Imprints of galaxy evolution on H II regions. Memory of the past uncovered by the CALIFA survey

Author(s)

S. F. Sánchez, E. Pérez, F. F. Rosales-Ortega, D. Miralles-Caballero, A. R. López-Sánchez, J. Iglesias-Páramo, R. A. Marino, L. Sánchez-Menguiano, R. García-Benito, D. Mast, M. A. Mendoza, P. Papaderos, S. Ellis, L. Galbany, C. Kehrig, A. Monreal-Ibero, R. González Delgado, M. Mollá, B. Ziegler, A. de Lorenzo-Cáceres, J. Mendez-Abreu, J. Bland-Hawthorn, S. Bekeraitė, M. M. Roth, A. Pasquali, A. Díaz, D. Bomans, G. van de Ven, L. Wisotzki

Abstract

Context. H ii regions in galaxies are the sites of star formation, so

they are special places for understanding the build-up of stellar mass

in the universe. The line ratios of this ionized gas are frequently used

to characterize the ionization conditions. In particular, the oxygen

abundances are assumed to trace the chemical enrichment of galaxies. Aims: We explore the connections between the ionization conditions

and the properties of the overall underlying stellar population

(ionizing or not-ionizing) in H ii regions, in order to uncover the

actual physical connection between them. Methods: We use the H ii

regions catalog from the CALIFA survey, which is the largest in

existence with more than 5000 H ii regions, to explore their

distribution across the classical [O iii] λ5007/Hβ vs. [N

ii] λ6583/Hα diagnostic diagram, and the way it depends on

the oxygen abundance, ionization parameter, electron density, and dust

attenuation. The location of H ii regions within this diagram is

compared with predictions from photoionization models. Finally, we

explore the dependence of the location within the diagnostic diagram on

the properties of the host galaxies, the galactocentric distances, and

the properties of the underlying stellar population. Results: The

H ii regions with weaker ionization strengths and more metal-rich are

located in the bottom righthand area of the diagram. In contrast, those

regions with stronger ionization strengths and more metal poor are

located in the upper lefthand end of the diagram. Photoionization models

per se do not predict these correlations between the parameters and the

line ratios. The H ii regions located in earlier-type galaxies, closer

to the center and formed in older and more metal-rich regions of the

galaxies are located in the bottom-right area of the diagram. On the

other hand, those regions located in late-type galaxies in the outer

regions of the disks and formed on younger and more metal-poor regions

lie in the top lefthand area of the diagram. The two explored line

ratios show strong correlations with the age and metallicity of the

underlying stellar population. Conclusions: These results

indicate that although H ii regions are short-lived events, they are

affected by the total underlying stellar population. One may say that H

ii regions keep a memory of the stellar evolution and chemical

enrichment that have left an imprint on both the ionizing stellar

population and the ionized gas.

 

Appendix A is available in electronic form at www.aanda.org

Organisation(s)

Department of Astrophysics

External organisation(s)

Universidad Nacional Autonoma de Mexico, Instituto de Astrofísica de Andalucía (CSIC), National Institute of Astrophysics, Optics and Electronics (INAOE), Universidad Autónoma de Madrid, Australian Astronomical Observatory, Macquarie University, Centro Astronómico Hispano Alemán (CAHA), Universidad Complutense de Madrid, Universidad de Granada, Centro Brasileiro de Pesquisas Físicas (CBPF), Universidade do Porto, The University of Sydney, Universidad de Chile, Université Paris VII - Paris-Diderot, Centro de Investigaciones Energeticas Medioambientales y Tecnológica, University of St. Andrews, Leibniz-Institut für Astrophysik Potsdam, Scientific Software Center, Ruhr-Universität Bochum (RUB), Max-Planck-Institut für Astronomie

Journal

Astronomy & Astrophysics

Volume

574

No. of pages

17

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201424873

Publication date

02-2015

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/imprints-of-galaxy-evolution-on-h-ii-regions-memory-of-the-past-uncovered-by-the-califa-survey(c7d17e38-810a-44fa-812e-69cdcc11e95b).html