电子密度模型
组成
- thick disk (warm interstellar medium)
- thin disk ( Galactic molecular ring)
- spiral arms based on a recent fit to Galactic H II regions, a Galactic Center disk,
- and seven local features the Local Bubble (LB), two regions of enhanced ne on the periphery of the Local Bubble (LB1, LB2), the GN, Loop I (LI), a region of enhanced ne in the Carina arm, and a region of reduced ne in the Sagittarius tangential region.
发展：
Manchester & Taylor (1981) and Lyne et al. (1985) 组成：a thin disk of scale height 70 pc and a z-independent component
Taylor & Cordes(1993), building on the work of Cordes et al. (1991) 组成：spiral structure， interstellar scattering
thick Galactic disks and made use of the $sech(x)^2$ function“NE2001” model (Cordes&Lazio 2002, 2003)
thin and thick axisymmetric disks, spiral arms, and local components including a local arm, a local hot bubble surrounding the Sun, and relatively large super-bubbles in the first and third Galactic quadrants, together with overdense components representing the GN, the Vela SNR, Galactic Loop I, and a small region around the Galactic Center.These results illustrate the clumpy nature of the ISM on scales of 100–1000 pc. An analysis by Schnitzeler (2012) considered a range of modified TC93 and NE2001 models with different parameters for the thick disk.
与前人的区别：
采用了新的银河系悬臂结构 Bd at 15 kpc and Ad at 2.5 kpc
不通过在单个脉冲星的方向上调用团块或空隙来校正单个脉冲星的模型距离差异
FRB与脉冲星的区别？河外脉冲星与河外FRB？
一些概念
河外脉冲星
pulsars believed to lie outside our Galaxy have only been found in the Magellanic Clouds, our nearest neighbor galaxies. A total of 29 pulsars are known in the Clouds, 6 in the SMC and 23 in the LMC.
脉冲星测距方法：
(a) fitting for annual parallax in precision timing solutions
(b) direct measurements of position shifts due to annual parallax using very-long-baseline interferometry (VLBI).
(c) Red shift
“Lutz–Kelker” effect (Lutz & Kelker 1973)？
红移：
多普勒红移
引力红移
宇宙学红移
银道坐标系 Sun-centered Galactic coordinates(l，b)
银纬（b）以0°至90°角度为单位度量
