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import numpy as np
+import pandas as pd
+import matplotlib.pyplot as plt
+%matplotlib inline
+from matplotlib.patches import Polygon
+
+from astropy.table import Table
+
+
+
+
+
+

Plotting Functions¶

+
+

Upper left¶

+
+
+
def plot_first_selection(df):
+    """Plot spatial distribution of stars selected based on Proper Motion
+    
+    df: Tale or DataFrame with proper motion selected coordinates in GD-1 reference frame
+    """
+    x = df['phi1']
+    y = df['phi2']
+
+    plt.plot(x, y, 'ko', markersize=0.3, alpha=0.3)
+
+    plt.xlabel('$\phi_1$ [deg]')
+    plt.ylabel('$\phi_2$ [deg]')
+    plt.title('Proper motion selection', fontsize='medium')
+
+    plt.axis('equal')
+
+
+
+
+
+
+
filename_pm_selected = 'gd1_candidates.hdf5'
+candidate_df = pd.read_hdf(filename_pm_selected, 'candidate_df')
+plot_first_selection(candidate_df)
+
+
+
+
+../_images/lesson_7_4_0.png +
+
+
+
+

Upper right¶

+
+
+
def plot_proper_motion(df):
+    """Plot proper motion of spatially selected stars in GD-1
+    
+    df: Table or DataFrame with spatially selected proper motions in GD-1 reference frame
+    """
+    pm1 = df['pm_phi1']
+    pm2 = df['pm_phi2']
+
+    plt.plot(pm1, pm2, 'ko', markersize=0.3, alpha=0.3)
+    
+    poly = Polygon(vertices, closed=True, 
+                   facecolor='C1', alpha=0.4)
+    plt.gca().add_patch(poly)
+    
+    plt.xlabel('$\mu_{\phi_1} [\mathrm{mas~yr}^{-1}]$')
+    plt.ylabel('$\mu_{\phi_2} [\mathrm{mas~yr}^{-1}]$')
+
+    plt.xlim(-12, 8)
+    plt.ylim(-10, 10)
+
+
+
+
+
+
+
pm1_min = -8.9
+pm1_max = -6.9
+pm2_min = -2.2
+pm2_max =  1.0
+
+pm1_rect = [pm1_min, pm1_min, pm1_max, pm1_max]
+pm2_rect = [pm2_min, pm2_max, pm2_max, pm2_min]
+
+
+
+
+
+
+
vertices = np.transpose([pm1_rect, pm2_rect])
+
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+
+
filename_pm = 'gd1_dataframe.hdf5'
+centerline = pd.read_hdf(filename_pm, 'centerline')
+plot_proper_motion(centerline)
+
+
+
+
+../_images/lesson_7_9_0.png +
+
+
+
+

Lower left¶

+
+
+
def plot_second_selection(df):
+    """Plot spatial distribution of photometry selected points
+    
+    df: Table or DataFrame with photometry selected positions in GD1 reference frame
+    """
+    x = df['phi1']
+    y = df['phi2']
+
+    plt.plot(x, y, 'ko', markersize=0.7, alpha=0.9)
+
+    plt.xlabel('$\phi_1$ [deg]')
+    plt.ylabel('$\phi_2$ [deg]')
+    plt.title('Proper motion + photometry selection', fontsize='medium')
+
+    plt.axis('equal')
+
+
+
+
+
+
+
filename = 'gd1_merged.hdf5'
+selected = pd.read_hdf(filename, 'selected')
+plot_second_selection(selected)
+
+
+
+
+../_images/lesson_7_12_0.png +
+
+
+
+

Lower right¶

+
+
+
def plot_cmd(table):
+    """Plot a color magnitude diagram.
+    
+    table: Table or DataFrame with photometry data
+    """
+    y = table['g_mean_psf_mag']
+    x = table['g_mean_psf_mag'] - table['i_mean_psf_mag']
+
+    plt.plot(x, y, 'ko', markersize=0.3, alpha=0.3)
+
+    plt.xlim([0, 1.5])
+    plt.ylim([14, 22])
+    plt.gca().invert_yaxis()
+
+    plt.ylabel('$g_0$')
+    plt.xlabel('$(g-i)_0$')
+
+
+
+
+
+
+
filename_poly = 'gd1_polygon.hdf5'
+coords_df = pd.read_hdf(filename_poly, 'coords_df')
+coords = coords_df.to_numpy()
+
+
+
+
+
+
+
merged = pd.read_hdf(filename, 'merged')
+plot_cmd(merged)
+
+
+
+
+../_images/lesson_7_16_0.png +
+
+
+
+ + + + +
+ +
+
+ + +
+ + +
+
+
+

+ + By Allen B. Downey
+ + © Copyright 2020.
+

+
+
+