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The blue compact dwarf galaxy VCC 848 formed by dwarf–dwarf merging

From National Research Council Canada

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DOIResolve DOI: https://doi.org/10.3847/2041-8213/ab7825
AuthorSearch for: ORCID identifier: https://orcid.org/0000-0003-1632-2541; Search for: ORCID identifier: https://orcid.org/0000-0003-2922-6866; Search for: ORCID identifier: https://orcid.org/0000-0001-5303-6830; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0003-0350-7061; Search for: ORCID identifier: https://orcid.org/0000-0002-2073-2781; Search for: 1; Search for: 1ORCID identifier: https://orcid.org/0000-0002-8224-1128; Search for: ORCID identifier: https://orcid.org/0000-0002-9795-6433; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0002-5648-9920
Affiliation
  1. National Research Council of Canada. Herzberg Astronomy and Astrophysics
FormatText, Article
Subjectdwarf galaxies; dwarf irregular galaxies; galaxies; galaxy pairs; interacting galaxies; irregular galaxies; late-type galaxies; starburst galaxies; amorphous irregular galaxies; blue compact dwarf galaxies; galaxy evolution; N galaxies
Abstract
It has long been speculated that many starburst or compact dwarf galaxies are resulted from dwarf–dwarf galaxy merging, but unequivocal evidence for this possibility has rarely been reported in the literature. We present the first study of deep optical broadband images of a gas-dominated blue compact dwarf galaxy (BCD) VCC 848 (M sstarf sime 2 × 10⁸ M ⊙) that hosts extended stellar shells and thus is confirmed to be a dwarf–dwarf merger. VCC 848 is located in the outskirts of the Virgo Cluster. By analyzing the stellar light distribution, we found that VCC 848 is the result of a merging between two dwarf galaxies with a primary-to-secondary mass ratio lesssim5 for the stellar components and lesssim2 for the presumed dark matter halos. The secondary progenitor galaxy has been almost entirely disrupted. The age–mass distribution of photometrically selected star cluster candidates in VCC 848 implies that the cluster formation rate (CFR, ∝ star formation rate) was enhanced by a factor of ~7–10 during the past ~1 Gyr. The merging-induced enhancement of CFR peaked near the galactic center a few hundred Myr ago and has started declining in the last few tens of Myr. The current star formation activities, as traced by the youngest clusters, mainly occur at large galactocentric distances (gsim1 kpc). The fact that VCC 848 is still (atomic) gas-dominated after the period of the most violent collision suggests that gas-rich dwarf galaxy merging can result in BCD-like remnants with extended atomic gas distribution surrounding a blue compact center, in general agreement with previous numerical simulations.
Publication date
PublisherIOP
American Astronomical Society
In
  • The Astrophysical Journal 891, no. 1, L23: 1–7.
LanguageEnglish
Peer reviewedYes
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Record identifierab0d44a5-cc0e-4aaa-a039-e0aab2c59a80
Record created2020-11-04
Record modified2020-12-10
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