.. _astroquery.irsa_dust: ************************************************************* IRSA Dust Extinction Service Queries (`astroquery.irsa_dust`) ************************************************************* Getting started =============== This module can be used to query IRSA dust extinction service. **Fetch images** Retrieve the image cut-outs for the specified oject name or coordinates. The images fetched in the FITS format and the result is returned as a list of `astropy.io.fits`_ 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. .. code-block:: python >>> from astroquery.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 [[], [], []] 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 :meth:`~astroquery.irsa_dust.core.IrsaDust.get_images` method. It can take on one of the three values `ebv`, `100um` and `extinction`, corresponding to each of the 3 kinds of images: .. code-block:: python >>> from astroquery.irsa_dust import IrsaDust >>> import astropy.units as u >>> image = IrsaDust.get_images("m81", image_type="100um", ... radius=200*u.arcmin) Downloading http://irsa.ipac.caltech.edu//workspace/TMP_007Vob_24557/DUST/m81.v0001/p414i100.fits |===========================================| 149k/149k (100.00%) 02s >>> image [[]] The image types that are available can also be listed out any time: .. code-block:: python >>> from astroquery.irsa_dust import IrsaDust >>> IrsaDust.list_image_types() ['ebv', 'extinction', '100um'] Rather than specifying the name, the target may also be specified via coordinates passed as strings. Examples of acceptable coordinate strings, can be found on this `IRSA Dust Extinction Service page`_. .. code-block:: python >>> from astroquery.irsa_dust import IrsaDust >>> import astropy.coordinates as coord >>> import astropy.units as u >>> image_list = IrsaDust.get_images("17h44m34s -27d59m13s", radius=5 * u.deg) Downloading http://irsa.ipac.caltech.edu//workspace/TMP_07raMc_4877/DUST/17h44m34s_-27d59m13s.v0001/p118Dust.fits |===========================================| 331k/331k (100.00%) 05s Downloading http://irsa.ipac.caltech.edu//workspace/TMP_07raMc_4877/DUST/17h44m34s_-27d59m13s.v0001/p118i100.fits |===========================================| 331k/331k (100.00%) 04s Downloading http://irsa.ipac.caltech.edu//workspace/TMP_07raMc_4877/DUST/17h44m34s_-27d59m13s.v0001/p118temp.fits |===========================================| 331k/331k (100.00%) 04s A list having the download links for the FITS image may also be fetched, rather than the actual images, via the :meth:`~astroquery.irsa_dust.core.IrsaDust.get_image_list` method. This also supports the `image_type` argument, in the same way as described for :meth:`~astroquery.irsa_dust.core.IrsaDust.get_images`. .. code-block:: python >>> from astroquery.irsa_dust import IrsaDust >>> image_urls = IrsaDust.get_image_list("34.5565 54.2321 gal") >>> 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 an `astropy.table.Table`_ . The input parameters are the same as in the queries discussed above, namely the target string and optionally a radius value: .. code-block:: python >>> from astroquery.irsa_dust import IrsaDust >>> table = IrsaDust.get_extinction_table("22h57m57.5s +26d09m00.09s Equatorial B1950") Downloading http://irsa.ipac.caltech.edu//workspace/TMP_UkhZqQ_9824/DUST/22h57m57.5s_+26d09m00.09s_Equatorial_B1950.v0001/extinction.tbl |===========================================| 1.3k/1.3k (100.00%) 00s >>> print(table) Filter_name LamEff(A) A/Av A/E(B-V) A(mag) ----------- --------- ----- -------- ------ CTIO U 0.3683 1.521 4.968 0.21 CTIO B 0.4393 1.324 4.325 0.183 DSS-II g 0.4814 1.197 3.907 0.165 CTIO V 0.5519 0.992 3.24 0.137 DSS-II r 0.6571 0.811 2.649 0.112 CTIO R 0.6602 0.807 2.634 0.111 CTIO I 0.8046 0.601 1.962 0.083 DSS-II i 0.8183 0.58 1.893 0.08 UKIRT J 1.266 0.276 0.902 0.038 UKIRT H 1.6732 0.176 0.576 0.024 UKIRT K 2.2152 0.112 0.367 0.016 IRAC-1 3.6 0.06 0.197 0.008 IRAC-2 4.5 0.055 0.18 0.008 IRAC-3 5.8 0.05 0.164 0.007 IRAC-4 8.0 0.045 0.148 0.006 **Get other query details** This fetches in a `astropy.table.Table`_ other additional details that may be returned in the query results. For instance additional details in the three sections - `ebv`, `100um` and `extinction` 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. .. code-block:: python >>> from astroquery.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 --------- -------- --------- ------- ... --------- -------- -------- -------- 346.23608 12.32286 equ J2000 5.0 ... 17.0721 0.0345 17.1189 17.0152 # fetch only one section of the table >>> table = IrsaDust.get_query_table('2MASXJ23045666+1219223', ... section='ebv') >>> print(table) ext desc ... ext min ---------------- ... ------- E(B-V) Reddening ... 0.1099 Reference/API ============= .. automodapi:: astroquery.irsa_dust :no-inheritance-diagram: .. _IRSA Dust Extinction Service page: http://irsa.ipac.caltech.edu/applications/DUST/docs/coordinate.html .. _astropy.table.Table: http://docs.astropy.org/en/latest/table/index.html .. _astropy.io.fits: http://docs.astropy.org/en/latest/io/fits/index.html