Non-equilibrium ionization collisional plasma model. This assumes a constant temperature and single ionization parameter. It provides a characterisation of the spectrum but is not a physical model. The references for this model can be found under the description of the equil model. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature (keV) | |||
par2 | = | Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are given by the Anders & Grevesse mixture. | |||
par3 | = | Ionization timescale in units of s/cm^{3}. | |||
par4 | = | redshift z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Plane-parallel shock plasma model with separate ion and electron temperatures. This model is slow. par1 provides a measure of the average energy per particle (ions+electrons) and is constant throughout the postshock flow in plane shock models (Borkowski et al., 2001, ApJ, 548, 820). par2 should always be less than par1. If par2 exceeds par1 then their interpretations are switched (ie the larger of par1 and par2 is always the mean temperature). Additional references can be found under the help for the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | mean shock temperature (keV) | |||
par2 | = | electron temperature immediately behind the shock front (keV). | |||
par3 | = | Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are given by the Anders & Grevesse mixture. | |||
par4 | = | Lower limit on ionization timescale (s/cm^{3}) to include. | |||
par5 | = | Upper limit on ionization timescale (s/cm^{3}) to include. | |||
par6 | = | redshift z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
This model provides the spectra in the X-ray range (0.05-10 keV) emitted from a hydrogen atmosphere of a neutron star. There are three options : nonmagnetized (B < 10^{8} - 10^{9} G) with a uniform surface (effective) temperature in the range of ; a field B = 10^{12} G with a uniform surface (effective) temperature in the range of ; a field B = 10^{13} G with a uniform surface (effective) temperature in the range of . The atmosphere is in radiative and hydrostatic equilibrium; sources of heat are well below the atmosphere. The Comptonization effects (significant at K) are taken into account. The model spectra are provided as seen by a distant observer, with allowance for the GR effects. The user is advised to keep M_{ns} and R_{ns} fixed and fit the temperature and the normalization. MagField must be fixed at one of 0, 10^{12}, or 10^{13}.
The values of the effective temperature and radius as measured by a distant observer (``values at infinity'') are :
where g_{r}=(1-2.952*M_{ns}/R_{ns})^{0}.5 is the gravitational redshift parameter.
Please send your comments/questions (if any) to Slava Zavlin (zavlin@mpe.mpg.de) and/or George Pavlov (pavlov@astro.psu.edu). If you publish results obtained using this model please reference Pavlov et al. (1992, MNRAS 253, 193) and Zavlin et al. (1996, A&A 315, 141).
par1 | = | logT_eff, (unredshifted) effective temperature | |||
par2 | = | M_ns, neutron star gravitational mass (in units of solar mass) | |||
par3 | = | R_ns, neutron star radius (in km) | |||
par4 | = | MagField, neutron star magnetic field (0, 1e12, or 1e13 G) | |||
K | = | 1/D^{2}, where D is the distance of the object in pc. |
A nonthermal pair plasma model based on that of Lightman & Zdziarski (1987, ApJ 319, 643) from Magdziarz and Zdziarski. It includes angle-dependent reflection from Magdziarz & Zdziarski (1995, MNRAS 273, 837). The abundances are set up by the command abund. Send questions or comments to aaz@camk.edu.pl.
par1 | = | nonthermal electron compactness | |||
par2 | = | blackbody compactness | |||
par3 | = | scaling factor for reflection (1 for isotropic source above disk) | |||
par4 | = | blackbody temperature in eV | |||
par5 | = | the maximum Lorentz factor | |||
par6 | = | thermal compactness (0 for pure nonthermal plasma) | |||
par7 | = | Thomson optical depth of ionization electrons (e.g., 0) | |||
par8 | = | electron injection index (0 for monoenergetic injection) | |||
par9 | = | minimum Lorentz factor of the power law injection (not used for monoenergetic injection) | |||
par10 | = | minimum Lorentz factor for nonthermal reprocessing (>1; ) | |||
par11 | = | radius in cm (for Coulomb/bremsstrahlung only) | |||
par12 | = | pair escape rate in c (0-1, see Zdziarski 1985, ApJ, 289, 514)) | |||
par13 | = | cosine of inclination angle | |||
par14 | = | iron abundance relative to that defined by abund | |||
par15 | = | redshift | |||
K | = | photon flux of the direct component (w/o reflection) at 1 keV in the observer's frame. |
par1 | = | photon index of power law (dimensionless) | |||
par2 | = | lower peg energy range | |||
par3 | = | upper peg energy range | |||
K | = | flux (in units of 10^{-12} erg/cm^{2}/s) over the energy par2- par3 unless par2 = par3, in which case it is the flux (in micro-Jy) at par2 |
Exponentially cut off power law spectrum reflected from neutral material (Magdziarz & Zdziarski 1995, MNRAS, 273, 837). The output spectrum is the sum of the cut-off power law and the reflection component. The reflection component alone can be obtained for rel_refl < 0. Then the actual reflection normalization is |rel_refl|. Note that you need to change then the limits of rel_refl excluding zero (as then the direct component appears). If E_{c} = 0there is no cutoff in the power law. The metal and iron abundance are variable with respect to those defined by the command abund. The opacities are from Balucinska & McCammon (ApJ 400, 699 and 1994, private communication). H and He are assumed to be fully ionized. Send questions or comments to aaz@camk.edu.pl.
par1 | = | , power law photon index, N_{E} prop. to | |||
par2 | = | E_{c}, the cutoff energy in keV (if E_{c} = 0 there is no cutoff; one needs to change the lower limit for that) | |||
par3 | = | rel_refl, scaling factor for reflection; if <0, no direct component (rel_refl=1 for isotropic source above disk) | |||
par4 | = | redshift | |||
par5 | = | abundance of elements heavier than He relative to that defined by abund | |||
par6 | = | iron abundance relative to that defined by abund | |||
par7 | = | cosine of inclination angle | |||
K | = | photon flux at 1 keV (photons/keV/cm^{2}/s) of the power-law only in the observed frame. |
Exponentially cut off power law spectrum reflected from ionized material (Magdziarz & Zdziarski MNRAS, 273, 837; 1995). Ionization and opacities of the reflecting medium is computed as in the procedure absori. The output spectrum is the sum of the cutoff power law and the reflection component. The reflection component alone can be obtained for rel_refl < 0. Then the actual reflection normalization is |rel_refl|. Note that you need to change then the limits of rel_refl excluding zero (as then the direct component appears). If E_{c} = 0 there is no cutoff in the power law. The metal and iron abundances are variable with respect to those defined by the command abund. Send questions or comments to aaz@camk.edu.pl.
par1 | = | , power law photon index, N_{E} prop. to | |||
par2 | = | E_{c}, the cutoff energy in keV (if E_{c} = 0 there is no cutoff; one needs to change the lower limit for that) | |||
par3 | = | rel_refl, scaling factor for reflection; if <0, no direct component (rel_refl=1 for isotropic source above disk) | |||
par4 | = | redshift, z | |||
par5 | = | abundance of elements heavier than He relative to that defined by abund | |||
par6 | = | iron abundance relative to that defined by abund | |||
par7 | = | cosine of inclination angle | |||
par8 | = | disk temperature in K | |||
par9 | = | disk ionization parameter, , where F_{ion} is the 5eV - 20keV irradiating flux, n is the density of the reflector; see Done et al., 1992, ApJ, 395, 275 | |||
K | = | photon flux at 1 keV (photons/keV/cm^{2}/s) of the power-law only in the observed frame. |
This model describes X-ray transmission of an isotropic source of photons located at the center of a uniform, spherical distribution of matter, correctly taking into account Compton scattering. The model can be used for radial column densities up to cm^{-2}. The valid energy range for which data can be mod!laeled is between 10 and 18.5 keV, depending on the column density. Details of the physics of the model, the approximations used and further details on the regimes of validity can be found in Yaqoob (1997; ApJ, 479, 184). In this particular incarnation, the initial spectrum is a power law modified by a high-energy exponential cut-off above a certain threshold energy.
Also, to improve the speed, a FAST option is available in which a full integration over the input spectrum is replaced by a simple mean energy shift for each bin. This option is obtained by setting parameter 9 to a value of 1 or greater and MUST BE FIXED. Further, for single-scattering albedos less than ACRIT (i.e. parameter 8) energy shifts are neglected altogether. The recommended value is ACRIT=0.1 which corresponds to about 4 keV for cosmic abundances and is more than adequate for ASCA data.
Note that for column densities in the range 10^{23} - 10^{24} cm^{-2}, the maximum number of scatterings which need be considered for convergence of the spectrum of better than 1% is between 1 and 5. For columns as high as , the maximum number of scatterings which need be considered for the same level of convergence is 12. **NOTE THAT NMAX MUST BE FROZEN **
par1 | = | Column density in units 10^{22} cm^{-2}. | |||
par2 | = | Maximum number of scatterings to consider. | |||
par3 | = | Iron abundance. | |||
par4 | = | Iron K edge energy. | |||
par5 | = | Power-law photon index. | |||
par6 | = | High-energy cut-off threshold energy. | |||
par7 | = | High-energy cut-off e-folding energy. | |||
par8 | = | Critical albedo for switching to elastic scattering. | |||
par9 | = | If function uses mean energy shift, not integration. | |||
par10 | = | Source redshift. |
Positronium continuum (Brown & Leventhal 1987 ApJ 319, 637).
for E < 511 keV, where :
K | = | normalization. |
par1 | = | photon index of power law (dimensionless) | |||
K | = | photons/keV/cm^{2}/s at 1 keV. |
Constant temperature, plane-parallel shock plasma model. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature (keV) | |||
par2 | = | Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are given by the Anders & Grevesse mixture. | |||
par3 | = | Lower limit on ionization timescale (s/cm^{3}) to include. | |||
par4 | = | Upper limit on ionization timescale (s/cm^{3}) to include. | |||
par5 | = | redshift z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | plasma temperature in keV | |||
par2 | = | Metal abundances (He fixed at cosmic) The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni and their relative abundances are set by the abund command. | |||
par3 | = | redshift | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Recombination edge emission.
par1 | = | threshold energy | |||
par2 | = | plasma temperature (keV) | |||
K | = | total photons/cm^{2}/s in the line |
Exponentially cut-off power-law spectrum reflected from an ionized relativistic accretion disk. In this model, spectrum of pexriv is convolved with a relativistic disk line profile diskline. See Magdziarz & Zdziarski 1995 MNRAS, 273, 837 for details of Compton reflection. See Fabian et al. 1989, MNRAS, 238, 729 for details of the disk line profile.
par1 | = | power law photon index, N_{E} prop. to | |||
par2 | = | E_{c}, the cutoff energy in keV (if E_{c}=0 there is no cutoff) | |||
par3 | = | rel_{refl}, reflection scaling factor (1 for isotropic source above disk) | |||
par4 | = | redshift, z | |||
par5 | = | abundance of elements heavier than He relative to the solar abundances | |||
par6 | = | iron abundance relative to the above | |||
par7 | = | inclination angle (degrees) | |||
par8 | = | disk temperature in K | |||
par9 | = | disk ionization parameter, where F_{ion} is the 5 eV - 20 keV irradiating flux, n is the density of the reflector; see Done et al., 1992, ApJ, 395, 275 | |||
par10 | = | power law index for reflection emissivity; emissivity is | |||
par11 | = | inner disk radius in units of GM/c^{2} | |||
par12 | = | outer disk radius in units of GM/c^{2} | |||
par13 | = | internal model accurancy - points of spectrum per energy decade | |||
K | = | photon flux at 1 keV of the cutoff broken power-law only (no reflection) in the observed frame. |
Sedov model with separate ion and electron temperatures. This model is slow. par1 provides a measure of the average energy per particle (ions+electrons) and is constant throughout the postshock flow in plane shock models (Borkowski et al., 2001, ApJ, 548, 820). par2 should always be less than par1. If par2 exceeds par1 then their interpretations are switched (ie the larger of par1 and par2 is always the mean temperature). Additional references can be found under the help for the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | mean shock temperature (keV) | |||
par2 | = | electron temperature immediately behind the shock front (keV). | |||
par3 | = | Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are given by the Anders & Grevesse mixture. | |||
par4 | = | ionization age (s/cm^{3}) of the remnant (== electron density immediately behind the shock front times age of remnant) | |||
par5 | = | redshift z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
This model performs an analytical deprojection of an extended, optically-thin and spherically-symmetric source. A thorough description of the model is given in Pizzolato et al. (ApJ 592, 62, 2003). In this model the 3D distributions of hydrogen, metals and temperature throughout the source are given specific functional forms dependent on a number of parameters, whose values are determined by the fitting procedure. The user has to extract the spectra in annular sectors, concentric about the emission peak. The inner boundary (in arcmin), the outer by the fitting procedure. The user has to extract the spectra in annular sectors, concentric about the emission peak. The inner boundary (in arcmin), the outer boundary (also in arcmin), and the width (in degrees) of each annular sector are specified (respectively) by the three additional keywords XFLT0001, XFLT0002, and XFLT0003, to be added to the spectrum extension in each input file (e.g. with the ftool FKEYPAR). Some parameters of smaug define the redshift and other options (see below). The other, 'relevant' ones define the 3D distributions of hydrogen density, temperature and metal abundance, determined by a simultaneous fit of the spectra. Before running smaug it is important to give the command xset forcecalc on. The cosmological parameters can be set using the cosmo command.
par1 | = | central temperature [keV] | |||
par2 | = | max difference of temperature [keV] | |||
par3 | = | exponent of the inner temperature | |||
par4 | = | radius of the inner temperature [Mpc] | |||
par5 | = | exponent of the middle temperature | |||
par6 | = | radius of the middle temperature [Mpc] | |||
par7 | = | exponent of the outer temperature | |||
par8 | = | radius of the outer temperature [Mpc] | |||
par9 | = | central hydrogen density [cm**-3] | |||
par10 | = | fraction of nH.cc relative to the 1st beta component | |||
par11 | = | exponent of the first beta component | |||
par12 | = | radius of the 1st beta component [Mpc] | |||
par13 | = | exponent of the 2nd beta component | |||
par14 | = | radius of the 2nd beta component [Mpc] | |||
par15 | = | central metallicity [solar units] | |||
par16 | = | exponent of the metal distribution | |||
par17 | = | radius of the metal distribution [Mpc] | |||
par18 | = | redshift of the source | |||
par19 | = | number of mesh-points of the dem summation grid | |||
par20 | = | cutoff radius for the calculation [Mpc] | |||
par21 | = | mode of spectral evaluation: 0 = calculate, 1 = interpolate, 2 = APEC interpolate | |||
par22 | = | type of plasma emission code, 1 = Raymond-Smith, 2 = Mekal, 3 = Meka, 4 = APEC | |||
K | = | model normalisation (nH.cc squared [cm**-6] ) |
Note that if the interactive chattiness level in XSPEC is set to a value > 10, smaug also prints on screen the following quantities:
H0 | = | Hubble constant [km/s/Mpc] | |||
q0 | = | deceleration parameter | |||
L0 | = | cosmological constant | |||
DA | = | source angular distance [Mpc] | |||
DSET | = | dataset no. to which the quantities listed below are | |||
IN | = | inner rim of the projected annular sector [Mpc] | |||
OUT | = | outer rim of the projected annular sector [Mpc] | |||
WID | = | width of the projected annular sector [deg] | |||
EVOL | = | emitting volume within the integration radius cutoff [Mpc^{3}] | |||
EINT | = | emission integral within the integration radius cutoff [ Mpc^{3} cm^{-}6]. If nH.cc is frozen to 1, the actual EI is obtaned by multiplying this figure by the square root of the model normalisation |
The synchrotron spectrum from an exponentially cut off power-law distribution of electrons in a homogeneous magnetic field. This spectrum is itself a power-law at lower energies, with a slow rolloff (slower than exponential) above some rolloff frequency. Though more realistic than a power-law, it is highly oversimplified, but does give the maximally curved physically plausible spectrum and can be used to set limits on maximum accelerated-electron energies even in supernova remnants whose X-rays are thermal. See Reynolds, S.P. & Keohane, J.W. 1999, ApJ, 525, 368 (but note that the numerical coefficient of equation (2) in that paper is incorrect: it should be 1.6e16) and Reynolds, S.P., 1998 ApJ 493, 357. The radio spectral index and flux can be obtained from Green's Catalogue at http://www.mrao.cam.ac.uk/surveys/snrs/ for galactic SNRs.
par1 | = | alpha: radio spectral index | |||
par2 | = | break Hz: the characteristic (not peak) frequency radiated by electrons with the e-folding energy E_{m} of the exponential cutoff. In cgs units, break = . It is also approximately the frequency at which the flux has dropped by a factor of about 4 below the straight It is also approximately the frequency at which the flux has dropped by a factor of about 4 below the straight power-law extrapolation from radio frequencies. | |||
K | = | 1 GHz flux (Jy) |
The synchrotron spectrum from an electron distribution limited by particle escape above some energy. The electrons are shock-accelerated in a Sedov blast wave encountering a constant-density medium containing a uniform magnetic field. The model includes variations in electron acceleration efficiency with shock obliquity, and post-shock radiative and adiabatic losses, as described in Reynolds, S.P., ApJ 493, 357 1998. This is a highly specific, detailed model for a fairly narrow set of conditions. See also Reynolds, S.P., ApJL 459, L13 1996. Note that the radio spectral index and flux can be obtained from Green's Catalogue at http://www.mrao.cam.ac.uk/surveys/snrs/ for galactic SNRs.
par1 | = | alpha: radio spectral index (flux proportional to frequency ) | |||
par2 | = | break Hz: approximately the frequency at which the flux has dropped by a factor of 6 below a straight powerlaw extrapolation from radio frequencies. This frequency is 5.3 times the peak frequency radiated by electrons with energy E_{m3} in a magnetic field of 4 B_{1}, in the notation of Reynolds (1998), Eq. (19). | |||
K | = | 1 GHz flux (Jy) |
par1 | = | start energy (keV) | |||
par2 | = | gaussian sigma (keV) | |||
K | = | step amplitude |
An emission spectrum from collisionally-ionized diffuse gas calculated using the APEC code v1.3.1. More information can be found at http://hea-www.harvard.edu/APEC/ which should be consulted by anyone running this model. By default this model reads atomic physics data from the files apec_v1.3.1_coco.fits and apec_v1.3.1_line.fits in the spectral/xspec/manager file. Different files can be specified by using the command xset set APECROOT. There are three options. APECROOT can be set to a version number (eg 1.2.0). In this case the value of APECROOT will be used to replace 1.3.1 in the name of the standard files and the resulting files will be assumed to be in the spectral/xspec/manager directory. Alternatively, a filename root (eg apec_v1.2.0) can be given. This root will be used as a prefix for the _coco.fits and _line.fits in the manager directory. Finally, if neither of these work then the model will assume that the APECROOT value gives the complete directory path e.g. XSPEC> xset APECROOT /foo/bar/apec_v1.2.0 will use /foo/bar/apec_v1.2.0_coco.fits and /foo/bar/apec_v1.2.0_line.fits as input files.
par1 | = | plasma temperature in keV | |||
par2-- par14 | = | Abundances for He, C, N, O, Ne, Mg, Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) | |||
par15 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | plasma temperature (keV) | |||
par2 | = | n(He)/n(H) (note that the Solar ratio is 0.085) | |||
K | = | , where D is the distance to the source (cm) and n_{e}, n_{I} are the electron and ion densities (cm^{-3}) |
Ionization equilibrium collisional plasma model. This is the equilibrium version of Kazik Borkowski's NEI models. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature in keV | |||
par2-- par13 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par14 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Non-equilibrium ionization collisional plasma model. This is a generalization of the nei model where the temperature is allowed to have been different in the past ie the ionization timescale averaged temperature is not necessarily equal to the current temperature. For example, in a standard Sedov model with equal electron and ion temperatures, the ionization timescale averaged temperature is always higher than the current temperature for each fluid element. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature in keV | |||
par2 | = | H density in cm^{-3} | |||
par3-- par14 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par15 | = | Ionization timescale in units of s/cm^{-3} | |||
par16 | = | Ionization timescale averaged plasma temperature in keV. | |||
par17 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | plasma temperature in keV | |||
par2 | = | hydrogen density in cm^{-3} | |||
par3-- par16 | = | Abundances for He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) | |||
par17 | = | redshift | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
An emission spectrum from hot diffuse gas based on the model calculations of Mewe and Kaastra with Fe L calculations by Liedahl (for references see the section on the mekal model). The model includes line emissions from several elements. Abundances are the number of nuclei per Hydrogen nucleus relative to the Solar abundances set by the abund command. The switch parameter determines whether the mekal code will be run to calculate the model spectrum for each temperature or whether the model spectrum will be interpolated from a pre-calculated table. The former is slower but more accurate.
par1 | = | plasma temperature in keV | |||
par2 | = | hydrogen density in cm^{-3} | |||
par3-- par16 | = | Abundances for He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) | |||
par17 | = | redshift | |||
par18 | = | 0 calculate, 1 interpolate | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | low temperature (keV) | |||
par2 | = | high temperature (keV) | |||
par3- par16 | = | Abundances for He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) | |||
par17 | = | redshift | |||
par18 | = | 0 calculate, 1 interpolate | |||
K | = | Mass accretion rate (solar mass/yr) |
Non-equilibrium ionization collisional plasma model. This assumes a constant temperature and single ionization parameter. It provides a characterisation of the spectrum but is not a physical model. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature in keV | |||
par2 | = | H density in cm^{-3} | |||
par3-- par14 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par15 | = | Ionization timescale in units of s/cm^{-3} | |||
par16 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Plane-parallel shock plasma model with separate ion and electron temperatures. This model is slow. par1 provides a measure of the average energy per particle (ions+electrons) and is constant throughout the postshock flow in plane shock models (Borkowski et al., 2001, ApJ, 548, 820). par2 should always be less than par1. If par2 exceeds par1 then their interpretations are switched (ie the larger of par1 and par2 is always the mean temperature). Additional references can be found under the help for the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | mean shock temperature in keV | |||
par2 | = | electron temperature immediately behind the shock front (keV) | |||
par3 | = | H density in cm^{-3} | |||
par4-- par15 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par16 | = | Lower limit on ionization timescales (s/cm^{3}) to include | |||
par17 | = | Upper limit on ionization timescales (s/cm^{3}) to include | |||
par18 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Constant temperature, plane-parallel shock plasma model. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | plasma temperature in keV | |||
par2 | = | H density in cm^{-3} | |||
par3-- par14 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par15 | = | Lower limit on ionization timescales (s/cm^{3}) to include | |||
par16 | = | Upper limit on ionization timescales (s/cm^{3}) to include | |||
par17 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | plasma temperature (keV) | |||
par2-- par13 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) | |||
par14 | = | redshift | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
Sedov model with separate ion and electron temperatures. This model is slow. par1 provides a measure of the average energy per particle (ions+electrons) and is constant throughout the postshock flow in plane shock models (Borkowski et al., 2001, ApJ, 548, 820). par2 should always be less than par1. If par2 exceeds par1 then their interpretations are switched (ie the larger of par1 and par2 is always the mean temperature). Additional references can be found under the help for the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), and xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum. Note that versions 1.x have no emission from Ar. The default is version 1.1.
par1 | = | mean shock temperature in keV | |||
par2 | = | electron temperature immediately behind the shock front (keV) | |||
par3 | = | H density in cm^{-3} | |||
par4-- par15 | = | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture) | |||
par16 | = | ionization age (s/cm^{3}) of the remnant (== electron density immediately behind the shock front times age of remnant) | |||
par17 | = | redshift, z | |||
K | = | , where D_{A} is the angular size distance to the source (cm), n_{e} and n_{H} are the electron and H densities (cm^{-3}) |
par1 | = | temperature kT in keV | |||
par2 | = | redshift | |||
K | = | L_{39}/D_{10}^{2}, where L39 is the source luminosity in units of 10^{39} ergs/sec and D_{10} is the angular size distance to the source in units of 10 kpc |
par1 | = | plasma temperature in keV | |||
par2 | = | redshift | |||
K | = | , where D is the distance to the source (cm) and n_{e}, n_{I} are the electron and ion densities (cm^{-3}) |
par1 | = | threshold energy | |||
par2 | = | absorption depth at threshold | |||
par3 | = | redshift |
par1 | = | line energy in keV | |||
par2 | = | line width (sigma) in keV | |||
par3 | = | redshift | |||
K | = | total photons/cm^{2}/s in the line |
par1 | = | photon index of power law (dimensionless) | |||
par2 | = | redshift | |||
K | = | photons/keV/cm^{2}/s at 1 keV |