IRSA Dust Extinction Service Queries (astroquery.ipac.irsa.irsa_dust)¶
Getting started¶
This module can be used to query the IRSA Dust Extinction Service.
Fetch images¶
Retrieve the image cut-outs for the specified object name or coordinates. The
images fetched in the FITS format and the result is returned as a list of
HDUList objects. For all image queries, the radius may be optionally
specified. If missing the radius defaults to 5 degrees. Note that radius may be
specified in any appropriate unit, however it must fall in the range of 2 to
37.5 degrees.
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> image_list = IrsaDust.get_images("m81")
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_pdTImE_1525/DUST/m81.v0001/p414Dust.fits
|===========================================| 331k/331k (100.00%) 15s
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_pdTImE_1525/DUST/m81.v0001/p414i100.fits
|===========================================| 331k/331k (100.00%) 13s
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_pdTImE_1525/DUST/m81.v0001/p414temp.fits
|===========================================| 331k/331k (100.00%) 05s
>>> image_list
[[<astropy.io.fits.hdu.image.PrimaryHDU at 0x39b8610>],
[<astropy.io.fits.hdu.image.PrimaryHDU at 0x39b8bd0>],
[<astropy.io.fits.hdu.image.PrimaryHDU at 0x39bd8d0>]]
Image queries return cutouts for 3 images - E(B-V) reddening, 100 micron
intensity, and dust temperature maps. If only the image of a particular type is
required, then this may be specified by using the image_type keyword argument
to the get_images() method. It can take on one of the three values
ebv, 100um and temperature, corresponding to each of the 3 kinds of
images:
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> import astropy.units as u
>>> image = IrsaDust.get_images("m81", image_type="100um", radius=2*u.deg)
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_007Vob_24557/DUST/m81.v0001/p414i100.fits
|===========================================| 149k/149k (100.00%) 02s
>>> image
[[<astropy.io.fits.hdu.image.PrimaryHDU at 0x3a5a650>]]
The image types that are available can also be listed out any time:
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> IrsaDust.list_image_types()
['temperature', 'ebv', '100um']
The target may also be specified via coordinates passed as strings. Examples of acceptable coordinate strings can be found on this IRSA DUST coordinates description page.
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> import astropy.coordinates as coord
>>> import astropy.units as u
>>> image_list = IrsaDust.get_images("17h44m34s -27d59m13s", radius=2.0 * u.deg)
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_46IWzq_9460/DUST/17h44m34s_-27d59m13s.v0001/p118Dust.fits
|==============================| 57k/ 57k (100.00%) 00s
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_46IWzq_9460/DUST/17h44m34s_-27d59m13s.v0001/p118i100.fits
|==============================| 57k/ 57k (100.00%) 00s
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_46IWzq_9460/DUST/17h44m34s_-27d59m13s.v0001/p118temp.fits
|==============================| 57k/ 57k (100.00%) 00s
A list having the download links for the FITS image may also be fetched, rather
than the actual images, via the get_image_list() method. This also
supports the image_type argument, in the same way as described for
get_images().
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> import astropy.coordinates as coord
>>> import astropy.units as u
>>> coo = coord.SkyCoord(34.5565*u.deg, 54.2321*u.deg, frame='galactic')
>>> image_urls = IrsaDust.get_image_list(coo)
>>> image_urls
['http://irsa.ipac.caltech.edu//workspace/TMP_gB3awn_6492/DUST/34.5565_54.2321_gal.v0001/p292Dust.fits',
'http://irsa.ipac.caltech.edu//workspace/TMP_gB3awn_6492/DUST/34.5565_54.2321_gal.v0001/p292i100.fits',
'http://irsa.ipac.caltech.edu//workspace/TMP_gB3awn_6492/DUST/34.5565_54.2321_gal.v0001/p292temp.fits']
Fetching the extinction table¶
This fetches the extinction table as a Table. The input parameters are the same as in
the queries discussed above, namely the target string and optionally a radius
value:
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> import astropy.coordinates as coord
>>> import astropy.units as u
>>> # "22h57m57.5s +26d09m00.09s Equatorial B1950"
>>> coo = coord.SkyCoord("22h57m57.5s +26d09m00.09s", frame='fk4')
>>> table = IrsaDust.get_extinction_table(coo)
Downloading http://irsa.ipac.caltech.edu//workspace/TMP_wuevFn_3781/DUST/345.094229457703_26.418650782801027.v0001/extinction.tbl
|=======================================================================================| 4.4k/4.4k (100.00%) 0s
>>> print(table)
Filter_name LamEff A_over_E_B_V_SandF A_SandF A_over_E_B_V_SFD A_SFD
micron mag mag
----------- ------ ------------------ ------- ---------------- -----
CTIO U 0.3734 4.107 0.174 4.968 0.21
CTIO B 0.4309 3.641 0.154 4.325 0.183
CTIO V 0.5517 2.682 0.113 3.24 0.137
CTIO R 0.652 2.119 0.09 2.634 0.111
CTIO I 0.8007 1.516 0.064 1.962 0.083
DSS-II g 0.4621 3.381 0.143 3.907 0.165
DSS-II r 0.6546 2.088 0.088 2.649 0.112
DSS-II i 0.8111 1.487 0.063 1.893 0.08
SDSS u 0.3587 4.239 0.179 5.155 0.218
SDSS g 0.4717 3.303 0.14 3.793 0.16
... ... ... ... ... ...
UKIRT K 2.19 0.302 0.013 0.367 0.016
2MASS J 1.23 0.723 0.031 0.937 0.04
2MASS H 1.64 0.46 0.019 0.591 0.025
2MASS Ks 2.16 0.31 0.013 0.382 0.016
IRAC-1 3.52 0.178 0.008 0.22 0.009
IRAC-2 4.46 0.148 0.006 0.183 0.008
IRAC-3 5.66 0.13 0.005 0.162 0.007
IRAC-4 7.68 0.122 0.005 0.151 0.006
WISE-1 3.32 0.189 0.008 0.234 0.01
WISE-2 4.57 0.146 0.006 0.18 0.008
Length = 25 rows
Get other query details¶
This fetches in a Table other additional details that may be
returned in the query results. For instance additional details in the three
sections - ebv, 100um and temperature as mentioned earlier and an
additional section location may be fetched using the section keyword
argument. If on the other hand, section is missing then the complete table
with all the four sections will be returned.
>>> from astroquery.ipac.irsa.irsa_dust import IrsaDust
>>> table = IrsaDust.get_query_table('2MASXJ23045666+1219223') # get the whole table
>>> print(table)
RA Dec coord sys regSize ... temp mean temp std temp max temp min
deg deg deg ...
--------- -------- --------- ------- ... --------- -------- -------- --------
346.23608 12.32286 equ J2000 5.0 ... 17.0721 0.0345 17.1189 17.0152
>>> table_ebv = IrsaDust.get_query_table('2MASXJ23045666+1219223', section='ebv') # get only one section
>>> print(table_ebv)
ext desc ... ext SFD min
...
---------------- ... -----------
E(B-V) Reddening ... 0.1099
Reference/API¶
astroquery.ipac.irsa.irsa_dust Package¶
IRSA Galactic Dust Reddening and Extinction Query Tool¶
Revision History
Refactored using common API as a part of Google Summer of Code 2013.
- Originally contributed by
David Shiga (dshiga.dev@gmail.com)
Classes¶
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Configuration parameters for |