Marta Gavilán Bouzas Mercedes Mollá Lorente
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Marta Gavilán Bouzas Mercedes Mollá Lorente Estallidos IV, Granada 2-04-07
description
Gas and Metalliciy in Dwarf Galaxies. Marta Gavilán Bouzas Mercedes Mollá Lorente. Estallidos IV, Granada 2-04-07. What are we looking for?. We are looking for some signs to know if dwarf galaxies lose some of their gas or not. How do we looking for it?. - PowerPoint PPT Presentation
Transcript of Marta Gavilán Bouzas Mercedes Mollá Lorente
Marta Gavilán BouzasMercedes Mollá Lorente
Estallidos IV, Granada 2-04-07
What are we looking for?• We are looking for some signs to know if dwarf galaxies
lose some of their gas or not.
How do we looking for it?
• Our aim is to have a large amount of model results (in an autoconsistent way) to obtain the maximum number of clues.
• We analized: gas content, metallicity and photometry and compare them with observations.
A short review
Galactic Chemical Evolution Model
Grid of models
Galactic Chemical Evolution Model
The free parameters are: • the collapse time: Tcol• the efficiency in forming molecular clouds:
• the efficiency in transform the clouds into stars: h
The SFR is a RESULT not an INPUT
There are no STAR BURSTS: the star forming process is continuous, but not constant
Grid of ModelsMass interval: Six values
From 8 106 M to 3 109M
Collapse time: Four values
From 8 Gyr to 60 Gyr
Star Formation Parameters: Four valuesS, M, L, XL
TOTAL GRID: 96 Models
SFR HISTORIES
Lower Tcol and Higher and h
Higher Tcol and Lower and h
SFR para 9 108 Msun
0
0.2
0.4
0.6
0.8
1
0 5 10 15
Tiempo (Gyr)
SF
R (
Msu
n/y
r)
Eficiencia = 0.88
Eficiencia = 0.40
Eficiencia = 0.17
Efficiency=0.88
Efficiency=0.40
Efficiency=0.17
Effective Yieldp = 0.0034
The gas fraction estimation
<Z> = 0.0034ln(1/) + 0.0008
0
0.005
0.01
0.015
0.02
0.025
0 0.5 1 1.5 2 2.5ln(1/)
<Z
>
CBM
Zo = 0,0025ln(1/) + 0,0007
0
0,002
0,004
0,006
0,008
0 0,5 1 1,5 2 2,5ln(1/)
Zo
CBM
LR
Oxygen Effective Yield
0
0,002
0,004
0,006
0,008
0,01
0 0,2 0,4 0,6 0,8 1
Ye
ff(O
)Garnett02 DwGx
Garnett02 SGx
f Mgas/f Yo
6 0.0017
25 0.001
35 0.0009
Mgas*f Yo
2 0.0017
4 0.0013
8 0.0008
Oxygen Abundance
Models
Garnett 02 DwGx
Van Zee 06
Garnett 02 S
0
0.002
0.004
0.006
0.008
0 0.5 1 1.5 2 2.5
ln(1/) Dyn
Zo
Zo = 0,0022ln(1/) + 0,0004
0
0,002
0,004
0,006
0,008
0 0,5 1 1,5 2 2,5
ln(1/)Z
o
CBM
LR
=1.33*M(HI)/1.33*M(HI)+MestrellasLn(1/) Tot
IIZw70
7.27.4
7.67.8
88.2
8.48.6
8.8
-7 -5 -3 -1
Log(SFR)
12
+L
og
(O/H
)
7.27.4
7.67.8
8
8.28.4
8.68.8
-7 -5 -3 -1
Log(SFR)
12
+L
og
(O/H
)
Historia de la Formación Estelar
0
0.01
0.02
0.03
0.04
0 5 10 15Tiempo (Gyr)
SF
R (
Msu
n/y
r)
Tcol = 8 Gyr Tcol = 20 GyrTcol = 40 Gyr Tcol = 60 Gyr
-2
-1.5
-1
-0.5
0
-7 -5 -3 -1
Log(SFR)
Lo
g(N
/O)
Kherig and col 2007
= 0.30
= 0.24
= 0.21
= 0.40
Other observationsM(HI) Observations
Kong 2004 3.28 108M
Cox et al 2001 1.0 108M
Larsen et al 2000 5.88 108M
Mas-Hesse & Kunth 99 3.4 108M
Our Model
5.2 107M< M(HI) < 1.0 108M
MB Observations
Kong 2004 -17.23
Gil de Paz et al 2003 -16.52
Cairós et al 2001 -16.31
Cox et al 2001 -16.53
Larsen et al 2000 -17.49
Our Model
-18.7 < MB <-16.7
CONCLUSIONS• Our models present an effective yield without gas
outflow according with most observations.
• The models with high efficiency give too much high abundances. It is possible that they do not match with any observations.
• In the case of IIZw70 we reproduce the SFR and the (O/H) value with no star burst .
• …but the gas content needs additional explanation.
