NEW ESTIMATES OF THE INCLINATION, POSITION ANGLE, PITCH ANGLE, AND SCALE HEIGHT OF THE WHIRLPOOL GALAXY

Journal Article · Thu Jan 10 00:00:00 EST 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/762/2/L27· OSTI ID:22078340

Tao, Hu ^[1]; Zhengyi, Shao ^[2]

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1. Department of Automation, Shanghai University, 149 Yanchang Rd., Shanghai 200072 (China)
2. Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Rd., Shanghai 200030 (China)

The inclination (i) and position angle (PA) of the Whirlpool galaxy (M51) are critical to modeling and interpreting observations. Here we make improved estimates of these parameters by fitting logarithmic spirals to the main arms. From separate fits to each major arm, we obtain i = 20. Degree-Sign 3 {+-} 2. Degree-Sign 8 and PA = 12. Degree-Sign 0 {+-} 2. Degree-Sign 5. We then use Poisson's equation for the logarithmic perturbation of the density to estimate the mean vertical scale height (H) of M51 to be 95-178 pc.

• OSTI ID: 22078340
• Journal Information: Astrophysical Journal Letters, Vol. 762, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DENSITY
DISTURBANCES
GALAXIES
INCLINATION
PERTURBATION THEORY
POISSON EQUATION
SCALE HEIGHT
SIMULATION