High-J CO emission in the Cepheus E protostellar outflow observed with SOFIA/GREAT
Abstract
We present and analyze two spectrally resolved high-J CO lines towards the molecular outflow Cep E, driven by an intermediate-mass class 0 protostar. Using the GREAT receiver on board SOFIA, we observed the CO (12--11) and (13--12) transitions (E_u ~ 430 and 500 K, respectively) towards one position in the blue lobe of this outflow, that had been known to display high-velocity molecular emission. We detect the outflow emission in both transitions, up to extremely high velocities (~ 100 km/s with respect to the systemic velocity). We divide the line profiles into three velocity ranges that each have interesting spectral features: standard, intermediate, and extremely high-velocity. One distinct bullet is detected in each of the last two. A large velocity gradient analysis for these three velocity ranges provides constraints on the kinetic temperature and volume density of the emitting gas, >~ 100 K and > ~ 10^4 cm^-3, respectively. These results are in agreement with previous ISO observations and are comparable with results obtained by Herschel for similar objects. We conclude that high-J CO lines are a good tracer of molecular bullets in protostellar outflows. Our analysis suggests that different physical conditions are at work in the intermediate velocity range compared with the standard and extremely high-velocity gas at the observed position.
Cite
@article{arxiv.1203.1890,
title = {High-J CO emission in the Cepheus E protostellar outflow observed with SOFIA/GREAT},
author = {A. I. Gómez-Ruiz and A. Gusdorf and S. Leurini and C. Codella and R. Güsten and F. Wyrowski and M. A. Requena-Torres and C. Risacher and S. F. Wampfler},
journal= {arXiv preprint arXiv:1203.1890},
year = {2015}
}
Comments
Accepted for publication in A&A (SOFIA/GREAT special issue)