J/A+A/648/A66 CORE high-mass star-forming regions (Gieser+, 2021)
Physical and chemical structure of high-mass star-forming regions.
Unraveling chemical complexity with CORE: the NOEMA large program.
Gieser C., Beuther H., Semenov D., Ahmadi A., Suri S., Moeller T.,
Beltran M.T., Klaassen P., Zhang Q., Urquhart J.S., Henning T., Feng S.,
Galvan-Madrid R., de Souza Magalhaes V., Moscadelli L., Longmore S.,
Leurini S., Kuiper R., Peters T., Menten K.M., Csengeri T., Fuller G.,
Wyrowski F., Lumsden S., Sanchez-Monge A., Maud L., Linz H., Palau A.,
Schilke P., Pety J., Pudritz R., Winters J.M., Pietu V.
<Astron. Astrophys. 648, A66 (2021)>
=2021A&A...648A..66G 2021A&A...648A..66G (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Interstellar medium ; Abundances
Keywords: astrochemistry - ISM: molecules - stars: formation
Abstract:
Characterizing the physical and chemical properties of forming massive
stars at the spatial resolution of individual high-mass cores lies at
the heart of current star formation research.
We use sub-arcsecond resolution (∼0.4arcsec) observations with the
NOrthern Extended Millimeter Array at 1.37mm to study the dust
emission and molecular gas of 18 high-mass star-forming regions. With
distances in the range of 0.7-5.5kpc this corresponds to spatial
scales down to 300-2300au that are resolved by our observations. We
combine the derived physical and chemical properties of individual
cores in these regions to estimate their ages. The temperature
structure of these regions are determined by fitting H2CO and
CH3CN line emission. The density profiles are inferred from the
1.37mm continuum visibilities. The column densities of 11 different
species are determined by fitting the emission lines with XCLASS.
Within the 18 observed regions, we identify 22 individual cores with
associated 1.37mm continuum emission and with a radially decreasing
temperature profile. We find an average temperature power-law index of
q=0.4±0.1 and an average density power-law index of p=2.0±0.2 on
scales on the order of several 1000au. Comparing these results with
values of p derived in the literature suggest that the density
profiles remain unchanged from clump to core scales. The column
densities relative to N(C18O) between pairs of dense gas tracers show
tight correlations. We apply the physical-chemical model MUlti Stage
ChemicaL codE (MUSCLE) to the derived column densities of each core
and find a mean chemical age of ∼60000yrs and an age spread of
20000-100000yrs. With this paper we release all data products of the
CORE project available at https://www.mpia.de/core.
The CORE sample reveals well constrained density and temperature
power-law distributions. Furthermore, we characterize a large variety
in molecular richness that can be explained by an age spread confirmed
by our physical-chemical modeling. The hot molecular cores show the
most emission lines, but we also find evolved cores at an evolutionary
stage, in which most molecules are destroyed and thus the spectra
appear line-poor again.
Description:
Physical and chemical properties of 120 positions toward 18 high-mass
star-forming regions of the CORE sample. Table A shows the position
(given by the region name and position number); coordinates (J2000);
systemic velocity determined by the C18O line; noise in the spectrum;
kinetic temperature determined by CH3CN, if detected, or H2CO;
1.37mm continuum intensity; continuum optical depth; and the molecular
hydrogen column density. Table E shows the column densities of 13CO,
C18O, SO, OCS, SO2, DCN, H2CO, HNCO, HC3N, HC3N v7=1, HC3N
v7=2, CH3OH, CH3OH vt=1, and CH3CN derived with XCLASS toward
the 120 positions. Lower and upper column density error estimates are
given as well. If no lower and upper column density error is shown,
the derived column density is an upper limit.
The reduced images and data cubes are all available at
https://www2.mpia-hd.mpg.de/core/DATA/www
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea.dat 91 120 Overview of the 120 positions
tablee.dat 350 120 Molecular column densities derived with XCLASS
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See also:
https://www2.mpia-hd.mpg.de/core/DATA/www : CORE data Home Page
Byte-by-byte Description of file: tablea.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Region Region
13- 14 I2 --- Number Position number
16- 17 I2 h RAh Right Ascension (J2000)
19- 20 I2 min RAm Right Ascension (J2000)
22- 26 F5.2 s RAs Right Ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 38 F4.1 arcsec DEs Declination (J2000)
40- 44 F5.1 km/s vLSR Systemic velocity
46- 49 F4.2 K sigmaline Noise in the spectral line data
51- 55 F5.1 K Tkin Kinetic temperature
57- 60 F4.1 K e_Tkin Kinetic temperature error
62- 67 F6.2 mJy/beam Int 1.37mm continuum intensity
69- 75 E7.1 --- tau Continuum optical depth
77- 83 E7.1 cm-2 N(H2) Molecular hydrogen column density
85- 91 E7.1 cm-2 e_N(H2) Molecular hydrogen column density error
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Byte-by-byte Description of file: tablee.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Region Region
13- 14 I2 --- Number Position number
16- 22 E7.1 cm-2 N(13CO) 13CO column density
24- 30 E7.1 cm-2 e_N(13CO) 13CO column density lower error
32- 38 E7.1 cm-2 E_N(13CO) 13CO column density upper error
40- 46 E7.1 cm-2 N(C18O) C18O column density
48- 54 E7.1 cm-2 e_N(C18O) C18O column density lower error
56- 62 E7.1 cm-2 E_N(C18O) C18O column density upper error
63 A1 --- l_N(SO) Limit flag on N(SO)
64- 70 E7.1 cm-2 N(SO) SO column density
72- 78 E7.1 cm-2 e_N(SO) ? SO column density lower error
80- 86 E7.1 cm-2 E_N(SO) ? SO column density upper error
87 A1 --- l_N(OCS) Limit flag on N(OCS)
88- 94 E7.1 cm-2 N(OCS) OCS column density
96-102 E7.1 cm-2 e_N(OCS) ? OCS column density lower error
104-110 E7.1 cm-2 E_N(OCS) ? OCS column density upper error
111 A1 --- l_N(SO2) Limit flag on N(SO2)
112-118 E7.1 cm-2 N(SO2) SO2 column density
120-126 E7.1 cm-2 e_N(SO2) ? SO2 column density lower error
128-134 E7.1 cm-2 E_N(SO2) ? SO2 column density upper error
135 A1 --- l_N(DCN) Limit flag on N(DCN)
136-142 E7.1 cm-2 N(DCN) DCN column density
144-150 E7.1 cm-2 e_N(DCN) ? DCN column density lower error
152-158 E7.1 cm-2 E_N(DCN) ? DCN column density upper error
159 A1 --- l_N(H2CO) Limit flag on N(H2CO)
160-166 E7.1 cm-2 N(H2CO) H2CO column density
168-174 E7.1 cm-2 e_N(H2CO) ? H2CO column density lower error
176-182 E7.1 cm-2 E_N(H2CO) ? H2CO column density upper error
183 A1 --- l_N(HNCO) Limit flag on N(HNCO)
184-190 E7.1 cm-2 N(HNCO) HNCO column density
192-198 E7.1 cm-2 e_N(HNCO) ? HNCO column density lower error
200-206 E7.1 cm-2 E_N(HNCO) ? HNCO column density upper error
207 A1 --- l_N(HC3N) Limit flag on N(HC3N)
208-214 E7.1 cm-2 N(HC3N) HC3N column density
216-222 E7.1 cm-2 e_N(HC3N) ? HC3N column density lower error
224-230 E7.1 cm-2 E_N(HC3N) ? HC3N column density upper error
231 A1 --- l_N(HC3Nv7=1) Limit flag on N(HC3Nv7=1)
232-238 E7.1 cm-2 N(HC3Nv7=1) HC3N,v7=1 column density
240-246 E7.1 cm-2 e_N(HC3Nv7=1) ? HC3N,v7=1 column density lower error
248-254 E7.1 cm-2 E_N(HC3Nv7=1) ? HC3N,v7=1 column density upper error
255 A1 --- l_N(HC3Nv7=2) Limit flag on N(HC3Nv7=2)
256-262 E7.1 cm-2 N(HC3Nv7=2) HC3N,v7=2 column density
264-270 E7.1 cm-2 e_N(HC3Nv7=2) ? HC3N,v7=2 column density lower error
272-278 E7.1 cm-2 E_N(HC3Nv7=2) ? HC3N,v7=2 column density upper error
279 A1 --- l_N(CH3OH) Limit flag on N(CH3OH)
280-286 E7.1 cm-2 N(CH3OH) CH3OH column density
288-294 E7.1 cm-2 e_N(CH3OH) ? CH3OH column density lower error
296-302 E7.1 cm-2 E_N(CH3OH) ? CH3OH column density upper error
303 A1 --- l_N(CH3OHvt=1) Limit flag on N(CH3OHvt=1)
304-310 E7.1 cm-2 N(CH3OHvt=1) CH3OH,vt=1 column density
312-318 E7.1 cm-2 e_N(CH3OHvt=1) ? CH3OH,vt=1 column density lower error
320-326 E7.1 cm-2 E_N(CH3OHvt=1) ? CH3OH,vt=1 column density upper error
327 A1 --- l_N(CH3CN) Limit flag on N(CH3CHN)
328-334 E7.1 cm-2 N(CH3CN) CH3CN column density
336-342 E7.1 cm-2 e_N(CH3CN) ? CH3CN column density lower error
344-350 E7.1 cm-2 E_N(CH3CN) ? CH3CN column density upper error
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Acknowledgements:
Caroline Gieser, gieser(at)mpia.de
(End) Patricia Vannier [CDS] 25-Feb-2021