.. _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 ... 37 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 ... ... ... ... ... ... 863 SSTSL2 J122918.24+020330.7 187.326 ... 0 0 864 SDSS J122918.38+020323.4 187.3266 ... 4 0 865 SSTSL2 J122918.52+020338.9 187.32718 ... 0 0 866 SSTSL2 J122918.64+020326.7 187.32767 ... 0 0 Length = 866 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 http://ned.ipac.caltech.edu/dss1B2/Bb/MESSIER_001:I:103aE:dss1.fits.gz |===========================================| 32k/ 32k (100.00%) 00s Downloading http://ned.ipac.caltech.edu/img5/1995RXCD3.T...0000C/p083n22a:I:0.1-2.4keV:cop1995.fits.gz |===========================================| 52k/ 52k (100.00%) 01s Downloading http://ned.ipac.caltech.edu/img5/1996RXCD6.T...0000C/p083n22a:I:0.1-2.4keV:cps1996.fits.gz |===========================================| 96k/ 96k (100.00%) 03s Downloading http://ned.ipac.caltech.edu/img5/1995RXCD3.T...0000C/p084n22a:I:0.1-2.4keV:cop1995.fits.gz |===========================================| 52k/ 52k (100.00%) 01s Downloading http://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: +NORMALIZE_WHITESPACE ['http://ned.ipac.caltech.edu/dss1B2/Bb/MESSIER_001:I:103aE:dss1.fits.gz', 'http://ned.ipac.caltech.edu/img/1995RXCD3.T...0000C/p084n22a:I:0.1-2.4keV:cop1995.fits.gz', 'http://ned.ipac.caltech.edu/img/1996RXCD6.T...0000C/p083n22a:I:0.1-2.4keV:cps1996.fits.gz', 'http://ned.ipac.caltech.edu/img/1998RXCD8.T...0000C/h083n22a:I:0.1-2.4keV:cps1998.fits.gz', 'http://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 http://ned.ipac.caltech.edu/spc1/2009A+A...495.1033B/3C_273:S:B:bcc2009.fits.gz |===========================================| 7.8k/7.8k (100.00%) 00s Downloading http://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 http://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 ['http://ned.ipac.caltech.edu/spc1/1992/1992ApJS...80..109B/PG_1226+023:S:B_V:bg1992.fits.gz', 'http://ned.ipac.caltech.edu/spc1/2009/2009A+A...495.1033B/3C_273:S:B:bcc2009.fits.gz', 'http://ned.ipac.caltech.edu/spc1/2009/2009A+A...495.1033B/3C_273:S:RI:bcc2009.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) No. RA ... Published Frequence Mode Qualifiers ... --- -------------- ... ------------------------ ------------------------- 0 12h29m06.6997s ... 1 12h29m06.7000s ... Uncertain origin 2 12h29m06.7000s ... Uncertain origin 3 12h29m06.7000s ... Uncertain origin ... ... ... ... ... 114 12h29m07.9s ... Uncertain origin 115 12h29m04s ... Uncertain origin 116 12h29m06s ... Uncertain origin 117 12h29m08s ... Uncertain origin Length = 118 rows Reference/API ============= .. automodapi:: astroquery.ipac.ned :no-inheritance-diagram: .. _IAU format: http://cdsweb.u-strasbg.fr/Dic/iau-spec.htx