On the origin of the anomalous gas, non-declining rotation curve, and disc asymmetries in NGC 253
Abstract
We present a multiwavelength (from far-ultraviolet to ${\rm H}\, \rm {\small I}$ emission) study of star formation feedback on the kinematics of the interstellar medium in the Sculptor galaxy, NGC 253. Its three well-known features (a disrupted stellar disc, a previously reported declining rotation curve, and anomalous ${\rm H}\, \rm {\small I}$ gas) are studied in a common context of disc asymmetries. About 170 h of on-source ATCA observations are collected and reduced into two versions of ${\rm H}\, \rm {\small I}$ data cubes of different angular resolution (30 arcsec/2 arcmin) and H I column density sensitivity (7.4 × 1019 cm-2/4 × 1018 cm-2). We separate the anomalous gas from the disc using a custom-made line profile fitting toolkit called FMG. Two star formation tracers (H α, FUV emission) are carefully processed and studied. We find that at R > 7.5 kpc, the star formation activity is strongly lopsided (SFRNE > SFRSW), and investigate several other properties (H α/FUV, dust temperature, stellar age, and disc stability parameters). We also find that the declining nature of the rotation curve perceived by previous studies is not intrinsic but a combined effect of kinematical asymmetries at R = 7.5-16 kpc. This is likely the consequence of star formation triggered outflow. The mass distribution and the time-scale of the anomalous gas also imply that it originates from gas outflow, which is perhaps caused by galaxy-galaxy interaction considering the crowded environment of NGC 253.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2023
- DOI:
- 10.1093/mnras/stad1772
- arXiv:
- arXiv:2306.06869
- Bibcode:
- 2023MNRAS.524.1169L
- Keywords:
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- galaxies: individual: NGC 253;
- galaxies: ISM;
- galaxies: kinematics and dynamics;
- galaxies: star formation;
- radio lines: galaxies;
- software: data analysis;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 22 pages, 23 figures, accepted for publication in MNRAS