J/A+A/706/A367ivo://CDS.VizieR/J/A+A/706/A367doi:10.26093/cds/vizier/bc-p2/ldghCDSFeltre A.Belfiore F.Cresci G.Corbelli E.Tomicic N.Mannucci F.,Marconi A.Bertola E.Bracci C.Cataldi E.Ceci M.Curti M.,D'Amato Q.Ginolfi M.Koch E.Lamperti I.Magrini L.Marconcini C.,Plat A.Scialpi M.Tozzi G.Ulivi L.Venturi G.Zanchettin M.V.,Chakraborty A.Amiri A.2026-02-20T20:00:55Z2026-02-20T09:43:57ZCDS support team

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

cds-question@unistra.frgalaxiesh-ii-regionsinterstellar-mediumastrometryextinctionchemical-abundancesspectroscopyvisible-astronomyWe present new VLT/MUSE mosaic observations of a 3x8 arcmin^2^ area along the southern major axis of the nearby galaxy M33 at a distance of 840kpc from the Milky Way. These data provide an unprecedented view of the galaxy interstellar medium (ISM), and allow us to resolve ionised nebulae at a spatial scale of ~=5pc. We identify and catalogue 124 HII regions, down to H{alpha} luminosities of ~=5*10^35^erg/s, one order of magnitude fainter than previous surveys on local galaxies, and compare these regions with the spatial distribution of ionising stars and embedded star clusters. For each region, we extract the corresponding integrated optical spectra and measured the intensity of key optical emission lines (H{beta}{lambda}4861, [OIII]4959,5007, [NII]{lambda}6548,6584, H{alpha}, [SII]{lambda}6716,6731, [SIII]{lambda}9069, other weaker optical lines when detectable, and Paschen lines) to characterize their physical properties of the ioinized gas such as density, dust attenuation, and metallicity. Our spatially resolved line ratio and flux maps reveal remarkable diversity in ionisation properties, from dust-obscured regions hosting young stellar objects to highly ionised bubbles exhibiting high [OIII]/H{beta} ratios (>5). Our data reveal a diversity of ionisation fronts, ranging from well-defined to partial to absent. Radial profiles indicate the presence of both optically thin (density-bounded) and optically thick (radiation-bounded) HII regions. Our study highlights the richness of this MUSE mosaic and their unparalleled view of the ISM. In particular, the ability to probe the ISM at ~=5pc resolution opens a new window onto the complex structure of the ionised gas, enabling direct insight into how stellar feedback operates on the scales where it originates.2026A&A...706A.367Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/706/A367CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/700/A125 : MUSE NGC 253 planetary nebulae (Congiu+, 2025)J/A+A/691/A173 : HII in galaxies abundances (Brazzini+, 2024)J/A+A/668/A74 : NGC 300 catalog of HII and DIG regions (Micheva+, 2022)J/A+A/666/A29 : M83 PNe in MUSE+HST dataset (Della+, 2022)J/A+A/658/A188 : PHANGS-MUSE sample HII regions catalog (Santoro+, 2022)J/A+A/648/A65 : The sHRD of OB stars in NGC 2070 (Castro+, 2021)J/A+A/601/A146 : M33 molecular clouds and young stellar clustersJ/A+A/552/A140 : SEDs of M33 HII regions (Relano+, 2013)J/A+A/534/A96 : Spitzer photometry of YSC in M33 (Sharma+, 2011)J/A+A/512/A63 : Abundances of M33 HII regions (Magrini+, 2010)J/A+A/367/498 : Candidate Planetary Nebulae in M 33 (Magrini+, 2001)J/ApJ/953/164 : ACA CO(J=2-1) mapping of M33. I. Molecular cloudsJ/ApJ/952/114 : HMXBs in M33 with Chandra X-ray and HST obs.J/ApJ/939/44 : CHAOS. VII. Large-scale abundance study in M33J/ApJ/915/21 : CHAOS. VI. Direct abundances in NGC 2403 (Rogers+, 2021)J/ApJ/893/96 : CHAOS IV: NGC3184 LBT obs. & 3 other gal. abundancesJ/ApJ/855/140 : MMT spectra of SNRs and SNR candidates in M33 (Long+, 2018)J/ApJ/806/16 : CHemical Abundances of Spirals (CHAOS). I. NGC628J/ApJ/793/134 : M33 SNR candidates properties (Lee+, 2014)J/ApJ/755/40 : HII regions in the Magellanic clouds from MCELSJ/ApJ/733/123 : The Wolf-Rayet content of M33 (NGC 598) (Neugent+, 2011)J/ApJ/675/1213 : Abundances in M33 HII regions (Rosolowsky+, 2008)J/ApJ/664/850 : Spitzer observations of stars in M33 (McQuinn+, 2007)J/ApJ/614/167 : Planetary nebulae in M33 (Ciardullo+, 2004)J/ApJ/505/793 : New WR star in M33 (Massey+, 1998)J/ApJS/253/53 : PHATTER. I. HST obs. of 22million stars in M33J/ApJS/218/9 : Deep XMM-Newton survey of M33 (Williams+, 2015)J/ApJS/193/31 : M33 Chandra ACIS survey: final catalog (Tullmann+, 2011)J/ApJS/187/495 : SNRs in M33 from optical and X-ray (Long+, 2010)J/ApJS/167/177 : Emission lines of evolving HII regions (Dopita+, 2006)J/ApJS/161/271 : The X-ray binary population in M33. I (Grimm+, 2005)J/AJ/134/2474 : H{alpha} emission-line stars in 7 dwarfs galaxiesJ/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006)J/MNRAS/527/10668 : JWST observations of M33 (Peltonen+, 2024)J/MNRAS/520/4902 : The PHANGS-MUSE nebular catalogue (Groves+, 2023)J/MNRAS/508/5425 : Study of NGC 300 objects with dendogram (McLeod+, 2021)J/MNRAS/498/4906 : Pressure components in the central HII regionsJ/MNRAS/421/1043 : Emission-line galaxies from SDSS DR7 (Shirazi+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/706/A367https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/706/A367http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/706/A367https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/706/A367https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/706/A367http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/706/A367GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/706/A367/catalog (MUSE M33 HII region catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/706/A367/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/706/A367/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/706/A367/catalog?GETtext/xml+votable180.050000true23.39830.50.0055555555555555566/2155https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/706/A367?format=asciiOpticaldefaultJ/A+A/706/A367/catalogMUSE M33 HII region catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification number of HII nebular mask (HII_ID)meta.id;meta.mainintRAJ2000Right ascension (J2000) (RA)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (DEC)degpos.eq.dec;meta.mainNpixNumber of pixel within the nebular mask (Npix)meta.numberintStarEqual to WR for 7 cases when a WR star is within the nebular mask (star)meta.codecharYSCC? Identification number of associated YSCC from Corbelli et al. (2017A&A...601A.146C, Cat. J/A+A/601/A146) (YSCC)meta.id.associntnullableE(B-V)E(B-V) value computed from the Balmer decrement (EBV)magphot.color.excessfloatneElectron density computed from the [SII]{lambda}6716/[SII]{lambda}6731 doublet ratio (ne)cm**-3phys.density;phys.electron;meta.modelledfloat(O/H)SOxygen abundance in terms of 12+log(O/H) from the S-calibration of Pilyugin & Grebel (2016MNRAS.457.3678P) (OH_Scal)phys.abund;meta.modelledfloat(O/H)N2S2HaOxygen abundance in terms of 12+log(O/H) from the N2S2H{alpha} indicator from Brazzini et al. (2024A&A...691A.173B, Cat. J/A+A/691/A173) (OH_N2S2Ha)phys.abund;meta.modelledfloatFHbExtracted H{beta}{lambda}4861 strong optical line flux at 4861{AA} summed over the entire nebular mask (Hb4861_FLUX)1e-23W.m**-2phot.flux;spect.line;em.line.HbetadoubleFOIII4958Extracted [OIII]4958 strong optical line flux at 4958{AA} summed over the entire nebular mask (OIII4958_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFOIII5006Extracted [OIII]5006 strong optical line flux at 5006{AA} summed over the entire nebular mask (OIII5006_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHeI5015Extracted HeI{lambda}5015 strong optical lines flux at 5015{AA} summed over the entire nebular mask (HeI5015_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFNII5754Extracted [NII]{lambda}5754 auroral line flux at 5754{AA} summed over the entire nebular mask (NII5754_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHeI5875Extracted HeI{lambda}5875 strong optical lines flux at 5875{AA} summed over the entire nebular mask (HeI5875_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFNII6548Extracted [NII]{lambda}6548 strong optical lines flux at 6548{AA} summed over the entire nebular mask (NII6548_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHa6562Extracted Ha{lambda}6562 strong optical lines flux at 6562{AA} summed over the entire nebular mask (Ha6562_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFNII6583Extracted [NII]{lambda}6584 strong optical lines flux at 6584{AA} summed over the entire nebular mask (NII6583_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHeI6678Extracted HeI{lambda}6678 strong optical lines flux at 6678{AA} summed over the entire nebular mask (HeI6678_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFSII6716Extracted [SII]{lambda}6716 strong optical lines flux at 6716{AA} summed over the entire nebular mask (SII6716_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFSII6730Extracted [SII]{lambda}6730 strong optical lines flux at 6730{AA} summed over the entire nebular mask (SII6730_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHeI7065Extracted HeI{lambda}7065 trong optical line flux at 7065{AA} summed over the entire nebular mask (HeI7065_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFArIII7135Extracted [ArIII]{lambda}7135 auroral lines flux at 7135{AA} summed over the entire nebular mask (ArIII7135_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFOII7325Extracted [OII]{lambda}7325 auroral line flux at 7325{AA} summed over the entire nebular mask (OII7325_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFArIII7751Extracted [ArIII]{lambda}7751 auroral lines flux at 7751{AA} summed over the entire nebular mask (ArIII7751_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHPa128750Extracted Pa12{lambda}8750 lines of the Hydrogen Paschen series flux at 8750{AA} summed over the entire nebular mask (HPa128750_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHPa118862Extracted Pa11{lambda}8862 lines of the Hydrogen Paschen series flux at 8862{AA} summed over the entire nebular mask (HPa118862_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHPa109015Extracted Pa10{lambda}9015 lines of the Hydrogen Paschen series flux at 9015{AA} summed over the entire nebular mask (HPa109015_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFSIII9068Extracted [SIII]{lambda}9069 strong optical lines flux at 9069{AA} summed over the entire nebular mask (SIII9068_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoubleFHPa99229Extracted Pa9{lambda}9229 lines of the Hydrogen Paschen series flux at 9229{AA} summed over the entire nebular mask (HPa99229_FLUX)1e-23W.m**-2phot.flux;spect.line;em.optdoublee_FHbError on the line flux FHb (Hb4861_FLUX_ERR)1e-23W.m**-2stat.errordoublee_FOIII4958? Error on the line flux FOIII4958 (OIII4958_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FOIII5006? Error on the line flux FOIII5006 (OIII5006_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHeI5015? Error on the line flux FHeI5015 (HeI5015_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FNII5754? Error on the line flux FNII5754 (NII5754_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHeI5875? Error on the line flux FHeI5875 (HeI5875_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FNII6548? Error on the line flux FNII6548 (NII6548_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHa6562? Error on the line flux FHa6562 (Ha6562_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FNII6583? Error on the line flux FNII6583 (NII6583_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHeI6678? Error on the line flux FHeI6678 (HeI6678_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FSII6716? Error on the line flux FSII6716 (SII6716_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FSII6730? Error on the line flux FSII6730 (SII6730_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHeI7065? Error on the line flux FHeI7065 (HeI7065_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FArIII7135? Error on the line flux FArIII7135 (ArIII7135_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FOII7325? Error on the line flux FOII7325 (OII7325_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FArIII7751? Error on the line flux FArIII7751 (ArIII7751_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHPa128750? Error on the line flux FHPa128750 (HPa128750_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHPa118862? Error on the line flux FHPa118862 (HPa118862_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHPa109015? Error on the line flux FHPa109015 (HPa109015_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FSIII9068? Error on the line flux FSIII9068 (SIII9068_FLUX_ERR)1e-23W.m**-2stat.errordoublenullablee_FHPa99229? Error on the line flux FHPa99229 (HPa99229_FLUX_ERR)1e-23W.m**-2stat.errordoublenullable