CALIFA, the Calar Alto Legacy Integral Field Area survey. III. Second
  public data release
  This paper describes the Second Public Data Release (DR2) of the Calar Alto
Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made
public, including the 100 galaxies of the First Public Data Release (DR1). Data
were obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5
m telescope at the Calar Alto observatory. Two different spectral setups are
available for each galaxy, (i) a low-resolution V500 setup covering the
wavelength range 3745-7500 \AA\ with a spectral resolution of 6.0 \AA\ (FWHM),
and (ii) a medium-resolution V1200 setup covering the wavelength range
3650-4840 \AA\ with a spectral resolution of 2.3 \AA\ (FWHM). The sample covers
a redshift range between 0.005 and 0.03, with a wide range of properties in the
Color-Magnitude diagram, stellar mass, ionization conditions, and morphological
types. All released cubes were reduced with the latest pipeline, including
improved spectrophotometric calibration, spatial registration and spatial
resolution. The spectrophotometric calibration is better than 6% and the median
spatial resolution is 2.5". Altogether the second data release contains over
1.5 million spectra. It is available at http://califa.caha.es/DR2.
