Year: 2010
Type: article
Abstract: We have mapped the northern area (30' × 20') of a Local Group spiral galaxy M33 in 12 CO( J = 1–0) line with the 45 m telescope at the Nobeyama Radio Observatory. Along with Hα and Spitzer 24 μm data, we have investigated the relationship between the surface density of molecular gas mass and that of star formation rate (SFR) in an external galaxy (Kennicutt–Schmidt law) with the highest spatial resolution (∼80 pc) to date, which is comparable to scales of giant molecular clouds (GMCs). At positions where CO is significantly detected, the SFR surface density exhibits a wide range of over four orders of magnitude, from Σ SFR ≲ 10 −10 to ∼10 −6 M ☉ yr −1 pc −2 , whereas the values are mostly within 10–40 M ☉ pc −2 . The surface density of gas and that of SFR correlate well at an ∼1 kpc resolution, but the correlation becomes looser with higher resolution and breaks down at GMC scales. The scatter of the Σ SFR – relationship in the ∼80 pc resolution results from the variety of star-forming activity among GMCs, which is attributed to the various evolutionary stages of GMCs and to the drift of young clusters from their parent GMCs. This result shows that the Kennicutt–Schmidt law is valid only in scales larger than that of GMCs, when we average the spatial offset between GMCs and star-forming regions, and their various evolutionary stages.
Authors: Sachiko Onodera, Nario Kuno, Tomoka Tosaki, Kotaro Kohno, Kouichiro Nakanishi, Tsuyoshi Sawada, Kazuyuki Muraoka, Shinya Komugi, Rie Miura, Hiroyuki Kaneko, Akihiko Hirota, Ryohei Kawabe
Institutions: National Astronomical Observatory of Japan, Nobeyama Radio Observatory, The University of Tokyo, The Graduate University for Advanced Studies, SOKENDAI, Joetsu University of Education, Osaka Prefecture University, Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2170512380