English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We calculate the effective temperature ($T_{\rm eff}$) of ionizing star(s),oxygen abundance of the gas phase $(\rm O/H)$, and the ionization parameter $U$for a sample of H\,{\sc ii} regions located in the disks of 59 spiral galaxiesin the 0.005 < z < 0.03 redshift range. We use spectroscopic data taken fromthe CALIFA data release 3 (DR3) and theoretical (for $T_{\rm eff}$ and $U$) andempirical (for O/H) calibrations based on strong emission-lines. We considerspatial distribution and radial gradients of those parameters in each galacticdisk for the objects in our sample. Most of the galaxies in our sample($\sim70$ \%) shows positive $T_{\rm eff}$ radial gradients even though somethem exhibit negative or flat ones. The median value of the $T_{\rm eff}$radial gradient is 0.762 kK/$R_{25}$. We find that radial gradients of both$\log U$ and $T_{\rm eff}$ depend on the oxygen abundance gradient, in thesense that the gradient of $\log U$ increases as $\log(\rm O/H)$ gradientincreases while there is an anti-correlation between the gradient of $T_{\rmeff}$ and the oxygen abundance gradient. Moreover, galaxies with flat oxygenabundance gradients tend to have flat $\log U$ and $T_{\rm eff}$ gradients aswell. Although our results are in agreement with the idea of the existence ofpositive $T_{\rm eff}$ gradients along the disk of the majority of spiralgalaxies, this seems not to be an universal property for these objects.

Effective temperature of ionizing stars of extragalactic HII regions -- II: nebular parameter relations based on CALIFA data