J/A+A/706/A367 MUSE M33 HII regions catalog (Feltre+, 2026)
M3D Mosaicking M33 with MUSE datacubes.
I. Unveiling the diversity of HII regions in M33 with MUSE.
Feltre 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.
<Astron. Astrophys. 706, A367 (2026)>
=2026A&A...706A.367F 2026A&A...706A.367F (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; H II regions ; Interstellar medium ;
Positional data ; Combined data ; Extinction ; Abundances ;
Spectroscopy ; Optical
Keywords: ISM: general - ISM: HII regions - galaxies: ISM -
galaxies: star formation -
Abstract:
We present new VLT/MUSE mosaic observations of a 3x8 arcmin2 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 Hα luminosities of
~=5*1035erg/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
(Hβλ4861, [OIII]4959,5007, [NII]λ6548,6584,
Hα, [SII]λ6716,6731, [SIII]λ9069, 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]/Hβ 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.
Description:
We present a sample of 131 spatially resolved HII regions identified
in 24 MUSE pointings along the southern major axis of M33. We provide
a catalogue with main information on this HII regions.
Objects:
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RA (2000) DE Designation(s)
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01 33 50.89 +30 39 36.6 M 33 = 1AXG J013351+3039
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 519 131 MUSE M33 HII region catalog
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See also:
J/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 clusters
(Corbelli+, 2017)
J/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 clouds
(Muraoka+, 2023)
J/ApJ/952/114 : HMXBs in M33 with Chandra X-ray and HST obs.
(Lazzarini+, 2023)
J/ApJ/939/44 : CHAOS. VII. Large-scale abundance study in M33
(Rogers+, 2022)
J/ApJ/915/21 : CHAOS. VI. Direct abundances in NGC 2403 (Rogers+, 2021)
J/ApJ/893/96 : CHAOS IV: NGC3184 LBT obs. & 3 other gal. abundances
(Berg+, 2020)
J/ApJ/855/140 : MMT spectra of SNRs and SNR candidates in M33 (Long+, 2018)
J/ApJ/806/16 : CHemical Abundances of Spirals (CHAOS). I. NGC628
(Berg+, 2015)
J/ApJ/793/134 : M33 SNR candidates properties (Lee+, 2014)
J/ApJ/755/40 : HII regions in the Magellanic clouds from MCELS
(Pellegrini+, 2012)
J/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 M33
(Williams+, 2021)
J/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 : Hα emission-line stars in 7 dwarfs galaxies
(Massey+, 2007)
J/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 regions
(Barnes+, 2020)
J/MNRAS/421/1043 : Emission-line galaxies from SDSS DR7 (Shirazi+, 2012)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Identification number of HII nebular
mask (HII_ID)
5- 10 F6.3 deg RAdeg Right ascension (J2000) (RA)
12- 17 F6.3 deg DEdeg Declination (J2000) (DEC)
19- 23 I5 --- Npix Number of pixel within the nebular
mask (Npix)
25- 26 A2 --- Star Equal to WR for 7 cases when a WR star
is within the nebular mask (star)
28- 30 I3 --- YSCC ? Identification number of associated
YSCC from Corbelli et al.
(2017A&A...601A.146C 2017A&A...601A.146C,
Cat. J/A+A/601/A146) (YSCC)
32- 36 F5.3 mag E(B-V) E(B-V) value computed from the Balmer
decrement (EBV)
38- 43 F6.3 cm-3 ne Electron density computed from the
[SII]λ6716/[SII]λ6731
doublet ratio (ne)
45- 49 F5.3 [-] (O/H)S Oxygen abundance in terms of 12+log(O/H)
from the S-calibration of
Pilyugin & Grebel (2016MNRAS.457.3678P 2016MNRAS.457.3678P)
(OH_Scal)
51- 55 F5.3 [-] (O/H)N2S2Ha Oxygen abundance in terms of 12+log(O/H)
from the N2S2Hα indicator from
Brazzini et al. (2024A&A...691A.173B 2024A&A...691A.173B,
Cat. J/A+A/691/A173) (OH_N2S2Ha)
57- 68 F12.3 10-23W/m2 FHb Extracted Hβλ4861 strong
optical line flux at 4861Å summed
over the entire nebular mask
(Hb4861_FLUX)
70- 80 F11.3 10-23W/m2 FOIII4958 Extracted [OIII]4958 strong optical line
flux at 4958Å summed over the entire
nebular mask (OIII4958_FLUX)
82- 93 F12.3 10-23W/m2 FOIII5006 Extracted [OIII]5006 strong optical line
flux at 5006Å summed over the entire
nebular mask (OIII5006_FLUX)
95-104 F10.3 10-23W/m2 FHeI5015 Extracted HeIλ5015 strong optical
lines flux at 5015Å summed over the
entire nebular mask (HeI5015_FLUX)
106-116 F11.3 10-23W/m2 FNII5754 Extracted [NII]λ5754 auroral line
flux at 5754Å summed over the entire
nebular mask (NII5754_FLUX)
118-129 F12.3 10-23W/m2 FHeI5875 Extracted HeIλ5875 strong optical
lines flux at 5875Å summed over the
entire nebular mask (HeI5875_FLUX)
131-142 F12.3 10-23W/m2 FNII6548 Extracted [NII]λ6548 strong
optical lines flux at 6548Å summed
over the entire nebular mask
(NII6548_FLUX)
144-155 F12.3 10-23W/m2 FHa6562 Extracted Haλ6562 strong optical
lines flux at 6562Å summed over the
entire nebular mask (Ha6562_FLUX)
157-168 F12.3 10-23W/m2 FNII6583 Extracted [NII]λ6584 strong
optical lines flux at 6584Å summed
over the entire nebular mask
(NII6583_FLUX)
170-180 F11.3 10-23W/m2 FHeI6678 Extracted HeIλ6678 strong optical
lines flux at 6678Å summed over the
entire nebular mask (HeI6678_FLUX)
182-192 F11.3 10-23W/m2 FSII6716 Extracted [SII]λ6716 strong
optical lines flux at 6716Å summed
over the entire nebular mask
(SII6716_FLUX)
194-204 F11.3 10-23W/m2 FSII6730 Extracted [SII]λ6730 strong
optical lines flux at 6730Å summed
over the entire nebular mask
(SII6730_FLUX)
206-216 F11.3 10-23W/m2 FHeI7065 Extracted HeIλ7065 trong optical
line flux at 7065Å summed over the
entire nebular mask (HeI7065_FLUX)
218-228 F11.3 10-23W/m2 FArIII7135 Extracted [ArIII]λ7135 auroral
lines flux at 7135Å summed over the
entire nebular mask (ArIII7135_FLUX)
230-240 F11.3 10-23W/m2 FOII7325 Extracted [OII]λ7325 auroral line
flux at 7325Å summed over the entire
nebular mask (OII7325_FLUX)
242-252 F11.3 10-23W/m2 FArIII7751 Extracted [ArIII]λ7751 auroral
lines flux at 7751Å summed over the
entire nebular mask (ArIII7751_FLUX)
254-263 F10.3 10-23W/m2 FHPa128750 Extracted Pa12λ8750 lines of the
Hydrogen Paschen series flux at
8750Å summed over the entire nebular
mask (HPa128750_FLUX)
265-275 F11.3 10-23W/m2 FHPa118862 Extracted Pa11λ8862 lines of the
Hydrogen Paschen series flux at
8862Å summed over the entire nebular
mask (HPa118862_FLUX)
277-287 F11.3 10-23W/m2 FHPa109015 Extracted Pa10λ9015 lines of the
Hydrogen Paschen series flux at
9015Å summed over the entire nebular
mask (HPa109015_FLUX)
289-299 F11.3 10-23W/m2 FSIII9068 Extracted [SIII]λ9069 strong
optical lines flux at 9069Å summed
over the entire nebular mask
(SIII9068_FLUX)
301-310 F10.3 10-23W/m2 FHPa99229 Extracted Pa9λ9229 lines of the
Hydrogen Paschen series flux at
9229Å summed over the entire nebular
mask (HPa99229_FLUX)
312-320 F9.3 10-23W/m2 e_FHb Error on the line flux FHb
(Hb4861FLUXERR)
322-330 F9.3 10-23W/m2 e_FOIII4958 ? Error on the line flux FOIII4958
(OIII4958FLUXERR)
332-339 F8.3 10-23W/m2 e_FOIII5006 ? Error on the line flux FOIII5006
(OIII5006FLUXERR)
341-349 F9.3 10-23W/m2 e_FHeI5015 ? Error on the line flux FHeI5015
(HeI5015FLUXERR)
351-359 F9.3 10-23W/m2 e_FNII5754 ? Error on the line flux FNII5754
(NII5754FLUXERR)
361-369 F9.3 10-23W/m2 e_FHeI5875 ? Error on the line flux FHeI5875
(HeI5875FLUXERR)
371-379 F9.3 10-23W/m2 e_FNII6548 ? Error on the line flux FNII6548
(NII6548FLUXERR)
381-390 F10.3 10-23W/m2 e_FHa6562 ? Error on the line flux FHa6562
(Ha6562FLUXERR)
392-400 F9.3 10-23W/m2 e_FNII6583 ? Error on the line flux FNII6583
(NII6583FLUXERR)
402-410 F9.3 10-23W/m2 e_FHeI6678 ? Error on the line flux FHeI6678
(HeI6678FLUXERR)
412-420 F9.3 10-23W/m2 e_FSII6716 ? Error on the line flux FSII6716
(SII6716FLUXERR)
422-430 F9.3 10-23W/m2 e_FSII6730 ? Error on the line flux FSII6730
(SII6730FLUXERR)
432-440 F9.3 10-23W/m2 e_FHeI7065 ? Error on the line flux FHeI7065
(HeI7065FLUXERR)
442-450 F9.3 10-23W/m2 e_FArIII7135 ? Error on the line flux FArIII7135
(ArIII7135FLUXERR)
452-460 F9.3 10-23W/m2 e_FOII7325 ? Error on the line flux FOII7325
(OII7325FLUXERR)
462-470 F9.3 10-23W/m2 e_FArIII7751 ? Error on the line flux FArIII7751
(ArIII7751FLUXERR)
472-480 F9.3 10-23W/m2 e_FHPa128750 ? Error on the line flux FHPa128750
(HPa128750FLUXERR)
482-490 F9.3 10-23W/m2 e_FHPa118862 ? Error on the line flux FHPa118862
(HPa118862FLUXERR)
492-500 F9.3 10-23W/m2 e_FHPa109015 ? Error on the line flux FHPa109015
(HPa109015FLUXERR)
502-509 F8.3 10-23W/m2 e_FSIII9068 ? Error on the line flux FSIII9068
(SIII9068FLUXERR)
511-519 F9.3 10-23W/m2 e_FHPa99229 ? Error on the line flux FHPa99229
(HPa99229FLUXERR)
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Acknowledgements:
Anna Feltre, anna.feltre(at)inaf.it
(End) Luc Trabelsi [CDS] 19-Dec-2025