J/ApJ/849/1ivo://CDS.VizieR/J/ApJ/849/1doi:10.26093/cds/vizier.18490001CDSKoepferl C.M.Robitaille T.P.Dale J.E.2019-11-11T22:00:00Z2018-12-03T10:15:04ZCDS support team

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

cds-question@unistra.frstar-forming-regionsastronomical-modelsWe use a large data set of realistic synthetic observations (produced in Paper I (2017ApJS..233....1K) of this series) to assess how observational techniques affect the measurement physical properties of star-forming regions. In this part of the series (Paper II), we explore the reliability of the measured total gas mass, dust surface density and dust temperature maps derived from modified blackbody fitting of synthetic Herschel observations. We find from our pixel-by-pixel analysis of the measured dust surface density and dust temperature a worrisome error spread especially close to star formation sites and low-density regions, where for those "contaminated" pixels the surface densities can be under/overestimated by up to three orders of magnitude. In light of this, we recommend to treat the pixel-based results from this technique with caution in regions with active star formation. In regions of high background typical in the inner Galactic plane, we are not able to recover reliable surface density maps of individual synthetic regions, since low-mass regions are lost in the far-infrared background. When measuring the total gas mass of regions in moderate background, we find that modified blackbody fitting works well (absolute error: +9%; -13%) up to 10kpc distance (errors increase with distance). Commonly, the initial images are convolved to the largest common beam-size, which smears contaminated pixels over large areas. The resulting information loss makes this commonly used technique less verifiable as now {chi}^2^ values cannot be used as a quality indicator of a fitted pixel. Our control measurements of the total gas mass (without the step of convolution to the largest common beam size) produce similar results (absolute error: +20%; -7%) while having much lower median errors especially for the high-mass stellar feedback phase.2017ApJ...849....1Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/849/1CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/591/A149 : Hi-GAL. inner Milky Way: +68>=l>=70 (Molinari+, 2016)J/ApJ/849/2 : Insights from synthetic star-forming regions. III.https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/849/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/849/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/849/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/849/1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/849/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/849/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/849/1/table1Intrinsic and measured properties for background B1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDRunning number (run)meta.id;meta.mainintTimeTime (time)Myrtime.epochfloatSorterSorter (sorter) (1)meta.id;stat.fitcharMgasGas mass (Mgas_sim)solMassphys.massfloatMgasB1Gas mass without a realistic background (B1) (Mgas_B1)solMassphys.massfloatMgasB1cMgasB1 {chi}^2^ corrected (Mgas_B1_chi5)solMassphys.massfloatR0Median ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_ (R0)src.density;arith.ratiofloate_R0R0 {sigma}_MAD_ (Re0)stat.errorfloatR1Median ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_ (R1)src.density;arith.ratiofloate_R1R1 {sigma}_MAD_ (Re1)stat.errorfloatR2Median ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_ (R2)src.density;arith.ratiofloate_R2R2 {sigma}_MAD_ (Re2)stat.errorfloatR3Median ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_ (R3)src.density;arith.ratiofloate_R3R3 {sigma}_MAD_ (Re3)stat.errorfloatR0cMedian ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_; {chi}^2^ corrected (R0c)src.density;arith.ratiofloate_R0cR0c {sigma}_MAD_ (Re0c)stat.errorfloatR1cMedian ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_; {chi}^2^ corrected (R1c)src.density;arith.ratiofloate_R1cR1c {sigma}_MAD_ (Re1c)stat.errorfloatR2cMedian ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_; {chi}^2^ corrected (R2c)src.density;arith.ratiofloate_R2cR2c {sigma}_MAD_ (Re2c)stat.errorfloatR3cMedian ratio of measured {Sigma}^dust^_{rho}_ to intrinsic {Sigma}^dust^_{rho}_ {chi}^2^ corrected (R3c)src.density;arith.ratiofloate_R3cR3c {sigma}_MAD_ (Re3c)stat.errorfloatT0Median ratio of measured T_dust_ to intrinsic <T>_dust_ (T0)phys.temperature;arith.ratiofloate_T0T0 {sigma}_MAD_ (Te0)stat.errorfloatT1Median ratio of measured T_dust_ to intrinsic <T>_dust_ (T1)phys.temperature;arith.ratiofloate_T1T1 {sigma}_MAD_ (Te1)stat.errorfloatT2Median ratio of measured T_dust_ to intrinsic <T>_dust_ (T2)phys.temperature;arith.ratiofloate_T2T2 {sigma}_MAD_ (Te2)stat.errorfloatT3Median ratio of measured T_dust_ to intrinsic <T>_dust_ (T3)phys.temperature;arith.ratiofloate_T3T3 {sigma}_MAD_ (Te3)stat.errorfloatT0cMedian ratio of measured T_dust_ to intrinsic <T>_dust_; {chi}^2^ corrected (T0c)phys.temperature;arith.ratiofloate_T0cT0c {sigma}_MAD_ (Te0c)stat.errorfloatT1cMedian ratio of measured T_dust_ to intrinsic <T>_dust_; {chi}^2^ corrected (T1c)phys.temperature;arith.ratiofloate_T1cT1c {sigma}_MAD_ (Te1c)stat.errorfloatT2cMedian ratio of measured T_dust_ to intrinsic <T>_dust_; {chi}^2^ corrected (T2c)phys.temperature;arith.ratiofloate_T2cT2c {sigma}_MAD_ (Te2c)stat.errorfloatT3cMedian ratio of measured T_dust_ to intrinsic <T>_dust_; {chi}^2^ corrected (T3c)phys.temperature;arith.ratiofloate_T3cT3c {sigma}_MAD_ (Te3c)stat.errorfloat