TY - JOUR
T1 - Turbulence statistics of H i clouds entrained in the Milky Way's nuclear wind
AU - Gerrard, Isabella A.
AU - Noon, Karlie A.
AU - Federrath, Christoph
AU - Di Teodoro, Enrico M.
AU - Marchal, Antoine
AU - McClure-Griffiths, N. M.
N1 - Publisher Copyright:
© 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2024/5/6
Y1 - 2024/5/6
N2 - The interstellar medium (ISM) is ubiquitously turbulent across many physically distinct environments within the Galaxy. Turbulence is key in controlling the structure and dynamics of the ISM, regulating star formation, and transporting metals within the Galaxy. We present the first observational measurements of turbulence in neutral hydrogen entrained in the hot nuclear wind of the Milky Way. Using recent MeerKAT observations of two extra-planar H i clouds above (gal. lat., similar to 7.0 degrees) and below (gal. lat.similar to -3.9 degrees) the Galactic disc, we analyse centroid velocity and column density maps to estimate the velocity dispersion (sigma(v,3D)), the turbulent sonic Mach number (M), the volume density dispersion (sigma(rho/rho 0)), and the turbulence driving parameter (b). We also present a new prescription for estimating the spatial temperature variations of H i in the presence of related molecular gas. We measure these turbulence quantities on the global scale of each cloud, but also spatially map their variation across the plane-of-sky extent of each cloud by using a roving kernel method. We find that the two clouds share very similar characteristics of their internal turbulence, despite their varying latitudes. Both clouds are in the sub-to-trans-sonic Mach regime, and have primarily compressively driven (b similar to 1) turbulence. Given that there is no known active star formation present in these clouds, this may be indicative of the way the cloud-wind interaction injects energy into the entrained atomic material on parsec scales.
AB - The interstellar medium (ISM) is ubiquitously turbulent across many physically distinct environments within the Galaxy. Turbulence is key in controlling the structure and dynamics of the ISM, regulating star formation, and transporting metals within the Galaxy. We present the first observational measurements of turbulence in neutral hydrogen entrained in the hot nuclear wind of the Milky Way. Using recent MeerKAT observations of two extra-planar H i clouds above (gal. lat., similar to 7.0 degrees) and below (gal. lat.similar to -3.9 degrees) the Galactic disc, we analyse centroid velocity and column density maps to estimate the velocity dispersion (sigma(v,3D)), the turbulent sonic Mach number (M), the volume density dispersion (sigma(rho/rho 0)), and the turbulence driving parameter (b). We also present a new prescription for estimating the spatial temperature variations of H i in the presence of related molecular gas. We measure these turbulence quantities on the global scale of each cloud, but also spatially map their variation across the plane-of-sky extent of each cloud by using a roving kernel method. We find that the two clouds share very similar characteristics of their internal turbulence, despite their varying latitudes. Both clouds are in the sub-to-trans-sonic Mach regime, and have primarily compressively driven (b similar to 1) turbulence. Given that there is no known active star formation present in these clouds, this may be indicative of the way the cloud-wind interaction injects energy into the entrained atomic material on parsec scales.
KW - Galaxy: centre
KW - ISM: clouds
KW - ISM: kinematics and dynamics
KW - Turbulence
UR - http://www.scopus.com/inward/record.url?scp=85192672274&partnerID=8YFLogxK
U2 - 10.1093/mnras/stae1144
DO - 10.1093/mnras/stae1144
M3 - Article
AN - SCOPUS:85192672274
SN - 0035-8711
VL - 530
SP - 4317
EP - 4330
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -