J/ApJ/746/170ivo://CDS.VizieR/J/ApJ/746/170doi:10.26093/cds/vizier.17460170CDSMorgan A.N.Long J.Richards J.W.Broderick T.Butler N.R.Bloom J.S.2017-12-18T07:57:45Z2013-10-17T13:53:13ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomyredshiftedAs the number of observed gamma-ray bursts (GRBs) continues to grow, follow-up resources need to be used more efficiently in order to maximize science output from limited telescope time. As such, it is becoming increasingly important to rapidly identify bursts of interest as soon as possible after the event, before the afterglows fade beyond detectability. Studying the most distant (highest redshift) events, for instance, remains a primary goal for many in the field. Here, we present our Random Forest Automated Triage Estimator for GRB redshifts (RATE GRB-z) for rapid identification of high-redshift candidates using early-time metrics from the three telescopes onboard Swift. While the basic RATE methodology is generalizable to a number of resource allocation problems, here we demonstrate its utility for telescope-constrained follow-up efforts with the primary goal to identify and study high-z GRBs. For each new GRB, RATE GRB-z provides a recommendation--based on the available telescope time--of whether the event warrants additional follow-up resources. We train RATE GRB-z using a set consisting of 135 Swift bursts with known redshifts, only 18 of which are z > 4. Cross-validated performance metrics on these training data suggest that ~56% of high-z bursts can be captured from following up the top 20% of the ranked candidates, and ~84% of high-z bursts are identified after following up the top ~40% of candidates. We further use the method to rank 200 + Swift bursts with unknown redshifts according to their likelihood of being high-z.2012ApJ...746..170Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/746/170CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/421/2692 : Optical/NIR observations of GRB 080310 (Littlejohns+, 2012)J/ApJ/731/103 : Redshift catalog for Swift long GRBs (Xiao+, 2011)J/ApJS/195/2 : The second Swift BAT GRB catalog (BAT2) (Sakamoto+, 2011)J/MNRAS/406/2473 : Photometry of GRB 071025 (Perley+, 2010)J/ApJ/720/1513 : The afterglows of Swift-era GRBs. I. (Kann+, 2010)J/ApJ/711/495 : Durations of Swift/BAT GRBs (Butler+, 2010)J/ApJ/690/163 : The first Swift UV-Opt GRB afterglow catalog (Roming+, 2009)J/ApJ/704/1405 : Testing the E_peak_-E_iso_ relation for GRBs (Krimm+, 2009)J/PAZh/35/10 : Gamma-ray bursts with known redshifts (Badjin+, 2009)J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)J/ApJ/642/L99 : R-band photometry of GRB 060206 (Wozniak+, 2006)J/A+A/427/87 : List of GRBs (Gorosabel+, 2004)J/ApJ/609/935 : Gamma-ray burst formation rate (Yonetoku+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/746/170https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/746/170http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/746/170https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/746/170https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/746/170http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/746/170GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/746/170/table4 (Test data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/746/170/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/746/170/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/746/170/table4?GETtext/xml+votable180.050000true348.383349.32170.005555555555555556Cone search capability for table J/ApJ/746/170/training (Training set data and results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/746/170/training?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/746/170/training?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/746/170/training?GETtext/xml+votable180.050000true271.3842-62.47230.0055555555555555566/314 393 453 462 500 503 646 918 923 944 1507 1526 2044 2296 2315 2456 2925 3316 3405 3536 3551 3589 3659 3700 3832 3894 4450 4485 4788 4955 4977 5051 5080 5376 5455 5525 5618 5625 5633 5718 5726 5745 5941 6004 6102 6593 6862 7043 7044 7156 7518 7620 7685 7747 7908 7980 8375 8641 8669 8798 8932 8954 9024 9069 9100 9143 9330 9370 9395 9682 9714 9750 9926 9989 10094 10135 10335 10447 10519 10666 10680 10723 10852 10912 10914 10948 11248 11307 11640 11657 11673 11749 11905 12020 12134 12287 13312 13475 13558 13694 13701 13762 13787 13898 13924 14020 14059 14144 14248 14754 14781 14852 14892 14977 15054 15197 15473 15505 15513 15595 15613 15683 15702 15915 15995 16072 16078 16172 16232 16282 16391 16489 16493 16546 16661 16769 16991 17279 17294 17453 17561 17721 17733 17814 17980 18097 18681 18777 18978 19049 19164 19168 19194 19293 19331 19544 19731 19865 19890 20263 20360 20401 20655 20668 20753 21082 21137 21360 21439 21498 21688 21903 21915 21962 22129 22157 22422 22580 22624 23138 23680 24036 24105 24424 25174 25293 25394 25529 25597 25901 25946 26036 26441 26671 27085 27289 27566 27906 27933 27962 28063 28467 28726 28863 29563 29612 30385 30461 30568 30692 31143 31185 31281 31385 31583 31607 31700 31730 31847 31934 31982 32110 32239 32676 32713 33000 33061 33278 33323 33358 33525 33617 33679 33735 33813 33845 34147 34435 34440 34465 34605 34788 34949 35088 35330 35440 35566 35633 35844 36297 36374 36460 36532 37071 37383 37428 37562 37830 38046 38146 38280 38301 38620 38926 39008 39059 39076 39199 39224 39374 39432 39829 39881 39912 40249 40389 40433 40482 40611 40642 40778 41020 41059 41135 41435 41442 41555 41989 42473 42914 43045 43280 43558 43920 44021 44212 44419 44493 44720 44822 44857 45008 45088 45192 45205 45361 45402 45409 45422 45510 45777 45836 45938 46022 46218 46250 46510 46594 46814 47136 47162 47251 47436 47459 47632 47945 47991 48054 48189 48422 48447 48458 49004https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/746/170?format=asciiGamma-rayOpticaldefaultJ/ApJ/746/170/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibcodemeta.bib.bibcodecharAutAuthor's name(s)meta.bib.authorcharJ/ApJ/746/170/table4Test dataSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGRBGRB identifier (YYMMDDA)meta.id;meta.maincharalpha[-2/5]? Power-law index {alpha} (1)spect.indexfloatnullableEpeak[11/1220] Energy at which most photons are emitted (1)keVphys.energy;phys.atmol.levelfloatSTotal gamma-ray (15-350 keV) fluence (1)mJ.m**-2phot.fluence;em.gamma.harddoubleS/N[4.6/725] Maximum signal-to-noise (1)stat.snr;stat.maxfloatNH? Excess neutral hydrogen column (2)1e+22cm**-2phys.abund.X;phot.color.excessfloatnullableT90[2.2/639] Burst duration (1)stime.durationfloatsig[5.64/25.8] Significance of BAT image (3)stat.likelihood;obsfloatRpeak[47/18400] BAT peak count ratect/sphot.count;em.gamma.hardfloatTrig[yes/no ] Rate trigger?meta.codechartBAT[0.06/320] Early time estimate of burst duration (4)stime.durationdoubleUVOT[yes/no ] UVOT detection?meta.codecharPpz[0/0.31] Fraction of posterior probability at z>4 (5)stat.fit.goodnessfloatQhat[0/1]? Decision criterion (G1)stat.fit.paramfloatnullable_RAPositions from SIMBAD database (right ascension part)degpos.eq.ra;meta.mainnullable_DEPositions from SIMBAD database (declination part)degpos.eq.dec;meta.mainnullableJ/ApJ/746/170/trainingTraining set data and resultsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGRBGRB identifier (YYMMDDA)meta.id;meta.maincharQhat-tr[0/1] Training decision criterion (G1)stat.fit.paramfloatz[0.0331/8.2] Redshiftsrc.redshiftfloatr_zReference(s) for z (see refs.dat file)meta.ref;pos.framecharalpha[-2/5]? Power-law index {alpha} (1)spect.indexfloatnullableEpeak[11/1220] Energy at which most photons are emitted (1)keVphys.energy;phys.atmol.levelfloatSTotal gamma-ray (15-350 keV) fluence (1)mJ.m**-2phot.fluence;em.gamma.harddoubleS/N[4.6/725] Maximum signal-to-noise (1)stat.snr;stat.maxfloatNH? Excess neutral hydrogen column (2)1e+22cm**-2phys.abund.X;phot.color.excessfloatnullableT90[2.2/639] Burst duration (1)stime.durationfloatsig[5.64/25.8] Significance of BAT image (3)stat.likelihood;obsfloatRpeak[47/18400] BAT peak count ratect/sphot.count;em.gamma.hardfloatTrig[yes/no ] Rate trigger?meta.codechartBAT[0.06/320] Early time estimate of burst duration (4)stime.durationdoubleUVOT[yes/no ] UVOT detection?meta.codecharPpz[0/0.31] Fraction of posterior probability at z>4 (5)stat.fit.goodnessfloat_RAPositions from SIMBAD database (right ascension part)degpos.eq.ra;meta.main_DEPositions from SIMBAD database (declination part)degpos.eq.dec;meta.main