SCORPIO API

Sky COllector of galaxy Pairs and Image Output (Scorpio).

Is a tool to quick generate images of galaxy pairs, using data from different surveys.

scorpio.SURVEYS = {'2MASS': {'default': ['-H', '-K'], 'filters': ['-J', '-H', '-K']}, 'SDSS': {'default': ['g', 'i'], 'filters': ['u', 'g', 'r', 'i', 'z']}, 'WISE': {'default': [' 4.6', ' 12'], 'filters': [' 3.4', ' 4.6', ' 12', ' 22']}}

SURVEYS

scorpio.COSMOLOGY = FlatLambdaCDM(name="Planck18", H0=67.7 km / (Mpc s), Om0=0.31, Tcmb0=2.725 K, Neff=3.05, m_nu=[0.   0.   0.06] eV, Ob0=0.049)

The default cosmology.

scorpio.DOWNLOAD_COORDINATE_SYSTEM = 'J2000'

The default coordinate system.

scorpio.DOWNLOAD_SHOW_PROGRESS = True

If a progress indicator will be showed when a file is downloaded.

scorpio.PLOT_DEFAULT_SIZE = (8, 8)

The default plot size for scorpio

exception scorpio.NoFilterToStackError[source]

Bases: ValueError

Error generated when data of stack galaxies is empty.

exception scorpio.NoSurveyInListToStackError[source]

Bases: ValueError

Error generated when survey of stack galaxies not in our list.

exception scorpio.InvalidCosmologyError[source]

Bases: TypeError

Error generated when cosmology is an invalid astropy cosmology.

class scorpio.GPInteraction(ra1, dec1, z1, ra2, dec2, z2, survey, resolution, cosmology, mtx_, header_, dist_physic_, dist_pix_, pos1_, pos2_)[source]

Bases: object

Representation of two interacting galaxies.

Parameters
  • ra1 (float) – Right ascension of primary galaxy in degrees.

  • dec1 (float) – Declination of primary galaxy in degrees.

  • z1 (float) – Redshift of secondary galaxy.

  • ra2 (float) – Right ascension of secondary galaxy in degrees.

  • dec2 (float) – Declination of secondary galaxy in degrees.

  • z2 (float) – Redshift of secondary galaxy.

  • resolution (int) – Size resolution value in pixels, by default it is 1000.

  • survey (string) – Survey for query and download data, by default it is “SDSS”.

  • filters (list of strings) – Filters for respective survey, by default it is [“g”, “i”] for “SDSS”.

mtx_

The image of the two galaxies interacting.

header_

header information of image fits file.

dist_physic_

Estimation of physical distance to the observer in kpc, from a given cosmology

dist_pix_

Physical distance as pixels in the image.

pos1_

RA, DEC, Z as pixels of the first galaxy.

pos2_

RA, DEC, Z as pixels of the second galaxy.

plot(ax=None, cmap='magma', center_color='cyan', center=True, scale=True, fmt='.4g', llimit=None, heatmap_kws=None, center_kws=None, center_text_kws=None, scalebar_kws=None, scalebar_text_kws=None, scalebar_bg_kws=None)[source]

Receives data from other functions to generate and export a image.

Parameters
  • ax (Axes) – Complete information of the properties to generate the image, by default it is None.

  • cmap (str, optional) – Name of the color map to be used (https://matplotlib.org/users/colormaps.html). If is None, the default colors of the matplotlib.pyplot.plot function is used, and if, and is a callable is used as colormap generator.

  • center_color (str, optional) – The color for the marker of the galaxy centers.

  • center (bool, optional.) – Whether to draw the galaxy center markers.

  • scale (bool, optional.) – Whether to draw the scale bar.

  • fmt (str, optional) – String formatting code to use in the coordinates.

  • llimit (float, optional.) – The lowest value to show in the plot. If some value is <= llimit then it was remplaced with llimit. By default this value is setted as 0.0005 times the maximun value of the image.

  • heatmap_kws (dict or None, optional) – Keyword arguments for seaborn.heatmap(). This routine is the one that draws the image of the interaction.

  • cbar_kws (dict or None, optional) – Keyword arguments for matplotlib.figure.Figure.colorbar().

  • center_kws (dict or None, optional) – Keyword arguments for matplotlib.pyplot.Axes.plot(). This routine is the one that draws the markers for the centers of the two galaxies.

  • center_text_kws (dict or None, optional) – Keyword arguments for matplotlib.pyplot.Axes.text(). This routine is the one that draws the names of the markers of the galactic centers.

  • scalebar_kws (dict or None, optional) – Keyword arguments for matplotlib.pyplot.Axes.hlines(). This routine is what draws the scale bar.

  • scalebar_text_kws (dict or None, optional) – Keyword arguments for matplotlib.pyplot.Axes.text(). This routine is what draws the scale bar text.

  • scalebar_bg_kws (dict or None, optional) – Keyword arguments for matplotlib.pyplot.Axes.broken_barh(). This routine is what draws the scale bar background color.

Returns

The axis where the method draws.

Return type

matplotlib.pyplot.Axis

scorpio.download_data(pos, survey, filters, pxl)[source]

Proxy to astroquery SkyviewService.

This functions is mostly for internal use.

Parameters
  • pos (SkyCoord) – Determines the center of the field to be retrieved.

  • survey (str) – The data to download the survey.

  • filters (list) – Specific astronomical filters of the data.

  • pxl – Selects the pixel dimensions of the image to be produced.

Returns

Return type

A list of ~astropy.io.fits.HDUList objects.

scorpio.stack_pair(ra1, dec1, ra2, dec2, resolution=1000, survey='SDSS', filters=None)[source]

Generate a individual image from RA, DEC data of galaxy pair.

Parameters
  • ra1 (float) – Right ascension of primary galaxy in degrees.

  • dec1 (float) – Declination of primary galaxy in degrees.

  • ra2 (float) – Right ascension of secondary galaxy in degrees.

  • dec2 (float) – Declination of secondary galaxy in degrees.

  • resolution (int) – Size resolution value in pixels, by default it is 1000.

  • survey (string) – Survey for query and download data, by default it is “SDSS”.

  • filters (list of strings) – Filters for respective survey, by default it is [“g”, “i”] for “SDSS”.

Returns

  • g1g2 (array_like) – Array with the stacked information of the galaxies in the survey and the selected filters.

  • header (string) – Header from the primary galaxy .fits file.

scorpio.distances(ra1, dec1, ra2, dec2, z1, z2, header, cosmology=None)[source]

Receives the RA, DEC, redshift parameters for the two galaxies.

As well as header information for the primary galaxy and cosmology within the options provided by Astropy.

Calculate the physical and pixel distances of the two galaxies necessary for their location in the final image.

Parameters
  • ra1 (float) – Right ascension of primary galaxy in degrees.

  • dec1 (float) – Declination of primary galaxy in degrees.

  • z1 (float) – Redshift of secondary galaxy.

  • ra2 (float) – Right ascension of secondary galaxy in degrees.

  • dec2 (float) – Declination of secondary galaxy in degrees.

  • z2 (float) – Redshift of secondary galaxy.

  • header (string) – Header from the primary galaxy .fits file.

  • survey (string) – Survey for query and download data, by default it is “SDSS”.

  • cosmology (optional) – Instance of class astropy.cosmology.FLRW. Defaults to astropy’s default cosmology (Planck18 since v4.2).

Returns

  • dist_physic (float) – physical distance between the pair in kpc.

  • dist_pix (float) – physical distance to pixels in the image.

  • c1, c2 (array_like) – Arrays with coordinates of both galaxies in pixels.

scorpio.gpair(ra1, dec1, ra2, dec2, z1, z2, survey='SDSS', filters=None, resolution=1000, cosmology=None)[source]

Receives the RA, DEC, redshift parameters for the two galaxies.

As well as the resolution in pixels, survey and filters. Returns the necessary characteristics to generate the final image.

Parameters
  • ra1 (float) – Right ascension of primary galaxy in degrees.

  • dec1 (float) – Declination of primary galaxy in degrees.

  • z1 (float) – Redshift of secondary galaxy.

  • ra2 (float) – Right ascension of secondary galaxy in degrees.

  • dec2 (float) – Declination of secondary galaxy in degrees.

  • z2 (float) – Redshift of secondary galaxy.

  • survey (string, optional (default='SDSS')) – Survey for query and download data.

  • filters (list of strings) – Filters for respective survey, by default it is [“g”, “i”] for “SDSS”.

  • resolution (int, optional (default=1000)) – Size resolution value in pixels.

  • cosmology (optional) – Instance of class astropy.cosmology.FLRW. Defaults to astropy’s default cosmology (Planck18 since v4.2).

Returns

An object with information about the two interacting galaxies.

Return type

GPInteraction

Notes

For a complete list of astropy predefined cosmologies see: https://docs.astropy.org/en/latest/cosmology/index.html#built-in-cosmologies