Change alpha_ox to det_alpha_ox, to use the empirical alpha_ox-L_2500 relation (not completed)

pcigale/sed_modules/xray.py

@@ -33,11 +33,14 @@ class Xray(SedModule):
             "The photon index (Gamma) of intrinsic X-ray spectrum.",
             1.6
         )),
-        ("alpha_ox", (
+        ("det_alpha_ox", (
             "cigale_list()",
-            "Power-law slope connecting L_nu at rest-frame 2500 A and 2 keV. "
-            "Defined as alpha_ox=0.3838*log(Lnu_2keV/Lnu_2500A)",
-            -1.5
+            "Deviation of alpha_ox from the empirical alpha_ox(Lnu_2500A) relation (Just et al. 2007),",
+            "defined as det_alpha_ox = alpha_ox - alpha_ox(Lnu_2500A).",
+            "Common (~3sigma) range of det_alpha_ox is [-0.3, 0.3]",
+            "Note: alpha_ox is the power-law slope connecting L_nu at rest-frame 2500 A and 2 keV, ",
+            "defined as alpha_ox = 0.3838*log(Lnu_2keV/Lnu_2500A)",
+            0.0
         ))
     ])
 
@@ -45,7 +48,7 @@ class Xray(SedModule):
         """Build the model for a given set of parameters."""
 
         self.gam = float(self.parameters["gam"])
-        self.alpha_ox = float(self.parameters["alpha_ox"])
+        self.det_alpha_ox = float(self.parameters["det_alpha_ox"])
 
         # We define various constants necessary to compute the model. For
         # consistency, we define speed of light in units of nm s¯¹
@@ -102,15 +105,17 @@ class Xray(SedModule):
         logT = np.log10( sed.info['stellar.age_m_star']/1e3 )
         # metallicity, units: none
         Z = sed.info['stellar.metallicity']
-        # AGN 2500A intrinsic luminosity
+        # Raise an error when Fritz's AGN module is not used
         if 'agn.agn_intrin_Lnu_2500A' not in sed.info:
-            sed.add_info('agn.agn_intrin_Lnu_2500A', 1., True)
+            raise Exception("Fritz's AGN module must be used before X-ray module")
         Lnu_2500A = sed.info['agn.agn_intrin_Lnu_2500A']
 
         # Add the configuration for X-ray module
         sed.add_module(self.name, self.parameters)
         sed.add_info("xray.gam", self.gam)
-        sed.add_info("xray.alpha_ox", self.alpha_ox)
+        sed.add_info("xray.det_alpha_ox", self.det_alpha_ox)
+
+        # Convert det_alpha_ox to alpha_ox
 
         # Calculate 0.5-2 keV hot-gas luminosities
         # Mezcua et al. 2018, Eq. 5