N2H+ Model

N2H+ fitter

Reference for line params: Daniel, F., Dubernet, M.-L., Meuwly, M., Cernicharo, J., Pagani, L. 2005, MNRAS 363, 1083

http://www.strw.leidenuniv.nl/~moldata/N2H+.html

http://adsabs.harvard.edu/abs/2005MNRAS.363.1083D

Does not yet implement: http://adsabs.harvard.edu/abs/2010ApJ…716.1315K

Module API

pyspeckit.spectrum.models.n2hp.n2hp_radex(xarr, density=4, column=13, xoff_v=0.0, width=1.0, grid_vwidth=1.0, grid_vwidth_scale=False, texgrid=None, taugrid=None, hdr=None, path_to_texgrid='', path_to_taugrid='', temperature_gridnumber=3, debug=False, verbose=False, **kwargs)

Use a grid of RADEX-computed models to make a model line spectrum

The RADEX models have to be available somewhere. OR they can be passed as arrays. If as arrays, the form should be: texgrid = ((minfreq1,maxfreq1,texgrid1),(minfreq2,maxfreq2,texgrid2))

xarr must be a SpectroscopicAxis instance xoff_v, width are both in km/s

grid_vwidth is the velocity assumed when computing the grid in km/s this is important because tau = modeltau / width (see, e.g., Draine 2011 textbook pgs 219-230) grid_vwidth_scale is True or False: False for LVG, True for Sphere

pyspeckit.spectrum.models.n2hp.relative_strength_total_degeneracy = {'101-010': 9.0, '101-011': 9.0, '101-012': 9.0, '110-011': 9.0, '111-010': 9.0, '111-011': 9.0, '111-012': 9.0, '112-011': 9.0, '112-012': 9.0, '121-010': 9.0, '121-011': 9.0, '121-012': 9.0, '122-011': 9.0, '122-012': 9.0, '123-012': 9.0}

Line strengths of the 15 hyperfine components in J=1-0 transition. The thickness of the lines indicates their relative weight compared to the others. Line strengths are normalized in such a way that summing over all initial J = 1 levels gives the degeneracy of the J = 0 levels, i.e., for JF1F 012, three for JF1F 011, and one for JF1F 010. Thus, the sum over all 15 transitions gives the total spin degeneracy

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