XstarN> Some of the commands are not currently completely documented.summary_of_commandsdescription_syntax`abundance_array column_density ¼density Øhelp fionization_parameter Élog_column_density4 log_densityalog_ionization_parameterlog_luminosityŒ log_pressurelog_temperature™ luminosity_38Cmax_iterations˜ max_steps¾pressureZprintárun:Sspecial;spectrumCÚspectrumFstep_print_optionJ“stopK¾ temperature_4KÛtitleMv abundance_array column_density density help ionization_parameter log_column_density log_density log_ionization_parameter log_luminosity log_temperature log_pressure luminosity_38 max_iterations max_steps pressure print run special spectrum step_print_option step_size stop temperature_4 title  ,Exceptional responses to the command prompt:4 an empty line - Nothing performed, prompt repeated.8 / - Any remaining arguments will have the values given9 on the last invocation of the command.9 - same as "quit". Under VAX/VMS this is ,& otherwise use `/*'.3 ? or anything else - Write a list of the commands. B The individual commands are treated in the following sections, inNalphabetical order. The novice would be well served by reading the treatmentsKof the data, model, newpar, and fit commands, in that order, then the otherNcommands as needed. The write-up for each command includes a brief descriptionKof the purpose, a syntax outline, a more detailed discussion of the commandMassumptions and purpose, and a series of examples. Some commands have one orImore subcommands which will be similarly described following the command.G In the command description, the syntax uses the following conventions:- - an argument to the command3 =:: , - the definition of a compound argument6 ... - a repeated string of arguments of the same type) [] - an optional argument< or - a choice between an argument of type D Define abundances. Abundances are relative to protons, and must beFin order: H, He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Defaults are values given in Withbroe (1972). A Define model column density, N. Units are cm^-2. This quantity>is used in calculation of thickness of model slab according toGDelta R_max=N/n where n is the density or an estimate based on pressureGand temperature inital values. The default value for N is 10^21 cm^-2. D Define model gas density, n. This is actually the hydrogen nucleusEdensity, so that, e.g., the total particle density in a fully-ionizedEplasma with solar abundances is 2.3 n. Units are cm^-3. The defaultFvalue is 1 cm^-3. If this quantity is specified then it is held fixedGuntil a new value is given, or until a pressure is given. The constant"density assumption is the default. @ Invoke the help facility which displays the information in thischapter of the manual. G Define initial value of model ionization parameter. If the density isDheld constant, the Tarter, Tucker, and Salpeter (1969) form is used:>xi = L/(nR^2). If the pressure is held constant, a version of2the Krolik, McKee, and Tarter (1981) form is used:?Xi = L/(4pi c R^2 P). Note that this differs from the originalKform by using the full isotropic pressure (neutral atoms + ions + electronsF+ trapped line radiation) instead of just the pressure due to hydrogenCatoms and protons. This quantity is used in calculating the radiusIof the innermost edge of the shell by inverting the parameter definition. 2 Define log (base 10) of model column density, N.'Units are cm^-2. This quantity is used6in calculation of thickness of model slab according toGDelta R_max=N/n where n is the density or an estimate based on pressureGand temperature inital values. The default value for N is 10^21 cm^-2. . Define log (base 10) of model gas density, n.%This is actually the hydrogen nucleusEdensity, so that, e.g., the total particle density in a fully-ionized&plasma with solar abundances is 2.3 n.:Units are cm^-3. The default value of density is 1 cm^-3.3If this quantity is specified then it is held fixedGuntil a new value is given, or until a pressure is given. The constant"density assumption is the default. 1 Define initial value of the log (base 10) of the.model ionization parameter. If the density isDheld constant, the Tarter, Tucker, and Salpeter (1969) form is used:>xi = L/(nR^2). If the pressure is held constant, a version of2the Krolik, McKee, and Tarter (1981) form is used:?Xi = L/(4pi c R^2 P). Note that this differs from the originalKform by using the full isotropic pressure (neutral atoms + ions + electronsF+ trapped line radiation) instead of just the pressure due to hydrogenCatoms and protons. This quantity is used in calculating the radiusIof the innermost edge of the shell by inverting the parameter definition. = Define log (base 10) of model luminosity. Units are erg/s.+Default value of luminosity is 10^38 erg/s. 8 Define log (base 10) of model pressure in dynes cm^-2.Note that this quantityHrepresents the full isotropic pressure (neutral atoms + ions + electronsF+ trapped line radiation) instead of just the pressure due to hydrogen6atoms and protons. If this quantity is specified thenKit is held fixed until a new value is given, and the appropriate definition(of ionization parameter (Xi) is adopted. G Define log (base 10) of temperature, in units of K. If the parameterBcimax_iterations is set to 0 then the temperature is fixed at thisGvalue. Otherwise the value is used as a first guess in calculating theHthermal equilibrium value. If the pressure is specified it is also usedand optical depth in the transmitted and reflected directions.@If this keyword is chosen at the end of the calculation, optical7depths are calculated assuming the point of observation$is at the outside edge of the shell. á"¬< This command allows the user access to the atomic rates andcross sections database. energy_limits"ìedges#<lines#±photo_cross_sections$ "KD Specifies the photon energy limits (in eV) for subsequent commands; "K2 Causes an energy ordered list of absorption edges6to be printed, along with the parent ion and subshell. "K1 Causes a list to be printed of line wavelengths,1energies and parent ions (ordered by wavelength). "K* Causes the photoionization cross sections;(in cm^2) to be printed. Ordering is as follows: Elements4are ordered by nuclear charge, ions by charge state.+(N.B.: the ciphoto_cross_section option can'produce a very large amount of output). áF Print execution times (in msec) for various parts of the calculation:Ktransfer, escape probability calculation, photoionization rate calculation,GAuger rate correction, thermal equilibrium solution, and emissivity andopacity calculation. á* Print input parameters: title, luminosity9(in units of 10^38 erg s^-1), density (in H atoms cm^-3),'log_10 of ionization parameter (Tarter,BTucker and Salpeter 1968 definition), and number of spatial zones. áF Print ion abundances and heating and cooling rates. For each ion withIfractional abundance (relative to its parent element) greater than 10^-10:the following information is printed: ion index, ion name,Dfractional abundance (relative to the relevant elemental abundance),Dabundance (relative to the total hydrogen abundance), and that ion's?contributions to heating and cooling rates (in erg cm^-3 s^-1).IThe elements are ordered by increasing nuclear charge, ions by increasing3free charge. Also printed are the Compton and totalCheating rates, and bremsstrahlung, Compton, and total cooling rates(in erg cm^-3 s^-1). á8 Print ionization and recombination rates. For each ionF(elements are ordered by increasing nuclear charge, ions by increasing free charge)Hwe print rate coefficients for: photoionization, collisional ionization,Iautoionization following collisional excitation, radiative recombination,Idielectronic recombination, 3-body recombination, that ion's contributionHto ionization of hydrogen by fast photoelectrons (secondary ionization),charge transferIwith neutral hydrogen, charge transfer with H^+, and charge transfer with$neutral helium. All are in units of(cm^3 s^-1 except for photoionization andFsecondary ionization, which are in units of s^-1. The total secondary ionization rate is also printed. á2 Print iron II line quantities: level populationsD(fractional, relative to total Fe II), followed by line emissivities>and luminosities. The format for these is: line upper level,4line lower level, transition label, wavelength (AA),2emissivity (cm^-3 s^-1), line luminosity reflected)and transmitted (in units of 10^38 s^-1),9total line flux reflected + transmitted (erg cm^-2 s^-1),Kand line center optical depths in the reflected and transmitted directions. á4 Print numbers of iterations needed to solve thermalCequilibrium and charge conservation. If this is called only at theHend of the calculation, it reflects the total iterations required by the calculation. áB Print hydrogen level populations (relative to total hydrogen, forHprincipal quantum numbers 1 thru 6 and continuum), LTE abundance ratios,9and departure coefficients. If called at the end of theLcalculation, it reflects the conditions at the last spatial zone calculated. á. Print line opacities (cm^-1) and emissivities>(erg cm^-3 s^-1) due to recombination, collisional excitation,Jinner shell fluorescence, dielectronic recombination, and charge transfer. á5 Print fluxes of selected strong UV and optical lines+(transmitted + relected) in erg cm^-2 s^-1./Only makes sense at the end of the calculation. áA Print a list of all line luminosities and depths: for each lineCwe print index, ion, wavelength (AA), luminosity (in units of 10^38=erg s^-1) transmitted and reflected, and optical depth in theFtransmitted and reflected directions. The list is sorted according toKparent ion, according to nuclear charge, and according to ion charge within each element. á0 Select lines for printing under the ciline_flux>option described below. This keyword must be followed by pairs'of wavelengths (in AA) representing theIminimum and maximum values of wavelength desired. There may be a maximumFof 50 of such pairs. For each pair the line list will be searched forKlines with wavelengths in the desired range, and the wavelengths and fluxesHof all the lines found will be printed, together with the total flux forMall the lines in that range. For an example, see the quasar broad line cloud%model in section 3.3.4 of the manual. áB Print radiation pressure (dyne cm^-2), due to lines. Sum is over all lines. á7 Print line luminosities sorted in order of wavelength.3The output consists of the line wavelength (in AA),*the parent ion, and the log_10 of the lineDluminosity in erg s^-1. Note that this option provides luminosities>in units which differ from all other print options (they scaleDluminosities in units of 10^38 erg s^-1, the scaling used internally9by the code). The output is separated into two wavelengthKranges, below and above 12.4 AA. If the most recent model was an iterativeJcalculation, then the reflected and transmitted line strengths are printed separately. á( Print radius (cm), ionization parameter;(Tarter, Tucker and Salpeter, 1969 definition), temperature-(in units of 10^4 K), electron number density'(cm^-3), proton number density (cm^-3),;total heating and cooling rates (erg cm^-3 s^-1), continuumEoptical depth at the Lyman continuum in the transmitted and reflectedAdirections, column densities due to protons and electrons (cm^-2)>from the cloud illuminated face, ionization parameters Xi (cf.GKrolik, McKee and Tarter, 1981, and chapter 3 of this manual), log(U_1)G(cf. Davidson and Netzer, 1978), and Gamma (cf. Kwan and Krolik, 1982),Aand Delta R (in cm, the distance frm the illuminated cloud face). < Calculate a model. Execution terminates (i.e. returns with@prompt for another command) when maximum number of spatial steps:is reached or when the slab thickness exceeds Delta R_max. ;y; Various additional options used for debugging and advancedfunctions. These include: pass_number;Å write_switch?‡ print_switch@ërelativistic_comptonAk;G The default parameter for this keyword is 1. If the default is taken,Ethe calculation proceeds once through the shell, and assumes that allHoptical depths from points within the shell to the far edge of the shellGare infinite. If an integer greater than 1 is supplied as a parameter,HXSTAR performs that number of iterations through the entire calculation,Fsetting the optical depths to the far edge at the values calculated inBthe previous iteration. Multi-pass calculations can substantiallyBimprove the quality of the predictions made for shells with finiteAthickness, but they are, of course, much more time consuming thanEsingle-pass calculations. They also make use of unformatted datasets,Enamed 'xstout.lis', 'xstout2.lis', and 'tmpout.lis', which can becomeDquite large, and a signifigant amount of time is spent rewinding andDsearching sequentially through these files for information about the)optical depth to the `back' of the model. ;3 If the argument is a non-zero integer, causes many>quantities of interest to be written to an unformatted dataset7at each spatial step for later examination or plotting.:The file is named 'xstout.lis', and can become quite largeG(sim 1 Mb) for a model with many spatial zones. The format of the file*can be learned by examination of the code. ;; Enables the printing of many quantities used internally by8xstar, and is of interest primarily as a debugging tool. ;8 Causes XSTAR to include relativistic corrections to the1Compton heating and cooling rates. The rates areEcalculated from a table contained in the file `coheat.dat' which mustClive in the same directory as XSTAR. This option is not a standardGfeature because it is very time-consuming, and the corrections are onlyAsignificant in specialized regimes. If the spectral index of theGhard X-ray spectrum is leq1 (in energy) and the ionization parameter is/log(xi)geq 3, or if the temperature is greaterCthan 10^8 K, `relativistic_compton' should be specified; otherwise,&one is probably better off without it.  @ Define Spectrum. Choices and formats are similar to those usedEby XSPEC and are given below. The default is a 10 KeV bremsstrahlungFwith a very low luminosity (10^8 erg/s); this radiation field is alsoMadded to whatever radiation field the user chooses in order to avoid possibleKnumerical problems. Such problems can arise if the radiation field is zeroNthroughout a siginifigant energy range, because then the photoionization ratesEfor some ions may be zero, and these appear in the denominator of the%equations for the ionization balance. F^@ Define Spectrum. Choices and formats are similar to those used by XSPEC. atableF½bbodyG¡bknpowerGÄbremssGädiskHOmtableHäpowerI[uvredI€wabsIæF8 Additive table model. The model must consist of a listNof photon energies followed by a list of fluxes at the corresponding energies.CFinally an overall normalization must be input. Up to 300 energies may be used. F A black body spectrum. F A broken power law. F: Thermal bremsstrahlung spectrum, including gaunt factors,$but not including e-e bremsstrahlung F< The spectrum from an accretion disk where the opacities areLdominated by free-free absorption, i.e. the so-called black body disk model. FB Multiplicative table model. The format is the same as for atable,(except that normalization is not needed. F Simple photon power law. F> UV reddening using Seaton's law (M.N.R.A.S., 187, 75p). Validfrom 1000 to 3704 Angstrom. FA Photoelectric absorption using Wisconsin (Morrison and McCammon)Fcross-sections, i.e. solar abundances and neutral atomic gas with zerodepletion onto grains.  ' Set up print format for spatial steps.$The parameter values are the same asIthe print keyword, and can consist of a list of values. The appropriate@quantities are then printed at each spatial step. Default is 9,Gcorresponding to temperature, radius, density and ionization parameter.  Quit from XSTAR. : Define temperature, in units of 10^4 K. If the parameterA max_iterations is set to 0 then the temperature is fixed at thisGvalue. Otherwise the value is used as a first guess in calculating theHthermal equilibrium value. If the pressure is specified it is also usedIto calculate an initial guess at the gas density, n=P/(kT), which is then7used to calculate Delta R_max=N/n. Default value is 1. ; Define model title, an 80 character string which is can be-printed using the appropriate print command.      re, in unit