Spatially resolved properties of the ionized gas in the H ii galaxy J084220+115000
Date
2023/01/09
Journal Title
Journal ISSN
Volume Title
Publisher
OXFORD UNIV PRESS
Abstract
We present a spatially resolved spectroscopic study for the metal poor H ii galaxy J084220+115000 using MEGARA Integral Field Unit observations at the Gran Telescopio Canarias. We estimated the gas metallicity using the direct method for oxygen, nitrogen, and helium and found a mean value of 12 + log (O/H) = 8.03 +/- 0.06, and integrated electron density and temperature of similar to 161 cm(-3) and similar to 15400 K, respectively. The metallicity distribution shows a large range of Delta(O/H) = 0.72 dex between the minimum and maximum (7.69 +/- 0.06 and 8.42 +/- 0.05) values, unusual in a dwarf star-forming galaxy. We derived an integrated log (N/O) ratio of -1.51 +/- 0.05 and found that both N/O and O/H correspond to a primary production of metals. Spatially resolved maps indicate that the gas appears to be photoionized by massive stars according to the diagnostic line ratios. Between the possible mechanisms to explain the starburst activity and the large variation of oxygen abundance in this galaxy, our data support a possible scenario where we are witnessing an ongoing interaction triggering multiple star-forming regions localized in two dominant clumps.
Description
Keywords
INTEGRAL FIELD SPECTROSCOPY, INDEPENDENT COSMOLOGICAL CONSTRAINTS, PRIMORDIAL HELIUM ABUNDANCE, EMISSION-LINE GALAXIES, COMPACT DWARF GALAXIES, STAR-FORMING REGIONS, METAL-POOR GALAXIES, LYMAN-BREAK ANALOGS, EQUATION-OF-STATE, HII GALAXIES