J/MNRAS/495/2342ivo://CDS.VizieR/J/MNRAS/495/2342doi:10.26093/cds/vizier/bg-ff-296CDSDalton T.Morris S.L.2026-08-03T07:29:47Z2023-11-16T09:07:16ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomygamma-ray-burstsh-i-line-emissionx-ray-sourcesradio-sourcesIt is known that the GRB equivalent hydrogen column density (N_HX_) changes with redshift and that, typically, N_HX_ is greater than the GRB host neutral hydrogen column density. We have compiled a large sample of data for GRB N_HX_ and metallicity [X/H]. The main aims of this paper are to generate improved N_HX_ for our sample by using actual metallicities, dust corrected where available for detections, and for the remaining GRB, a more realistic average intrinsic metallicity using a standard adjustment from solar. Then, by approximating the GRB host intrinsic hydrogen column density using the measured neutral column (N_HI,IC_) adjusted for the ionization fraction, we isolate a more accurate estimate for the intergalactic medium (IGM) contribution. The GRB sample mean metallicity is =-1.17+/-0.09 rms (or 0.07+/-0.05 Z/Z_sol_) from a sample of 36 GRB with a redshift 1.76<=z<=5.91, substantially lower than the assumption of solar metallicity used as standard for many fitted N_HX_. Lower GRB host mean metallicity results in increased estimated N_HX_ with the correction scaling with redshift as {Delta}log(N_HX_cm^-2^)=(0.59+/-0.04)log(1+z)+0.18+/-0.02. Of the 128 GRB with data for both N_HX_ and N_HI,IC_ in our sample, only six have N_HI,IC_>N_HX_ when revised for realistic metallicity, compared to 32 when solar metallicity is assumed. The lower envelope of the revised N_HX_-N_HI,IC_, plotted against redshift can be fit by log(N_HX_-N_HI,IC_cm^-2^)=20.3+2.4log(1+z). This is taken to be an estimate for the maximum IGM hydrogen column density as a function of redshift. Using this approach, we estimate an upper limit to the hydrogen density at redshift zero (n_0_) to be consistent with n_0_=0.17x10^-7^cm^-3^.2020MNRAS.495.2342Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/495/2342CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/495/2342https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/495/2342http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/495/2342https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/495/2342https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/495/2342http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/495/2342GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/495/2342/table1 (The GRB full sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/495/2342/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/495/2342/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/495/2342/table1?GETtext/xml+votable180.050000true245.077083329.44305560.0055555555555555566/186 207 314 393 500 503 576 646 699 744 908 923 1001 2315 2336 2357 2682 2735 2948-2949 3089 3111 3536 3586 3839 3935 4271 4312 4323 4371 4449-4450 4809 4955 5051 5135 5184 5376 5625 5657 5726 5745 5790 5840 5941 6258 6261 6523 6758 7156 7227 7518 7532 7589 7750 8074 8345 8425 8459 8641 8669 8693 8733 8761 8798 8932 8954 9022 9100 9321 9363 9370 9643 9662 9682 9750 9897 9989 10080 10094 10335 10400 10407 10424 10447 10519 10602 10680 10704 10723 10761-10762 10852 11058 11220 11308 11657 11673 11749 11756 11822 11905 12006 12020 12134 12199 12425 12438 12597 13312 13331 13694 13779 13924 14259 14892 15004 15054 15340 15348 15360 15530 15915 16057 16282 16489 16546 16661 16845 16991 17086 17316 17411 17453 17561 17703 17721 17733 17749 17814 17980 17982 18681 18728 18777 18910 18945 18978 19049 19082 19097 19164 19168 19194 19293 19334 19731 19864-19865 19890 19911 20030 20053 20191 20348 20372 20401 20460 20679 20753 20774 21015 21284 21498 21595 21766 21962 22129 22518 22559 22619 22624 22793 22816 22916 23138 23306 24007 24534 24993 25131 25146 25148 25174 25192 25336 25426 25761 25901 25946 26011 26036 26441 26503 26671 27085 27262 27284 27289 27320 27434 27541 27566 27841 27906 27933 27961-27962 27965 27983 28032 28063 28071 28234 28467 28497 28546 28555 28930 29019 29052 29731 30088 30195 30557 30947 31185 31281 31385 31494 31521 31583 31700 31934 32110 32239 32310 32646 32713 32790 33004 33066 33146 33265 33278 33525 33617 33679 33735 33813 33860 34147 34168 34174 34364 34440 34465 34590 34605 34699 34788 34832 34949 35045 35285 35330 35392-35393 35427 35569 35633 35844 36066 36074 36107 36142 36297 36361 36460 37383 37391 37459 37505 38280 38869 38926 39008 39076 39553 39594 39993 40249 40433 40736 40778 40784 41064 42133 42545 42901 42952 43193 44212 44223 44715 44857 45008 45205 45361 45401 45409 45510 45777 45828 45835-45836 45938 46022 46057 46150 46212 46218 46250 46365 46395 46594 46899 46989 47031 47136 47148 47162 47245 47251 47257 47436 47459 47588 47620 47991 48007 48054 48151 48189 48371 48447 48458 48921 48968 49004 49034https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/495/2342?format=asciiGamma-rayX-rayRadiodefaultJ/MNRAS/495/2342/table1The GRB full sampleGRBGRB namemeta.id;meta.maincharSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintzSpectroscopic redshiftsrc.redshiftfloatlogNHX? Equivalent hydrogen column densitylog(cm**-2)phys.columnDensityfloatnullableE_logNHX? Error on logNHX (upper value)log(cm**-2)stat.error;stat.maxfloatnullablee_logNHX? Error on logNHX (lower value)log(cm**-2)stat.errorfloatnullabler_logNHXReference for logNHX (1)meta.ref;pos.framecharlogNHI-IC? HI column density (from Tanvir et al., 2019MNRAS.483.5380T)log(cm**-2)phys.columnDensityfloatnullablee_logNHI-IC? Error on logNHI-IClog(cm**-2)stat.errorfloatnullablen_logNHI-IC[IC ] IC for corrected for ionization fractionmeta.notecharl_[X/H][< >=] Limit flag on [X/H]meta.code.error;phys.abundchar[X/H]? Metal abundancephys.abund.ZfloatnullableE_[X/H]? Error on [X/H] (upper value)stat.error;stat.maxfloatnullablee_[X/H]? Error on [X/H] (lower value)stat.error;phys.abundfloatnullabler_[X/H]Reference for [X/H] (1)meta.ref;pos.framechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable