TY - CHAP
T1 - Molecular Clouds with CO-dark Envelopes in the Extended Ultraviolet (XUV) Disk of M83
AU - Koda, Jin
N1 - Publisher Copyright:
© The Author(s), 2023. Published by Cambridge University Press on behalf of International Astronomical Union.
PY - 2021/8/9
Y1 - 2021/8/9
N2 - We report a CO(3-2) detection of 23 molecular clouds in the extended ultraviolet (XUV) disk of the spiral galaxy M83 with ALMA. The observed 1 kpc2 region is at about 1.24R25 from the disk center, where CO(2-1) was previously not detected. The detection and non-detection, as well as the level of star formation (SF) activity in the region, can be explained consistently if the clouds have the mass distribution common among Galactic clouds, such as Orion A - with star-forming dense clumps embedded in thick layers of bulk molecular gas, but in a low-metallicity regime where their outer layers are CO-deficient and CO-dark. The cloud masses, estimated from CO(3-2), range from 8.2 × 102 to 2.3 × 104M⊙. The most massive clouds appear similar to Orion A in SF activity as well as in gas mass. The common cloud mass structure also justifies the use of high-J CO transitions to trace the total gas mass of clouds, or galaxies, even in the high-z universe. This study is the first demonstration that CO(3-2) is an efficient tracer of molecular clouds even in low-metallicity environments. This study is published in the Astronomical Journal, entitled “First Detection of the Molecular Cloud Population in the Extended Ultraviolet (XUV) Disk of M83” by J. Koda, L. Watson, F. Combes, M. Rubio, S. Boissier, M. Yagi, D. Thilker, A. M Lee, Y. Komiyama, K. Morokuma-Matsui, and C. Verdugo.
AB - We report a CO(3-2) detection of 23 molecular clouds in the extended ultraviolet (XUV) disk of the spiral galaxy M83 with ALMA. The observed 1 kpc2 region is at about 1.24R25 from the disk center, where CO(2-1) was previously not detected. The detection and non-detection, as well as the level of star formation (SF) activity in the region, can be explained consistently if the clouds have the mass distribution common among Galactic clouds, such as Orion A - with star-forming dense clumps embedded in thick layers of bulk molecular gas, but in a low-metallicity regime where their outer layers are CO-deficient and CO-dark. The cloud masses, estimated from CO(3-2), range from 8.2 × 102 to 2.3 × 104M⊙. The most massive clouds appear similar to Orion A in SF activity as well as in gas mass. The common cloud mass structure also justifies the use of high-J CO transitions to trace the total gas mass of clouds, or galaxies, even in the high-z universe. This study is the first demonstration that CO(3-2) is an efficient tracer of molecular clouds even in low-metallicity environments. This study is published in the Astronomical Journal, entitled “First Detection of the Molecular Cloud Population in the Extended Ultraviolet (XUV) Disk of M83” by J. Koda, L. Watson, F. Combes, M. Rubio, S. Boissier, M. Yagi, D. Thilker, A. M Lee, Y. Komiyama, K. Morokuma-Matsui, and C. Verdugo.
KW - Galaxy disks (589)
KW - Galaxy evolution (594)
KW - Interstellar medium (847)
KW - Molecular clouds (1072)
KW - Spiral galaxies (1560)
KW - Star formation (1569)
UR - https://www.scopus.com/pages/publications/85163798533
U2 - 10.1017/S1743921322003684
DO - 10.1017/S1743921322003684
M3 - Chapter
AN - SCOPUS:85163798533
T3 - Proceedings of the International Astronomical Union
SP - 15
EP - 20
BT - Proceedings of the International Astronomical Union
A2 - Wong, T.
A2 - Kim, W.-T.
PB - Cambridge University Press
ER -