Article

The Power Spectrum of Supersonic Turbulence in Perseus

The Astrophysical Journal (Impact Factor: 5.99). 11/2006; 653(2). DOI: 10.1086/510620
Source: arXiv

ABSTRACT

We test a method of estimating the power spectrum of turbulence in molecular clouds based on the comparison of power spectra of integrated intensity maps and single-velocity-channel maps, suggested by Lazarian and Pogosyan. We use synthetic 13CO data from non-LTE radiative transfer calculations based on density and velocity fields of a simulation of supersonic hydrodynamic turbulence. We find that the method yields the correct power spectrum with good accuracy. We then apply the method to the Five College Radio Astronomy Observatory 13CO map of the Perseus region, from the COMPLETE website. We find a power law power spectrum with slope beta=1.81+-0.10. The values of beta as a function of velocity resolution are also confirmed using the lower resolution map of the same region obtained with the AT&T Bell Laboratories antenna. Because of its small uncertainty, this result provides a useful constraint for numerical codes used to simulate molecular cloud turbulence. Comment: 4 pages, 3 figures. ApJ Letters, in press

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    • "As new techniques for studying turbulence are being applied to observational data, the evidence of the turbulent nature of astrophysical media becomes really undeniable. For instance, the Velocity Channel Analysis (VCA) and Velocity Coordinate Spectrum (VCS) techniques (Lazarian and Pogosyan, 2000, 2004, 2006) provided unique insight into the velocity spectra of turbulence in molecular clouds (see Padoan et al, 2006, 2010), galactic and extragalactic atomic hydrogen (Stanimirovi´c and Lazarian (2001); Chepurnov et al (2010, 2015), see also the review by Lazarian (2009), where a compilation of velocity and density spectra obtained with contemporary HI and "
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    • "In addition, it is now generally accepted that the " Big Power Law in the Sky " indicates the presence of turbulence on scales from tens of parsecs to thousands of kilometers (Armstrong et al., 1995; Chepurnov and Lazarian, 2010). Among other sources, evidence for this comes from studies of atomic hydrogen spectra in molecular clouds and galaxies (see Lazarian and Pogosyan, 1999; Stanimirovi´c and Lazarian, 2001; Padoan et al., 2006, 2009; Chepurnov et al., 2010, see also review by Lazarian, 2009 and references therein), as well as recent studies of emission lines and Faraday rotation (see Burkhart et al., 2010; Gaensler et al., 2011). LV99's model uses the properties of turbulence to predict broad outflows from extended current sheets. "
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