TY - JOUR
T1 - The Population of the Galactic Center Filaments
T2 - Position Angle Distribution Reveals a Degree-scale Collimated Outflow from Sgr A* along the Galactic Plane
AU - Yusef-Zadeh, F.
AU - Arendt, R. G.
AU - Wardle, M.
AU - Heywood, I.
N1 - Funding Information:
Work by R.G.A. was supported by NASA under award number 80GSFC21M0002. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation.
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/6/1
Y1 - 2023/6/1
N2 - We have examined the distribution of the position angle (PA) of the Galactic center filaments with lengths L > 66″ and <66″ as well as their length distribution as a function of PA. We find bimodal PA distributions of the filaments, and long and short populations of radio filaments. Our PA study shows the evidence for a distinct population of short filaments with PA close to the Galactic plane. Mainly thermal, short-radio filaments (<66″) have PAs concentrated close to the Galactic plane within 60° < PA < 120°. Remarkably, the short filament PAs are radial with respect to the Galactic center at l < 0° and extend in the direction toward Sgr A*. On a smaller scale, the prominent Sgr E H ii complex G358.7-0.0 provides a vivid example of the nearly radial distribution of short filaments. The bimodal PA distribution suggests a different origin for two distinct filament populations. We argue that the alignment of the short-filament population results from the ram pressure of a degree-scale outflow from Sgr A* that exceeds the internal filament pressure, and aligns them along the Galactic plane. The ram pressure is estimated to be 2 × 106 cm−3 K at a distance of 300 pc, requiring biconical mass outflow rate 10−4 M ⊙ yr−1 with an opening angle of ∼40°. This outflow aligns not only the magnetized filaments along the Galactic plane but also accelerates thermal material associated with embedded or partially embedded clouds. This places an estimate of ∼6 Myr as the age of the outflow.
AB - We have examined the distribution of the position angle (PA) of the Galactic center filaments with lengths L > 66″ and <66″ as well as their length distribution as a function of PA. We find bimodal PA distributions of the filaments, and long and short populations of radio filaments. Our PA study shows the evidence for a distinct population of short filaments with PA close to the Galactic plane. Mainly thermal, short-radio filaments (<66″) have PAs concentrated close to the Galactic plane within 60° < PA < 120°. Remarkably, the short filament PAs are radial with respect to the Galactic center at l < 0° and extend in the direction toward Sgr A*. On a smaller scale, the prominent Sgr E H ii complex G358.7-0.0 provides a vivid example of the nearly radial distribution of short filaments. The bimodal PA distribution suggests a different origin for two distinct filament populations. We argue that the alignment of the short-filament population results from the ram pressure of a degree-scale outflow from Sgr A* that exceeds the internal filament pressure, and aligns them along the Galactic plane. The ram pressure is estimated to be 2 × 106 cm−3 K at a distance of 300 pc, requiring biconical mass outflow rate 10−4 M ⊙ yr−1 with an opening angle of ∼40°. This outflow aligns not only the magnetized filaments along the Galactic plane but also accelerates thermal material associated with embedded or partially embedded clouds. This places an estimate of ∼6 Myr as the age of the outflow.
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U2 - 10.3847/2041-8213/acd54b
DO - 10.3847/2041-8213/acd54b
M3 - Article
AN - SCOPUS:85161519405
SN - 2041-8205
VL - 949
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L31
ER -