Bar
Shen（讨论 | 贡献）2024年9月23日 (一) 14:17的版本 （创建页面，内容为“*描述棒星系的三个参数，长度，强度，和pattern speed [https://arxiv.org/pdf/1501.05498] ==strength== The bar strength is a parameter that measures the non-axisymmetric forces produced by the bar potential in the disc of galaxies (see, e.g., Laurikainen & Salo, 2002). * measure the torques of the bar (e.g., Combes & Sanders , 1981; Quillen et al. , 1994; Buta & Block , 2001; Laurikainen et al. , 2007; Salo et al. , 2010) * bar ellipticity Martin…”）
- 描述棒星系的三个参数，长度，强度，和pattern speed [1]
strength
The bar strength is a parameter that measures the non-axisymmetric forces produced by the bar potential in the disc of galaxies (see, e.g., Laurikainen & Salo, 2002).
- measure the torques of the bar (e.g., Combes & Sanders , 1981; Quillen et al. , 1994; Buta & Block ,
2001; Laurikainen et al. , 2007; Salo et al. , 2010)
- bar ellipticity Martinet & Friedli (1997); Aguerri (1999); Whyte et al.
(2002); Marinova & Jogee (2007); Aguerri et al. (2009)
- Fourier decomposition of the galaxy light Ohta et al.
(1990); Marquez et al. (1996); Aguerri et al. (2000); Athanassoula & Misiriotis (2002); Laurikainen et al. (2005).
pattern speed
- the rotational frequency of the bar.
- physical upper limit: bar cannot extend beyond the corotation resonance (CR) radius
of the galaxy, which is the region of the galaxy where the angular speed of the stars of the disc in circular motions equals the bar pattern speed.
- This limit is imposed by the stability of the main family of orbits forming the bar (the so-called x1 family; Contopoulos 1980) which are only stable within R(CR). Orbits in the outer region of the disc (R > RCR) can�not support a bar structure.