TY - JOUR

T1 - Physical properties and real nature of massive clumps in the galaxy

AU - Lu, Zu-Jia

AU - Pelkonen, Veli-Matti

AU - Juvela, Mika

AU - Padoan, Paolo

AU - Haugbolle, Troels

AU - Nordlund, Ake

PY - 2022/2/2

Y1 - 2022/2/2

N2 - Systematic surveys of massive clumps have been carried out to study the conditions leading to the formation of massive stars. These clumps are typically at large distances and unresolved, so their physical properties cannot be reliably derived from the observations alone. Numerical simulations are needed to interpret the observations. To this end, we generate synthetic Herschel observations using our large-scale star-formation simulation, where massive stars explode as supernovae driving the interstellar-medium turbulence. From the synthetic observations, we compile a catalogue of compact sources following the exact same procedure as for the Hi-GAL compact source catalogue. We show that the sources from the simulation have observational properties with statistical distributions consistent with the observations. By relating the compact sources from the synthetic observations to their 3D counterparts in the simulation, we find that the synthetic observations overestimate the clump masses by about an order of magnitude on average due to line-of-sight projection, and projection effects are likely to be even worse for Hi-GAL Inner Galaxy sources. We also find that a large fraction of sources classified as protostellar are likely to be starless, and propose a new method to partially discriminate between true and false protostellar sources.

AB - Systematic surveys of massive clumps have been carried out to study the conditions leading to the formation of massive stars. These clumps are typically at large distances and unresolved, so their physical properties cannot be reliably derived from the observations alone. Numerical simulations are needed to interpret the observations. To this end, we generate synthetic Herschel observations using our large-scale star-formation simulation, where massive stars explode as supernovae driving the interstellar-medium turbulence. From the synthetic observations, we compile a catalogue of compact sources following the exact same procedure as for the Hi-GAL compact source catalogue. We show that the sources from the simulation have observational properties with statistical distributions consistent with the observations. By relating the compact sources from the synthetic observations to their 3D counterparts in the simulation, we find that the synthetic observations overestimate the clump masses by about an order of magnitude on average due to line-of-sight projection, and projection effects are likely to be even worse for Hi-GAL Inner Galaxy sources. We also find that a large fraction of sources classified as protostellar are likely to be starless, and propose a new method to partially discriminate between true and false protostellar sources.

KW - MHD

KW - radiative transfer

KW - methods: numerical

KW - catalogues

KW - stars: formation

KW - ADAPTIVE MESH REFINEMENT

KW - COMPACT SOURCE CATALOG

KW - ORDER GODUNOV SCHEME

KW - STAR-FORMATION

KW - HI-GAL

KW - CONSTRAINED TRANSPORT

KW - TURBULENCE

KW - I.

U2 - 10.1093/mnras/stab3517

DO - 10.1093/mnras/stab3517

M3 - Journal article

VL - 510

SP - 1697

EP - 1715

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 2

ER -