The outer rotation curve of the Milky Way
نویسندگان
چکیده
منابع مشابه
Milky Way Rotation from Cepheids
The 87 new 0 determinations were added to the existing sample of cepheids with known radial velocities, forming an extended sample of 278 galactic classical cepheids with reliable radial velocity and photometry. We then calculated distances for these objects through a Period-Luminosity-Colour relation due to Feast & Walker (1987). The position of the cepheids in the galactic disk as given by th...
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We measure the Galactic rotation curve and its first two vertical derivatives in the first and fourth quadrants of the Milky Way using the 21 cm VGPS and SGPS. We find tangent velocities of the atomic gas as a function of galactic longitude and latitude by fitting an analytic line profile to the edges of the velocity profiles. The shape of the analytic profile depends only on the tangent veloci...
متن کاملThe spiral structure of the outer Milky Way in hydrogen.
We produce a detailed map of the perturbed surface density of neutral hydrogen in the outer Milky Way disk, demonstrating that the Galaxy is a non-axisymmetric multiarmed spiral. Spiral structure in the southern half of the Galaxy can be traced out to at least 25 kiloparsecs, implying a minimum radius for the gas disk. Overdensities in the surface density are coincident with regions of reduced ...
متن کاملThe Vertical Structure of the Outer Milky Way Hi Disk
We examine the outer Galactic HI disk for deviations from the b = 0 plane by constructing maps of disk surface density, mean height, and thickness. We find that the Galactic warp is well described by a vertical offset plus two Fourier modes of frequency 1 and 2, all of which grow with Galactocentric radius. Adding the m = 2 mode accounts for the large asymmetry between the northern and southern...
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Using an outer rotation curve of the Galaxy, we explore the galactic constants and the mass of the Galaxy. We show that Θ0 of 200 km s −1 is more favorable than the IAU standard value of 220 km s, and also show that if Θ0 is smaller than 207 km s −1 the rotation curve beyond 2R0 is declining in Keplerian fashion. In the case of Θ0= 200 km s −1 and R0= 7.6 kpc, the total mass and the extent of t...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1997
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/287.1.l5