Sample Selection Tutorial¶

Select Main Sample Galaxies¶

To select the Main Sample galaxies (Primary + Secondary + Color Enhanced samples), we need to download the MPL-5 DRPall file and put it in the expected directory $SAS_BASE_DIR/mangawork/manga/spectro/redux/v2_0_1/. For more information on the location of your $SAS_BASE_DIR environment variable, see the Getting Started page.

Let’s open the DRPall file:

import os
from astropy.io import fits
from marvin import config

config.setRelease('MPL-5')
drpver, __ = config.lookUpVersions()

drpall_path = os.path.join(os.environ['SAS_BASE_DIR'], 'mangawork', 'manga', 'spectro', 'redux',
                           drpver, 'drpall-{}.fits'.format(drpver))
drpall = fits.open(drpall_path)
data = drpall[1].data

The Main Sample consists of the Primary, Secondary, and Color-Enhanced Samples, which correspond to MNGTARG1 bits 10, 11, and 12, respectively.

import numpy as np
primary        = data['mngtarg1'] & 2**10                                 # 1278 galaxies
secondary      = data['mngtarg1'] & 2**11                                 #  947 galaxies
color_enhanced = data['mngtarg1'] & 2**12                                 #  447 galaxies

main_sample = np.logical_or.reduce((primary, secondary, color_enhanced))  # 2672 galaxies

plateifus = data['plateifu'][main_sample]

Now we can use the downloadList() function to download all of the files of type map (other valid dltypes: map, image, rss, mastar, default, or plate).

from marvin.utils.general import downloadList
downloadList(plateifus, dltype='map')