J/ApJ/861/130ivo://CDS.VizieR/J/ApJ/861/130doi:10.26093/cds/vizier.18610130CDSLandoni M.Paiano S.Falomo R.Scarpa R.Treves A.2020-01-31T15:49:59Z2019-08-07T10:09:28ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frbl-lacertae-objectsredshiftedvisible-astronomyspectroscopyline-intensitiesWe report on 16 BL Lacertae objects that were proposed to be at z>1. We present spectroscopic observations secured at the 10.4m GTC that allowed us to assess the redshift of these sources. In particular, for five objects, we disprove the previous value of the redshift reported in the literature and found that they lie at z<1. Moreover, two of them exhibit broad emission lines that are not characteristic of BL Lacertae objects. On the other hand, for eight targets, we improve the tentative value of z, previously based on only one feature, by detecting a number of emission lines. Finally, in three cases, we detect the onset of the Ly{alpha} forest at z>2.50. Based on the new high quality spectra, we found that only half of the observed objects can be classified as bona-fide BL Lacs.2018ApJ...861..130Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/861/130CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)J/AJ/139/390 : Opt. selected BL Lac objects from SDSS-DR7 (Plotkin+, 2010)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/ApJ/764/135 : Spectroscopic redshifts of BL Lac objects (Shaw+, 2013)J/ApJ/780/73 : Redshifts of BL Lac objects from Fermi (Ajello+, 2014)J/A+A/570/A126 : XShooter spectrum of 4 BL Lacs (Landoni+, 2014)J/ApJS/217/2 : Refined associations of Fermi/LAT sources (Massaro+, 2015)J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/861/130https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/861/130http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/861/130https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/861/130https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/861/130http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/861/130GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/861/130/bllac (The high redshift SDSS BLLac candidates with their observation log obtained at the Gran Telescopio CANARIAS (GTC) and the properties of the optical spectra (tables 1-3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/861/130/bllac?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/861/130/bllac?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/861/130/bllac?GETtext/xml+votable180.050000true111.74837.57305560.0055555555555555566/4507 4869 6386 9143 9618 9859 10788 10843 10949 11005 11323 26270 26563 27198 27249 28669https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/861/130?format=asciiOpticaldefaultJ/ApJ/861/130/bllacThe high redshift SDSS BLLac candidates with their observation log obtained at the Gran Telescopio CANARIAS (GTC) and the properties of the optical spectra (tables 1-3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNsNumber of spectral line measurements (link to Table 4)meta.numberintnullableSDSSObject Namemeta.id;meta.maincharprimaryf_SDSSc = Published in Paiano+ (2017ApJ...844..120P)meta.codecharRAJ2000[7/17] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainGLONGalactic longitude, decimal degreesdegpos.galactic.lonGLATGalactic latitude, decimal degreesdegpos.galactic.latfloatVmag[17.3/19.9] Magnitude from catalogmagphot.mag;em.opt.VfloatE(B-V)[0.01/0.2] Reddening (from NED)magphot.color.excessfloatl_z[<=>] Redshift limit flagmeta.code.error;src.redshiftcharz[0.9/3.4] Redshift (1)src.redshiftfloatn_zRedshift type (T=Tentative; LL=Lower limit from intervening systems)meta.notecharExpB[300/7200] Exposure time for R1000B grismstime.duration;obs.exposureintDateBDate of observation of R1000B grismtime.epochnullableSeeB[0.9/2.8] Seeing during acquisition of R1000B grismarcsecinstr.obsty.seeingfloatExpR[700/7200] Exposure time for R1000R grismstime.duration;obs.exposureintDateRDate of observation of R1000R grismtime.epochnullableSeeR[0.8/2.4] Seeing during acquisition of R1000R grismarcsecinstr.obsty.seeingfloatrmag[17/19.8] Magnitude measured from acquisition image in r bandmagphot.mag;em.opt.RfloatSNR[20/100] Average GTC S/N of the spectrumstat.snrintb_EWmin[0.2/1] Lower range of the minimum equivalent width (1)0.1nmspect.line.eqWidth;stat.minfloatB_EWmin[0.8/1.5] Upper range of the minimum equivalent width (1)0.1nmspect.line.eqWidth;stat.min;stat.maxfloatl_zspec[<=>] Redshift limit flagmeta.code.errorcharzspec[0.3/3.4] Proposed redshift from this worksrc.redshiftfloatf_zspecFlags on proposed redshift (2)meta.codecharClassClass of the object (B=BLL or Q=FSRQ)meta.code.classcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharJ/ApJ/861/130/table4Measurements of spectral linesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSObject Namemeta.id;meta.maincharl_lambda[~ ] Uncertainty flag on lambdameta.code.errorcharlambda[4235.4/9298] Barycenter of the detected line, in Angstrom units0.1nmem.wlfloatf_lambda[* ] Barycenter contamination flagmeta.codecharEW[0.2/87] Measured equivalent width, Angstroms0.1nmspect.line.eqWidthfloatLineLine identificationmeta.id;spect.linel_zspec[~ ] Uncertainty flag on zspecmeta.code.errorcharzspec[0.5/3.4]? Spectroscopic redshiftsrc.redshiftfloatnullablef_zspecFlag on zspec (1)meta.codecharLum[41/43.7]? Line (log) luminosity; only for emission features; in solar unitslog(solLum)phys.luminosityfloatnullableTypeFeature Type (2)meta.codechar