title: Plot vertical arrows for my points
body: <p>I am trying to figure out a way to add a vertical arrow pointing up for each of my data points. I have scatter plot and code below. I need the vertical arrows to start from the points going upwards to a length of about 0.2 in th graph scale. </p>
  
  <pre><code>import matplotlib.pyplot as plt
  fig = plt.figure()
  a1 = fig.add_subplot(111)
  
  simbh = np.array([5.3,  5.3,  5.5,  5.6,  5.6,  5.8,  5.9,  6.0,   6.2,  6.3,  6.3])
  simstel =np.array([10.02, 10.08, 9.64, 9.53, 9.78, 9.65, 10.05, 10.09, 10.08, 10.22, 10.42])
  sca2=a1.scatter(simstel, simbh )
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/vJs6F.png" alt="enter image description here"></p>