J/AJ/126/2421ivo://CDS.VizieR/J/AJ/126/2421doi:10.26093/cds/vizier.51262421CDSCruz K.L.Reid I.N.Liebert J.Kirkpatrick J.D.Lowrance P.J.2026-01-13T18:44:18Z2007-10-22T14:51:27ZCDS support team

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

cds-question@unistra.frdwarf-starsinfrared-sourcesinfrared-photometrylate-type-starsstellar-distanceWe present the initial results of our effort to create a statistically robust, volume-limited sample of ultracool dwarfs from the Two Micron All Sky Survey Second Incremental Data Release (<II/241>). We are engaged in a multifaceted search for nearby late-type objects, and this is the first installment of our search using purely photometric selection. The goal of this work is a determination of the low-mass star and brown dwarf luminosity function in the infrared. Here we outline the construction of the sample, dubbed 2MU2, and present our first results, including the discovery of 186 M7-L6 dwarfs, 47 of which are likely to be within 20pc of the Sun. These results represent 66% of the ultracool candidates in our sample yet constitute a 127% increase in the number of ultracool dwarfs known within the volume searched (covering 40% of the sky out to 20pc). In addition, we have identified 10 M4-M6.5 objects that are likely to be within 20pc (or within 1{sigma}). Finally, based on these initial data, we present a preliminary luminosity function and discuss several interesting features of the partial sample presented here. Once our sample is complete, we will use our measured luminosity function to constrain the mass function of low-mass stars and brown dwarfs.2003AJ....126.2421Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/126/2421CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/241 : 2MASS Catalog Intermediate Data Release (IPAC/UMass, 2000)J/AJ/123/2806 : Nearby stars in the NLTT catalogue (Reid+, 2002)J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002)J/AJ/123/2828 : Spectroscopy of northern NLTT stars (Cruz+, 2002)J/AJ/126/2449 : Nearby ultracool dwarfs in galactic plane (Reid+, 2003)J/AJ/126/3007 : Spectroscopy of faint red NLTT dwarfs (Reid+, 2003)J/AJ/128/463 : A preliminary 20pc census from the NLTT cat. (Reid+, 2004)J/AJ/130/1680 : LSPM-North proper-motion catalog nearby stars (Lepine+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/126/2421https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/126/2421http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/126/2421https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/126/2421https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/126/2421http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/126/2421GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/126/2421/old (Previously known cool dwarfs recovered in the 2MU2 sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/old?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/old?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/old?GETtext/xml+votable180.050000true6.1025-1.9719440.005555555555555556Cone search capability for table J/AJ/126/2421/new (Newly discovered stars (tables 7, 8, 9 and 10 of the paper))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/new?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/new?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/new?GETtext/xml+votable180.050000true4.85916746.2352780.005555555555555556Cone search capability for table J/AJ/126/2421/table11 (Young objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/table11?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/table11?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/table11?GETtext/xml+votable180.050000true43.4987532.1102780.005555555555555556Cone search capability for table J/AJ/126/2421/table12 (Spectroscopically confirmed giants)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/table12?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/table12?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/table12?GETtext/xml+votable180.050000true3.1425-22.9211110.005555555555555556Cone search capability for table J/AJ/126/2421/table13 (Spectroscopically confirmed carbon stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/table13?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/table13?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/table13?GETtext/xml+votable180.050000true39.1025-20.6841670.005555555555555556Cone search capability for table J/AJ/126/2421/lis (2MASS bright stars having known counterparts (tables 15, 16, 17, 18 and 19 of the paper))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/2421/lis?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/2421/lis?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/2421/lis?GETtext/xml+votable180.050000true0.33916751.2036110.0055555555555555566/285 319 334 337-338 360 369 376 399 466 537-538 544 557 609 672 728 733 749 763 823 826 864 909 945 968 985 1023 1668 1671 1674 1686 1699-1700 1703 2087 2110 2149 2187 2196 2255 2325 2382 2403-2404 2436 2441 2446 2456 2496-2498 2502 2509 2511 2547 2569 2583 2616 2694 2736 2759 2772 2774-2775 2784 2791 2801 2807 2810 2874 2978 3072 3075 3078 4253 4285 4336 4436 4442 4536 4568 4614 4623 4630 4632 4645 4662 4685 4710 4719 4737 4739 4766 4768 4775 4782 4793 4813-4814 4836 4875 4886 5042 5134 5147 5186 5264 5352 5402 5413 5429 5540 5691 5694 5744 5787 6142 6179 6255 6257 6280 6285 6295 6317 6459 6474 6522 6531 6563 6586 6597 6669 6671 6676 6732 6734 6753 6783 6839 6859 6882 6886 6946 6968 7046 7052 7194 7220 7444 7533 7659 7662 7668 7881 7893 7935 8065 8402 8431 8473 8735 8779 9068 9103 9124 9255 9311 9422 9449 9470 9479 9499 9540 9569 9576 9588 9628 9643 9677 9709 9731 9779 9820 9823 9880 9982 10003 10035 10064 10110 10202 10215 10332 10363 10555 10612 10657 10665 10676 10753 10770 10813 10830 10850 11048 11103 11146 11164 11273 11292 11303 11336 11347 11363 11422 11496 11544-11545 11602 11608 11639 11661 11719 11846 11856 11938 11940 12152 12211 12240 12413 12477 12499 12518 12534-12535 12564 12570 12589 12591 12600 12676 12682 12688 12707 12719 12737 12743 13072 13336 13338 13378 13389 13396 13403 13412 13519 13559 13568 13608 13686 13722 13736 13742 13746-13747 13769 13772 13779 13786 13793 13845 14083-14084 14858 14885 14894 14910 14944 14951 14988 14992 14999 15005 15008 15011 15024 15074 15085 15097 15146 15249 15251 15255 15338 16111 16125-16126 16502 16607 16645 16722 16785 16850 16873 17074 17283 17328 17530 17567 17594 17677 17712 17927 17953 17985 18060 18385 18478 18571 18600 18655 18681 18683 18711 18726 18742 18979 19044 19098 19106 19409 19575 19577 19671 19680 19694 19733 19813 19895 19925 19987 20047 20069 20089 20135-20136 20138 20155 20181 20281 20318 20349 20357 20362 20447 20527 20531 20557 20585 20591 20594 20618 20624 20675 20677 20701 20711 20719 20738 20744 20775 20913 20915 20922 21110 21116-21117 21171 21189 21195 21209 21267-21268 21271 21385 21791 21808 21820 21834-21835 21862 21866 22480 22513 22520-22521 22535 22543 22555 22657 22682 22687 22691 22720 22737 22739 22759 22950 23124 23144 23493 23525 23894 24029 24701 24745 24757 24782 24891 24896-24897 25015 25078 25149 25156 25162 25223 25266 25310 25314 25411 25444 25463 25470 25538 25549 25558 25619 25672 25801 25807 25818 25893 26002 26196 26279 26656 26731 26735 26763 26858 26861 26915 26954 27019 27162 27201 27214 27271 27510 27618 27635 27847 27855 28006 28018 28028 28153 28178 28234 28277 28316 28365 28370 28417 28454 28498 28513 28537 28612 29712 29720-29721 29724 29726 29972-29973 29978 29981-29982 29991 29999-30000 30007 30009-30011 30014 30017 30030 30048 30060-30061 30066 30085 30097 30850 31607 31736 31926 31978 31984 32167-32168 32184-32185 32234 32284 32294 32310 32325 32328 32516 32532 32562 32576 32588 32622 32625-32626 32628 32632 32677 32725 32729 32737 32887 33024 33034 33059 33159 33172 33174 33220 33242 33767 34219 34289 34303 34535 34580 34598 34613 34622 34626 34640 34645 34660 34678 34743 34767 34780 34803 35325 35630 35685 35804 35923 35943 36058 36081 36134 36223 36237 36240 36253 36281 36313 36348 36421 36430 36458 36467 36602 36640 36667 36740 36765 36769 36821-36822 36826 36845 37415 37521 37549 38917 38928 38937 38949 39525 39533 39546-39548 39550 39635 39639-39640 39643 39674 39851 40181 40191 40297 40313 40361 40375 40421 40428 40530 40534 40540 40572 40714 40738 40783 40812 40826 40832 40836 40865-40866 40882 40901-40903 40941 40946 43254 43481 43827 43877 43929 43966 44016 44054 44059 44081 44131 44136 44151 44186 44208 44213 44226 44230 44232 44235 44254 44256 44270 44272 44274 44327 44329 44336 44341 44349 44351 44389 44398 44400 44433 44451 44454 44456 44471 44487 44491 44502 44578 44603 44610 44633 44718 44743 44765 44807 44829 44844 44864 45007 45055 46656 46671 46821 46918 46961 47021 47039 47072 47074 47089 47100 47592 47708 47882 47888 47891 47924-47926 47931 47950 47959 47969 47981 47989 47995 48103 48108 48111 48116 48122 48150 48234 48248 48301 48303 48401 48423 48455 48462 48664 48675 48686 48697 48701 48703 48723 48745-48746 48801 48818 48836 48844 48847 48862 48865 48870 48957 48995 48998 49036 49054 49139-491401.398457827073138e-19 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/126/2421?format=asciiInfrareddefaultJ/AJ/126/2421/oldPreviously known cool dwarfs recovered in the 2MU2 samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSI2MASSI Designationmeta.id;meta.maincharn_Dist[fhijkm] Note on JMAG and Dist (2)meta.notecharJpiMAG? Absolute J magnitude based on trigonometric parallax datamagphys.magAbsfloatnullablee_JpiMAG? rms uncertainty on JpiMAGmagstat.errorfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharONameOther Namesmeta.idcharJmagJ magnitudemagphot.mag;em.IR.Jfloatn_Jmag[a] Note on Jmag (2)meta.notecharJ-HJ-H colour indexmagphot.color;em.IR.J;em.IR.HfloatJ-KsJ-Ks colour indexmagphot.color;em.IR.J;em.IR.KfloatSpTypeSpectral typesrc.spTypecharn_SpType[cd] Note on SpType (2)meta.notecharJMAG? Estimated absolute J magnitudemagphys.magAbsfloatnullablee_JMAG? rms uncertainty on JMAGmagstat.errorfloatnullableu_JMAG[)] ): estimate based on the system's combined spectral type and photometrymeta.code.errorcharDist? Estimated distancepcpos.distance;pos.heliocentricfloatnullablee_Dist? rms uncertainty on Distpcstat.errorfloatnullableu_Dist[)] ): estimate based on the system's combined spectral type and photometrymeta.code.errorcharf_JpiMAG[bge] Note on JpiMAG (2)meta.codecharDistpi? Distance based on trigonometric parallax datapcpos.distance;pos.heliocentricfloatnullablee_Distpi? rms uncertainty on Distpipcstat.errorfloatnullabler_DistpiTrigonometric Parallax references, in refs.dat filemeta.ref;pos.framecharr_MultMultiplicity references, in refs.dat filemeta.ref;pos.framecharr_DiscDiscovery references, in refs.dat filemeta.ref;pos.framechar2MASSDisplay 2MASS datameta.ref.urlchar_RAPosition from 2MASSI (II/241) name (right ascension part)degpos.eq.ra;meta.main_DEPosition from 2MASSI (II/241) name (declination part)degpos.eq.dec;meta.mainf_2MASSI[* ] star included in preliminary LF (1)meta.codecharJ/AJ/126/2421/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notecharJ/AJ/126/2421/newNewly discovered stars (tables 7, 8, 9 and 10 of the paper)n_SpTypeNote on SpType, in notes.dat filemeta.notecharn_JMAGNote on JMAG, in notes.dat filemeta.notecharDistDistance (3)pcpos.distance;pos.heliocentricfloate_Dist? Error in Distpcstat.errorfloatnullablen_DistNote on Dist detailed in notes.dat filemeta.notecharr_2MASSIOther references, in refs.dat filemeta.ref;pos.framechar2MASSDisplay 2MASS datameta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPosition from 2MASSI (II/241) name (right ascension part)degpos.eq.ra;meta.mainSpTypeSpectral typesrc.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSIThe 2MASS designationmeta.id;meta.maincharONameOther namemeta.idcharJmagThe 2MASS J-band magnitudemagphot.mag;em.IR.JfloatJ-HThe 2MASS (J-H) colormagphot.color;em.IR.J;em.IR.HfloatJ-KsThe 2MASS (J-K_s_) colormagphot.color;em.IR.J;em.IR.KfloatDateDate of spectroscopic observationtime.epochnullableTCodeTelescope used for spectroscopic observation (G1)meta.id;instr.telcharu_SpType[?] Uncertainty flag on SpType (2)meta.code.error;src.spTypecharJMAGAbsolute J-band magnitude (3)magphot.magfloate_JMAG? Error in JMAGmagstat.errorfloatnullable_DEPosition from 2MASSI (II/241) name (declination part)degpos.eq.dec;meta.mainJ/AJ/126/2421/notesNotes of tables 7, 8, 9 and 10recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoteNote codemeta.notecharTextText of the notemeta.notecharJ/AJ/126/2421/table11Young objectsJ-KsThe 2MASS (J-K_s_) colormagphot.color;em.IR.J;em.IR.KfloatDateDate of spectroscopic observationtime.epochnullableSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSIThe 2MASSI designationmeta.id;meta.maincharJmagThe 2MASS J-band magnitudemagphot.mag;em.IR.JfloatJ-HThe 2MASS (J-H) colormagphot.color;em.IR.J;em.IR.HfloatTCodeTelescope used for spectroscopic observation (G1)meta.id;instr.telcharSpTypeSpectral typesrc.spTypecharComCommentsmeta.notechar2MASSDisplay 2MASS datameta.ref.urlchar_RAPosition from 2MASSI (II/241) name (right ascension part)degpos.eq.ra;meta.main_DEPosition from 2MASSI (II/241) name (declination part)degpos.eq.dec;meta.mainJ/AJ/126/2421/table12Spectroscopically confirmed giantsSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSIThe 2MASSI designationmeta.id;meta.maincharJmagThe 2MASS J-band magnitudemagphot.mag;em.IR.JfloatJ-HThe 2MASS (J-H) colormagphot.color;em.IR.J;em.IR.HfloatJ-KsThe 2MASS (J-K_s_) colormagphot.color;em.IR.J;em.IR.KfloatDateDate of spectroscopic observationtime.epochnullableTCodeTelescope used for spectroscopic observation (G1)meta.id;instr.telcharSpTypeSpectral typesrc.spTypecharComCommentsmeta.notechar2MASSDisplay 2MASS datameta.ref.urlchar_RAPosition from 2MASSI (II/241) name (right ascension part)degpos.eq.ra;meta.main_DEPosition from 2MASSI (II/241) name (declination part)degpos.eq.dec;meta.mainJ/AJ/126/2421/table13Spectroscopically confirmed carbon starsSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSIThe 2MASSI designationmeta.id;meta.maincharJmagThe 2MASS J-band magnitudemagphot.mag;em.IR.JfloatJ-HThe 2MASS (J-H) colormagphot.color;em.IR.J;em.IR.HfloatJ-KsThe 2MASS (J-K_s_) colormagphot.color;em.IR.J;em.IR.KfloatDateDate of spectroscopic observationtime.epochnullableTCodeTelescope used for spectroscopic observation (G1)meta.id;instr.telcharVisPM[Yes No] Visual proper motion (2)meta.codecharEpochEpochtime.epochcharComComments (3)meta.notecharNote[b] Note (4)meta.notechar2MASSDisplay 2MASS datameta.ref.urlchar_RAPosition from 2MASSI (II/241) name (right ascension part)degpos.eq.ra;meta.main_DEPosition from 2MASSI (II/241) name (declination part)degpos.eq.dec;meta.mainJ/AJ/126/2421/table14JMAG/Spectral type calibration dataSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNamemeta.id;meta.maincharSpTypeSpectral type (M5 = 5, L0 = 10, L8 = 18)src.spTypefloatJMAGAbsolute J magnitudemagphys.magAbsfloate_JMAGrms uncertainty on JMAGmagstat.errorfloatRefReference (1)meta.ref;pos.frameintJ/AJ/126/2421/lis2MASS bright stars having known counterparts (tables 15, 16, 17, 18 and 19 of the paper)J-H? The 2MASS (J-H) colormagphot.color;em.IR.J;em.IR.HfloatnullableH-Ks? The 2MASS (H-K_s_) colormagphot.color;em.IR.H;em.IR.KfloatnullableKsmag? The 2MASS K_s_ band magnitudemagphot.mag;em.IR.KfloatnullableJ-Ks? The 2MASS (J-K_s_) colormagphot.color;em.IR.J;em.IR.Kfloatnullablen_IDsrc.classcharIDOther identificationsmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainVmag? The V-band magnitudemagphot.mag;em.opt.Vfloatnullable