J/ApJ/814/133ivo://CDS.VizieR/J/ApJ/814/133doi:10.26093/cds/vizier.18140133CDSGoldsmith P.F.Yildiz U.A.Langer W.D.Pineda J.L.2017-11-28T12:07:38Z2017-10-23T13:26:04ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyinterstellar-mediumspectroscopyWe present the first large-scale high angular resolution survey of ionized nitrogen in the Galactic Plane through emission of its two fine structure transitions ([N II]) at 122 and 205 {mu}m. The observations were largely obtained with the PACS instrument onboard the Herschel Space Observatory. The lines of sight were in the Galactic plane, following those of the Herschel OTKP project GOT C+. Both lines are reliably detected at the 10^-8^-10^-7^ W/m^2^/sr level over the range -60{deg}<=l<=60{deg}. The rms of the intensity among the 25 PACS spaxels of a given pointing is typically less than one third of the mean intensity, showing that the emission is extended. [N II] is produced in gas in which hydrogen is ionized, and collisional excitation is by electrons. The ratio of the two fine structure transitions provides a direct measurement of the electron density, yielding n(e) largely in the range 10-50 cm^-3^ with an average value of 29 cm^-3^ and N^+^ column densities 10^16^-10^17^ cm^-2^. [N II] emission is highly correlated with that of [C II], and we calculate that between 1/3 and 1/2 of the [C II] emission is associated with the ionized gas. The relatively high electron densities indicate that the source of the [N II] emission is not the warm ionized medium (WIM), which has electron densities more than 100 times smaller. Possible origins of the observed [N II] include the ionized surfaces of dense atomic and molecular clouds, the extended low-density envelopes of H II regions, and low-filling factor high-density fluctuations of the WIM.2015ApJ...814..133Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/814/133CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVI/139 : Herschel Observation Log (Herschel Science Centre, 2013)J/ApJ/829/93 : CO, [CI] and [NII] lines from Herschel spectrahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/814/133https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/814/133http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/814/133https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/814/133https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/814/133http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/814/133GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/814/133/table3 (PACS Results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/814/133/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/814/133/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/814/133/table3?GETtext/xml+votable180.050000true55.95635554.9443870.005555555555555556Cone search capability for table J/ApJ/814/133/table2 (Observed PACS Integrated Intensities for [N II] 122 and 205 {mu}m Transitions are Tabulated Together with the Inferred Electron Volume Densities and N^+^ Column Densities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/814/133/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/814/133/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/814/133/table2?GETtext/xml+votable180.050000true266.404996-28.9361720.0055555555555555566/1331 1433 1952 3164 3607 3640 12971 14299 14307 14340 14341 14353 14412 14429 14618 14666 14683 15372 15389 15442 21650 21689 22247 23635 24324 24359 28808 28809 28812 28813 28826 28827 28830 28831 28874 28897 28900 28901 28912 28915 28918 28919 29090 29097 29100 29101 29114 29115 29118 29461 29504 29505 29510 29511 29522 29529 29533 29535 30218 30219 30244 30245 30258 30262 30269 30312 30318 30319 30416 30420 30423 30594 30604 30605 30619 30622 30645 30689 30694 30695 30713 30716 30719 37717 37748 37843 37881 37903 37931 38026 39258 39376 39410 39804 39903 41599 41655 41658 41660 41675 41676 41682 41683 41684 41696 41767 41769 41772 41777 41780 41802 41803 41805 41813 41814 42159 42170 42171 42172 42173 42214 42215 42217 42225 42226 42228 42378 42379 42381 42382 42393 42396 42397 42440 42441 42444 42445 42456 42457 42460 42461 42500 43015 43020https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/814/133?format=asciiOpticaldefaultJ/ApJ/814/133/table3PACS ResultsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDLine of sight (LOS) label (GLLL.l+B.b)meta.id;spect.linecharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latOBSIDHerschel OBSIDmeta.id;obsR[0/3]? Detection status (1)meta.codeintnullablel_NII122[<] Limit flag on NII122meta.code.errorcharNII122? [N II] 122 {mu}m intensity averaged over the 25 PACS spaxels1e-08W.m**-2.sr**-1spect.line.intensityfloatnullablee_NII122? Uncertainty in NII1221e-08W.m**-2.sr**-1stat.errorfloatnullableRMS? RMS variation among the 25 spaxels at 122 {mu}m wavelengthstat.errorfloatnullableR1[0/3]? Detection status (1)meta.codeintnullablel_NII205[<] Limit flag on NII205meta.code.errorcharNII205? [N II] 205 {mu}m intensity averaged over the 25 PACS spaxels1e-08W.m**-2.sr**-1spect.line.intensityfloatnullablee_NII205? Uncertainty in NII2051e-08W.m**-2.sr**-1stat.errorfloatnullablen(e)? Electron densitycm**-3phys.density;phys.electronfloatnullablee_n(e)? Uncertainty in n(e)cm**-3stat.errorfloatnullableN(N+)? N^+^ column density1e+16cm**-2phys.columnDensityfloatnullablee_N(N+)? Uncertainty in N(N+)1e+16cm**-2stat.errorfloatnullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexedJ/ApJ/814/133/table2Observed PACS Integrated Intensities for [N II] 122 and 205 {mu}m Transitions are Tabulated Together with the Inferred Electron Volume Densities and N^+^ Column DensitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDLine of sight (LOS) label (GLLL.l+B.b)meta.id;spect.linecharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latOBSIDHerschel OBSIDmeta.id;obsR[0/3]? Detection status (1)meta.codeintnullablel_NII122[<] Limit flag on NII122meta.code.errorcharNII122? [N II] 122 {mu}m intensity averaged over the 25 PACS spaxels1e-08W.m**-2.sr**-1spect.line.intensityfloatnullablee_NII122? Uncertainty in NII1221e-08W.m**-2.sr**-1stat.errorfloatnullableRMS? RMS variation among the 25 spaxels at 122 {mu}m wavelengthstat.errorfloatnullableR1[0/3]? Detection status (1)meta.codeintnullablel_NII205[<] Limit flag on NII205meta.code.errorcharNII205? [N II] 205 {mu}m intensity averaged over the 25 PACS spaxels1e-08W.m**-2.sr**-1spect.line.intensityfloatnullablee_NII205? Uncertainty in NII2051e-08W.m**-2.sr**-1stat.errorfloatnullablen(e)? Electron densitycm**-3phys.density;phys.electronfloatnullablee_n(e)? Uncertainty in n(e)cm**-3stat.errorfloatnullableN(N+)? N^+^ column density1e+16cm**-2phys.columnDensityfloatnullablee_N(N+)? Uncertainty in N(N+)1e+16cm**-2stat.errorfloatnullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed