The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies
By T. Davis, K. Alatalo, M. Sarzi, M. Bureau, L. M. Young, L. Blitz, P. Serra, A. Crocker, D. Krajnovi'c, R. McDermid and 15 more. 2011
231 citations recorded by the source corpus.
We make use of interferometric CO and HI observations, and optical integral-field spectroscopy from the ATLAS 3D survey to probe the origin of the molecular and ionised interstellar medium (ISM) in local early-type galaxies. We find th at 36±5% of our sample of fast rotating early-type galaxies have their ionised gas kinematically misaligned with respect to the stars, setting a strong lower limit on the importance of e xternally acquired gas (e.g. from mergers and cold accretion). Slow rotators have a flat distri bution of misalignments, indicating that the dominant source of gas is external. The molecular, ionised and atomic gas in all the detected galaxies are always kinematically aligned, even when they are misaligned from the stars, suggesting that all these three phases of the interst ellar medium share a common origin. In addition, we find that the origin of the cold and warm ga s in fast-rotating early-type galaxies is strongly affected by environment, despite the molecular gas detection rate and mass fractions being fairly independent of group/cluster membership. Galaxies in dense groups and the Virgo cluster nearly always have their molecular gas kinematically aligned with the stellar kinematics, consistent with a purely internal origin (pres umably stellar mass loss). In the field, however, kinematic misalignments between the stellar and gaseous components indicate that at least 42±5% of local fast-rotating early-type galaxies have their ga s supplied from external sources. When one also considers evidence of accretion present in the galaxies’ atomic gas distributions, > 46% of fast-rotating field ETGs are likely to have acquired a d etectable amount of ISM from accretion and mergers. We discuss several scenarios which could explain the environmental dichotomy, including preprocessing in galaxy groups/cluster outskirts and the morphological transformation of spiral galaxies, but we find it difficult to simultaneously explain the kinematic misalignment difference and the constant detection rate. Furthermore, our results suggest that galaxy mass may be an important independent factor associated with the origin of the gas, with the most massive fast-rotating ga laxies in our sample (MK < 24 mag; stellar mass of �8×10 10 M⊙) always having kinematically aligned gas. This mass dependence appears to be independent of environment, suggesting it is caused by a separate physical mechanism.
Subfields: Astronomy and Astrophysics, Instrumentation
View Paper: https://www.semanticscholar.org/paper/77afd067cab8ebc3940d37682ebea6241c1c537b
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Citations in the corpus
- The ATLAS3D project - XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images (2014, background): “The possible external origin of these apparently decoupled structures will be investigated coupling H I (Serra et al. 2012), CO (Davis et al. 2011) and optical observations.”
- Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, background): “Moreover the gas versus stars misalignment indicates external accretion (Sarzi et al. 2006; Davis et al. 2011).”
- The ATLAS3D Project – XXX. Star formation histories and stellar population scaling relations of early-type galaxies (2015, background): “In Davis et al. (2011), we showed that gas in various phases (ionized, molecular or neutral) is almost always aligned with the stars in Virgo galaxies, in contrast to galaxies in lowdensity environments where more than half show misalignments.”
- Raining on black holes and massive galaxies: the top-down multiphase condensation model (2016, background): “Ionized gas (Hβ, [O++] and [N I]) is observed in 73 per cent of the sample (Davis et al. 2011), H I gas in 40 per cent (Serra et al. 2012) and molecular MNRAS 466, 677–704 (2017) D ow nloaded from https://academ ic.oup.com /m nras/article-abstract/466/1/677/2617731 by guest on 15 M arch 2020 CO gas…”
- The ATLAS3D project - XIV. The extent and kinematics of the molecular gas in early-type galaxies (2012, background): “Furthermore, we continue a theme presented in Paper V of this series (Davis et al. 2011), evaluating the use of molecular gas as a circular velocity tracer in ETGs, this time in a spatially-resolved manner.”
- THE HERSCHEL REFERENCE SURVEY: DUST IN EARLY-TYPE GALAXIES AND ACROSS THE HUBBLE SEQUENCE (2011, methodology): “For example, Davis et al. (2011) have used the misalignment between the kinematics of the stars and the gas in ETGs to conclude that at least one-third of ETGs have acquired much of their ISM by this means.”
- CONNECTING ANGULAR MOMENTUM AND GALACTIC DYNAMICS: THE COMPLEX INTERPLAY BETWEEN SPIN, MASS, AND MORPHOLOGY (2015, result): “This result is supported by the findings of the ATLAS3D-project (Cappellari et al. 2011) that a kinematical misalignment of the gas component with respect to the stars is not unusual (Davis et al. 2011).”
- Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions (2016, background): “The gas content and kinematics tell us about the role of gas accretion in galaxy assembly (e.g. Sarzi et al. 2006; Davis et al. 2011; Barrera-Ballesteros et al. ?”
- The ATLAS3D Project – XXVIII. Dynamically driven star formation suppression in early-type galaxies (2014, methodology): “…calculate this using the re- solved CO maps from Paper XVIII, laying down an elliptical aperture at the turnover radius (with ellipticity calculated using the inclinations of these objects from Paper V; Davis et al. 2011b), and determining the fraction of the CO flux coming from inside this radius.”