2020-10-16T10:16:41Z 100 LAMOST DR6 Spectra LAMOST, the The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (or Guoshoujing Telescope) is an instrument tailored for producing large number of optical medium- and low-resolution spectra. Here, we publish both the medium (MRS) and low (LRS) resolution spectra from Data Release 6, http://dr6.lamost.org/v2/, to the Virtual Observatory. spectroscopy surveys stars National Astronomical Observatories of the Chinese Academy of Sciences LAMOST CAS, NAO http://dr6.lamost.org/v2/ Research Survey Optical Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences. Funding for the project has been provided by the National Development and Reform Commission. LAMOST is operated and managed by the National Astronomical Observatories, Chinese Academy of Sciences. Please also see the `LAMOST Data Policy`_. .. _LAMOST Data Policy: http://dr.lamost.org/ucenter/doc/lssdp survey archival spectrum MAXREC=1 Table material for both low-res and med-res spectra. //products#table //ssap#plainlocation //ssap#simpleCoverage Metadata of LAMOST DR6 medium resolution spectra. This table is only used to feed the ssa_mrs view; use that to query data in this table. bandid, source b0, the B spectrum after continuum removal r0, the R spectrum after continuum removal br0, the B and R spectra after continuum removal lasp0, the LAMOST stellar parameter pipeline bandid, source b1, b0 r1, r0 br1, br0 lasp1, lasp0 bandid b r br Meaning of the bits in fibermask (note: while upstream counts bits from 1, we count bits from 0): === ================================================ Bit Meaning === ================================================ 0 Fiber not allotted 1 Bad trace from the TRACECENTER routine 2 Low counts in flat field 3 Bad arc solution 4 <10% pixels are bad on the CCD 5 <10% pixels are saturated 6 Whopping fiber 7 Near a whopping fiber 8 Sky fiber shows extreme residuals === ================================================ Metadata of LAMOST DR6 low resolution spectra. This table is only used to feed the ssa_lrs view; use that to query data in this table. 3.71e-19 4.01e-19 Common build material for lo-res and med-res data items. Config: * target_table -- id of the table to build * id_fragment -- lrs or mrs * id_source -- mobsid for mrs, obsid for lrs The rowmakers include a stream lrs-extramaps or mrs-extramaps with mapping special to the low and med res tables. make_\target_table\+_view "\\schema.\target_table" "lamost6/\id_fragment/"+str(@\id_source) ("\\internallink{\\rdId/sdl_\id_fragment/dlget}?ID=lamost6/" +"\id_fragment/"+str(@\id_source)) 100000 "\\rdId#sdl_\id_fragment" "application/x-votable+xml" makeAbsoluteURL("\\rdId/preview/qp/" "\id_fragment/"+str(@obsid)+"/"+str(@\id_source)) "image/png" dateTimeToMJD(parseDate(@obsdate)) ok_terms = {"star", "k2star", "fs", "rvcandi", "gal"} key = @objtype.lower() if key in ok_terms: @objtype = key else: @objtype = "unknown (%s)"%key @ra @dec 1/3600. The material for both the low- and medres SSA views. Config: * sourcetable -- medres or lowres * collection_name -- LAMOST6 MRS or LRS * datalinksvc -- id of the associated datalink service * ssa_specstart/ssa_specend -- literals for lrs, colrefs for mrs * ssa_length \datalinksvc ssa_pubDID //ssap#view //obscore#publishSSAPMIXC SSA-compliant metadata for LAMOST DR6 medium resolution spectra; this data is also availble through Obscore; the collection name there is LAMOST6 MRS. SSA-compliant metadata for LAMOST DR6 low resolution spectra; this data is also availble through Obscore; the collection name there is LAMOST6 LRS. //ssap#sdm-instanceA medium-resolution LAMOST spectrum //ssap#sdm-instanceA low-resolution LAMOST spectrum # this expects both mobsid and obsid in sourceToken and # will locate the file and extension based on that. obsid = str(self.sourceToken["obsid"]) sourcePath = rd.getAbsPath("data/MRS/%s/%s.fits"%( obsid[5:], obsid)) maskField = "PIXMASK" specid = self.sourceToken["mobsid"][len(obsid):] if len(specid)==1: specid = "COADD_"+specid maskField = "ORMASK" else: specid = "%s-%s"%(specid[-1], specid[:-1]) with pyfits.open(sourcePath, memmap=True) as hdus: for row in hdus[specid].data: yield { "spectral": 10**row["LOGLAM"], "flux": row["FLUX"], "flux_error": 1/math.sqrt(row["IVAR"]) if row["IVAR"] else None, "flags": row[maskField], } \schema MRS Datalink Service Spectrum datalink service for LAMOST6 medium-resolution spectra. This gives you access to single-exposure spectra and the original FITS files. data/MRS "\rdId#ssa_mrs" "\rdId#build_mrs_spectrum" if descriptor.ssaRow.get("coadd")==1: # add rows for the spectra that went into this coadd with base.getTableConn() as conn: for row in conn.queryToDicts("SELECT mobsid, accref" " FROM lamost6.ssa_mrs" " WHERE obsid=%(obsid)s" " AND coadd=0", {"obsid": descriptor.ssaRow["obsid"]}): yield descriptor.makeLink( makeAbsoluteURL("\rdId/sdl_mrs/dlmeta?ID="+row["accref"]), description="A single-exposure LAMOST spectrum" " of this source.", contentType="application/x-votable+xml;content=datalink", contentQualifier="#spectrum") if descriptor.ssaRow.get("coadd")==0: # add a rows for the coadd if this a a single-exposure with base.getTableConn() as conn: for row in conn.queryToDicts("SELECT mobsid, accref" " FROM lamost6.medres" " WHERE obsid=%(obsid)s" " AND coadd=1", {"obsid": descriptor.ssaRow["obsid"]}): if row["accref"][-1]==descriptor.pubDID[-1]: # same band, coadd is a derivation yield descriptor.makeLink( makeAbsoluteURL("\rdId/sdl_mrs/dlmeta?ID="+row["accref"]), description="The co-added spectrum this went into", contentType="application/x-votable+xml;content=datalink", contentQualifier="#spectrum") else: # same band, coadd is a counterpart yield descriptor.makeLink( makeAbsoluteURL("\rdId/sdl_mrs/dlmeta?ID="+row["accref"]), semantics="#counterpart", description="A co-added spectrum of this object" " in the %s band."%row["accref"][-1], contentType="application/x-votable+xml;content=datalink", contentQualifier="#spectrum") obsid = str(descriptor.ssaRow["obsid"]) yield descriptor.makeLink( makeAbsoluteURL("\rdId/sdl_mrs/static/%s/%s.fits"%( obsid[5:], obsid)), description="Original, multi-extension, dataset in FITS" " binary table", contentType="application/fits", contentQualifier="#spectrum") LAMOST6 spectra preview maker specid # This is complicated because there are several # spectra per MRS file; that's why the products#define # apply adds two segments: for LRS, that's both obsid, # but for MRS that's obsid and mobsid. These we # feed to the grammar of build_mrs_spectrum as appropriate. obsid, mobsid = inputTable.args["specid"].split("/")[-2:] if obsid==mobsid: # LRS sourcePath = rd.getAbsPath("data/LRS/%s/%s.fits"%( obsid[5:], obsid)) with pyfits.open(sourcePath) as hdus: arr = hdus[0].data res = list(zip(arr[2], arr[0])) else: # MRS sourceToken = {"obsid": obsid, "mobsid": mobsid} res = [(r["spectral"], r["flux"]) for r in rd.getById("build_mrs_spectrum" ).grammar.parse(sourceToken)] return ("image/png", SpectralPreviewMaker.get2DPlot(res, linear=True)) # This wants obsid in sourceToken and will build the # source file name from that. obsid = str(self.sourceToken["obsid"]) sourcePath = rd.getAbsPath("data/LRS/%s/%s.fits"%( obsid[5:], obsid)) with pyfits.open(sourcePath, memmap=True) as hdus: # LAMOST WCS is severely broken: CD1_1 for a spectral axis. Oh my. # Let's fiddle things by hand, and then do log/10** manually below. hdr, data = hdus[0].header, hdus[0].data specWCS = fitstools.WCSAxis( "spectral", hdr["CRVAL1"], hdr["CRPIX1"], hdr["CD1_1"], axisLength=hdr["NAXIS1"]) for pixInd, row in enumerate(data.T): yield { "spectral": row[2], "flux": row[0], "flux_error": 1/math.sqrt(row[1]) if row[1] else None, "flags": int(row[4]) } \schema LRS Datalink Service Spectrum datalink service for LAMOST6 low-resolution spectra. This gives you access to the SDM-compliant data in various formats as well as the original FITS files. data/LRS "\rdId#ssa_lrs" "\rdId#build_lrs_spectrum" obsid = str(descriptor.ssaRow["obsid"]) yield descriptor.makeLink( makeAbsoluteURL("\rdId/sdl_lrs/static/%s/%s.fits"%( obsid[5:], obsid)), description="Original dataset as a FITS array", contentType="application/fits", contentQualifier="#spectrum") accref, mime, ssa_targname, ssa_aperture, ssa_dateObs LM6 MRS Web LAMOST DR6 Medium Resolution Spectra Web A form-based interface to the LAMOST6 medium resolution spectra yield "coadd=1" LM6 MRS SSAP full LAMOST DR6 Medium Resolution Spectra A machine-readable interface to the LAMOST6 medium resolution spectra based on SSAP and datalink. auto LM6 LRS Web LAMOST DR6 Low Resolution Spectra Web A form-based interface to the LAMOST6 low resolution spectra LM6 LRS SSAP full LAMOST DR6 Low Resolution Spectra A machine-readable interface to the LAMOST6 low resolution spectra based on SSAP and datalink. auto sdl_mrs/dlmeta rows = self.getVOTableRows() self.assertEqual(len(rows), 22) triples = set((r["semantics"], r["content_type"], r["access_url"] and r["access_url"][-30:]) for r in rows) self.assertTrue(('#progenitor', 'application/x-votable+xml;content=datalink', 'lamost6/mrs/58890200383556105R') in triples, "single-exposure link missing") self.assertTrue( ('#preview', 'image/png', 'ew/qp/mrs/588902003/588902003B') in triples, "No preview?") # The link in the next test is tested for existence below. self.assertTrue( ('#progenitor', 'application/fits', 'mrs/static/2003/588902003.fits') in triples, "No FITS source?") for r in rows: if r["semantics"] in ("#this", "#progenitor", "#counterpart"): self.assertEqual(r["content_qualifier"], "#spectrum") sdl_mrs/dlmeta rows = self.getVOTableRows() self.assertEqual(len(rows), 6) triples = set((r["semantics"], r["content_type"], r["access_url"] and r["access_url"][-30:]) for r in rows) self.assertTrue(('#derivation', 'application/x-votable+xml;content=datalink', 'meta?ID=lamost6/mrs/588902003R') in triples, "link to co-add missing") self.assertTrue(('#counterpart', 'application/x-votable+xml;content=datalink', 'meta?ID=lamost6/mrs/588902003B') in triples, "link to alt-band co-add missing") # The link in the next text is tested for existence below. self.assertTrue( ('#progenitor', 'application/fits', 'mrs/static/2003/588902003.fits') in triples, "No FITS source?") sdl_mrs/dlget self.assertHasStrings( "NAXIS2 = 4136", "TUTYP1 = 'spec:spectrum.data.spectralaxis.value'") sdl_mrs/dlget r0 = self.getFirstVOTableRow(rejectExtras=False) self.assertAlmostEqual(r0["flux"], 0) self.assertAlmostEqual(r0["flux_error"], 13.357676506042) self.assertAlmostEqual(r0["spectral"], 4916.0905436843, places=2) svc_mrs/ssap.xml res = self.getVOTableRows() self.assertEqual(len(res), 2) for r in res: self.assertEqual(res[0]["ssa_pubDID"][:-1], "ivo://org.gavo.dc/~?lamost6/mrs/588902003") if res[0]["ssa_pubDID"].endswith("B"): break else: raise AssertionError("No blue spectrum?") self.assertEqual(res[0]["ssa_dateObs"], 58024.0) preview/qp/588902003/58890200383556078B self.assertHasStrings("PNG", b"IDATx\\x9c\\xed") preview/qp/588902003/588902003B self.assertHasStrings("PNG", "BBF", "BBD") sdl_mrs/static/2003/588902003.fits self.assertHasStrings("SIMPLE", "LAMOST DR6 INTER", "PCOUNT =") sdl_lrs/dlmeta rows = self.getVOTableRows() self.assertEqual(len(rows), 4) triples = set((r["semantics"], r["content_type"], r["access_url"] and r["access_url"][-30:]) for r in rows) # the individual links are tested below self.assertTrue( ('#progenitor', 'application/fits', 'q/sdl_lrs/static/6/101026.fits') in triples, "No source fits?") self.assertTrue( ('#preview', 'image/png', 'q/preview/qp/lrs/101026/101026') in triples, "No preview?") self.assertTrue( ('#this', 'application/x-votable+xml', '/getproduct/lamost6/lrs/101026') in triples, "No this?") /getproduct/lamost6/lrs/101026 self.assertHasStrings("DESCRIPTION>Flux error, comuted as sqrt(invs", 'value="http://dr6.lamost.org/v2/"') row = self.getFirstVOTableRow(rejectExtras=False) self.assertAlmostEqual(row["spectral"], 3699.986328125) self.assertAlmostEqual(row["flux"], 235.5823516845703) self.assertAlmostEqual(row["flux_error"], 134.980453491211) sdl_lrs/static/6/101026.fits self.assertHasStrings("SIMPLE =", "MAG1 = 17.58") preview/qp/lrs/101026/101026 self.assertHasStrings("PNG", "q;MGW") svc_lrs/ssap.xml res = self.getVOTableRows() self.assertEqual(len(res), 1) self.assertEqual(res[0]["designation"], "J220612.29-014103.6")