2015-07-16T09:19:00 100 The HSOY Catalog HSOY is a catalog of 583'001'653 objects with precise astrometry based on PPMXL and Gaia DR1. Typical formal errors at mean epoch in proper motion are below 1 mas/yr for objects brighter than 10 mag, and about 5 mas/yr at the faint end (about 20 mag). South of -30 degrees, astrometry is significantly worse. HSOY also contains, where available, USNO-B, Gaia, and 2MASS photometry. HSOY's positions and proper motions are given for epoch J2000. The catalog becomes severely incomplete faintwards of 16 mag in the G-band. The mean epochs are typically very close to Gaia's J2015. HSOY still contains about 0.7% spurious close "binaries" (non-matched stars) from the original USNO-B (marked with non-NULL clone). Also, failed matches within Gaia DR1 contribute another 1.5% spurious pairs (marked with non-NULL comp). In both cases, astrometry presumably is sub-standard. More information is available at http://dc.g-vo.org/hsoy. Demleitner, M.; Röser, S.; Altmann, M.; Bastian, U.; Schilbach, E. stars surveys astrometry proper-motions Research Gaia 2017A&A...600L...4A 10.21938/HP1ASPBYWElyXb6qdqyolg Added a column no_sc to mark objects without a counterpart in SuperCOSMOS; these are presumably spurious, and filtering on no_sc is NULL significantly improves proper motion statistics. Optical 2000-01-01 2000-01-01 0/0-11 8.277e-20 5.369e-19 150 mas/yr are left, well within a factor of two of the gold standard set by LSPM. Here are comparisons of the distributions of total proper motions in HSOY for all (blue) and ``no_sc IS NULL`` (red) objects. Top or left is for the total catalog, bottom or right just the northern sky. .. image:: /\rdId/q/static/pm_histograms.png .. image:: /\rdId/q/static/pm_histograms_north.png To get an idea of where the obvious problem on the southern sky comes from, see this density map of stars faster than 150 mas/yr in HEALPixes of order 6, plotted in galactic coordinates. Only objects for which all of no_sc, comp, and clone are NULL are shown. Note that the scale on the aux axis is logarithmic: .. image:: /\rdId/q/static/highpm_density.png Essentially, in areas so crowded that almost any movement of a star will hit another (within our match criteria) there will be many spurious high-pm stars, in particular when there are many spurious sources to begin with (plate borders). In sufficient distance from the bulge and the Magellanic clouds, high proper motions in HSOY should be fairly reliable when filtering out the suspicious (no_sc, clone, comp) objects. (4) HSOY inherits the USNO photometry in B, R, and I. It has many known issues (including, but not limited to, ridiculous values like 65.47 shown in the table above). Do not lightly use b1mag, b2mag, r1mag, r2mag, and imag, as many of them are invalid. (5) At the bright end, HSOY is severely incomplete. This reflects the corresponding incompleteness of Gaia DR1. Trivia ------ The primary key of HSOY is the tuple (ipix,comp). The suggested reference to a HSOY object is "HSOY .0" when comp is NULL, and "HSOY ." otherwise. If you want to cite HSOY, please see `our citation advice`_. .. _HSOY resource descriptor: http://svn.ari.uni-heidelberg.de/svn/gavo/hdinputs/hsoy/q.rd .. _our citation advice: /hsoy/q/q/howtocite ]]> Hsoy Object Catalog During the construction of USNO-B, numerous observations were not matched properly. As a result, at least 10% of USNO-B objects are spurious. Most of these carried over into PPMXL. Since many of these objects have completely errneous proper motions, much fewer will be in HSOY. However, they are present, and they are characterised by multiple PPMXL objects being matched to one Gaia object. Since PPMXL's resolution is much worse than Gaia's, these will almost always be spurious; also, since the Gaia position is fixed in both solutions, their paths will cross fairly near to J2015.0. Download guard for hsoy dump from gavo import svcs if inputTable.getParam("input")=="yes": raise svcs.WebRedirect( "http://vo.ari.uni-heidelberg.de/hsoy/hsoy.dump.xz?") else: raise base.ValidationError("This must be 'yes' (without any" " quotes)", "input") HSOY SCS static testQuery.ra: 31.9 testQuery.dec: 61.7 q/scs.xml rows = self.getVOTableRows() self.assertEqual(len(rows), 1) self.assertEqual(rows[0]["hsoyid"], "HSOY 5055227856149121395.0") self.assertAlmostEqual(rows[0]["e_phot_g_mean_mag"], 0.00177645) download/form self.assertHasStrings("You are about to download HSOY", "I read the warning</label>") download/form self.assertHeader("location", "http://vo.ari.uni-heidelberg.de/hsoy/hsoy.dump.xz?") self.assertHTTPStatus(301) http://vo.ari.uni-heidelberg.de/hsoy/hsoy.dump.xz? self.assertHTTPStatus(200)