.. _astroquery.ipac.ned: *********************************** NED Queries (`astroquery.ipac.ned`) *********************************** Getting Started =============== This module can be used to query the Ned web service. All queries other than image and spectra queries return results in a `~astropy.table.Table`. Image and spectra queries on the other hand return the results as a list of `~astropy.io.fits.HDUList` objects. Below are some working examples that illustrate common use cases. Query an object --------------- This may be used to query the object *by name* from the NED service. For instance if you want to query NGC 224 .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> result_table = Ned.query_object("NGC 224") >>> print(result_table) # an astropy.table.Table No. Object Name RA ... Redshift Points Diameter Points Associations degrees ... --- ----------- ---------- ... --------------- --------------- ------------ 1 MESSIER 031 10.68479 ... 40 13 2 Query a region -------------- These queries may be used for querying a region around a named object or coordinates (i.e *near name* and *near position* queries). The radius of the region should be specified in degrees or equivalent units. An easy way to do this is to use an `~astropy.units.Quantity` object to specify the radius and units. The radius may also be specified as a string in which case it will be parsed using `~astropy.coordinates.Angle`. If no radius is specified, it defaults to 1 arcmin. Another optional parameter is the equinox if coordinates are specified. By default this is J2000.0 but can also be set to B1950.0. .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> import astropy.units as u >>> result_table = Ned.query_region("3c 273", radius=0.05 * u.deg) >>> print(result_table) No. Object Name RA ... Diameter Points Associations degrees ... --- -------------------------- ---------- ... --------------- ------------ 1 WISEA J122855.03+020309.1 187.22917 ... 0 0 2 SSTSL2 J122855.02+020313.7 187.22925 ... 0 0 3 SSTSL2 J122855.23+020341.5 187.23013 ... 0 0 4 SSTSL2 J122855.36+020346.9 187.23068 ... 0 0 ... ... ... ... ... ... 864 SSTSL2 J122918.24+020330.7 187.326 ... 0 0 865 SDSS J122918.38+020323.4 187.3266 ... 4 0 866 SSTSL2 J122918.52+020338.9 187.32718 ... 0 0 867 SSTSL2 J122918.64+020326.7 187.32767 ... 0 0 Length = 867 rows Instead of using the name, the target may also be specified via coordinates. Any of the coordinate systems available in `astropy.coordinates` may be used (ICRS, Galactic, FK4, FK5). Note also the use of the equinox keyword argument: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> import astropy.units as u >>> from astropy import coordinates >>> co = coordinates.SkyCoord(ra=56.38, dec=38.43, ... unit=(u.deg, u.deg), frame='fk4') >>> result_table = Ned.query_region(co, radius=0.1 * u.deg, equinox='B1950.0') >>> print(result_table) No. Object Name RA ... Diameter Points Associations degrees ... --- ------------------------- ---------- ... --------------- ------------ 1 WISEA J035137.90+384313.7 57.90793 ... 0 0 2 WISEA J035138.59+384305.6 57.91062 ... 0 0 3 WISEA J035139.28+384324.4 57.91371 ... 0 0 4 WISEA J035139.77+384507.4 57.91572 ... 0 0 ... ... ... ... ... ... 631 WISEA J035237.78+384519.3 58.15743 ... 0 0 632 WISEA J035238.62+384431.9 58.16083 ... 0 0 633 WISEA J035238.74+384352.1 58.16145 ... 0 0 634 WISEA J035238.84+384437.0 58.16177 ... 0 0 Length = 634 rows Query in the IAU format ^^^^^^^^^^^^^^^^^^^^^^^ The `IAU format`_ for coordinates may also be used for querying purposes. Additional parameters that can be specified for these queries is the reference frame of the coordinates. The reference frame defaults to ``Equatorial``. But it can also take the values ``Ecliptic``, ``Galactic`` and ``SuperGalactic``. The equinox can also be explicitly chosen (same as in region queries). It defaults to ``B1950`` but again it may be set to ``J2000.0``. Note that Ned report results by searching in a 15 arcmin radius around the specified target. .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> result_table = Ned.query_region_iau('1234-423', frame='SuperGalactic', equinox='J2000.0') >>> print(result_table) No. Object Name RA ... Diameter Points Associations degrees ... --- ------------------------- ---------- ... --------------- ------------ 1 WISEA J123639.37-423822.9 189.16406 ... 0 0 2 WISEA J123639.47-423656.3 189.16458 ... 0 0 3 WISEA J123639.61-423637.9 189.16506 ... 0 0 4 WISEA J123639.91-423709.9 189.1663 ... 0 0 ... ... ... ... ... ... 760 2MASS J12374631-4236174 189.44299 ... 0 0 761 WISEA J123746.44-423727.9 189.44359 ... 0 0 762 WISEA J123746.48-423838.1 189.4437 ... 0 0 763 WISEA J123747.07-423742.9 189.44616 ... 0 0 Length = 763 rows Query a reference code for objects ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ These queries can be used to retrieve all objects that appear in the specified 19 digit reference code. These are similar to the :meth:`~astroquery.simbad.SimbadClass.query_bibobj` queries. .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> result_table = Ned.query_refcode('1997A&A...323...31K') >>> print(result_table) No. Object Name RA ... Diameter Points Associations degrees ... --- ------------------------- ---------- ... --------------- ------------ 1 NGC 0262 12.19642 ... 12 0 2 NGC 0449 19.0302 ... 7 0 3 NGC 0591 23.38028 ... 7 0 4 UGC 01214 25.99084 ... 12 0 ... ... ... ... ... ... 33 WISEA J202325.39+113134.6 305.85577 ... 2 0 34 UGC 12149 340.28163 ... 8 0 35 MRK 0522 345.07954 ... 4 0 36 NGC 7674 351.98635 ... 8 0 Length = 36 rows Image and Spectra Queries ^^^^^^^^^^^^^^^^^^^^^^^^^ The image queries return a list of `~astropy.io.fits.HDUList` objects for the specified name. For instance: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> images = Ned.get_images("m1") # doctest: +IGNORE_OUTPUT Downloading https://ned.ipac.caltech.edu/dss1B2/Bb/MESSIER_001:I:103aE:dss1.fits.gz |===========================================| 32k/ 32k (100.00%) 00s Downloading https://ned.ipac.caltech.edu/img5/1995RXCD3.T...0000C/p083n22a:I:0.1-2.4keV:cop1995.fits.gz |===========================================| 52k/ 52k (100.00%) 01s Downloading https://ned.ipac.caltech.edu/img5/1996RXCD6.T...0000C/p083n22a:I:0.1-2.4keV:cps1996.fits.gz |===========================================| 96k/ 96k (100.00%) 03s Downloading https://ned.ipac.caltech.edu/img5/1995RXCD3.T...0000C/p084n22a:I:0.1-2.4keV:cop1995.fits.gz |===========================================| 52k/ 52k (100.00%) 01s Downloading https://ned.ipac.caltech.edu/img5/1998RXCD8.T...0000C/h083n22a:I:0.1-2.4keV:cps1998.fits.gz |===========================================| 35k/ 35k (100.00%) 00s >>> images # doctest: +IGNORE_OUTPUT [[], [], [], [], []] To get the URLs of the downloadable FITS images: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> image_list = Ned.get_image_list("m1") >>> image_list # doctest: +IGNORE_OUTPUT ['https://ned.ipac.caltech.edu/dss1B2/Bb/MESSIER_001:I:103aE:dss1.fits.gz', 'https://ned.ipac.caltech.edu/img/1995RXCD3.T...0000C/p084n22a:I:0.1-2.4keV:cop1995.fits.gz', 'https://ned.ipac.caltech.edu/img/1996RXCD6.T...0000C/p083n22a:I:0.1-2.4keV:cps1996.fits.gz', 'https://ned.ipac.caltech.edu/img/1998RXCD8.T...0000C/h083n22a:I:0.1-2.4keV:cps1998.fits.gz', 'https://ned.ipac.caltech.edu/img/1995RXCD3.T...0000C/p083n22a:I:0.1-2.4keV:cop1995.fits.gz'] Spectra can also be fetched in the same way: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> spectra = Ned.get_spectra('3c 273') # doctest: +IGNORE_OUTPUT Downloading https://ned.ipac.caltech.edu/spc1/2009A+A...495.1033B/3C_273:S:B:bcc2009.fits.gz |===========================================| 7.8k/7.8k (100.00%) 00s Downloading https://ned.ipac.caltech.edu/spc1/1992ApJS...80..109B/PG_1226+023:S:B_V:bg1992.fits.gz |===========================================| 5.0k/5.0k (100.00%) 00s Downloading https://ned.ipac.caltech.edu/spc1/2009A+A...495.1033B/3C_273:S:RI:bcc2009.fits.gz |===========================================| 9.4k/9.4k (100.00%) 00s >>> spectra # doctest: +IGNORE_OUTPUT [[], [], []] Similarly the list of URLs for spectra of a particular object may be fetched: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> spectra_list = Ned.get_image_list("3c 273", item='spectra') >>> spectra_list ['https://ned.ipac.caltech.edu/spc1/1992/1992ApJS...80..109B/PG_1226+023:S:B_V:bg1992.fits.gz', 'https://ned.ipac.caltech.edu/spc1/2009/2009A+A...495.1033B/3C_273:S:B:bcc2009.fits.gz', ... 'https://ned.ipac.caltech.edu/spc1/2016/2016ApJS..226...19F/3C_273:S:CII158.3x3.fits.gz'] Fetching other data tables for an object ---------------------------------------- Several other data tables for an object may be fetched via the :meth:`~astroquery.ipac.ned.NedClass.get_table` queries. These take a keyword argument ``table``, which may be set to one of ``photometry``, ``diameters``, ``redshifts``, ``references`` or ``object_notes``. For instance the ``table=photometry`` will fetch all the relevant photometric data for the specified object. We look at a simple example: .. doctest-remote-data:: >>> from astroquery.ipac.ned import Ned >>> result_table = Ned.get_table("3C 273", table='positions') >>> print(result_table) # doctest: +IGNORE_OUTPUT No. RA ... Published Frequence Mode Qualifiers ... --- -------------- ... ------------------------ ------------------------- 0 12h29m06.6997s ... 1 12h29m06.7000s ... Uncertain origin 2 12h29m06.7000s ... Uncertain origin 3 12h29m06.7000s ... Uncertain origin 4 12h29m06.7000s ... Uncertain origin 5 12h29m06.7000s ... Uncertain origin 6 12h29m06.7001s ... Uncertain origin 7 12h29m06.6996s ... Uncertain origin 8 12h29m06.7001s ... Uncertain origin 9 12h29m06.7001s ... Uncertain origin ... ... ... ... ... 144 12h29m06.05s ... Broad-band measurement From new, raw data 145 12h29m06.5s ... Broad-band measurement From new, raw data 146 12h29m06.5s ... Broad-band measurement From reprocessed raw data 147 12h29m09.0s ... Uncertain origin 148 12h29m08.9s ... Uncertain origin 149 12h29m07.9s ... Uncertain origin 150 12h29m04s ... Uncertain origin 151 12h29m06s ... Uncertain origin 152 12h29m08s ... Uncertain origin 153 12h29m06s ... Uncertain origin Length = 154 rows Troubleshooting =============== If you are repeatedly getting failed queries, or bad/out-of-date results, try clearing your cache: .. code-block:: python >>> from astroquery.ned import Ned >>> Ned.clear_cache() If this function is unavailable, upgrade your version of astroquery. The ``clear_cache`` function was introduced in version 0.4.7.dev8479. Reference/API ============= .. automodapi:: astroquery.ipac.ned :no-inheritance-diagram: .. _IAU format: https://cds.unistra.fr/Dic/iau-spec.html