Cutouts¶

Everything related to cutouts is documented bellow:

hostphot.cutouts.check_existing_images(name, filters, survey)¶

Checks if images exist for the given filters+survey combination, for the given object.

Parameters:

name (str) – Name of the object.
filters (str or list) – Filters to use.
survey (str) – Survey name.

Returns:

filters_without_image – Filters without images.

Return type:

list

hostphot.cutouts.download_images(name, ra, dec, size=3, filters=None, overwrite=True, survey='PS1', version=None)¶

Download images for a given object in the given filters of a given survey.

The surveys that use the version parameter are: GALEX (AIS, MIS, DIS, NGS and GII), unWISE (allwise and neo{i} for {i}=1-7), VISTA (VHS, VIDEO and VIKING) and SDSS (dr{i} for {i}=12-17).

Parameters:

name (str) – Name used for tracking the object in your local directory.
ra (float) – Right ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters for the images.
overwrite (bool, default True) – If True, the images are overwritten if they already exist.
survey (str, default PS1) – Survey used to download the images.
version (str, default None) – Version used by some surveys including multiple surveys. E.g. VHS for VISTA.

Examples

>>> from hostphot.cutouts import download_images
>>> name = 'SN2004eo'
>>> host_ra, host_dec = 308.2092, 9.92755  # coords of host galaxy of SN2004eo
>>> survey = 'PS1'
>>> download_images(name, host_ra, host_dec, survey=survey)

hostphot.cutouts.get_2MASS_images(ra, dec, size=3, filters=None)¶

Downloads a set of 2MASS fits images for a given set of coordinates and filters.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses FUV, NUV.

Returns:

hdu_list – List with fits images for the given filters. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_DES_images(ra, dec, size=3, filters=None)¶

Gets DES fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses grizY.

Returns:

hdu_list – List of fits images.

Return type:

list

hostphot.cutouts.get_DES_urls(ra, dec, fov, filters='grizY')¶

Obtains the URLs of the DES images+weights with the largest exposure times in the given filters.

Parameters:

ra (float) – Right ascension in degrees.
dec (float) – Declination in degrees.
fov (float) – Field of view in degrees.
filters (str, default None) – Filters to use. If None, uses grizY.

Returns:

url_list (list) – List of URLs with DES images.
url_w_list (list) – List of URLs with DES images weights.

hostphot.cutouts.get_GALEX_images(ra, dec, size=3, filters=None, version=None)¶

Downloads a set of GALEX fits images for a given set of coordinates and filters.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses FUV, NUV.
version (str, default None) – Version of GALEX images. Either Deep (DIS), Medium (MIS) or All-Sky Imaging Survey (AIS), or Nearby Galaxy Survey (NGS) or Guest Investigator Survey (GII). If None, take the image with the longest exposure time.

Returns:

hdu_list – List with fits images for the given filters. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_HST_images(ra, dec, size=3, filt=None)¶

Downloads a set of HST fits images for a given set of coordinates and filters using the MAST archive.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filt (str, default None) – Filter to use, e.g. WFC3_UVIS_F225W.

Returns:

hdu_list – List with fits image for the given filter. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_LegacySurvey_images(ra, dec, size=3, filters=None, version='dr10')¶

Gets Legacy Survey fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses grz.
version (str, default dr10) – Data release version. E.g. dr10, dr9, dr8, etc..

Returns:

fits_files – List of fits images.

Return type:

list

hostphot.cutouts.get_PS1_images(ra, dec, size=3, filters=None)¶

Gets PS1 fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses grizy.

Returns:

fits_files – List of fits images.

Return type:

list

hostphot.cutouts.get_PS1_urls(ra, dec, size=3, filters=None)¶

Get URLs for images obtained with query_ps1().

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses grizy.

Returns:

url_list – List of URLs for the fits images.

Return type:

list

hostphot.cutouts.get_SDSS_images(ra, dec, size=3, filters=None, version=None)¶

Downloads a set of SDSS fits images for a given set of coordinates and filters using SkyView.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses ugriz.
version (str, default None) – Data release version to use. If not given, use the latest one (dr17).

Returns:

hdu_list – List with fits images for the given filters. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_SPLUS_images(ra, dec, size=3, filters=None)¶

Gets S-Plus fits images for the given coordinates and filters.

The available filters are: ‘F378’, ‘F395’, ‘F410’, ‘F430’, ‘F515’, ‘F660’, ‘F861’, ‘G’, ‘I’, ‘R’, ‘U’, ‘Z’.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses all available filters.

Returns:

hdu_list – List of fits images.

Return type:

list

hostphot.cutouts.get_SPlus_urls(ra, dec, fov, filters=None)¶

Obtains the URLs of the S-Plus images.

The available filters are: ‘F378’, ‘F395’, ‘F410’, ‘F430’, ‘F515’, ‘F660’, ‘F861’, ‘G’, ‘I’, ‘R’, ‘U’, ‘Z’.

Parameters:

ra (float) – Right ascension in degrees.
dec (float) – Declination in degrees.
fov (float) – Field of view in degrees.
filters (str, default None) – Filters to use. If None, uses all available filters.

Returns:

url_list – List of URLs with S-Plus images.

Return type:

list

hostphot.cutouts.get_SkyMapper_images(ra, dec, size=3, filters=None)¶

Gets SkyMapper fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses uvgriz.

Returns:

hdu_list – List of fits images.

Return type:

list

hostphot.cutouts.get_SkyMapper_urls(ra, dec, fov, filters='uvgriz')¶

Obtains the URLs of the SkyMapper images.

The images closest to the given coordinates are retrieved

Parameters:

ra (float) – Right ascension in degrees.
dec (float) – Declination in degrees.
fov (float) – Field of view in degrees.
filters (str, default None) – Filters to use. If None, uses uvgriz.

Returns:

url_list – List of URLs with SkyMapper images.

Return type:

list

hostphot.cutouts.get_Spitzer_images(ra, dec, size=3, filters=None)¶

Gets Spitzer fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses IRAC.1, IRAC.2, IRAC.3, IRAC.4, MIPS.1.

Returns:

fits_files – List of fits images.

Return type:

list

hostphot.cutouts.get_UKIDSS_images(ra, dec, size=3, filters='ZYJHK')¶

Gets UKIDSS fits images for the given coordinates and filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses ZYJHK.

Returns:

fits_files – List of fits images.

Return type:

list

hostphot.cutouts.get_VISTA_images(ra, dec, size=3, filters=None, version='VHS')¶

Gets VISTA fits images for the given coordinates and filters.

Note: the different surveys included in VISTA cover different parts of the sky and do not necessarily contain the same filters.

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses Z, Y, J, H, Ks.
version (str, default VHS) – Survey to use: VHS, VIDEO or VIKING.

Returns:

fits_files – List of fits images.

Return type:

list

hostphot.cutouts.get_WISE_images(ra, dec, size=3, filters=None)¶

Downloads a set of WISE fits images for a given set of coordinates and filters.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses all WISE filters.

Returns:

hdu_list – List with fits images for the given filters. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_unWISE_images(ra, dec, size=3, filters=None, version='allwise')¶

Downloads a set of unWISE fits images for a given set of coordinates and filters.

Parameters:

ra (str or float) – Right ascension in degrees.
dec (str or float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses all WISE filters.
version (str, default allwise) – Version of the unWISE images. Either allwise or neo{i} for {i} = 1 to 7.

Returns:

hdu_list – List with fits images for the given filters. None is returned if no image is found.

Return type:

list

hostphot.cutouts.get_used_image(header)¶

Obtains the name of the image downloaded by SkyView.

Parameters:: header (fits header) – Header of an image.
Returns:: used_image – Name of the image.
Return type:: str

hostphot.cutouts.match_wcs(fits_files)¶

Matches the WCS of all the images, taking the first ones as a reference.

Parameters:: fits_files (list) – List of fits files.
Returns:: matched_fits_files – List of fits files with matched WCS.
Return type:: list

hostphot.cutouts.query_ps1(ra, dec, size=3, filters=None)¶

Query ps1filenames.py service to get a list of images

Parameters:

ra (float) – Right Ascension in degrees.
dec (float) – Declination in degrees.
size (float or ~astropy.units.Quantity, default 3) – Image size. If a float is given, the units are assumed to be arcmin.
filters (str, default None) – Filters to use. If None, uses grizy.

Returns:

table – Astropy table with the results.

Return type:

astropy Table

hostphot.cutouts.set_HST_image(file, filt, name)¶

Moves a previously downloaded HST image into the work directory.

The image’s header is updated with the necessary keywords to obtain photometry and is also moved under the objects directory inside the work directory.

HST images take very long to download, so the user might prefer to download the images manually and then use this function to include the image into the workflow.

Parameters:

file (str) – HST image to use.
filt (str) – HST filter, e.g. WFC3_UVIS_F275W.
name (str) – Object’s name.

hostphot.cutouts.update_HST_header(hdu)¶

Updates the HST image header with the necessary keywords.

Parameters:: hdu (Header Data Unit.) – HST FITS image.