The Galactic center wind

“For the derived wind model, the required pressure P0=k 6 107 K cm 3 is an order of magnitude higher than what is possible with stellar winds from the central regions (Chevalier 1992).”

“…is not clear whether the filaments represent only a small fraction of vertical fields that pervade the Galactic center (Serabyn & Morris 1996; Chandran, Cowley, & Morris 2000), or whether they represent purely local magnetic features (Chevalier 1992; LaRosa, Lazio, & Kassim 2001; Yusef-Zadeh 2003).”

“This extends previous work on a Galactic Center wind (e.g., Chevalier 1992) to incorporate the effects of the central black hole.”

“Chevalier (1992) investigated the outflow of this hot gas from the central 0.8 pc of the Galaxy and the formation of a shocked wind bubble.”

“However, it should be noted that modelling of this environment (e.g., Chevalier 1992; Ruffert & Melia 1994) has itself provided compelling evidence for a substantial mass outflow from the inner few lightyears of the Galaxy.”

“Still in the category of outflow scenarios, a poloidal largescale magnetic field in the GC region could find its roots in stellar activity very close to the GC (e.g., Sofue 1984; Chevalier 1992) – for instance, in a relatively recent nuclear starburst (e.g., Bland-Hawthorn & Cohen 2003).”

“…solutions exist for determining the speed of a wind out of a starburst region as a function of distance given certain simplifying assumptions (Chevalier 1992; Veilleux, Cecil & Bland-Hawthorn 2005; Zirakashvili & Völk 2006; Strickland & Heckman 2009) like absence of halo drag, radiative…”

“Ejection or expansion of magnetic fields from an accretion disk (Heyvaerts, Norman, & Pudritz 1998; Uchida et al. 1985) or a shocked Galactic wind (Bland-Hawthorn & Cohen 2003; Chevalier 1992) are possibilities for the origin of these structures.”

“In one model, the magnetic field was amplified by thermal instability (Rosner & Bodo 1996), whereas in another the filaments were considered to be magnetized wakes produced as a result of an interaction of the molecular clouds with a Galactic center wind (Chevalier 1992; Shore & LaRosa 1999).”

“The shape and location of the shell motivated several models for its formation, including starburst (Chevalier 1992), active galactic nucleus (AGN; Melia & Falcke 2001), and magnetodynamic effects (Uchida et al. 1985).”

“The high stellar densities and large energy and mass deposition rates, provided by stellar winds and supernovae (SNe) explosions, suggest that SSCs are potentially strong X-ray emitters (Chevalier 1992).”

“01 M ⊙ yr − 1 ) at the GC (Chevalier 1992; Law 2010; Zhang et al. 2021).”

“The resemblance of the GCL to a wind-driven mass outflow was striking and led to several models for its formation (e.g., Chevalier 1992; Melia & Falcke 2001).”

“It was suggested by Chevalier & Clegg (1985) (CC85) and Chevalier (1992) that the kinetic energy supplied by supernovae and stellar winds is thermalized within the star cluster volume.”

“1 of Chevalier (1992) for the quasi-spherical case, assuming σM = 0.001, which is readily applicable to the shocked wind bubbles of PNe.”

“In principle, the Galactic center outflow may also be driven by stellar winds (Chevalier 1992).”

“…gas dynamics around the GC region, since the magnetic fields should have played a significant role in producing such nonthermal spectra and the threadlike shapes of these filaments, and the gas motion is usually coupled with the magnetic fields (e.g., Chevalier 1992; Boldyrev & Yusef-Zadeh 2006).”

“Such proto-galactic winds should be detected as sources of a diffuse X-ray emission, as it is the case in the local Universe (e.g. Chevalier 1992; Strickland & Stevens 2000; Silich et al. 2005; Strickland & Heckman 2009): LX = 4π ∫ Rout Rst r2n2ΛX(T, Z)dr, (4) where n(r) is the atomic number…”

“Numerous ideas have been advanced to account for the NTFs (references in Morris 1996; Chevalier 1992; Rosner & Bodo 1996; Shore & LaRosa 1999; Bicknell & Li 2001; Yusef-Zadeh 2003; Boldyrev & Yusef-Zadeh 2006), but there is presently no consensus on the nature of thmechanism that has produced them.”

“Due to the high temperatures produced by the multiple shock waves and the large amount of mass deposited by the sources, both superwinds and superbubbles are potential diffuse X-ray emitt rs (Chevalier 1992; Chu et al. 1995, C95 henceforth; Cantó, Raga & Rodrı́guez 2000; Stevens & Hartwell 2003).”

“…direction of the magnetic field in the diffuse intercloud medium can be explained by various scenarios, including inward advection from the Galactic disk (Sofue & Fujimoto 1987; Chandran, Cowley, & Morris 2000), outflows from the Galactic nucleus (Sofue 1984; Chevalier 1992), and a local dynamo.”

“Mechanisms to explain the origin of this gas include supernovae (Yamauchi et al. 1990) and stellar winds (Chevalier 1992; Quataert 2004).”

“The four standard models presented for the formation of the GCL are: • A small-scale starburst (Chevalier 1992, Bland-Hawthorn & Cohen 2003) — Stellar winds and supernovae create a hot, buoyant bubble of gas that rises from the disk.”