%0 Generic %1 james2015resolving %A James, Bethan L. %A Auger, Matthew %A Aloisi, Alessandra %A Calzetti, Daniela %A Kewley, Lisa %D 2015 %K compact dwarfs ionsation line ratios %T Resolving Ionisation and Metallicity on Parsec Scales Across Mrk 71 (NGC2363) with HST-WFC3 %U http://arxiv.org/abs/1510.02447 %X Blue Compact Dwarf (BCD) Galaxies in the nearby Universe provide a means for studying feedback mechanisms and star-formation processes in low-metallicity environments in great detail. Due to their vicinity, these local analogues to young galaxies are well suited for high-resolution studies that would be unfeasible for primordial galaxies in the high-redshift universe. Here we present HST-WFC3 observations of one such BCD, Mrk 71 (NGC 2363), one of the most powerful local starbursts known, in the light of O II, He II, Hb, O III, Ha, and S II. At D=3.44 Mpc, this extensive suite of emission line images enables us to explore the chemical and physical conditions of Mrk 71 on ~2 pc scales. Using these high spatial-resolution observations, we use emission line diagnostics to distinguish ionisation mechanisms on a pixel-by-pixel basis and show that despite the previously reported hypersonic gas and super-bubble blow out, the gas in Mrk 71 is photoionised, with no sign of shock-excited emission. Using strong-line metallicity diagnostics, we present the first 'metallicity image' of a galaxy, revealing chemically inhomogeneity on scales of <50 pc. We additionally demonstrate that while chemical structure can be lost at large spatial scales, metallicity-diagnostics can break down on spatial scales smaller than a HII region. HeII emission line images are used to identify up to six Wolf-Rayet stars in Mrk 71, three of which lie on the edge of blow-out region. This study not only demonstrates the benefits of high-resolution spatially-resolved observations in assessing the effects of feedback mechanisms, but also the limitations of fine spatial scales when employing emission-line diagnostics. Both aspects are especially relevant as we enter the era of extremely large telescopes, when observing structure on ~10 pc scales will no longer be limited to the local universe.

@misc{james2015resolving, abstract = {Blue Compact Dwarf (BCD) Galaxies in the nearby Universe provide a means for studying feedback mechanisms and star-formation processes in low-metallicity environments in great detail. Due to their vicinity, these local analogues to young galaxies are well suited for high-resolution studies that would be unfeasible for primordial galaxies in the high-redshift universe. Here we present HST-WFC3 observations of one such BCD, Mrk 71 (NGC 2363), one of the most powerful local starbursts known, in the light of [O II], He II, Hb, [O III], Ha, and [S II]. At D=3.44 Mpc, this extensive suite of emission line images enables us to explore the chemical and physical conditions of Mrk 71 on ~2 pc scales. Using these high spatial-resolution observations, we use emission line diagnostics to distinguish ionisation mechanisms on a pixel-by-pixel basis and show that despite the previously reported hypersonic gas and super-bubble blow out, the gas in Mrk 71 is photoionised, with no sign of shock-excited emission. Using strong-line metallicity diagnostics, we present the first 'metallicity image' of a galaxy, revealing chemically inhomogeneity on scales of <50 pc. We additionally demonstrate that while chemical structure can be lost at large spatial scales, metallicity-diagnostics can break down on spatial scales smaller than a HII region. HeII emission line images are used to identify up to six Wolf-Rayet stars in Mrk 71, three of which lie on the edge of blow-out region. This study not only demonstrates the benefits of high-resolution spatially-resolved observations in assessing the effects of feedback mechanisms, but also the limitations of fine spatial scales when employing emission-line diagnostics. Both aspects are especially relevant as we enter the era of extremely large telescopes, when observing structure on ~10 pc scales will no longer be limited to the local universe.}, added-at = {2015-10-09T09:52:48.000+0200}, author = {James, Bethan L. and Auger, Matthew and Aloisi, Alessandra and Calzetti, Daniela and Kewley, Lisa}, biburl = {https://www.bibsonomy.org/bibtex/253a8fded4026aa0ec8a43176144c815c/miki}, description = {[1510.02447] Resolving Ionisation and Metallicity on Parsec Scales Across Mrk 71 (NGC2363) with HST-WFC3}, interhash = {893a4d390908b3bde58d304a46d11a75}, intrahash = {53a8fded4026aa0ec8a43176144c815c}, keywords = {compact dwarfs ionsation line ratios}, note = {cite arxiv:1510.02447Comment: 20 pages, 14 figures, submitted to ApJ}, timestamp = {2015-10-09T09:52:48.000+0200}, title = {Resolving Ionisation and Metallicity on Parsec Scales Across Mrk 71 (NGC2363) with HST-WFC3}, url = {http://arxiv.org/abs/1510.02447}, year = 2015 }