Ionizing stellar population in the disc of NGC 3310 – I. The impact of a minor merger on galaxy evolution

Numerical simulations of minor mergers predict little enhancement in the global star formation activity. However, it is still unclear the impact they have on the chemical state of the whole galaxy and on the mass build-up in the galaxy bulge and disc. We present a two-dimensional analysis of NCG 310...

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Bibliographic Details
Published inMonthly notices of the Royal Astronomical Society Vol. 440; no. 3; pp. 2265 - 2289
Main Authors Miralles-Caballero, D., Díaz, A. I., Rosales-Ortega, F. F., Pérez-Montero, E., Sánchez, S. F.
Format Journal Article
LanguageEnglish
Published London Oxford University Press 21.05.2014
Subjects
Astrophysics
Dimensional analysis
Dust
Nebulae
Simulation
Spectrum analysis
Star & galaxy formation
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Summary:Numerical simulations of minor mergers predict little enhancement in the global star formation activity. However, it is still unclear the impact they have on the chemical state of the whole galaxy and on the mass build-up in the galaxy bulge and disc. We present a two-dimensional analysis of NCG 310, currently undergoing an intense starburst likely caused by a recent minor interaction, using data from the PPAK Integral Field Spectroscopy Nearby Galaxies Survey (PINGS). With data from a large sample of about a hundred H ii regions identified throughout the disc and spiral arms, we derive, using strong-line metallicity indicators and direct derivations, a rather flat gaseous abundance gradient. Thus, metal mixing processes occurred, as in observed galaxy interactions. Spectra from PINGS data and additional multiwavelength imaging were used to perform a spectral energy distribution fitting to the stellar emission and a photoionization modelling of the nebulae. The ionizing stellar population is characterized by single populations with a narrow age range (2.5-5 Myr) and a broad range of masses (10...-6 x 10... M...). The effect of dust grains in the nebulae is important, indicating that 25-70 per cent of the ultraviolet photons can be absorbed by dust. The ionizing stellar population within the H ii regions represents typically a few per cent of the total stellar mass. This ratio, a proxy to the specific star formation rate, presents a flat or negative radial gradient. Therefore, minor interactions may indeed play an important role in the mass build-up of the bulge. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stu435