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 ...
152 Conclusions and future work other two, very similar. Knots B and C of IIZw71 have the same metallicity, within the errors, but they are slightly lower than the abundances previously reported from measurements of the integrated galaxy according to strong-line calibrations. The metallicity in the other two fainter knots of this galaxy, where the temperature sensitive line could not be detected, was estimated by means of different strong-line parameters. In all cases, the estimated abundances are consistent with those derived for knots B and C by the direct method with the parameter involving the sulphur lines providing the abundance closer to it. The rest of the parameters slightly overestimate the oxygen abundance. The N/O abundance, as derived from the N2O2 parameter (the ratio of the [Nii] and [Oii] intensities), is remarkably constant over the ring indicating that local pollution processes are absent. In the case of J1657, it has been found that oxygen abundances of knot B and C are very close, with knot A showing a slightly higher value. This behaviour is mirrored by the N/O ratio, but for the S/O and Ar/O, knots A and B have a similar value, knot C being the one with a different value. Regarding the Ne/O ratio, this is remarkably similar for all knots. Therefore, similar to what has been found for the GEHR, no conclusive spatial variations of the total elemental abundances throughout the two observed Hii galaxies are found, so the same considerations made above apply here although at a different scale. Although the underlying stellar population of the host galaxy of IIZw71 is detected in the spectrum of the central knot (knot C), the similarity of the star formation histories in the four knots, as deduced from the fitting of SSPs, as well as the derived metallicities, point to a common chemical evolution of the polar ring. In the case of J1657, the star formation history for the three knots derived from STARLIGHT are remarkably similar, with an old population of about 8 Gyr presenting more than the 95% contribution to the mass fraction. This result is somewhat unexpected and data on its surface brightness distribution would be very valuable to explore further this finding. Regarding IIZw71, for the differential velocity, we used the wavelength position of Hα and [Sii] to measure an asymmetric rotation of the ring with a mean value of 85 km s −1 at an optical radius of 20 ′′ . This gives a dynamical mass of (2.8 ± 0.2) × 10 9 M ⊙ and a M/L B ratio of 3.9, close to the value reported previously by Reshetnikov and Combes (1994). The kinematics of the ring is significantly affected by the expanding bubbles of ionised gas, which in the case of knot C reaches 60 km s −1 . Future work Several results of this work have revealed interesting new paths for further investigation. This will entail the obtention of new data in a much wider wavelength range and the 3D modelling of Hii regions, among others. NGC 5471 is truly a very amazing object which deserves more detailed analysis. We have spectrophotometric data of this region with the aim to perform a kinematical study of
Conclusions and future work 153 Figure 5.1: Multiwavelength 30 Doradus nebula image. Red: IRAC 8 µm image. Green: ESO B- band image. Blue: broadband soft X-ray image, 0.5-2 keV. White contours: 1 2CO(1-0) emission. Black contour: a single level of 3 cm radio emission. Magenta mark: the star cluster R136, core of NGC 2070. Cyan mark: the star cluster Hodge 301. Yellow mark: an IR point source in the molecular cloud Dor-06. Figure from Indebetouw et al. (2009). the processes which are taking place in this gigantic bubble, without ruling out the use of IFS. Of great interest would be to obtain a complete SED with OSIRIS at the GTC, with tunable filters covering from the extreme ultraviolet up to the further infrared filter available. Obtaining the ionization structure, by means of narrow filters as [Oii], Heii, Hβ, [Oiii], Hei, Hα, [Nii] and [Siii], would also be a priority. Radiocontinuum at 6 or 20 cm would allow to build an opacity map of the region. One important issue is to extend the wavelength window and combine all available data. Observations at mid-infrared (MID) wavelengths offer several advantages for studying star formation and its interaction with circumcluster dust and gas (Indebetouw et al., 2009). This wavelength range can pierce cold molecular clouds and reveal the star-forming regions that they shroud. Thus, MIR, combined with ultraviolet and optical data, can provide a huge amount of information that will help us to understand star formation processes (see Figure 5.1). Therefore, XXI century starburst studies demands to undertake wide multiwavelength analysis.
- 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 156 and 157: 136 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 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
- Page 207: D • Stellar photometry results of
- Page 210 and 211: 190 REFERENCES Bertelli, G., Bressa
- Page 212 and 213: 192 REFERENCES Girardi, L. & Bertel
- Page 214 and 215: 194 REFERENCES Kunth, D. & Sargent,
- Page 216 and 217: 196 REFERENCES Pérez-Montero, E.,
- Page 218 and 219: 198 REFERENCES Terlevich, R., Melni
Conclusions and future work 153<br />
Figure 5.1: Multiwavelength 30 Doradus nebula image. Red: IRAC 8 µm image. Green: ESO B-<br />
band image. Blue: broadband s<strong>of</strong>t X-ray image, 0.5-2 keV. White contours: 1 2CO(1-0) emission. Black<br />
contour: a s<strong>in</strong>gle level <strong>of</strong> 3 cm radio emission. Magenta mark: the star cluster R136, core <strong>of</strong> NGC<br />
2070. Cyan mark: the star cluster Hodge 301. Yellow mark: an IR po<strong>in</strong>t source <strong>in</strong> the molecular cloud<br />
Dor-06. Figure from Indebetouw et al. (2009).<br />
the processes which are tak<strong>in</strong>g place <strong>in</strong> this gigantic bubble, without rul<strong>in</strong>g out the use <strong>of</strong><br />
IFS. Of gre<strong>at</strong> <strong>in</strong>terest would be to obta<strong>in</strong> a complete SED with OSIRIS <strong>at</strong> the GTC, with<br />
tunable filters cover<strong>in</strong>g from the extreme ultraviolet up to the further <strong>in</strong>frared filter available.<br />
Obta<strong>in</strong><strong>in</strong>g the ioniz<strong>at</strong>ion structure, by means <strong>of</strong> narrow filters as [Oii], Heii, Hβ, [Oiii], Hei,<br />
Hα, [Nii] and [Siii], would also be a priority. Radiocont<strong>in</strong>uum <strong>at</strong> 6 or 20 cm would allow to<br />
build an opacity map <strong>of</strong> the region.<br />
One important issue is to extend the wavelength w<strong>in</strong>dow and comb<strong>in</strong>e all available d<strong>at</strong>a.<br />
Observ<strong>at</strong>ions <strong>at</strong> mid-<strong>in</strong>frared (MID) wavelengths <strong>of</strong>fer several advantages for <strong>study</strong><strong>in</strong>g star<br />
form<strong>at</strong>ion and its <strong>in</strong>teraction with circumcluster dust and gas (Indebetouw et al., 2009). This<br />
wavelength range can pierce cold molecular clouds and reveal the star-form<strong>in</strong>g <strong>regions</strong> th<strong>at</strong><br />
they shroud. Thus, MIR, comb<strong>in</strong>ed with ultraviolet and optical d<strong>at</strong>a, can provide a huge<br />
amount <strong>of</strong> <strong>in</strong>form<strong>at</strong>ion th<strong>at</strong> will help us to understand star form<strong>at</strong>ion processes (see Figure<br />
5.1). Therefore, XXI century starburst studies demands to undertake wide multiwavelength<br />
analysis.
Change language