Morphological and kinematical analysis of the double-barred galaxy NGC3504 using ALMA CO (2–1) data
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Oxford University Press
Methods: observationalGalaxies: kinematics and dynamicsGalaxies: structureRadio lines: galaxies
Yu-Ting Wu... [et al.]. Morphological and kinematical analysis of the double-barred galaxy NGC 3504 using ALMA CO (2–1) data, Monthly Notices of the Royal Astronomical Society, Volume 504, Issue 3, July 2021, Pages 3111–3127, [https://doi.org/10.1093/mnras/stab1087]
SponsorshipSpanish Government BG20/00224
We present results obtained from ALMA CO (2–1) data of the double-barred galaxy NGC3504.With three times higher angular resolution (∼0. 8) than previous studies, our observations reveal an inner molecular gas bar, a nuclear ring, and four inner spiral arm-like structures in the central 1-kpc region. Furthermore, the CO emission is clearly aligned with the two dust lanes in the outer bar region, with differences in shape and intensity between them. The total molecular gas mass in the observed region (50 arcsec×57 arcsec) is estimated to be∼3.1 × 109M , which is 17 per cent of the stellarmass.We used the Kinemetry package to fit the velocity field and found that circular motion strongly dominates at R = 0.3–0.8 kpc, but radial motion becomes important at R < 0.3 kpc and R = 1.0–2.5 kpc, which is expected due to the presence of the inner and outer bars. Finally, assuming that the gas moves along the dust lanes in the bar rotating frame, we derived the pattern speed of the outer bar to be 18 ± 5 kms−1 kpc−1, the average streaming velocities on each of the two dust lanes to be 165 and 221 km s−1, and the total mass inflow rate along the dust lanes to be 12M yr−1. Our results give a new example of an inner gas bar within a gas-rich double-barred galaxy and suggest that the formation of double-barred galaxies could be associated with the existence of such gas structures.