Catalogue mixins¶

In addition to the raw data, Marvin provides additional catalogue information about the object via several attributes that are available for most Tools classes.

DRPall / NSA¶

Data from the NASA Sloan Atlas can be accessed for each Cube, RSS, Maps, and ModelCube object via the nsa attribute. The feature is implemented as part of the NSAMixIn class. For example:

>>> my_cube = Cube('8485-1901', mode='remote')
>>> my_cube.nsa
{'iauname': 'J153010.73+484124.8',
'subdir': '15h/p48/J153010.73+484124.8',
'ra': 232.544703894,
'dec': 48.6902009334,
'isdss': 225926,
'ined': 167868,
'isixdf': -1,
'ialfalfa': -1,
'izcat': 373580,
'itwodf': -1,
'mag': 17.3247,
'z': 0.0407447,
'zsrc': 'sdss   ',
'size': 0.07,
...

How much NSA information is available depends on the mode in which the object was created. If you instantiated the Tools object from a file, Marvin will try to use the local DRPall file, which contains only a subset of the NSA data. If loaded remotely, Marvin will make an API call to retrieve the full NSA information from the server. You can change this behaviour during instantiation by setting the nsa_source attribute from 'drpall' to 'nsa'

>>> my_cube_from_file = Cube('path/to/file/manga-8485-1901-LOGCUBE.fits.gz', nsa_source='nsa')

DAPall¶

The DAPall file contains galaxy-summed, derived information from the Data Analysis Pipeline, such as total fluxes, SFR, etc. Similarly to the NSA data, it can be accessed from Maps and ModelCube objects via the dapall attribute in the DAPallMixIn

>>> maps.dapall
{'plate': 8485,
 'ifudesign': 1901,
 'plateifu': '8485-1901',
 'mangaid': '1-209232',
 'drpallindx': 3505,
 'mode': 'CUBE',
 'daptype': 'SPX-GAU-MILESHC',
 'dapdone': 'true',
 'objra': 232.545,
 'objdec': 48.6902,
 'ifura': 232.545,
 'ifudec': 48.6902,
 ...}

Value-Added Catalogs (VACS)¶

While the core of SDSS data releases centers around its base projects’ science deliverables, smaller teams frequently contribute added value to its core deliverables with additional science products. These value-added data products or catalogs (VACS) are derived data products based on the core deliverables that are vetted, hosted, and released by SDSS in order to maximize the impact of SDSS data sets.

Marvin provides access to any VACs that have been contributed into Marvin’s framework. To contribute a MaNGA VAC to Marvin, see how to contribute. Marvin collects all contributed VACs for a given release and places them inside a VACContainer object. This container is available as a vacs attribute on most Marvin Tools relevant to that VAC.

# load a MaNGA cube and access any VAC information for 8485-1901
from marvin.tools import Cube
cube = Cube('8485-1901')
cube.vacs  #  prints <VACContainer ('mangahi')>

# it is also available from a Maps object
maps = cube.getMaps()
m.vacs  #  prints <VACContainer ('mangahi')>

The VACContainer will list the names of all available VACS for the current release. These names are dottable attributes on the class. For example, the MaNGA DR15 release contains the MaNGA-HI VAC, which has been integrated into Marvin. It is available as mangahi.

# access the MaNGA-HI VAC
hi = cube.vacs.mangahi
print(hi)  #  prints HI(8485-1901)
print(hi.data)  #  prints 'No HI data exists for 8485-1901'

Each VAC is different and thus may return entirely different data structures, depending on how that VAC was integrated into Marvin. It may return e.g. a single number, dict, class instance, or FITS record. VAC integrations can be arbitrarily simple or complex. Note also that not all VACs will be available for every MaNGA release, and not all targets will have VAC information available, as indicated in the above example. Let’s try a different galaxy

cube = Cube('7443-12701')
hi = cube.vacs.mangahi
print(hi)  ## prints HI(7443-12701)
print(hi.data)

#  prints
#  FITS_rec([('7443-12701', '12-98126', 230.5074624, 43.53234133, 6139, '16A-14', 767.4, 1.76, 8.82, -999., -999., -999., -999., -999, -999., -999, -999, -999, -999, -999, -999., -999., -999., -999., -999., -999.)],
#  dtype=(numpy.record, [('plateifu', 'S10'), ('mangaid', 'S9'), ('objra', '>f8'), ('objdec', '>f8'), ('vopt', '>i2'), ('session', 'S12'), ('Exp', '>f4'), ('rms', '>f4'), ('logHIlim200kms', '>f4'), ('peak', '>f4'), ('snr', '>f4'), ('FHI', '>f4'), ('logMHI', '>f4'), ('VHI', '>i2'), ('eV', '>f4'), ('WM50', '>i2'), ('WP50', '>i2'), ('WP20', '>i2'), ('W2P50', '>i2'), ('WF50', '>i2'), ('Pr', '>f4'), ('Pl', '>f4'), ('ar', '>f4'), ('br', '>f4'), ('al', '>f4'), ('bl', '>f4')]))

This galaxy has HI data. This VAC has also provided two convenience methods for quickly interacting with HI data, plot_spectrum, and plot_massfraction.

# plot the HI spectrum for 7443-12701
hi.plot_spectrum()

(Source code)

Reference¶

Classes¶

`marvin.tools.mixins.nsa.NSAMixIn`([nsa_source])	A mixin that provides access to NSA paremeters.
`marvin.tools.mixins.dapall.DAPallMixIn`	A mixin that provides access to DAPall paremeters.

Available VACS¶

marvin.contrib.vacs.mangahi.HIVAC() Provides access to the MaNGA-HI VAC.