Issue |
A&A
Volume 662, June 2022
|
|
---|---|---|
Article Number | A94 | |
Number of page(s) | 28 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/202142659 | |
Published online | 23 June 2022 |
Physics of ULIRGs with MUSE and ALMA: The PUMA project
III. Incidence and properties of ionised gas disks in ULIRGs, associated velocity dispersion, and its dependence on starburstiness
1
Centro de Astrobiología, (CAB, CSIC–INTA), Departamento de Astrofísica, Cra. de Ajalvir Km. 4, 28850 Torrejón de Ardoz, Madrid, Spain
e-mail: mperna@cab.inta-csic.es
2
INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
3
Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
4
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
5
University of Cambridge, Cavendish Laboratory, Cambridge CB3 0HE, UK
6
University of Cambridge, Kavli Institute for Cosmology, Cambridge CB3 0HE, UK
7
INAF – Astronomical Observatory of Brera, Via Brera 28, 20121 Milano, Italy
8
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
9
Centro de Astrobiología (CSIC-INTA), ESAC Campus, 28692 Villanueva de la Cañada, Madrid, Spain
10
IAA – Instituto de Astrofísica de Andalucía (CSIC), Apdo. 3004, 18008 Granada, Spain
Received:
12
November
2021
Accepted:
4
February
2022
Context. A classical scenario suggests that ultra-luminous infrared galaxies (ULIRGs) transform colliding spiral galaxies into a spheroid-dominated early-type galaxy. Recent high-resolution simulations have instead shown that, under some circumstances, rotation disks can be preserved during the merging process or rapidly regrown after coalescence. Our goal is to analyse in detail the ionised gas kinematics in a sample of ULIRGs to infer the incidence of gas rotational dynamics in late-stage interacting galaxies and merger remnants.
Aims. We analysed integral field spectrograph MUSE data of a sample of 20 nearby (z < 0.165) ULIRGs (with 29 individual nuclei) as part of the Physics of ULIRGs with MUSE and ALMA (PUMA) project. We used multi-Gaussian fitting techniques to identify gaseous disk motions and the 3D-Barolo tool to model them.
Methods. We found that 27% (8 out of 29) individual nuclei are associated with kiloparsec-scale disk-like gas motions. The rest of the sample displays a plethora of gas kinematics, dominated by winds and merger-induced flows, which makes the detection of rotation signatures difficult. On the other hand, the incidence of stellar disk-like motions is ∼2 times larger than gaseous disks, as the former are probably less affected by winds and streams. The eight galaxies with a gaseous disk present relatively high intrinsic gas velocity dispersion (σ0 ∈ [30 − 85] km s−1), rotationally supported motions (with gas rotation velocity over velocity dispersion vrot/σ0 ∼ 1 − 8), and dynamical masses in the range (2 − 7)×1010 M⊙. By combining our results with those of local and high-z disk galaxies (up to z ∼ 2) from the literature, we found a significant correlation between σ0 and the offset from the main sequence (δMS), after correcting for their evolutionary trends.
Results. Our results confirm the presence of kiloparsec-scale rotating disks in interacting galaxies and merger remnants in the PUMA sample, with an incidence going from 27% (gas) to ≲50% (stars). Their gas σ0 is up to a factor of ∼4 higher than in local normal main sequence galaxies, similar to high-z starbursts as presented in the literature; this suggests that interactions and mergers enhance the star formation rate while simultaneously increasing the velocity dispersion in the interstellar medium.
Key words: galaxies: starburst / galaxies: interactions / galaxies: active / galaxies: ISM / galaxies: kinematics and dynamics
© ESO 2022
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