ATLASGAL-selected massive clumps in the inner Galaxy, II: Characterisation of different evolutionary stages and their SiO emission - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2016

ATLASGAL-selected massive clumps in the inner Galaxy, II: Characterisation of different evolutionary stages and their SiO emission

T., Csengeri
F., Wyrowski
  • Fonction : Auteur
K. M., Menten
  • Fonction : Auteur
Sylvain Bontemps
H., Beuther
  • Fonction : Auteur
Q., Nguyen-Luong
  • Fonction : Auteur
F., Schuller
  • Fonction : Auteur
Annie Zavagno
C., Sanna
  • Fonction : Auteur

Résumé

The processes leading to the birth of high-mass stars are poorly understood. We characterise here a sample of 430 massive clumps from the ATLASGAL survey, which are representative of different evolutionary stages. To establish a census of molecular tracers of their evolution we performed an unbiased spectral line survey covering the 3-mm atmospheric window between 84-117 GHz with the IRAM 30m. A smaller sample of 128 clumps has been observed in the SiO (5-4) transition with the APEX telescope to complement the SiO (2-1) line and probe the excitation conditions of the emitting gas, which is the main focus of the current study. We report a high detection rate of >75% of the SiO (2-1) line and a >90% detection rate from the dedicated follow-ups in the (5-4) transition. The SiO (2-1) line with broad line profiles and high detection rates, is a powerful probe of star formation activity, while the ubiquitous detection of SiO in all evolutionary stages suggests a continuous star formation process in massive clumps. We find a large fraction of infrared-quiet clumps to exhibit SiO emission, the majority of them only showing a low-velocity component (FWHM~5-6 km/s) centred at the rest velocity of the clump. In the current picture, where this is attributed to low-velocity shocks from cloud-cloud collisions, this can be used to pinpoint the youngest, thus, likely prestellar massive structures. Based on the line ratio of the (5-4) to the (2-1) line, our study reveals a trend of changing excitation conditions that lead to brighter emission in the (5-4) line towards more evolved sources. Our analysis delivers a more robust estimate of SiO column density and abundance than previous studies and questions the decrease of jet activity in massive clumps as a function of age.

Dates et versions

hal-01238870 , version 1 (07-12-2015)

Identifiants

Citer

T., Csengeri, S., Leurini, F., Wyrowski, J. S., Urquhart, K. M., Menten, et al.. ATLASGAL-selected massive clumps in the inner Galaxy, II: Characterisation of different evolutionary stages and their SiO emission. Astronomy and Astrophysics - A&A, 2016, 586, pp.id.A149. ⟨10.1051/0004-6361/201425404⟩. ⟨hal-01238870⟩
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