.. _book_fig_chapter1_fig_SDSS_specgals:


SDSS Spectroscopic Galaxy Sample
--------------------------------
Figure 1.3.

The r vs. u-r color-magnitude diagram for the first 10,000 entries in the
catalog of spectroscopically observed galaxies from the Sloan Digital Sky
Survey (SDSS). Note two "clouds" of points with different morphologies
separated by u-r ~ 2.3. The abrupt decrease of the point density for
r > 17.7 (the bottom of the diagram) is due to the selection function for
the spectroscopic galaxy sample from SDSS. This example shows how to fetch
photometric data from the SDSS spectroscopic sample and plot a simple
color-magnitude diagram.



.. image:: ../images/chapter1/fig_SDSS_specgals_1.png
    :scale: 100
    :align: center


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