H α Emission and H ii Regions at the Locations of Recent Supernovae in Nearby Galaxies

Journal article

We present a statistical analysis of the local, ≈50–100 pc scale, Hα emission at the locations of recent (≤125 yr) supernovae (SNe) in nearby star-forming galaxies. Our sample consists of 32 SNe in 10 galaxies that are targets of the PHANGS-MUSE survey. We find that 41% (13/32) of these SNe occur coincident with a previously identified H ii region. For comparison, H ii regions cover 32% of the area within ±1 kpc of any recent SN. Contrasting this local covering fraction with the fraction of SNe coincident with H ii regions, we find a statistical excess of 7.6% ± 8.7% of all SNe to be associated with H ii regions. This increases to an excess of 19.2% ± 10.4% when considering only core-collapse SNe (CCSNe). These estimates appear to be in good agreement with qualitative results from new, higher-resolution Hubble Space Telescope Hα imaging, which also suggests many CCSNe detonate near but not in H ii regions. Our results appear consistent with the expectation that only a modest fraction of stars explode during the first ≲5 Myr of the life of a stellar population when Hα emission is expected to be bright. Of the H ii region associated SNe, 85% (11/13) also have associated detected CO (2–1) emission, indicating the presence of molecular gas. The SNe associated with H ii regions have typical extinctions of A V ∼ 1 mag, consistent with a significant amount of pre-clearing of gas from the region before the SNe explode.

Authors: Mayker Chen, N; Leroy, AK; Sarbadhicary, SK; Lopez, LA; Thompson, TA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Astronomical Journal
• Volume: 168
• Issue: 1
• Article number: 5
• Publication date: 2024-06-18
• Acceptance date: 2024-04-15
• DOI: 10.3847/1538-3881/ad3fb7
• EISSN: 1538-3881
• ISSN: 0004-6256
• Language: English
• Keywords: H II regions; Supernovae; Galaxy evolution; Stellar feedback; Core-collapse supernovae; Star forming regions