.. _astroquery.ipac.irsa: ************************************* IRSA Queries (`astroquery.ipac.irsa`) ************************************* Getting started =============== This module can has methods to perform different types of queries on the catalogs present in the IRSA general catalog service. All queries can be performed by calling :meth:`~astroquery.ipac.irsa.IrsaClass.query_region`, with different keyword arguments. There are 4 different region queries that are supported: ``Cone``, ``Box``, ``Polygon`` and ``All-Sky``. All successful queries return the results in a `~astropy.table.Table`. We now look at some examples. Available catalogs ------------------ All region queries require a ``catalog`` keyword argument, which is the name of the catalog in the IRSA database, on which the query must be performed. To take a look at all the available catalogs: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> Irsa.list_catalogs() # doctest: +IGNORE_OUTPUT {'a1763t2': 'Abell 1763 Source Catalog', 'a1763t3': 'Abell 1763 MIPS 70 micron Catalog', 'acs_iphot_sep07': 'COSMOS ACS I-band photometry catalog September 2007', 'akari_fis': 'Akari/FIS Bright Source Catalogue', 'akari_irc': 'Akari/IRC Point Source Catalogue', 'astsight': 'IRAS Minor Planet Survey', ... ... 'xmm_cat_s05': "SWIRE XMM_LSS Region Spring '05 Spitzer Catalog"} This returns a dictionary of catalog names with their description. If you would rather just print out this information: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> Irsa.print_catalogs() allwise_p3as_psd AllWISE Source Catalog allwise_p3as_mep AllWISE Multiepoch Photometry Table allwise_p3as_psr AllWISE Reject Table ... wisegalhii WISE Catalog of Galactic HII Regions v2.2 denis3 DENIS 3rd Release (Sep. 2005) Performing a cone search ------------------------ A cone search query is performed by setting the ``spatial`` keyword to ``Cone``. The target name or the coordinates of the search center must also be specified. The radius for the cone search may also be specified - if this is missing, it defaults to a value of 10 arcsec. The radius may be specified in any appropriate unit using a `~astropy.units.Quantity` object. It may also be entered as a string that is parsable by `~astropy.coordinates.Angle`. .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> import astropy.units as u >>> table = Irsa.query_region("m31", catalog="fp_psc", spatial="Cone", ... radius=2 * u.arcmin) >>> print(table) ra dec clon clat ... j_h h_k j_k deg deg ... ---------- ---------- ------------ ------------ ... ----- ------ ----- 10.684737 41.269035 00h42m44.34s 41d16m08.53s ... 0.785 0.193 0.978 10.685657 41.269550 00h42m44.56s 41d16m10.38s ... -- -- -- ... ... ... ... ... ... ... ... 10.702501 41.299492 00h42m48.60s 41d17m58.17s ... -- -- -- 10.728661 41.273312 00h42m54.88s 41d16m23.92s ... -- -- -- 10.728869 41.265533 00h42m54.93s 41d15m55.92s ... 0.803 0.613 1.416 Length = 500 rows The coordinates of the center may be specified rather than using the target name. The coordinates can be specified using the appropriate `astropy.coordinates` object. ICRS coordinates may also be entered directly as a string, as specified by `astropy.coordinates`: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> import astropy.coordinates as coord >>> table = Irsa.query_region(coord.SkyCoord(121.1743, ... -21.5733, unit=(u.deg,u.deg), ... frame='galactic'), ... catalog='fp_psc', radius='0d2m0s') >>> print(table) ra dec clon clat ... angle j_h h_k j_k deg deg ... deg ---------- ---------- ------------ ------------ ... ---------- ----- ----- ----- 10.684737 41.269035 00h42m44.34s 41d16m08.53s ... 10.37715 0.785 0.193 0.978 10.683469 41.268585 00h42m44.03s 41d16m06.91s ... 259.028985 -- -- -- 10.685657 41.269550 00h42m44.56s 41d16m10.38s ... 43.199247 -- -- -- ... ... ... ... ... ... ... ... ... 10.656898 41.294655 00h42m37.66s 41d17m40.76s ... 321.14224 1.237 -- -- 10.647116 41.286366 00h42m35.31s 41d17m10.92s ... 301.969315 -- -- -- Length = 500 rows Performing a box search ----------------------- The box queries have a syntax similar to the cone queries. In this case the ``spatial`` keyword argument must be set to ``Box``. Also the width of the box region is required. The width may be specified in the same way as the radius for cone search queries, above - so it may be set using the appropriate `~astropy.units.Quantity` object or a string parsable by `~astropy.coordinates.Angle`. .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> import astropy.units as u >>> table = Irsa.query_region("00h42m44.330s +41d16m07.50s", ... catalog='fp_psc', spatial='Box', ... width=5 * u.arcsec) >>> print(table) ra dec clon clat ... ext_key j_h h_k j_k deg deg ... ---------- ---------- ------------ ------------ ... ------- ----- ----- ----- 10.684737 41.269035 00h42m44.34s 41d16m08.53s ... -- 0.785 0.193 0.978 Note that in this case we directly passed ICRS coordinates as a string to the :meth:`~astroquery.ipac.irsa.IrsaClass.query_region`. Queries over a polygon ---------------------- Polygon queries can be performed by setting ``spatial='Polygon'``. The search center is optional in this case. One additional parameter that must be set for these queries is ``polygon``. This is a list of coordinate pairs that define a convex polygon. The coordinates may be specified as usual by using the appropriate `astropy.coordinates` object (Again ICRS coordinates may be directly passed as properly formatted strings). In addition to using a list of `astropy.coordinates` objects, one additional convenient means of specifying the coordinates is also available - Coordinates may also be entered as a list of tuples, each tuple containing the ra and dec values in degrees. Each of these options is illustrated below: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> from astropy import coordinates >>> table = Irsa.query_region("m31", catalog="fp_psc", spatial="Polygon", ... polygon=[coordinates.SkyCoord(ra=10.1, dec=10.1, unit=(u.deg, u.deg), frame='icrs'), ... coordinates.SkyCoord(ra=10.0, dec=10.1, unit=(u.deg, u.deg), frame='icrs'), ... coordinates.SkyCoord(ra=10.0, dec=10.0, unit=(u.deg, u.deg), frame='icrs') ... ]) >>> print(table) ra dec clon clat ... ext_key j_h h_k j_k deg deg ... ---------- ---------- ------------ ------------ ... ------- ----- ----- ----- 10.015839 10.038061 00h40m03.80s 10d02m17.02s ... -- 0.552 0.313 0.865 10.015696 10.099228 00h40m03.77s 10d05m57.22s ... -- 0.602 0.154 0.756 10.011170 10.093903 00h40m02.68s 10d05m38.05s ... -- 0.378 0.602 0.98 10.031016 10.063082 00h40m07.44s 10d03m47.10s ... -- 0.809 0.291 1.1 10.036776 10.060278 00h40m08.83s 10d03m37.00s ... -- 0.468 0.372 0.84 10.059964 10.085445 00h40m14.39s 10d05m07.60s ... -- 0.697 0.273 0.97 10.005549 10.018401 00h40m01.33s 10d01m06.24s ... -- 0.662 0.566 1.228 Another way to specify the polygon is directly as a list of tuples - each tuple is an ra, dec pair expressed in degrees: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> table = Irsa.query_region("m31", catalog="fp_psc", spatial="Polygon", ... polygon = [(10.1, 10.1), (10.0, 10.1), (10.0, 10.0)]) >>> print(table) ra dec clon clat ... ext_key j_h h_k j_k deg deg ... ---------- ---------- ------------ ------------ ... ------- ----- ----- ----- 10.015839 10.038061 00h40m03.80s 10d02m17.02s ... -- 0.552 0.313 0.865 10.015696 10.099228 00h40m03.77s 10d05m57.22s ... -- 0.602 0.154 0.756 10.011170 10.093903 00h40m02.68s 10d05m38.05s ... -- 0.378 0.602 0.98 10.031016 10.063082 00h40m07.44s 10d03m47.10s ... -- 0.809 0.291 1.1 10.036776 10.060278 00h40m08.83s 10d03m37.00s ... -- 0.468 0.372 0.84 10.059964 10.085445 00h40m14.39s 10d05m07.60s ... -- 0.697 0.273 0.97 10.005549 10.018401 00h40m01.33s 10d01m06.24s ... -- 0.662 0.566 1.228 Selecting Columns -------------------- The IRSA service allows to query either a subset of the default columns for a given table, or additional columns that are not present by default. This can be done by listing all the required columns separated by a comma (,) in a string with the ``selcols`` argument. An example where the AllWISE Source Catalog needs to be queried around the star HIP 12 with just the ra, dec and w1mpro columns would be: .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> table = Irsa.query_region("HIP 12", catalog="allwise_p3as_psd", spatial="Cone", selcols="ra,dec,w1mpro") >>> print(table) ra dec clon clat w1mpro dist angle deg deg mag arcsec deg ----------- ----------- ------------ ------------- ------- -------- ---------- 0.0407905 -35.9602605 00h00m09.79s -35d57m36.94s 4.837 0.350806 245.442148 A list of available columns for each catalog can be found at https://irsa.ipac.caltech.edu/holdings/catalogs.html. The "Long Form" button at the top of the column names table must be clicked to access a full list of all available columns. Changing the precision of ascii output -------------------------------------- The precision of the table display of each column is set upstream by the archive, and appears as the ``.format`` attribute of individual columns. This attribute affects not only the display of columns, but also the precision that is output when the table is written in ``ascii.ipac`` or ``ascii.csv`` formats. The ``.format`` attribute of individual columns may be set to increase the precision. .. doctest-remote-data:: >>> from astroquery.ipac.irsa import Irsa >>> table = Irsa.query_region("HIP 12", catalog="allwise_p3as_psd", spatial="Cone", selcols="ra,dec,w1mpro") >>> table['ra'].format = '{:10.6f}' >>> table['dec'].format = '{:10.6f}' >>> print(table) ra dec clon clat w1mpro dist angle deg deg mag arcsec deg ---------- ---------- ------------ ------------- ------- -------- ---------- 0.040791 -35.960260 00h00m09.79s -35d57m36.94s 4.837 0.350806 245.442148 Other Configurations -------------------- By default the maximum number of rows that is fetched is set to 500. However, this option may be changed by changing the astroquery configuration file. To change the setting only for the ongoing python session, you could also do: >>> from astroquery.ipac.irsa import Irsa >>> Irsa.ROW_LIMIT = 1000 # 1000 is the new value for row limit here. Reference/API ============= .. automodapi:: astroquery.ipac.irsa :no-inheritance-diagram: