NAME

USAGE

DESCRIPTION

The skyback task simulates the discrete and diffuse high-energy astrophysical background over a large energy range. The skyback task currently includes the following three basic background components, any or all of which may be included.

(1) Galactic Halo and Local Hot Bubble (LHB) components are derived (following the approach of the quicksim simulator for XMM-Newton) from ROSAT all-sky survey (RASS) surface brightness maps (Snowden et al., ApJ, 485, 125) to create a model background spectrum appropriate for the part of the sky being observed. The model consists of an absorbed thermal plasma at T(halo)~1.0E6.6 K, representing the excess over the extragalactic component seen in the RASS hard bands, plus an unabsorbed thermal plasma at T(LHB)~1.0E6 K, representing the additional excess in the soft band. To generate this component, the skyback parameter 'flaggal' must be set to yes.

(2) Solar Wind Charge Exchange (SWCX) emission (Cumbee et al., Astrophysical Journal, 852, 7) may be modeled as either a pure emission-line spectrum, or a continuous spectrum based on Diffuse X‐ray emission from the Local Galaxy (DXL) sounding rocket measurements of the local galaxy diffuse X-ray emission (Galeazzi et al. 2014, Nature, 5121, 171). The parameters that control the SWCX background component are: (a) 'flagswcx', which must be set to yes, (b) 'swcxOVII', and/or (c) 'swcxcont'. The 'swcxOVII' parameter represents the total flux (in LU; 1 LU == 1 photon s^{-1} cm^{-2} str^{-1}) in the brightest feature (0.57 keV OVII), and is used as described henceforth. The flux is distributed among the forbidden, resonance, and intercombination OVII lines with the following scaling. F(OVII forbidden 0.5609 keV) = 2/3*F(0.57 keV OVII), F(OVII resonance 0.5740 keV) = 1/6*F(0.57 keV OVII), F(OVII intercombination 0.5685 keV) = 1/6*F(0.57 keV OVII). In addition, the OVIII lines are added by scaling this input flux with the following factors: F(OVIII Lalpha 0.6536 keV) = 0.25*F(0.57 keV OVII) and F(OVIII Kbeta 0.6657 keV) = 0.083*F(OVIII Lalpha 0.6536 keV). The 'swcxcont' parameter represents the total flux in the 0.2-2.0 keV band of the continuous SWCX emission, modeled as 0.102 keV thermal (currently, Raymond-Smith) emission, in erg cm^{-2} s^{-1} arcmin^{-2}. The norm based on DXL observations corresponds to the default value ~3.17E-16 erg cm^{-2} s^{-1} arcmin^{-2}. If 'flagswcx' is set to no, 'swcxOVII' and 'swcxcont' parameters are ignored.

(3) The third background component is modeled (based on the ximage simulator) as a two-subcomponent logN-logS distribution of point sources, and is calculated if the parameter 'flaglogns' is set to yes. The first logN-logS is a broken power-law designed to allow the inclusion of an extragalactic point-source population. The bright-end slope is determined by the parameter 'slopebright1', the faint-end slope by 'slopefaint1', the flux where the slope changes from 'slopebright1' to 'slopefaint1' is set by the parameter 'fluxbreak', and the normalization is set by the parameter 'norm1' (in units of sources per square degree). The fluxes that are distributed according to the logN-logS distribution are defined over the energy range [keV] given by the parameters 'bandpasslo' and 'bandpasshi'. The parameters 'fluxmin' and 'fluxmax' are the minimum and maximum fluxes, respectively in this bandpass of the logN-logS distributions. The parameter 'fluxsens' is the flux threshold defined such that sources fainter than 'fluxsens' are treated as undetected, and their emission subsumed into the diffuse background based on their individual spectra (see below). However, if 'fluxsens=0', the threshold is defined by the optional parameters 'ctstoflux' (flux per unit count rate), 'sigtonoise' (signal-to-noise ratio), and 'exposure' (in seconds), according to ctstoflux*sigtonoise*sigtonoise/exposure (e.g., a value of 'ctstoflux' of 1.0E-11 corresponds to a threshold of 2.5E-15 erg cm^{-2} s^{-1} for 'sigtonoise=5.0' and 'exposure=100'). The second logN-logS is a single power-law that may be used to create, for example, a Galactic or an additional extragalactic point source background. The optional parameters 'slope2' and 'norm2' determine its logN-logS slope and normalization (in sources per square degree); by default, 'norm2=0'. The two logN-logS functions have several parameters in common -- namely 'bandpasslo', 'bandpasshi', 'fluxmin', 'fluxmax', 'fluxsens', 'ctstoflux', 'sigtonoise', and 'exposure'.

Spectra for the point sources drawn from the broken power-law logN-logS background are assigned based on the parameter 'spectype1'. If 'spectype1=0', the sources are assigned heasim-supported spectral models. In this case, the model is specified by the skyback parameters 'specmod1' and 'specpar1'. The choices for specmod1 are: pow (power-law), bbod (blackbod), brem (thermal bremsstrahlung), rs (Raymond-Smith thermal plasma), or mono (mono-energetic). The parameter 'specpar1' can be the photon index for the power-law, the temperature in keV for the blackbody/bremsstrahlung/Raymond-Smith models, or the line energy in keV for the mono-energetic case). The foreground column density is given by the parameter 'nhmod1'. If 'spectype1=2', the background is given by the torus model, based on the approach of Ueda et al. 2014 (ApJ, 786, 104). Each source spectrum is determined by one of the torus models from Brightman & Nandra 2011 (MNRAS, 413,1206; BN) with a distinct intrinsic column density and opening angle, and with a randomly selected inclination angle. The opening angle distribution is determined by fractions in five bins (<30, 30-45, 45-60, 60-75, >75), specified by the parameters 'fpar0', 'fpar1', 'fpar2', 'fpar3', and 'fpar4'. The intrinsic column density distribution is determined by fractions in six logarithmic NH bins (<21, 21-22, 22-23, 23-24, 24-25, >25), specified by the parameters 'fabs0', 'fabs1', 'fabs2', 'fabs3', 'fabs4', and 'fabs5'. Redshifts are drawn from a distribution assumed to be a simple linear ramp up to z=1, followed by an exponential decline. If 'spectype1=1', the background is given by the multi model, based on the approach of Gilli, Comastri & Hasinger 2007 (A&A, 463, 792), where each point source is an absorbed power-law with index and NH drawn from two distributions. The power law index distribution is determined by fractions in five index bins (1.5-1.7, 1.7-1.9, 1.9-2.1, 2.1-2.3, 2.3-2.5), specified by 'fpar0', 'fpar1', 'fpar2', 'fpar3', and 'fpar4'. Again, the intrinsic column density distribution is determined by fractions in six logarithmic NH bins (<21, 21-22, 22-23, 23-24, 24-25, >25), specified by 'fabs0', 'fabs1', 'fabs2', 'fabs3', 'fabs4', and 'fabs5'. Redshifts are assigned as described above. For multi models, in the highest NH-bin the power-law is replaced by a reflection model approximated by a BN torus model with the largest available opening angle, inclination of 0 degrees, the assigned power-law, and the assigned NH (>1.0E25 cm^{-2}) - with the power-law subtracted off. In the next-to-highest NH-bin, the absorbed power-law is supplemented with this same reflection model, scaled down by 0.37 (Gilli et al. 2007).

Spectra for the point sources drawn from the single power-law logN-logS background are assigned in an identical way to those of the broken power-law logN-logS background if 'samespec=yes' (i.e. the lists are merged before the spectra are assigned). If 'samespec=no', the sources are assigned heasim-supported spectral models. In this case the model is specified by parameter 'specmod2': pow (power-law), bbod (blackbod), brem (thermal bremsstrahlung), rs (Raymond-Smith thermal plasma), or mono (mono-energetic). The value of the spectral parameter for this model is specified by 'specpar2', and the foreground column density by the parameter 'nhmod2', as described above for 'specmod1' and 'nhmod1'.

If 'flaglogns=yes', 'slopebright', 'slopefaint1', 'fluxbreak', 'norm1', 'bandpasslo', 'bandpasshi', 'fluxmin', 'fluxmax', 'fluxsens', and 'spectype1' must be set. If 'flaglogns=no', these parameters are ignored, as are all of the other optional parameters associated with the logN-logS component, such as those associated with the single power-law logN-logs, or with the details of the spectral model.

The skyback output may include the following files, which have names constructed from the input parameter 'outfileroot'. (1) A catalog of resolved point sources that includes source positions with spectral specifications. The format follows the heasim source definition file for point sources. The name of the output is constructed by appending the string "'outfileroot'.txt" to the string "pscat_". (2) A file that supplements the point source catalog that contains values of the redshift and intrinsic absorption. The name of the output is constructed by appending the string "'outfileroot'.txt" to the string "pszcat_". (3) A catalog with a single line representing the diffuse emission. The format follows the heasim source definition file format for an extended source with a flat distribution. The flat distribution is centered at the position given by the parameters 'ra' and 'dec', and covers a circular region extending out to parameter 'radius' [arcmin]. The name of the output is constructed by appending the string "'outfileroot'.txt" to the string "difcat_". (4) The total diffuse background spectrum corresponding to (3) in the form of a heasim user input spectrum ASCII file (flux in photons cm^{-2} s^{-1} channel^{-1} vs. energy in keV). The diffuse spectrum is calculated on a user-specified energy grid [keV] ranging from the parameter 'emin' to the parameter 'emax' with a constant grid spacing given by the parameter 'de'. For example, one might select 'emin=0.1', 'emax=16.0', and 'de=0.0005' for the Hitomi/SXS and 'emin=0.1', 'emax=120.0', and 'de=0.025' for the Hitomi/HXI. The name of the output ASCII file is constructed by appending the string "'outfileroot'.dat" to the string "difspec_". (5) An xspec table model (FITS) file is also output, with a name constructed by appending the string "'outfileroot'.fits" to the string "difspec_". This may be directly examined (e.g., via the command "model atable{difspec_outfileroot.fits}" within xspec).

PARAMETERS

outfileroot = heasim [string]

The root name used to construct the file names of the skyback outputs. The outputs are: pscat_outfileroot.txt, pszcat_outfileroot.txt, difcat_outfileroot.txt, difspec_outfileroot.dat, and difspec_outfileroot.fits.

ra [double]

The right ascension (RA) of the region center to be populated with background (discrete and diffuse) sources. This parameter is given in decimal degrees, J2000 epoch.

dec [double]

The declination (DEC) of the region center to be populated with background (discrete and diffuse) sources. This parameter is given in decimal degrees, J2000 epoch.

radius [double]

Radius [arcmin] of the circular region to be populated with background (discrete and diffuse) sources.

emin = 0.1 [double]

Energy [keV] of the lower limit of the energy grid for the computed background spectrum.

emax = 10.0 [double]

Energy [keV] of the upper limit of the energy grid for the computed background spectrum.

de = 0.025 [double]

Constant energy spacing [keV] of the points in the energy array for the background spectrum.

(flaglogns = yes) [boolean yes|no]

If 'flaglogns=yes', the background component originating from point sources drawn from a logN-logS distribution is computed.

fluxsens = 1.0e-14 [double]

Flux for the point source sensitivity limit used for both logN-logS distributions. Sources with flux above this threshold are treated as discrete point sources, sources below are treated as unresolved and subsumed into the diffuse background. This parameter is required if 'flaglogns=yes', but may be set to 0, in which case the threshold is determined by the 'exposure', 'sigtonoise', and 'ctstoflux' parameters. This paramter is ignored if 'flaglogns=no'.

fluxmin = 1.0e-16 [double]

Flux lower limit [erg cm^{-2} s^{-1}] used for both logN-logS distributions. Required if 'flaglogns=yes', otherwise ignored.

fluxmax = 5.0e-13 [double]

Flux upper limit [erg cm^{-2} s^{-1}] used for both logN-logS distributions. Required if 'flaglogns=yes', otherwise ignored.

bandpasslo = 2.0 [double]

Bandpass lower limit [keV] over which both logN-logS distributions are defined. Fluxes output in the "pscat_outfileroot.txt" file refer to the energy range defined by 'bandpasslo' and 'bandpasshi'. Required if 'flaglogns=yes', otherwise ignored.

bandpasshi = 10.0 [double]

Bandpass upper limit [keV] over which both logN-logS distributions are defined. Fluxes output in the "pscat_outfileroot.txt" file refer to the energy range defined by 'bandpasslo' and 'bandpasshi'. Required if 'flaglogns=yes', otherwise ignored.

slopebright1 = 1.7 [double]

Bright-end slope of the first (broken power-law) logN-logS distribution. Required if 'flaglogns=yes', otherwise ignored.

slopefaint1 = 0.9 [double]

Faint-end slope of the first (broken power-law) logN-logS distribution. Required if 'flaglogns=yes', otherwise ignored.

fluxbreak = 3.5e-14 [double]

Flux level [erg cm^{-2} s^{-1}] where the first (broken power-law) logN-logS distribution changes slope (i.e. 'slope=slopebright1' ('slopefaint1') above (below) 'fluxbreak'). Required if 'flaglogns=yes', otherwise ignored.

norm1 = 1.9e4 [double]

Normalization (in sources per square degree) of the first (broken power-law) logN-logS distribution. Required if 'flaglogns=yes', otherwise ignored.

spectype1 = 2 [integer 0|1|2]

Type of spectral model assigned to the point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second distrbution, if 'samespec=yes'. If 'spectype1=0' (single), all sources have identical spectral models as specified in the parameters 'specmod1', 'specpar1', and 'nhmod1'. If 'spectype1=1' (multi), spectra are absorbed power-laws with column densities and slopes drawn from the distributions specified in the parameters 'fabs0' to 'fabs5', and 'fpar0' to 'fpar4', respectively, with a special treatment in the mildly and fully Compton thick regimes. If 'spectype1=2' (torus), spectra are BN torus models, with column densities and opening angles drawn from the distributions specified by the parameters 'fabs0' to 'fabs5', and 'fpar0' to 'fpar4' respectively, and with randomly selected inclination angles. Required if 'flaglogns=yes', otherwise ignored.

(specmod1 = pow) [string pow|bbod|brem|rs|mono]

Available spectral models that are assigned to the point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. These are: pow (power-law), bbod (blackbody), brem (thermal bremsstrahlung), rs (Raymond-Smith thermal plasma), or mono (mono-energetic). This parameter is ignored if 'flaglogns=no'.

(specpar1 = 1.9) [double]

Parameter value of the spectral model specified in 'specmod1'. The possible parameters are: photon index (for power-law model), temperature (in keV for blackbody, bremsstrahlung, or Raymond-Smith models), or line energy (in keV for mono-energetic model). This parameter is ignored if 'flaglogns=no'.

(nhmod1 = 0.0) [double]

Value for the column density [cm^{-2}] used with the spectral model specified in 'specmod1'. This parameter is ignored if 'flaglogns=no'.

(fabs0 = 0.24) [double]

Fraction of sources which have assigned NH<1.0E21 cm^{-2} and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The value for the fraction ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fabs1 = 0.24) [double]

Fraction of sources which have assigned column density, NH, between 1.0E21 and 1.0E22 cm^{-2} and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The fraction values range between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fabs2 = 0.24) [double]

Fraction of sources which have assigned NH between 1.0E22 and 1.0E23 cm^{-2} and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The fraction values range between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fabs3 = 0.24) [double]

Fraction of sources which have assigned NH between 1.0E23 and 1.0E24 cm^{-2} and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The fraction values range between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fabs4 = 0.03) [double]

Fraction of sources which have assigned NH between 1.0E24 and 1.0E25 cm^{-2} ("mildly Compton thick" regime) and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The fraction values range between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fabs5 = 0.01) [double]

Fraction of sources which have assigned NH > 1.0E25 cm^{-2} ("Compton thick" regime) and are drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. This is applicable if 'spectype1' is either 1 or 2. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fpar0 = 0.2) [double]

Fraction of sources which have assigned a power-law photon index between 1.5 and 1.7 if 'spectype1=1', or torus opening angles<30 degrees 'if spectype1=2'. Applied to point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fpar1 = 0.2) [double]

Fraction of sources which have assigned a power law index between 1.7 and 1.9 if 'spectype1=1', or torus opening angles between 30 and 45 degrees if 'spectype1=2'. Applied to point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fpar2 = 0.2) [double]

Fraction of sources which have assigned a power law index between 1.9 and 2.1 if 'spectype1=1', or torus opening angles between 45 and 60 degrees if 'spectype1=2'. Applied to point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fpar3 = 0.2) [double]

Fraction of sources which have assigned a power law index between 2.1 and 2.3 if 'spectype1=1', or torus opening angles between 60 and 75 degrees if 'spectype1=2'. Applied to point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(fpar4 = 0.2) [double]

Fraction of sources which have assigned a power law index between 2.3 and 2.5 if 'spectype1=1', or torus opening angles between 75 and 90 degrees if 'spectype1=2'. Applied to point sources drawn from the first logN-logS distribution (broken power-law) - as well as the second if 'samespec=yes'. The fraction values ranges between 0 and 1. This parameter is ignored if 'flaglogns=no'.

(slope2 = 1.1) [double]

Slope of the second (single power-law) logN-logS distribution. This parameter is ignored if 'flaglogns=no'.

(norm2 = 0.0e0) [double]

Normalization (in sources per square degree) of the second (single power-law) logN-logS distribution. This parameter is ignored if 'flaglogns=no'.

(samespec = yes) [boolean yes|no]

If 'samespec=yes', the spectral model for the point sources from the second logN-logS distribution (single power-law) is assigned in the same way as for the point sources from the first logN-logS distribution (broken power-law), i.e. identical spectra if 'spectype1=0', or spectra drawn from identical spectral parameter distributions if 'spectype=1 or 2'. This parameter is ignored if 'flaglogns=no'.

(specmod2 = pow) [string pow|bbod|brem|rs|mono]

Available spectral models that are assigned to the point sources drawn from the second logN-logS distribution (broken power-law) if 'samespec=no'. These are: pow (power-law), bbod (blackbody), brem (thermal bremsstrahlung), rs (Raymond-Smith thermal plasma), or mono (mono-energetic). This parameter is ignored if 'flaglogns=no'.

(specpar2 = 1.9) [double]

Parameter value of the spectral model specified in 'specmod2'. The possible parameters are: index (for power-law model), temperature (in keV for blackbody, bremsstrahlung, Raymond-Smith models), or line energy (in keV for mono-energetic model). This parameter is ignored if 'flaglogns=no'.

(nhmod2 = 0.0) [double]

Value for the column density [cm^{-2}] used with the spectral model specified in 'specmod2'. This parameter is ignored if 'flaglogns=no'.

(flaggal = yes) [boolean yes|no]

If yes, the diffuse background component originating from Galactic halo and Local Hot Bubble hot gas is computed.

(flagswcx = no) [boolean yes|no]

If yes, the background component originating from Solar Wind Charge Exchange is computed.

(swcxOVII = 0.0) [double]

Total flux (in LU, where 1 LU = erg cm^{-2} s^{-1} arcmin^{-2}) of the OVII line complex for the discrete SWCX component. This parameter is ignored if 'flagswcx=no'.

(swcxcont = 3.17e-16) [double]

Total flux [erg cm^{-2} s^{-1} arcmin^{-2}] of the continuous SWCX component. This parameter is ignored if 'flagswcx=no'.

(flagdgrb = no) [boolean yes|no]

NOT IMPLEMENTED. If yes, the diffuse gamma-ray background component is computed.

(flaggrxe = no) [boolean yes|no]

NOT IMPLEMENTED. If yes, the Galactic Ridge background component is computed.

(exposure = 10000.) [double]

Exposure time [s] used to calculate the point-source logN-logS flux threshold (in combination with 'sigtonoise' and 'ctstoflux', i.e. as ctstoflux*sigtonoise*sigtonoise/exposure) if an explicit value ('fluxsens') is not input. The threshold determines which sources are treated as discrete background sources and which as contributing to the diffuse background emission.

(sigtonoise = 5.0) [double]

Minimum signal-to-noise ratio used (in combination with 'exposure' and 'ctstoflux') to determine the flux threshold if 'fluxsens=0'.

(ctstoflux = 1.0e-11) [double]

Count-rate to flux conversion used (in combination with 'sigtonoise' and 'exposure') to determine the flux threshold if 'fluxsens=0'.

(seed = 1) [integer]

Random number generator seed. If 'seed=0' the system time is used. If 'iseed>0', consecutive applications with identical seed parameter yield identical output.

(clobber = no) [boolean yes|no]

Overwrites the existing output file if set to yes.

(debug = no) [boolean yes|no]

Diagnostic output is printed to the screen if set to yes.

EXAMPLES

1. Create skyback point source, diffuse source, and auxiliary point source catalog output files pscat_heasim.txt, difcat_heasim.txt, and pszcat_heasim.txt, respectively, for a background field centered at (ra,dec) = (150.0,50.0) and radial extent of 10 arcmin. Create a diffuse spectrum text file (difspec_heasim.dat) and xspec table model file (difspec_heasim.fits). The background components include the galactic and logN-logS components, where the latter consists of point sources drawn from a single broken power-law logN-logS distribution with default parameters and identical power-law spectra with a photon index of 1.9. The output spectra are created on an energy grid spanning 0.1-12 keV with 1 eV grid spacing.

   skyback outfileroot=heasim ra=150.0 dec=50.0 radius=10.0 emin=0.1 emax=12.0 de=0.001 flaglogns=yes fluxsens=1.0e-14 \
      fluxmin=1.0e-16 fluxmax=5.0e-13 bandpasslo=0.5 bandpasshi=2.0  slopebright1=1.7 slopefaint1=0.9 fluxbreak=2.5e-14 \
      norm1=8.0e3 spectype1=0

2. Create skyback point source, diffuse source, and auxiliary point source catalog output files pscat_cxb_hxi.txt, difcat_cxb_hxi.txt, and pszcat_cxb_hxi.txt, respectively, for a background field centered at (ra,dec) = (151.8606,16.1085) and radial extent of 20 arcmin. Create a diffuse spectrum text file (difspec_cxb_hxi.dat) and xspec table model file (difspec_cxb_hxi.fits). The background components include the galactic and logN-logS components, where the latter consists of point sources drawn from a single broken power-law logN-logS distribution defined in the 2-10 keV bandpass with a bright-end slope of 1.7, faint-end slope of 0.9, flux where the slope breaks of 3.5E-14 erg cm^{-2} s^{-1}, and 19000 sources deg^{-2} between 1.0E-16 and 7.0E-13 erg cm^{-2} s^{-1}. The spectra are torus models drawn from a distribution with probabilities of 0.2, 0.2, 0.2, 0.2, 0.1, and 0.1 for the 6 defined column density bins, and equal probabilities in the 5 defined torus opening angle bins. The output spectra are created on an energy grid spanning 0.1-120 keV with 25 eV grid spacing.

   skyback outfileroot=cxb_hxi ra=151.8606 dec=16.1085 radius=20.0 emin=0.1 emax=120.0 de=0.025 fluxsens=1.0e-14 \
      fluxmin=1.0e-16 fluxmax=7.0e-13 bandpasslo=2.0 bandpasshi=10.0 slopebright1=1.7 slopefaint1=0.9 fluxbreak=3.5e-14 \
      norm1=1.9e4  spectype1=2 fabs0 = 0.2 fabs1 = 0.2 fabs2 = 0.2 fabs3 = 0.2 fabs4 = 0.1 fabs5 = 0.1 

SEE ALSO

LAST MODIFIED