ALMA-IMF XI. The sample of hot core candidates: A rich population of young high-mass protostars unveiled by the emission of methyl formate

被引：10

作者：

Bonfand, M. ^{[1
,2
,3
]}

Csengeri, T. ^{[3
]}

Bontemps, S. ^{[3
]}

Brouillet, N. ^{[3
]}

Motte, F. ^{[4
]}

Louvet, F. ^{[4
]}

Ginsburg, A. ^{[5
]}

Cunningham, N. ^{[4
]}

Galvan-Madrid, R. ^{[6
]}

Herpin, F. ^{[3
]}

Wyrowski, F. ^{[7
]}

Valeille-Manet, M. ^{[3
]}

Stutz, A. M. ^{[8
,9
]}

Di Francesco, J. ^{[10
]}

Gusdorf, A. ^{[11
,12
]}

Fernandez-Lopez, M. ^{[13
]}

Lefloch, B. ^{[3
]}

Liu, H-L. ^{[8
,14
]}

Sanhueza, P. ^{[15
,16
]}

Alvarez-Gutierrez, R. H. ^{[8
]}

Olguin, F. ^{[17
]}

Nony, T. ^{[6
]}

Lopez-Sepulcre, A. ^{[4
,18
]}

Dell'Ova, P. ^{[11
,12
]}

Pouteau, Y. ^{[4
]}

Jeff, D. ^{[5
]}

Chen, H. -R. V. ^{[17
]}

Armante, M. ^{[11
,12
]}

Towner, A. ^{[19
]}

Bronfman, L. ^{[20
]}

Kessler, N. ^{[3
]}

机构：

[1] Univ Virginia, Dept Astron, Charlottesville, VA 22904 USA

[2] Univ Virginia, Dept Chem, Charlottesville, VA 22904 USA

[3] Univ Bordeaux, Lab Astrophys Bordeaux, CNRS, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France

[4] Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France

[5] Univ Florida, Dept Astron, POB 112055, Gainesville, FL USA

[6] Univ Nacl Autonoma Mexico, Inst Radioastron & Astrofis, Morelia 58089, Michoacan, Mexico

[7] Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany

[8] Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion 4030000, Chile

[9] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany

[10] Natl Res Council Canada, Herzberg Astron & Astrophys Res Ctr, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada

[11] Univ Paris, Lab Phys, ENS, Univ PSL,CNRS,Sorbonne Univ,Ecole Normale Super, Paris, France

[12] Sorbonne Univ, PSL Univ, Observ Paris, LERMA, F-75014 Paris, France

[13] Inst Argentino Radioastron CCT La Plata, CONICET, CICPBA, CC 5, RA-1894 Buenos Aires, Argentina

[14] Yunnan Univ, Dept Astron, Kunming 650091, Peoples R China

[15] Natl Inst Nat Sci, Natl Astron Observ Japan, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan

[16] SOKENDAI Grad Univ Adv Studies, Dept Astron Sci, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan

[17] Natl Tsing Hua Univ, Inst Astron, Hsinchu 30013, Taiwan

[18] Inst Radioastron Millimetr IRAM, 300 Rue Piscine, F-38406 St Martin Dheres, France

[19] Univ Arizona, Steward Observ, 933 North Cherry Ave, Tucson, AZ 85721 USA

[20] Univ Chile, Dept Astron, Casilla 36-D, Santiago, Chile

来源：

ASTRONOMY & ASTROPHYSICS | 2024年 / 687卷

基金：

欧洲研究理事会; 美国国家科学基金会;

关键词：

astrochemistry; catalogs; stars: formation; stars: massive; ISM: molecules; submillimeter: ISM; COMPLEX ORGANIC-MOLECULES; STAR-FORMING CORES; II METHANOL MASERS; DYNAMICAL COLLAPSE; DIMETHYL ETHER; GRAIN-SURFACE; GROUND-STATE; INTERSTELLAR; GAS; CHEMISTRY;

D O I：

10.1051/0004-6361/202347856

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Context. The star formation process leads to an increased chemical complexity in the interstellar medium. Sites associated with high-mass star and cluster formation exhibit a so-called hot core phase, characterized by high temperatures and column densities of complex organic molecules. Aims: We aim to systematically search for and identify a sample of hot cores toward the 15 Galactic protoclusters of the ALMA-IMF Large Program and investigate their statistical properties. Methods: We built a comprehensive census of hot core candidates toward the ALMA-IMF protoclusters based on the detection of two CH3OCHO emission lines at 216.1 GHz. We used the source extraction algorithm GExt2D to identify peaks of methyl formate (CH3OCHO) emission, a complex species commonly observed toward sites of star formation. We performed a cross-matching with the catalog of thermal dust continuum sources from the ALMA-IMF 1.3 mm continuum data to infer their physical properties. Results: We built a catalog of 76 hot core candidates with masses ranging from similar to 0.2 M-circle dot to similar to 80 M-circle dot, of which 56 are new detections. A large majority of these objects, identified from methyl formate emission, are compact and rather circular, with deconvolved full width at half maximum (FWHM) sizes of similar to 2300 au on average. The central sources of two target fields show more extended, but still rather circular, methyl formate emission with deconvolved FWHM sizes of similar to 6700 au and 13 400 au. About 30% of our sample of methyl formate sources have core masses above 8 M-circle dot and range in size from similar to 1000 au to 13 400 au, which is in line with measurements of archetypical hot cores. The origin of the CH3OCHO emission toward the lower-mass cores may be explained as a mixture of contributions from shocks or may correspond to objects in a more evolved state (i.e., beyond the hot core stage). We find that the fraction of hot core candidates increases with the core mass, suggesting that the brightest dust cores are all in the hot core phase. Conclusions: Our results suggest that most of these compact methyl formate sources are readily explained by simple symmetric models, while collective effects from radiative heating and shocks from compact protoclusters are needed to explain the observed extended CH3OCHO emission. The large fraction of hot core candidates toward the most massive cores suggests that they rapidly enter the hot core phase and that feedback effects from the forming protostar(s) impact their environment on short timescales.

引用

页数：42