Physical structure of H2O masers in W49N

Details Physical structure of H2O masers in W49N Physical structure of H2O masers in W49N

Jul 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...429..253g&link_type=abstract

The Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 429, no. 1, p. 253-267

Astronomy and Astrophysics

Astrophysics

32

Supersonic Flow, Velocity Distribution, Water Masers, Line Spectra, Pressure Broadening, Radiant Flux Density, Very Long Base Interferometry

Scientific paper

Physical structures of H2O masers in W49N reflect subsonic motions witin maser features, and recent acceleration of high-velocity features, as revealed by very long baseline interferometry (VLBI) observations of individual maser features. The most common line width is also the minimum line width, of 0.5 km/s full width at half maximum (FWHM). This is narrower than the theoretically expected thermal line width in the masing material, but broader than that of a single, unsaturated maser. It is equal to the line width of an unsaturated maser if the three strongest hyperfine components mase. Maser features show a range of angular sizes, down to the minimum of 200 micro arcsec as set by interstellar scattering. Brightness temperature inferred from size follows a continuous distribution from less than 1012 K to greater than 1015 K. Small angular size is correlated with broad line width, and large size with narrow line width. I suggest that velocity gradients within the masing fas produce broader line width and smaller size, accounting for this correlation. High-velocity features show broader line width and smaller size, indicating greater internal velocity gradients, and so recent acceleration of the masing gas. Maser features have lifetimes of up to 4 yr. Lifetime is about equal to linear size divided by Doppler line width, suggesting that the features are not confined by external forces, but are disrupted by internal velocity gradients. High-velocity features have shorter lifetimes, consistent with their greater internal velocities. The brightest features observed have brightness temperatures of as much as 1.2 x 1015 K and isotropic luminosities of as much as 0.05 solar luminosity. Aside from their extremely high flux denstities, these features do not appear unusual.

Affiliated with

Also associated with

No associations

Rating

Physical structure of H2O masers in W49N does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Physical structure of H2O masers in W49N, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Physical structure of H2O masers in W49N will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1252875