A spatially resolved study of ionized regions in galaxies at different ...
A spatially resolved study of ionized regions in galaxies at different ... A spatially resolved study of ionized regions in galaxies at different ...
136 4 • Long-slit spectrophotometry of multiple knots of Hii galaxies (2005) were derived using empirical calibrations since no temperature sensitive lines were observed. The logarithmic N/O ratios found for J1657 are -1.23 ± 0.11, -1.35 ± 0.16 and -1.36 ± 0.15 for knots A, B, and C, respectively, which are remarkably constant. The derived values are on the high log(N/O) side of the distribution for this kind of objects (see Figure 4.15). For IIZw71, although the difference between knots B and C is of 0.2 dex, due to the large errors, it can be consider as well fairly constant. In general, the common procedure of obtaining t e ([Oii]) from t e ([Oiii]) using Stasińska (1990) relation and assuming t e ([Oii]) = t e ([Nii]), yields N/O ratios larger than using the measured t e ([Oii]) values since, in most cases, the model sequence over-predicts t e ([Oii]). In our particular case, as we have seen, for the three knots of J1657 t e ([Oii]) is under-predicted by Stasińska (1990) models; for Knot B the difference is more than 2000 K. This would decrease the N/O ratio by more than 0.1 dex. The log(S/O) ratios found are the quite similar for Knots A and B of J1657, with -1.53 and -1.57, respectively, and higher for Knot C, with -1.32. The average error is 0.12. For IIZw71, both knots shows a very similar value. They are consistent with log(S/O) ⊙ = -1.36, the solar value (Grevesse and Sauval, 1998) within the observational errors (see Figure 4.15). The logarithmic Ne/O ratio is remarkably constant of both objects, with a mean value of 0.75, despite, for example, the differences in oxygen abundances between knot A and the other two in J1657. They are consistent with solar value, log(Ne/O) = -0.61 dex 4 , as shown in Figure 4.16. Finally, the Ar/O ratios found show a very similar value for Knot A and B, while Knot C has a ratio higher by 0.2 dex. Both knots of IIZw71 have the same ratio. The mean value is consistent with solar 5 (see Figure 4.16). 4.4.2 Chemical abundances from empirical calibrators for Knots A and D of IIZw71 The emission-line spectra of the four star-forming knots in IIZw71 are remarkably similar, implying similar values for ionization parameter, ionization temperature, and chemical abundances. We derived the ionization parameters from the ratio of the [Oii] and [Oiii] lines according to the expression given in Díaz et al. (2000) (see Chapter §3). They are similar in all the knots ranging from 6.42×10 −4 for knot A to 9.67×10 −4 for knot C. Using these values, the corrected Hα fluxes, and the sizes of the regions from Hα images we can calculate the density of the emitting gas (Diaz et al., 1991). This is similar for the four knots with a value of about 20 particles · cm −3 , consistent with the upper limits we derived from the ratio of the [Sii] lines and providing filling factor for the gas of a few times 10 −2 , values common 4 Oxygen from Allende Prieto et al. (2001) and neon from Grevesse and Sauval (1998). 5 Oxygen from Allende Prieto et al. (2001) and argon from Grevesse and Sauval (1998).
4.4. Discussion 137 -0.6 -0.8 HII Galaxies Hagele et al. (2006,2008) J1657 Knots IIZw71 Knots -1.0 log(N/O) -1.2 -1.4 -1.6 -1.8 IZw18 NW IZw18 SE -2.0 7.0 8.0 9.0 12+log(O/H) -1.0 -1.2 HII galaxies Hagele et al. (2006,2008) J1657 Knots IIZw71 Knots log (S/O) -1.4 -1.6 IZw18 NW IZw18 SE -1.8 -2.0 5.0 6.0 7.0 8.0 9.0 10.0 12 + log (O/H) Figure 4.15: N/O (upper panel) and S/O (lower panel) ratios as a function of 12+log(O/H) for the knots of J1657 (filled yellow diamonds), knots of IIZw71 (filled red triangles), the objects of Hägele et al. (2006) and Hägele et al. (2008) (blue circles) and the Hii galaxies (open squares) from the literature. The solar values are shown with the sun symbol; oxygen from Allende Prieto et al. (2001), nitrogen from Holweger (2001) and Grevesse and Sauval (1998) for sulphur. These values are linked by a solid line with the solar ratios from Asplund et al. (2005).
- Page 106 and 107: 86 3 • IFS of a GEHR in NGC 6946
- Page 108 and 109: 88 3 • IFS of a GEHR in NGC 6946
- Page 110 and 111: 90 3 • IFS of a GEHR in NGC 6946
- Page 112 and 113: 92 3 • IFS of a GEHR in NGC 6946
- Page 114 and 115: 94 3 • IFS of a GEHR in NGC 6946
- Page 116 and 117: 96 3 • IFS of a GEHR in NGC 6946
- Page 118 and 119: 98 3 • IFS of a GEHR in NGC 6946
- Page 120 and 121: 100 3 • IFS of a GEHR in NGC 6946
- Page 122 and 123: 102 3 • IFS of a GEHR in NGC 6946
- Page 124 and 125: 104 3 • IFS of a GEHR in NGC 6946
- Page 126 and 127: 106 4 • Long-slit spectrophotomet
- Page 128 and 129: 108 4 • Long-slit spectrophotomet
- Page 130 and 131: 110 4 • Long-slit spectrophotomet
- Page 132 and 133: 112 4 • Long-slit spectrophotomet
- Page 134 and 135: 114 4 • Long-slit spectrophotomet
- Page 136 and 137: Hδ 116 4 • Long-slit spectrophot
- Page 138 and 139: 118 4 • Long-slit spectrophotomet
- Page 140 and 141: 120 4 • Long-slit spectrophotomet
- Page 142 and 143: 122 4 • Long-slit spectrophotomet
- Page 144 and 145: Table 4.4 continued SDSS J1657 Knot
- Page 146 and 147: 126 4 • Long-slit spectrophotomet
- Page 148 and 149: 128 4 • Long-slit spectrophotomet
- Page 150 and 151: 130 4 • Long-slit spectrophotomet
- Page 152 and 153: 132 4 • Long-slit spectrophotomet
- Page 154 and 155: 134 4 • Long-slit spectrophotomet
- Page 158 and 159: 138 4 • Long-slit spectrophotomet
- Page 160 and 161: 140 4 • Long-slit spectrophotomet
- Page 162 and 163: 142 4 • Long-slit spectrophotomet
- Page 164 and 165: 144 4 • Long-slit spectrophotomet
- Page 166 and 167: 146 4 • Long-slit spectrophotomet
- Page 168 and 169: 148 4 • Long-slit spectrophotomet
- Page 170 and 171: 150 Conclusions and future work has
- Page 172 and 173: 152 Conclusions and future work oth
- Page 174 and 175: 154 Conclusions and future work The
- Page 176 and 177: 156 Conclusiones Las abundancias to
- Page 178 and 179: 158 Conclusiones consistentes con l
- Page 180 and 181: 160 Appendix A where c=0.434C. This
- Page 182 and 183: 162 Appendix B where R S2 = I(6717
- Page 184 and 185: 164 Appendix B Sulphur As in the ca
- Page 186 and 187: 166 Appendix B Argon For argon, the
- Page 189 and 190: Appendix C Empirical calibrators In
- Page 191 and 192: C • Empirical calibrators 171 One
- Page 193 and 194: Appendix D Stellar photometry resul
- Page 195 and 196: D • Stellar photometry results of
- Page 197 and 198: D • Stellar photometry results of
- Page 199 and 200: D • Stellar photometry results of
- Page 201 and 202: D • Stellar photometry results of
- Page 203 and 204: D • Stellar photometry results of
- Page 205 and 206: D • Stellar photometry results of
4.4. Discussion 137<br />
-0.6<br />
-0.8<br />
HII Galaxies<br />
Hagele et al. (2006,2008)<br />
J1657 Knots<br />
IIZw71 Knots<br />
-1.0<br />
log(N/O)<br />
-1.2<br />
-1.4<br />
-1.6<br />
-1.8<br />
IZw18 NW<br />
IZw18 SE<br />
-2.0<br />
7.0 8.0 9.0<br />
12+log(O/H)<br />
-1.0<br />
-1.2<br />
HII <strong>galaxies</strong><br />
Hagele et al. (2006,2008)<br />
J1657 Knots<br />
IIZw71 Knots<br />
log (S/O)<br />
-1.4<br />
-1.6<br />
IZw18 NW<br />
IZw18 SE<br />
-1.8<br />
-2.0<br />
5.0 6.0 7.0 8.0 9.0 10.0<br />
12 + log (O/H)<br />
Figure 4.15: N/O (upper panel) and S/O (lower panel) r<strong>at</strong>ios as a function <strong>of</strong> 12+log(O/H) for the<br />
knots <strong>of</strong> J1657 (filled yellow diamonds), knots <strong>of</strong> IIZw71 (filled red triangles), the objects <strong>of</strong> Hägele<br />
et al. (2006) and Hägele et al. (2008) (blue circles) and the Hii <strong>galaxies</strong> (open squares) from the<br />
liter<strong>at</strong>ure. The solar values are shown with the sun symbol; oxygen from Allende Prieto et al. (2001),<br />
nitrogen from Holweger (2001) and Grevesse and Sauval (1998) for sulphur. These values are l<strong>in</strong>ked<br />
by a solid l<strong>in</strong>e with the solar r<strong>at</strong>ios from Asplund et al. (2005).
Change language