%0 Journal Article %T H2 mass–velocity relationship from 3D numerical simulations of jet-driven molecular outflows %+ Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) %+ INAF - Osservatorio Astrofisico di Arcetri (OAA) %A Cerqueira, A, H %A Lefloch, B %A Esquivel, A %A Rivera-Ortiz, P, R %A Codella, C %A Ceccarelli, C %A Podio, L %< avec comité de lecture %@ 0004-6361 %J Astronomy and Astrophysics - A&A %I EDP Sciences %V 645 %8 2021-01 %D 2021 %R 10.1051/0004-6361/202039269 %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]Journal articles %X Context. Previous numerical studies have shown that in protostellar outflows, the outflowing gas mass per unit velocity, or massvelocity distribution m(v), can be well described by a broken power law ∝ v −γ. On the other hand, recent observations of a sample of outflows at various stages of evolution show that the CO intensity-velocity distribution, closely related to m(v), follows an exponential law ∝ exp(−v/v 0). Aims. In the present work, we revisit the physical origin of the mass-velocity relationship m(v) in jet-driven protostellar outflows. We investigate the respective contributions of the different regions of the outflow, from the swept-up ambient gas to the jet. Methods. We performed 3D numerical simulations of a protostellar jet propagating into a molecular cloud using the hydrodynamical code Yguazú-a. The code takes into account the most abundant atomic and ionic species and was modified to include the H 2 gas heating and cooling. Results. We find that by excluding the jet contribution, m(v) is satisfyingly fitted with a single exponential law, with v 0 well in the range of observational values. The jet contribution results in additional components in the mass-velocity relationship. This empirical mass-velocity relationship is found to be valid locally in the outflow. The exponent v 0 is almost constant in time and for a given level of mixing between the ambient medium and the jet material. In general, v 0 displays only a weak spatial dependence. A simple modeling of the L1157 outflow successfully reproduces the various components of the observed CO intensity-velocity relationship. Our simulations indicate that these components trace the outflow cavity of swept-up gas and the material entrained along the jet, respectively. Conclusions. The CO intensity-velocity exponential law is naturally explained by the jet-driven outflow model. The entrained material plays an important role in shaping the mass-velocity profile. %G English %2 https://cnrs.hal.science/hal-03381423/document %2 https://cnrs.hal.science/hal-03381423/file/Cerqueira_HD_aa39269-20.pdf %L hal-03381423 %U https://cnrs.hal.science/hal-03381423 %~ INSU %~ METEO %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ CNES %~ IPAG %~ INRAE %~ UGA-EPE %~ RESEAU-EAU