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Star formation and environment: a step in understanding the formation and evolution of local dwarf galaxies

Published online by Cambridge University Press:  30 October 2019

Elena Sacchi Open the ORCID record for Elena Sacchi [Opens in a new window] ,
Michele Cignoni ,
Alessandra Aloisi  and
Monica Tosi
Elena Sacchi
Affiliation:
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA, email: esacchi@stsci.edu
Michele Cignoni
Affiliation:
Department of Physics, Pisa University, Largo Bruno Pontecorvo, 3, I-56127 Pisa, Italy
Alessandra Aloisi
Affiliation:
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA, email: esacchi@stsci.edu
Monica Tosi
Affiliation:
INAF–Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, I-40129 Bologna, Italy
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Abstract

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We present here the results obtained from studying the resolved stellar populations of two dwarf irregular galaxies in the nearby Universe. These galaxies, DDO 68 and NGC 4449, were studied within the Legacy ExtraGalactic UV Survey, an HST program aimed to uncover the many ways in which the star formation (SF) process occurs at different scales. Thanks to the deep photometry obtained in different bands (from λ2704 Å to λ8057 Å), we were able to connect the location and timescales of the star forming regions within the galaxies to merging and interaction with gas clouds and satellites, a crucial aspect of galaxy evolution, even in such small systems. From the color-magnitude diagrams of the analyzed galaxies we were able to recover their star formation history (up to ∼ 2 − 3 Gyr ago since we do not observe the oldest main sequence turn-off or horizontal branch, due to the systems’ distance), finding that the SF never really stopped, but proceeded continuously even with the succession of high and low activity. The time intervals where we find higher SF rates in the two galaxies well agree with the dynamical timescales of previous interactions events, which might represent a major channel for triggering the SF in relatively isolated galaxies.

Keywords

dwarf galaxiesgalaxy evolutionstar formationenvironment
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 14 , Symposium S344: Dwarf Galaxies: From the Deep Universe to the Present , August 2018 , pp. 413 - 416
Copyright
© International Astronomical Union 2019 

References

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