Analysis 大質量星 Telescope Resolution Reference !"CO(2 −1) ALMA 1.12” (53 pc) Leroy et al. (2021) Hα VLT 0.92” (44 pc) Emsellem et al. (2022) Giant molecular clouds and their Type classification in M74 Fumika Demachi 1, Yasuo Fukui 1, Kengo Tachihara 1, Rin Yamada 1, Kazuki Tokuda 2,3, Shinji Fujita 4, Masato Kobayashi 5 Kazuyuki Muraoka 6, Ayu Konishi 6, Tsuge Kisetsu 4, Toshikazu Onishi 6, Akiko Kawamura 3 (Nagoya university 1, Kyushu university 2, National Astronomical Observatory of Japan 3, University of Tokyo 4, University of Cologne5, Osaka Metropolitan university 6 ) 1. 3. Need to expand samples to establish a general picture of GMC evolution. [ The goal of this study ] Establish the method of Type classification based on 𝐿!" Suitable for resolving GMCs without contamination in a line of sight Distance: 9.7 Mpc (Anand et al. 2021) Inclination: 8.9° (Lang et al. 2020) 𝑀()*+ = 10,-./0𝑀⊙, 𝑀23 = 104.5-𝑀⊙ (Leroy et al. 2021) M74 Giant molecular clouds (GMCs) are the main star formation sites and their evolutions are important to understand galaxy evolution. In this poster, we discuss GMC evolution in nearby spiral galaxy M74 by using spatially resolved GMC samples. We classified GMCs into 3 types based on Hα luminosity (𝐿67) of HII regions with GMCs, and Type I (without star formation) are 58, Type II (with 𝐿67 < 10/5.8 erg s9,) are 202, and Type III (𝐿67 > 10/5.8 erg s9,) are 172, then obtained these results, (1) the young star clusters clearly associated with Type II and III GMCs, and 𝐿67 and cluster mass show tight correlation for Type III (2) massive Type I GMCs show the sign of embedded star formation and Type II GMCs are affected by extinction more than Type III, and (3) Type III are the most virialized state. For these results, we interpreted GMC Type classification as GMC evolutionary sequence from Type I to III with active star formation. In this study, Type classification are applied in grand design spiral galaxy out of the local group for the first time. 1. Identify GMC by PYCPROPS*1 and HII region by Astrodendro*2. 2. Determine the association between GMC and HII region if their boundaries are overlapped, and classify GMCs based on 𝐿2:. 3. Compare Type GMCs with clusters*3 obtained by HST and 21 µm emissions*4 obtained by JWST to check consistency with results of LMC and the effects of Hα extinction, respectively. → Classify GMCs based on Hα luminosity (𝐿67) 10/5.8 erg s9, of associated HII regions because Hα is more uniformly surveyed Results 4. We identified 58 Type I, 202 Type II, 172 Type III (Fig.1). The median of GMC mass and radius increase Type I<II<III. Type III GMCs are in the most virialized states (Fig.2). 1-4 Myr clusters are located closer to GMCs than typical GMCs separation (Fig. 3). GMC evolution 5. Fig.2 → Type III GMCs are most gravitationally relaxed. Conclusions 6Type classification base on 𝐿2: is useful method to distinguish different evolutionary phases as tested in M74, out of the Local group, for the first time. Extend into other galaxies to validate the universality and for the future work. Assume GMCs evolve steadily and the timescale of Type III is 4 Myr based on associated cluster age. Estimate the timescale of Type I and II by the ratio with Type III statistically → Type I: 1Myr, Type II: 5Myr, Type III: 4Myr [Problem] GMC [Type I ] No star formation [Type II ] With HII region (𝐿!" < 10#$.&) [Type III ] With HII region (𝐿!" > 10#$.&) HII region *1: Rosolowsky et al. 2021, *2: Rosolowsky et al. 2008, *3: Adamo et al. 2017, *4: Lee et al. 2023 Fig.3) Histogram of separation between nearest GMCs and clusters. The orange line indicates typical GMC-GMC separation. Fig.4) Scatter plot between total cluster mass and Hα luminosity associated common GMCs. The size of marker indicate the number of clusters with each GMC. The cluster mass increase with 𝐿2: especially for Type III (Fig. 4). 35% of Type I and more than 80% of Type II and III are associated with 21 µm emission. Correct Hα extinct lu