Interstellar masers: Then and now

Anderson, Nels; Genzel, R.

doi:10.1007/3-540-56343-1_220

Cited by 2 publications

(2 citation statements)

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“…It has recently been recognized that the 1.35-cm wavelength H 2 O masers [see reviews on masers in Elitzur (1992); Clegg and Nedoluha (1993); Migenes and Reid (2002)] may be promising tools for the study of "Kolmogorov-type" supersonic turbulence. VLBI studies of the proper motions of several bright H 2 O maser sources associated with newly-born stars have revealed expansion of the clusters of maser spots -participation in gas outflows from these stars (see Anderson and Genzel 1993 for a review). This type of regular motion had been theoretically predicted before its discovery (Strelnitski & Sunyaev 1973).…”

Section: Introductionmentioning

confidence: 99%

H₂O Masers and Supersonic Turbulence

Strelnitski

Alexander

Gezari

et al. 2002

ApJ

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We use unpublished and published VLBI results to investigate the geometry and the statistical properties of the velocity field traced by H2O masers in five galactic regions of star formation -- Sgr B2(M), W49N, W51(MAIN), W51N, and W3(OH). In all sources the angular distribution of the H2O hot spots demonstrates approximate self-similarity (fractality) over almost four orders of magnitude in scale, with the calculated fractal dimension d between (approximately) 0.2 and 1.0. In all sources, the lower order structure functions for the line-of-sight component of the velocity field are satisfactorily approximated by power laws, with the exponents near their classic Kolmogorov values for the high-Reynolds-number incompressible turbulence. These two facts, as well as the observed significant excess of large deviations of the two-point velocity increments from their mean values, strongly suggest that the H2O masers in regions of star formation trace turbulence. We propose a new conceptual model of these masers in which maser hot spots originate at the sites of ultimate dissipation of highly supersonic turbulence produced in the ambient gas by the intensive gas outflow from a newly-born star. Due to the high brightness and small angular sizes of masing hot spots and the possibility of measuring their positions and velocities with high precision, they become a unique probe of supersonic turbulence.Comment: 40 pages with 14 total figures (figures 9 and 10 are multi-part) Accepted for publication ApJ, December 20, 2002, Vol. 581, n

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Section: Introductionmentioning

confidence: 99%

H₂O Masers and Supersonic Turbulence

Strelnitski

Alexander

Gezari

et al. 2002

ApJ

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“…Reid & Moran 1981;Cohen 1989;Elitzur 1992;Anderson & Genzel 1993;Bowers 1993), and the present number of known galactic H 2 O maser sources has been increased to more than seven hundred in the northern sky.…”

Section: Introductionmentioning

confidence: 99%