add another simple SFH (constant uniform disc)

Author: TomWagg

cogsworth/sfh.py

@@ -459,6 +459,17 @@ def get_metallicity(self):
         return np.repeat(self.Z_all, self.size) * u.dimensionless_unscaled
 
 
+class ConstantUniformDisc(BurstUniformDisc):
+    """A simple star formation history, with all stars formed at a constant rate between ``t_burst`` 
+    and the present day in a uniform disc with height ``z_max`` and radius ``R_max`` disc, all with
+    metallicity ``Z``.
+
+    Based on :class:`BurstUniformDisc`.
+    """
+    def draw_lookback_times(self, size=None, component=None):
+        return np.random.uniform(0, self.t_burst.value, size) * self.t_burst.unit
+
+
 class Wagg2022(StarFormationHistory):
     """A semi-empirical model defined in
     `Wagg+2022 <https://ui.adsabs.harvard.edu/abs/2021arXiv211113704W/abstract>`_

cogsworth/tests/test_sfh.py

@@ -58,6 +58,18 @@ def test_burst_uniform_disc(self):
         self.assertTrue(np.all(g.rho <= 20 * u.kpc))
         self.assertTrue(np.all(g.Z == 0.02))
 
+    def test_constant_uniform_disc(self):
+        """Ensure the constant uniform disc class works"""
+        g = sfh.ConstantUniformDisc(size=10000,
+                                    t_burst=5 * u.Gyr,
+                                    R_max=20 * u.kpc,
+                                    z_max=1 * u.kpc,
+                                    Z=0.02)
+        self.assertTrue(np.all(g.tau <= 5 * u.Gyr))
+        self.assertTrue(np.all(g.z <= 1 * u.kpc))
+        self.assertTrue(np.all(g.rho <= 20 * u.kpc))
+        self.assertTrue(np.all(g.Z == 0.02))
+
     def test_bad_inputs(self):
         """Ensure the classes fail with bad input"""
         g = sfh.Wagg2022(size=None, immediately_sample=False)