Varosi vlibm AstroContrib Library

The following is a listing of the entire contents of this library for IDL. Click on an individual procedure name to view its header and source code. This listing is a shortened form of the much longer entire library help file. This may be handy for text searchs, be beware that some of these are huge and may take a long time to load or even crash your browser.

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List of Routines

• BLACK_BODY Compute black body emission spectrum (Planck function) in units of Janskys/arcsec^2 at either an array of temperatures or array of wavelengths.
• CHI_AUTO_CORR Frank Varosi NASA/GSFC 1992.
• CHI_RESID_CORR Used by procedure Max_Resid_Like, Based on: "Incorporation of Spatial Information in Bayesian Image Reconstruction: the Maximum Residual Likelihood (MRL) Criterion", by Robert Pina and Richard Puetter UCSD 1992. coded by Frank Varosi NASA/GSFC 1992.
• DECONV_ANALYZE Analyze current deconvolution result by computing residuals and its auto-correlation, then display result with residuals, and print statistics. Called by DeConv_Tool and DeConv_Review.
• DECONV_GET_IMAG Function extracts a region from the input image, and adjusts for deconv. CALLING EXAMPLE: image = deconv_get_imag( image, image_stats )
• DECONV_GET_PSF Function extracts and models a PSF from the input image. CALLING EXAMPLE: psf = deconv_get_psf( image, psf_stats, /MENUS, /TV )
• DECONV_INIT Frank Varosi NASA/GSFC 1992.
• DECONV_ITERATE Apply one iteration of specified deconvolution method. Frank Varosi NASA/GSFC 1992.
• DECONV_RESTORE Restore deconvolution results from files. Frank Varosi NASA/GSFC 1992.
• DECONV_REVIEW Review previously computed deconvolution results saved by Deconv_Tool. Routine prompts user for file/directory selection. CALLING EXAMPLE: deconv_review, deconv_result, deconv_infos, obs_image, obs_psf, /TV
• DECONV_SAVE Save current deconvolution results to file. Frank Varosi NASA/GSFC 1992.
• DECONV_SETUP Select deconvolution options. Frank Varosi NASA/GSFC 1992.
• DECONV_STRUCT Frank Varosi NASA/GSFC 1992.
• DECONV_TOOL Apply deconvolution algorithms to image data, monitor and save results. CALLING EXAMPLES:
• DEF_MGEP Define structures used in Mega-Grains Escape Probability (MGEP) model for which the code is in mg_ep_2phase.pro (pro MG_EP_2phase):
• DEF_MGEP_ICM Define structures used in Mega-Grains Escape Probability (MGEP) model for which the code is in mg_ep_2phase.pro (pro MG_EP_2phase):
• DTEMP_PROB Compute the probabilities of given dust temperatures around a star, assuming a distribution of temperatures of power law form. Normalization is based on the range (min-max) of input temperatures. Based on optically thin theory of Luminosity vs. radius and temperature vs. absorbed Luminosity, coupled with density vs. radius.
• DUST_EMISSION Compute dust temperature distributions and infrared emission spectrum from the absorbed Luminosities as computed by MGEP_RAD_TRANS. All input luminosities and output spectra are in solar units.
• DUST_SPECTRUM Compute spectrum of emission from dust heated by point source(s) assuming a distribution of temperatures of power law form. Based on optically thin theory of Luminosity vs. radius and temperature vs. absorbed Luminosity, coupled with density vs. radius.
• DUST_TEMP Compute the radiative equilibrium temperature of dust by matching absorbed luminosity and emission integrated over given wavelengths. The emision spectrum is placed in common dust_emit_spec for retrieval.
• DUST_TMIN Solve for the minimum Temperature of dust emitting over a distribution of temperatures, thus the emission spectrum is more realistic. The distribution of temperature is composed of two power laws (for low and high temps. resp.) and depends on dust emissivity indices (see function in file dust_spectrum.pro). The dust emission spectrum of solution is stored in: common dust_Tmin_spec, dtd_spec.
• EP_HOMOG Approximate the radiative transfer of photons in a homogenous medium (dust & gas) of spherical/disk geometry, by calling EP_Rad_Trans, and then compute equilibrium dust temperatures and infrared emission using function Dust_Emission.
• EP_LYA Compute escape probability of Lyman alpha in spheriod of gas & dust. The Lyman alpha emission is assumed to be uniformly distributed. The effects of resonant scattering in a dusty medium are approximated by computing an effective random walk path length thru the dust, thus increasing the effective optical depth of the dust, based on the parameter alpha indicating the amount of frequency redistribution occuring with the Lyman alpha resonant scattering.
• EP_RAD_TRANS Approximate the radiative transfer of photons emitted in or impacting a homogenous medium (dust & gas) of spherical/disk geometry, using escape/interaction probability formulae: Osterbrock-Lucy E.P. for uniformly distributed internal source, Varosi's interaction prob. for uniformly illuminating external source, or Varosi's E.P. approximation for central source. An approximation of absorption, ionization of gas, and resultant heating of dust by Lyman-alpha from gas is also attempted, but this needs more work.
• ESCAPE_PROB Compute the probability of escape for photons emitted uniformly in a homogenous sphere of absorbers, possibly with scattering. For no scattering (albedo = 0) the equation is exact (Osterbrock 1989). With scattering the accuracy of generalized formula (Lucy 1989) has been tested against Monte-Carlo simulations (Varosi 1995) and was found to depend also on the angular distribution of the scattering. For small optical depths ( < 1 ) the formual agrees with Monte-Carlo to better than 5% for scattering ranging from isotropic to slightly forward. As optical depth increases the formula over-estimates the escape probability for isotropic scattering, but
• FRACTAL_CLOUD FRACTAL_CLOUD Generate a fractal cloud as a density distribution map, returning a 3D array (1D or 2D if requested). The density map is generated by binning points generated by a randomn recursive fractal algorithm, as described by Elmegreen, 1997, ApJ 477: 196-203. dens_map = Fractal_Cloud( NDIM=, NLEVELS=, NP_FACTOR=, LSCALE=, $
• FRACTAL_SYNTH Synthesize a fractal embedded in either 2-D (a fractal curve) or in 3-D (a fractal surface) using power-law spectral technique.
• INTERP_TAU_EFF Compute effective optical depth of a sphere including scattering. Effective optical depth is estimated by interpolating a grid of Monte Carlo simulations stored in a structure in common. Inputs can be scalar or arrays, but must be all same dimensions.
• IONFRAC Compute local ionization equilibrium, returning what fraction of hydrogen is ionized, given density of Lyman continuum photons.
• IR_DUST_MODEL Model the infrared emission from dust in an image-spectrum data cube. Each line of sight is modeled independentaly (no scattering) by fitting a simple 1D radiative transfer model of single temperature dust emission and absorption to the spectrum at each image pixel. The user can modify the model control parameters with X-widget GUI that is automatically presented, or just accept the default values. Assumes that IDL/XDR save file "Dust_Kappa.idl" containing the dust absorption coefficients is in current directory.
• IR_SPECTRUM_FIT Fit an infrared emission spectrum with a simple 1D radiative transfer model of single temperature dust emission from a homogenous source and line of sight absorption by colder dust.
• MAX_ENTROPY Deconvolution of data by Maximum Entropy analysis, given the instrument point spread response function (spatially invariant psf). Data can be an observed image or spectrum, result is always positive. Default is convolutions using FFT (faster when image size = power of 2).
• MAX_LIKELIHOOD Deconvolution of an observed image (or spectrum), given the instrument point spread response function (spatially invariant psf). Performs iteration based on the Maximum Likelihood solution for the restoration of a blurred image (or spectrum) with additive noise. Maximum Likelihood formulation can assume Poisson noise statistics or Gaussian additive noise, yielding two types of iteration.
• MAX_RESID_LIKE CALLING EXAMPLE:
• MEGA_GRAINS Approximate the effective absorption and scattering properties of a two-phase clumpy medium of dust by considering the randomly located spherical clumps as large grains: "mega-grains". Assumes that clumps are uniformly distributed, all of same radius and same density relative to the inter-clump medium (ICM). Based on the theory of Hobson & Padman 1993, MNRAS, 264, 161-164, and extended to the case when the filling factor of the clumps > 0.3. Effective albedo of the clumps (albedo_CL) is estimated using the Osterbrock-Lucy escape probability instead of Hobson & Padman eq., thereby improving agreement with Monte Carlo simulations.
• MEGA_GRAIN_ABS Compute fraction of photons absorbed by the inter-clump medium (ICM) for the case of photons emitted uniformly/centrally in a spheriod/disk. Returns what fraction of the photons absorbed in the two-phase clumpy medium are actually absorbed by the inter-clump medium (ICM). Uses a variation of the Mega-Grains approximation (see mega_grains.pro) but this theory is NOT in the original paper by Hobson & Padman 1993. The clumps are treated totally separate from ICM (not just overdensity). (See Varosi and Dwek, 1999 ApJ 523, 265 for all equations).
• MGEP_RAD_TRANS Approximate the radiative transfer of photons emitted in or impacting a two-phase clumpy medium (dust & gas) of spherical/disk geometry, using the Mega-Grains approximation of Hobson & Padman, combined with the escape/interaction probability formulae: Osterbrock-Lucy E.P. for uniformly distributed internal source, Varosi's interaction prob. for uniformly illuminating external source, or Varosi's E.P. approximation for central source. See Varosi & Dwek 1999, ApJ 523, 265 for complete discussion. An approximation for the ionization of Hydrogen, and resultant heating of dust by Lyman-alpha photons is also attempted.
• MG_EP_2PHASE Approximate the radiative transfer of photons in a two-phase clumpy medium (dust & gas) of spherical/disk geometry, by calling MGEP_Rad_Trans, and then compute equilibrium dust temperatures and infrared emission using function Dust_Emission. Can optionally model an environment where the SED of stars in clumps is different that stars in ICM (see keywords SED_CLUMPS and SRC_CLUMPS), or case of the dust in ICM different than in clumps (KAPPA_ICM_DUST).
• PINTERACT Compute and return the probability that a photon entering a sphere of absorbers and/or scatterers (e.g. dust or gas) at a random angle will interact with an absorber/scatterer. In otherwords, it gives the interacting fraction of a collection of randomly impacting photons. If the scattering albedo is given, then the actual absorbed fraction is computed approximately. When scattering is specified to be purely forward then an exact formula used.
• PLOT_DCINFO CALLING EXAMPLE:
• POSITIVITY For use in nonlinear functional fitting or minimization that require a positivity constraint on solution parameters. Take unconstrained parameter array x (usually an image), and map it uniquely and smoothly into positive values. Negative values of x get mapped to interval ( 0, sqrt( EPSILON )/2 ], positive values go to ( sqrt( EPSILON )/2, oo ) with derivative approaching unity. Derivative is always 1/2 at x=0. Derivative is used by the MRL deconvolution algorithm. If EPSILON=0 then mapping reduces to truncation > 0. If EPSILON LT 0 then mapping reduces to identity (no change).
• PSF_MERGE Merge two psf matrices together by smoothly splicing/glueing. CALLING EXAMPLE: psf_combo = psf_merge( psf_inner, psf_outer, RADIUS=7 )
• RAD_STROMGREN Compute Stromgren radius of an idealized spherical HII region with central source of ionizing photons.
• RAD_TRANS_1D Compute single temperature dust emission/absorption spectrum with line of sight (LOS) absorption, in Janskys/arcsec^2. If third argument is present, compute partial derivatives for fitting.
• SETUP_MLG Frank Varosi NASA/GSFC 1992. Lag = round_off( deconv_info.psf_stats.fwhm ) > 1 read," select residual auto-correlation Lag range (default=" + $ strtrim( Lag,2 ) + " to 2) ",text if strlen( text ) GT 0 then Lag = fix( get_words( text ) ) > 0 deconv_info.Lag_chisq = Lag(0)
• SETUP_MLP Frank Varosi NASA/GSFC 1992.
• SETUP_MRL Frank Varosi NASA/GSFC 1992.
• SHOW_PSF Display the PSF (image) in pseudo-color with Linear and Log-10 scale, and as surface (Log-10) with contours (SHOW3). Centroid is determined and marked, and optionally the FWHM and other parameters are determined and printed.
• SIGMA_CLEAN Frank Varosi NASA/GSFC 1992. (still in code development stage...) using W.C.Keel, Proc.Astro.Soc.Pacific, July 1991.
• TAU_EFF_SCAT Compute effective optical depth of a sphere including scattering. Effective optical depth is estimated by interpolating between approximate solutions at large optical depths and small optical depths. Inputs can be scalar or arrays, but must be all same dimensions.