The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. We thank you in advance for your valuable feedback.
Fermi Gamma-ray Space Telescope

XML Model Definitions for Likelihood

Example model definitions for Likelihood:

PowerLaw

<source name="PowerLaw_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="PowerLaw">
<parameter free="1" max="1000.0" min="0.001" name="Prefactor" scale="1e-09" value="1"/>
<parameter free="1" max="-1.0" min="-5." name="Index" scale="1.0" value="-2.1"/>
<parameter free="0" max="2000.0" min="30.0" name="Scale" scale="1.0" value="100.0"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

BrokenPowerLaw

<source name="BrokenPowerLaw_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="BrokenPowerLaw">
<parameter free="1" max="1000.0" min="0.001" name="Prefactor" scale="1e-09" value="1"/>
<parameter free="1" max="-1.0" min="-5." name="Index1" scale="1.0" value="-1.8"/>
<parameter free="1" max="2000.0" min="30.0" name="BreakValue" scale="1.0" value="1000.0"/>
<parameter free="1" max="-1.0" min="-5." name="Index2" scale="1.0" value="-2.3"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

PowerLaw2

<source name="PowerLaw2_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="PowerLaw2">
<parameter free="1" max="1000.0" min="1e-05" name="Integral" scale="1e-06" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index" scale="1.0" value="-2.0"/>
<parameter free="0" max="200000.0" min="20.0" name="LowerLimit" scale="1.0" value="20.0"/>
<parameter free="0" max="200000.0" min="20.0" name="UpperLimit" scale="1.0" value="2e5"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel> </source>

BrokenPowerLaw2

<source name="BrokenPowerLaw2_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="BrokenPowerLaw2">
<parameter free="1" max="1000.0" min="0.001" name="Integral" scale="1e-04" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index1" scale="1.0" value="-1.8"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index2" scale="1.0" value="-2.3"/>
<parameter free="1" max="10000.0" min="30.0" name="BreakValue" scale="1.0" value="1000.0"/>
<parameter free="0" max="200000.0" min="20.0" name="LowerLimit" scale="1.0" value="20.0"/>
<parameter free="0" max="200000.0" min="20.0" name="UpperLimit" scale="1.0" value="2e5"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

SmoothBrokenPowerLaw

<source name="SmoothBrokenPowerLaw_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="SmoothBrokenPowerLaw">
<parameter free="1" max="1e10" min="0.0" name="Prefactor" scale="1e-06" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index1" scale="1.0" value="-2.0"/>
<parameter free="0" max="2000.0" min="30.0" name="Scale" scale="1.0" value="100.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index2" scale="1.0" value="-2.0"/>
<parameter free="1" max="5e5" min="20" name="BreakValue" scale="1.0" value="1e3"/>
<parameter free="1" max="10" min="0.01" name="Beta" scale="1.0" value="0.2"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

LogParabola

<source name="LogParabola_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="LogParabola">
<parameter free="1" max="1000.0" min="0.001" name="norm" scale="1e-9" value="1"/>
<parameter free="1" max="10" min="0" name="alpha" scale="1.0" value="1"/>
<parameter free="1" max="1e4" min="20" name="Eb" scale="1" value="300."/>
<parameter free="1" max="10" min="0" name="beta" scale="1.0" value="2"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

ExpCutoff

<source name="ExpCutoff_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="ExpCutoff">
<parameter free="1" max="100000.0" min="0.01" name="Prefactor" scale="1e-09" value="50"/>
<parameter free="1" max="-1.0" min="-5." name="Index" scale="1.0" value="-2.1"/>
<parameter free="0" max="2000.0" min="30.0" name="Scale" scale="1.0" value="100.0"/>
<parameter free="1" max="300.0" min="1.0" name="Ebreak" scale="1.0" value="10.0"/>
<parameter free="1" max="300.0" min="0.1" name="P1" scale="1000.0" value="100."/>
<parameter free="0" max="1.0" min="-1.0" name="P2" scale="1.0" value="0"/>
<parameter free="0" max="1.0" min="-1.0" name="P3" scale="1.0" value="0"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

BPLExpCutoff

<source name="BPLExpCutoff_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="BPLExpCutoff">
<parameter free="1" max="100000.0" min="0.01" name="Prefactor" scale="1e-09" value="1"/>
<parameter free="1" max="-1.001" min="-5." name="Index1" scale="1.0" value="-2.1"/>
<parameter free="1" max="-1.001" min="-5." name="Index2" scale="1.0" value="-2.1"/>
<parameter free="1" max="10000.0" min="1.0" name="BreakValue" scale="1.0" value="1000.0"/>
<parameter free="1" max="300.0" min="1.0" name="Eabs" scale="1.0" value="10.0"/>
<parameter free="1" max="300.0" min="0.1" name="P1" scale="1000.0" value="100."/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

Gaussian

<source name="Gaussian_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="Gaussian">
<parameter free="1" max="1000.0" min="0.001" name="Prefactor" scale="1e-09" value="1"/>
<parameter free="1" max="1e5" min="1e3" name="Mean" scale="1.0" value="7e4"/>
<parameter free="1" max="30" min="1e4" name="Sigma" scale="1.0" value="1e3"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

ConstantValue

<source name="ConstantValue_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="ConstantValue">
<parameter free="0" max="10" min="0" name="Value" scale="1" value="1"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

FileFunction

<source name="FileFunction_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum file="foo.dat" type="FileFunction">
<parameter free="1" max="1e5" min="1e-5" name="Normalization" scale="1" value="1.0"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

BandFunction

<source name="BandFunction_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="BandFunction">
<parameter free="1" max="1000.0" min="1e-05" name="norm" scale="1e-09" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="alpha" scale="1.0" value="-1.8"/>
<parameter free="1" max="-1.0" min="-5.0" name="beta" scale="1.0" value="-2.5"/>
<parameter free="1" max="-1.0" min="-5.0" name="Ep" scale="1." value="0.1"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

PLSuperExpCutoff

<source name="PLSuperExpCutoff_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="PLSuperExpCutoff">
<parameter free="1" max="1000" min="1e-05" name="Prefactor" scale="1e-07" value="1"/>
<parameter free="1" max="0" min="-5" name="Index1" scale="1" value="-1.7"/>
<parameter free="0" max="1000" min="50" name="Scale" scale="1" value="200"/>
<parameter free="1" max="30000" min="500" name="Cutoff" scale="1" value="3000"/>
<parameter free="1" max="5" min="0" name="Index2" scale="1" value="1.5"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

PLSuperExpCutoff2

<source name="PLSuperExpCutoff2_source" type="PointSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 -->
<spectrum type="PLSuperExpCutoff2">
<parameter free="1" max="1000" min="0" name="Prefactor" scale="1e-11" value="10.976"/>
<parameter free="1" max="5" min="-1.5" name="Index1" scale="-1" value="1.436"/>
<parameter free="0" max="1000" min="0.001" name="Scale" scale="1000" value="1"/>
<parameter free="1" max="1" min="-1" name="Expfactor" scale="1.0" value="0.001"/>
<parameter free="0" max="2" min="0" name="Index2" scale="1" value="1"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360." min="-360." name="RA" scale="1.0" value="83.45"/>
<parameter free="0" max="90." min="-90." name="DEC" scale="1.0" value="21.72"/>
</spatialModel>
</source>

DMFitFunction

<source name="DM_Example" type="PointSource">
<spectrum file="$(BASE_DIR)/data/Likelihood/gammamc_dif.dat" type="DMFitFunction">
<parameter error="1." free="0" max="1.e+5" min="1.e-5" name="norm" scale="1.e+20" value="5.0" />
<parameter error="1." free="0" max="5000.0" min="0." name="sigmav" scale="1.e-26" value="3.0" />
<parameter error="1." free="0" max="5000.0" min="1." name="mass" scale="1.0" value="10"/>
<parameter error="0.1" free="0" max="1.0" min="0.0" name="bratio" scale="1.0" value="1"/>
<parameter free="0" max="10" min="1" name="channel0" scale="1.0" value="4"/>
<parameter free="0" max="10" min="1" name="channel1" scale="1.0" value="1"/>
</spectrum>
<spatialModel type="SkyDirFunction">
<parameter free="0" max="360" min="-360" name="RA" scale="1.0" value="128.8272"/>
<parameter free="0" max="90" min="-90" name="DEC" scale="1.0" value="-45.1762"/>
</spatialModel>
</source>

Spatial Models

To use an extended spatial model such as SpatialMap or MapCubeFunction with Unbinned Likelihood, one must include the map_based_integral attribute in the spatialModel portion of the XML model definition. This attribute should not be used in a Binned Likelihood analysis. An example is provided below:

SpatialMap

<source name="SpatialMap_source" type="DiffuseSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 sr^-1 -->
<spectrum type="PowerLaw2">
<parameter free="1" max="1000.0" min="1e-05" name="Integral" scale="1e-06" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index" scale="1.0" value="-2.0"/>
<parameter free="0" max="200000.0" min="20.0" name="LowerLimit" scale="1.0" value="20.0"/>
<parameter free="0" max="200000.0" min="20.0" name="UpperLimit" scale="1.0" value="2e5"/>
</spectrum>
<spatialModel file="$(PATH_TO_FILE)/SpatialMap_source.fits" type="SpatialMap" map_based_integral="true">
<parameter free="0" max="1000.0" min="0.001" name="Prefactor" scale= "1.0" value="1.0"/>
</spatialModel>
</source>

MapCubeFunction

<source name="MapCubeFunction_source" type="DiffuseSource">
<!-- point source units are cm^-2 s^-1 MeV^-1 sr^-1 -->
<spectrum type="PowerLaw2">
<parameter free="1" max="1000.0" min="1e-05" name="Integral" scale="1e-06" value="1.0"/>
<parameter free="1" max="-1.0" min="-5.0" name="Index" scale="1.0" value="-2.0"/>
<parameter free="0" max="200000.0" min="20.0" name="LowerLimit" scale="1.0" value="20.0"/>
<parameter free="0" max="200000.0" min="20.0" name="UpperLimit" scale="1.0" value="2e5"/>
</spectrum>
<spatialModel file="$(PATH_TO_FILES)/MapCubeFunction_source.fits" type="SpatialMap" map_based_integral="true">
<parameter free="0" max="1000.0" min="0.001" name="Normalization" scale= "1.0" value="1.0"/>
</spatialModel>
</source>

Radial Models

Users can now model individual sources with RadialDisk or RadialGaussian models. An example is provided below:

RadialDisk

<spatialModel type="RadialDisk">
<parameter free="0" max="10" min="0" name="Radius" scale="1" value="0.2" />
<parameter free="0" max="360" min="-360" name="RA" scale="1" value="166.1138" />
<parameter free="0" max="90" min="-90" name="DEC" scale="1" value="38.2088" />
</spatialModel>

RadialGaussian

<spatialModel type="RadialGaussian">
<parameter free="0" max="10" min="0" name="Sigma" scale="1" value="0.2" />
<parameter free="0" max="360" min="-360" name="RA" scale="1" value="166.1138" />
<parameter free="0" max="90" min="-90" name="DEC" scale="1" value="38.2088" />
</spatialModel>