Lunch talk on Sep. 2, 2024

Unraveling the Low-Metallicity Merging Dwarf Galaxies: Insights into Starburst and Metal Dilution/Enrichment

Speaker: Yulong Gao (NJU)

Venue: SWIFAR Building 2111

Time: 12:45 PM, Monday, Sep. 2, 2024

Abstract: 

Understanding the physical mechanisms that drive starbursts in dwarf galaxies remains a significant challenge in astrophysics. The impact of mergers on star formation activity within these galaxies is particularly unclear. In this talk, we present observations from VLT/MUSE and ALMA to explore how mergers influence star formation in metal-poor dwarf galaxies, focusing on Haro 11 and NGC 4809/4810. Haro 11, which is in the late stages of a merger, shows morphology and kinematics similar to the Antennae galaxy, providing valuable insights into merger-induced starburst phenomena. In contrast, the ongoing collision between NGC 4809 and NGC 4810 offers a rare opportunity to study the effects of mergers on dwarf galaxies in real-time, especially in their overlapping regions. Our findings suggest that post-merger events between low-mass galaxies, such as Haro 11, can trigger global starbursts similar to those observed in ULIRGs. Notably, Haro 11 could serve as an analog to high-redshift dwarf starbursts and a potential progenitor of nearby, less massive elliptical galaxies. Additionally, the interaction zone between NGC 4809 and NGC 4810 exhibits an enhanced star formation rate (sSFR) and reduced metallicity, indicating that dwarf galaxy mergers can indeed stimulate significant star formation even in metal-poor environments. Moreover, we detect clear evidence of metal enrichment from the Type Ic SN 2011jm within NGC 4809, marking a pioneering detection of chemical pollution through stellar feedback beyond the Local Volume. These findings shed light on the mechanisms driving starbursts and stellar feedback processes in dwarf galaxies.

Report PPT:  SWIFAR_Yulong Gao.pdf