| Full text | |
| Author(s): |
Kehrig, C.
;
Vilchez, J. M.
;
Perez-Montero, E.
;
Iglesias-Paramo, J.
;
Hernandez-Fernandez, J. D.
;
Duarte Puertas, S.
;
Brinchmann, J.
;
Durret, F.
;
Kunth, D.
Total Authors: 9
|
| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 459, n. 3, p. 2992-3004, JUL 1 2016. |
| Web of Science Citations: | 16 |
| Abstract | |
We present a detailed 2D study of the ionized ionized interstellar medium (ISM) of IZw18 using new Potsdam Multi-Aperture Spectrophotometer-integral field unit (PMAS-IFU) optical observations. IZw18 is a high-ionization galaxy which is among the most metal-poor starbursts in the local Universe. This makes IZw18 a local benchmark for understanding the properties most closely resembling those prevailing at distant starbursts. Our IFU aperture (similar to 1.4 x 1.4 kpc(2)) samples the entire IZw18 main body and an extended region of its ionized gas. Maps of relevant emission lines and emission line ratios show that higher-excitation gas is preferentially located close to the north-west knot and thereabouts. We detect a Wolf-Rayet feature near the north-west knot. We derive spatially resolved and integrated physical-chemical properties for the ionized gas in IZw18. We find no dependence between the metallicity indicator R-23 and the ionization parameter (as traced by {[}O III]/{[}O II]) across IZw18. Over similar to 0.30 kpc(2), using the {[}O III] lambda 4363 line, we compute T-e{[}O III] values (similar to 15 000-25 000 K), and oxygen abundances are derived from the direct determinations of T-e{[}O III]. More than 70 per cent of the higher-T-e{[}O III] (greater than or similar to 22 000 K) spaxels are He II lambda 4686-emitting spaxels too. From a statistical analysis, we study the presence of variations in the ISM physical-chemical properties. A galaxy-wide homogeneity, across hundreds of parsecs, is seen in O/H. Based on spaxel-by-spaxel measurements, the error-weighted mean of 12 + log(O/H) = 7.11 +/- 0.01 is taken as the representative O/H for IZw18. Aperture effects on the derivation of O/H are discussed. Using our IFU data we obtain, for the first time, the IZw18 integrated spectrum. (AU) | |
| FAPESP's process: | 12/13381-0 - EXPLORING THE IMPACT OF ENVIRONMENTAL PROCESSES ON CLUSTERS AND GROUPS OF GALAXIES |
| Grantee: | Jonathan David Hernández Fernández |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |