TY - JOUR
T1 - Molecular gas content and high excitation of a massive main-sequence galaxy at z = 3
AU - Lei, Han
AU - Valentino, Francesco
AU - Magdis, Georgios E.
AU - Kokorev, Vasily
AU - Liu, Daizhong
AU - Rigopoulou, Dimitra
AU - Jin, Shuowen
AU - Daddi, Emanuele
N1 - Funding Information:
The authors warmly thank the anonymous referee for the insightful comments that improved the presentation of our work and Isabella Cortzen for her contribution to the data reduction. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. SJ is supported by the European Union’s Horizon Europe research and innovation program under the Marie Skłodowska-Curie grant agreement No. 101060888.
Publisher Copyright:
© The Authors 2023.
PY - 2023/5
Y1 - 2023/5
N2 - We present new CO (J = 5-4 and 7-6) and [C I] (3P2-3P1 and 3P1-3P0) emission line observations of the star-forming galaxy D49 at the massive end of the main sequence at z = 3. We incorporate previous CO (J = 3-2) and optical-to-millimetre continuum observations to fit its spectral energy distribution. Our results hint at high-J CO luminosities exceeding the expected location on the empirical correlations with the infrared luminosity. [CI] emission fully consistent with the literature trends is found. We do not retrieve any signatures of a bright active galactic nucleus that could boost the J = 5-4, 7-6 lines in either the infrared or X-ray bands, but warm photon-dominated regions, shocks, or turbulence could in principle do so. We suggest that mechanical heating could be a favourable mechanism able to enhance the gas emission at fixed infrared luminosity in D49 and other main-sequence star-forming galaxies at high redshift, but further investigation is necessary to confirm this explanation. We derive molecular gas masses from dust, CO, and [C I] that all agree within the uncertainties. Given its high star formation rate ~500 Mo yr-1 and stellar mass > 1011.5 Mo, the short depletion timescale of < 0.3 Gyr might indicate that D49 is experiencing its last growth spurt and will soon transit to quiescence.
AB - We present new CO (J = 5-4 and 7-6) and [C I] (3P2-3P1 and 3P1-3P0) emission line observations of the star-forming galaxy D49 at the massive end of the main sequence at z = 3. We incorporate previous CO (J = 3-2) and optical-to-millimetre continuum observations to fit its spectral energy distribution. Our results hint at high-J CO luminosities exceeding the expected location on the empirical correlations with the infrared luminosity. [CI] emission fully consistent with the literature trends is found. We do not retrieve any signatures of a bright active galactic nucleus that could boost the J = 5-4, 7-6 lines in either the infrared or X-ray bands, but warm photon-dominated regions, shocks, or turbulence could in principle do so. We suggest that mechanical heating could be a favourable mechanism able to enhance the gas emission at fixed infrared luminosity in D49 and other main-sequence star-forming galaxies at high redshift, but further investigation is necessary to confirm this explanation. We derive molecular gas masses from dust, CO, and [C I] that all agree within the uncertainties. Given its high star formation rate ~500 Mo yr-1 and stellar mass > 1011.5 Mo, the short depletion timescale of < 0.3 Gyr might indicate that D49 is experiencing its last growth spurt and will soon transit to quiescence.
KW - Galaxies: evolution
KW - Galaxies: high-redshift
KW - Galaxies: individual: D49
KW - Galaxies: ISM
KW - Galaxies: star formation
KW - Submillimeter: ISM
UR - http://www.scopus.com/inward/record.url?scp=85160336958&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202345925
DO - 10.1051/0004-6361/202345925
M3 - Comment/Letter to the editor
AN - SCOPUS:85160336958
SN - 0004-6361
VL - 673
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - L13
ER -