LTE
NLTE
+PHOT
Ruchti et al. (2012)
Application : metal-poor stars
LTE
NLTE+PHOT
Serenelli et al. (2013)
3D (LTE/NLTE)
Is it really
necessary?
Is it safe?
Stagger grid
Magic et al. 2014
Abundance patterns
Keller et al. (2014)
3D
Dashed –200 Msun PISN
Solid – 60Msun fallback
NLTE
Worst-case scenario III
Li isotopic abundances
3D
NLTE
Lind et al. 2013
Asplund et al. 2006
Observational tests: the Sun
Pereira et al. 2013
“We confronted the models with observational diagnostics of
the [solar] temperature profile: continuum centre-to-limb
variations (CLVs), absolute continuum fluxes, and the wings of
hydrogen lines. We also tested the 3D models for the intensity
distribution of the granulation and spectral line shapes. ”
“We conclude that the 3D hydrodynamical model is superior
to any of the tested 1D models.”
Observational tests: low [Fe/H]
Klevas et al. 2013
FeI line assymmetries
in the metal-poor
giant HD122563
1.5/3D + NLTE
LiI : Asplund et al. 2003, Sbordone et al. 2010
OI, FeI : Shchukina et al. 2005
OI : Pereira et al. 2010, Prakapavičius et al. 2013
LiI, NaI, CaI : Lind et al. 2013
Ways forward
Model
LTE/NLTE
Time
1D
LTE
Seconds
1D
NLTE
Minutes (seconds
using interpolation)
3D
LTE
Hours
3D
NLTE
Days
<3D>
LTE
Seconds
<3D>
NLTE
Minutes (seconds
using interpolation)
Performance
The ultimate goal, reference point
Normalised flux
1.0
0.5
0.0
−0.5
−1.0
5172.0
5173.0
5172.5
Wavelength [Å]
A(Mg)=5.304
A(Mg)=5.300
A(Mg)=5.273
A(Mg)=5.081
sini=0.532
sini=1.743
sini=4.281
vrotsini=3.071
Teff=5780K
log(g)=3.7
[Fe/H]=-2.4
0.4
0.6
0.8
5173.5
HD140283
% residual
1.0
Mg b in a VMP SG
“No” free parameters!
1D LTE
1D NLTE
<3D> LTE
<3D> NLTE
Yeisson Osorio
HD19445
Teff=6000K
log(g)=4.5
[Fe/H]=-2.0
0.2
0.4
0.6
0.8
1.0
0.5
0.0
−0.5
−1.0
0.2
0.4
NLTE
4226.2 4226.4 4226.6 4226.8 4227.0 4227.2 4227.4
Wavelength [Å]
A(Ca)=4.670
A(Ca)=4.606
A(Ca)=4.780
vrotrotsini=5.847
sini=5.622
sini=2.821
4226.2 4226.4 4226.6 4226.8 4227.0 4227.2 4227.4
Wavelength [Å]
A(Ca)=4.579
A(Ca)=4.362
A(Ca)=4.554
sini=0.247
vrotrotsini=5.422
sini=6.034
1D
<3D>
3D
0.6
0.8
1.0
1.0
0.5
0.0
−0.5
−1.0
Normalised flux
% residual
Normalised flux
LTE
% residual
1.0
Ca in a VMP dwarf
HD19445
Teff=6000K
log(g)=4.5
[Fe/H]=-2.0
0.4
0.6
0.8
1.0
0.5
0.0
−0.5
−1.0
8540
0.4
8541
8541
8542
Wavelength [Å]
8542
Wavelength [Å]
8543
A(Ca)=4.698
A(Ca)=4.633
A(Ca)=4.678
vrotsini=5.201
sini=6.759
sini=3.128
8543
A(Ca)=4.661
A(Ca)=4.728
A(Ca)=4.681
vrotsini=3.537
sini=0.990
sini=0.247
8544
1D
<3D>
3D
0.6
0.8
1.0
1.0
0.5
0.0
−0.5
−1.0
8540
Normalised flux
% residual
Normalised flux
LTE
% residual
1.0
NLTE
8544
Ca in a VMP dwarf
A(Ca)
Bullets: Optical CaI lines
Squares: NIR CaII triplet
3.0
3.2
3.4
0
3
2
1
Excitation potential [eV]
3D NLTE
1
2
3
Excitation potential [eV]
?
3.6
3.8
4.0
4.2
0
Start
4.4
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
Ca in a EMP TO
Goal
G64-12
Teff=6430K
log(g)=4.0
[Fe/H]=-3.0
A(Ca)
Bullets: Optical CaI lines
Squares: NIR CaII triplet
3.0
3.2
3.4
0
0
3
2
1
Excitation potential [eV]
3
2
1
Excitation potential [eV]
3D NLTE
1
2
3
Excitation potential [eV]
?
3.6
3.8
4.0
4.2
3.0
4.4
3.2
0
<3D> LTE
Start
3.4
3.6
3.8
4.0
4.2
3.0
4.4
3.2
3.4
3.6
3.8
4.0
4.2
4.4
Ca in a EMP TO
Goal
A(Ca)
Bullets: Optical CaI lines
Squares: NIR CaII triplet
3.0
3.2
3.4
0
0
3
2
1
Excitation potential [eV]
3
2
1
Excitation potential [eV]
3D NLTE
1
2
3
Excitation potential [eV]
?
3.6
3.8
4.0
4.2
3.0
4.4
3.2
0
3D LTE
Start
3.4
3.6
3.8
4.0
4.2
3.0
4.4
3.2
3.4
3.6
3.8
4.0
4.2
4.4
Ca in a EMP TO
Goal
A(Ca)
Bullets: Optical CaI lines
Squares: NIR CaII triplet
3.0
3.2
3.4
0
0
3
2
1
Excitation potential [eV]
3
2
1
Excitation potential [eV]
3D NLTE
1
2
3
Excitation potential [eV]
?
3.6
3.8
4.0
4.2
3.0
4.4
3.2
0
1D NLTE
Start
3.4
3.6
3.8
4.0
4.2
3.0
4.4
3.2
3.4
3.6
3.8
4.0
4.2
4.4
Ca in a EMP TO
Goal
A(Ca)
Bullets: Optical CaI lines
Squares: NIR CaII triplet
3.0
3.2
3.4
0
0
3
2
1
Excitation potential [eV]
3
2
1
Excitation potential [eV]
3D NLTE
1
2
3
Excitation potential [eV]
?
3.6
3.8
4.0
4.2
3.0
4.4
3.2
0
<3D> NLTE
Start
3.4
3.6
3.8
4.0
4.2
3.0
4.4
3.2
3.4
3.6
3.8
4.0
4.2
4.4
Ca in a EMP TO
Goal
Ways forward
A : NLTE-sensitive, B : not NLTE-sensitive
Model
LTE/NLTE
Time
Performance
1D
LTE
Seconds
Varied
1D
NLTE
Minutes (seconds
using interpolation)
Improves for A
No change for B
3D
LTE
Hours
May worsen for A
Improves for B
3D
NLTE
Days
The ultimate goal, reference point
<3D>
LTE
Seconds
May worsen for A
Improves for B
<3D>
NLTE
Minutes (seconds
using interpolation)
Improves for A
Improves for B

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