All Figures

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F1.eps} \end{figure}$ Figure 1: Different stellar yields for ¹²C (upper panel) and ¹⁶O (lower panel) as functions of the initial stellar mass for massive stars, at solar metallicity: MM for $V_{\rm rot} =0$ km s^-1 (open squares) and $V_{\rm rot} =300$ km s^-1 (filled squares); Thielemann et al. (1996) (circles); WW (triangles); Maeder (1992) (open pentagons). In the upper panel, the filled circles and filled triangles show the carbon yields of Thielemann et al. (1996) and WW, respectively, multiplied by a factor of 3 in the 40-100 $M_{\odot }$ mass range (see text).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F2.eps} \end{figure}$ Figure 2: Comparison of MM (squares) and vdHG (asterisks) yields of ¹²C for 3 different values of metallicities (solid lines: solar, dashed line: Z= 0.004 and long dashed line: Z= 0.001 for vdHG and Z= 0.00001 for MM), for masses up to 8 $M_{\odot }$ . Above 9 $M_{\odot }$ we show the yields of MM for different metallicities.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F3.eps} \end{figure}$ Figure 3: Different stellar yields for ¹⁴N (upper panel) and ⁴He (lower panel), for the whole stellar mass range. The symbols are as in Fig. 1. The asterisks represent the yields of van den Hoek & Groenewegen (1997).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F4.eps} \end{figure}$ Figure 4: MM stellar yields for ¹⁴N, for the whole stellar mass range, for different metallicities. The symbols and lines are as in Fig. 2. The yields of MM for stellar models were rotation is not taken into account are also plotted (open squares).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F5.eps} \end{figure}$ Figure 5: [C/Fe] vs. [Fe/H]. The dotted line in all panels markes the solar ratio. Panel a) shows a model computed with vdHG + WW yields (model A - solid line) compared to abundance data from the compilation of Chiappini et al. (1999). Both the model predictions and the abundance data show an almost solar [C/Fe] ratio (down to $[{\rm Fe/H}]\simeq -2$ ). In panel b) we compare the model A shown in a) with a model computed with MM yields (model B - short dashed line). Panel c) shows again the model A (solid line) compared with a similar model where the contribution from LIMS is suppressed (long-dashed line).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=12cm,angle=0]{H4552F6.eps} \end{figure}$ Figure 6: Model predictions for the galactic evolution of the C/O ratio as a function of O/H compared with data obtained by Nissen (2003). The abundance data include only stars in the Milky Way (halo, thick disk and thin disk stars) whose abundances are representative of the ISM from which they formed. The solar value from Allende-Prieto et al. (2001, 2002) is also shown. In the left upper panel a chemical evolution model for the MW computed with vdHG + WW yields (model A) is shown (solid line). The dashed line shows the same model computed with stellar yields for LIMS given in the table for Z= 0.001 from vdHG with $\eta_{\rm AGB} =~1$ (an upper limit for the C production in LIMS). In the right upper panel we show again model A but with no contribution from LIMS. In the lower left panel model B prediction is shown (computed with stellar yields including rotation effects from Meynet & Maeder 2002). In the lower right panel we plot directly the integrated yields (for different ranges of masses - squares) at different metallicities (without the use of a chemical evolution model). This is a simplistic approach that implicitly assumes instantaneous recycling approximation and thus neglects the effects due to stellar lifetimes.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F7.eps} \end{figure}$ Figure 7: Diagram showing log (N/O) vs. log (O/H) + 12 for the Milky Way (model A: solid curve, and model B: dashed curve; see CRM2003 for a description of the abundance data).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F8.eps} \end{figure}$ Figure 8: Diagram showing log (N/O) vs. log (O/H) + 12 obtained by integrating the MM yields in different mass ranges as indicated in brackets (filled squares). As it can be seen by comparing with Fig. 7 the main stars contributing at metallicities of the order of log $({\rm O/H})+12 \sim 5.8$ are those above $\sim$ 20 $M_{\odot }$ .The empty square refers to the case with rotational velocity of 400 km s^-1.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0]{H4552F9.eps} \end{figure}$ Figure 9: The same diagram as in Fig. 6 but now for dwarf galaxies of Izotov & Thuan (1999) and DLAs from Centurion et al. (2003a) (filled pentagons - with a new determination from Centurion et al. 2003b). Model predictions are explained in the text. For the lower family of curves an abundance ratio log $({\rm N/O}) \sim -2.5$ is attained after 53 Myr from the start of the star formation, while for the upper curves log $({\rm N/O})=-1.8$ after 53 Myr.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F10.eps} \end{figure}$ Figure 10: Log (N/O) vs. log (N/H) + 12 diagram. Dwarf galaxies are from of Izotov & Thuan (1999 - black dots); DLAs from Centurion et al. (2003a,b) (filled hexagons). The models are the same shown in Fig. 9 (lower family of curves, with MM yields). The $\Delta t =~53$ Myr indicates the time elapsed from the beginning of star formation and the dotted line represents an isochrone. In other words, the objects on that line have the same age but different star formation efficiency.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0]{H4552F11.eps} \end{figure}$ Figure 11: Log (N/O) vs. log (N/H) + 12 diagram. DLAs from Centurion et al. (2003a,b) (filled hexagons). Model prediction for MW (with MM yields) at an outer region - 16 kpc in this example. The $\Delta t$ s indicate the time elapsed from the beginning of star formation, in other words the various galactic ages.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0]{H4552F12.eps} \end{figure}$ Figure 12: Same as Fig. 10 but now we show model predictions for BCGs (see text). Also shown is a log (C/O) vs. (O/H) plot. Details on the abundance data can be find in CRM2003.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=6cm,angle=0]{H4552F13.eps} \end{figure}$ Figure 13: Y vs. 10⁶O/H predicted by model A (solid line) and B (dashed line). The dotted-line shows a model which is the same as model B but computed with $Y_{\rm p} = 0.248$ (see text). The solar value is also shown (where oxygen is from Allende-Prieto et al. 2001 and Y is from Anders & Grevesse 1989 - open circle with thin errorbar and Grevesse & Sauval 1998 - black circle with thick errorbar).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F2.eps} \end{figure}$	Figure 2: Comparison of MM (squares) and vdHG (asterisks) yields of ¹²C for 3 different values of metallicities (solid lines: solar, dashed line: Z= 0.004 and long dashed line: Z= 0.001 for vdHG and Z= 0.00001 for MM), for masses up to 8 $M_{\odot }$ . Above 9 $M_{\odot }$ we show the yields of MM for different metallicities.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F3.eps} \end{figure}$	Figure 3: Different stellar yields for ¹⁴N (upper panel) and ⁴He (lower panel), for the whole stellar mass range. The symbols are as in Fig. 1. The asterisks represent the yields of van den Hoek & Groenewegen (1997).
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F4.eps} \end{figure}$	Figure 4: MM stellar yields for ¹⁴N, for the whole stellar mass range, for different metallicities. The symbols and lines are as in Fig. 2. The yields of MM for stellar models were rotation is not taken into account are also plotted (open squares).
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,angle=0,clip]{H4552F7.eps} \end{figure}$	Figure 7: Diagram showing log (N/O) vs. log (O/H) + 12 for the Milky Way (model A: solid curve, and model B: dashed curve; see CRM2003 for a description of the abundance data).
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,angle=0]{H4552F11.eps} \end{figure}$	Figure 11: Log (N/O) vs. log (N/H) + 12 diagram. DLAs from Centurion et al. (2003a,b) (filled hexagons). Model prediction for MW (with MM yields) at an outer region - 16 kpc in this example. The $\Delta t$ s indicate the time elapsed from the beginning of star formation, in other words the various galactic ages.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,angle=0]{H4552F12.eps} \end{figure}$	Figure 12: Same as Fig. 10 but now we show model predictions for BCGs (see text). Also shown is a log (C/O) vs. (O/H) plot. Details on the abundance data can be find in CRM2003.
Open with DEXTER