Water in star-forming regions withHerschel(WISH)(Corrigendum)

J C Mottram,F F S Van Der Tak,E F Van Dishoeck,T A Van Kempen,M R Hogerheijde,M Tafalla,A O Benz,P Caselli,F Wyrowski,A Karska,L E Kristensen,G Santangelo,S Bruderer,B Nisini,R Liseau,R Visser,Doug Johnstone ,Fabrice Herpin ,E A Bergin,I San José-García

doi:10.1051/0004-6361/201424267e

Abstract

Context. Outflows are an important part of the star formation process as both the result of ongoing active accretion and one of the main sources of mechanical feedback on small scales. Water is the ideal tracer of these effects because it is present in high abundance for the conditions expected in various parts of the protostar, particularly the outflow. Aims. We constrain and quantify the physical conditions probed by water in the outflow-jet system for Class 0 and I sources. Methods. We present velocity-resolved Herschel HIFI spectra of multiple water-transitions observed towards 29 nearby Class 0/ Ip rotostars as part of the WISH guaranteed time key programme. The lines are decomposed into different Gaussian components, with each component related to one of three parts of the protostellar system; quiescent envelope, cavity shock and spot shocks in the jet and at the base of the outflow. We then use non-LTE radex models to constrain the excitation conditions present in the two outflow-related components. Results. Water emission at the source position is optically thick but effectively thin, with line ratios that do not vary with velocity, in contrast to CO. The physical conditions of the cavity and spot shocks are similar, with post-shock H2 densities of order 10 5 −10 8 cm −3 and H2O column densities of order 10 16 −10 18 cm −2 .H 2O emission originates in compact emitting regions: for the spot shocks these correspond to point sources with radii of order 10−200 AU, while for the cavity shocks these come from a thin layer along the outflow cavity wall with thickness of order 1−30 AU. Conclusions. Water emission at the source position traces two distinct kinematic components in the outflow; J shocks at the base of the outflow or in the jet, and C shocks in a thin layer in the cavity wall. The similarity of the physical conditions is in contrast to off-source determinations which show similar densities but lower column densities and larger filling factors. We propose that this is due to the differences in shock properties and geometry between these positions. Class I sources have similar excitation conditions to Class 0 sources, but generally smaller line-widths and emitting region sizes. We suggest that it is the velocity of the wind driving the outflow, rather than the decrease in envelope density or mass, that is the cause of the decrease in H2O intensity between Class 0 and I sources.

Highlights

France CNRS, LAB, UMR 5804, Laboratoire d’Astrophysique de Bordeaux, 2 rue de l’Observatoire, BP 89, 33270 Floirac Cedex, France Joint Astronomy Centre, 660 North Aohoku Place, University Park, Hilo, HI 96720, USA Department of Physics and Astronomy, University of Victoria, PO Box 3055 STN CSC, Victoria, BC V8W 3P6, Canada NRC-Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden Observatorio Astronómico Nacional (IGN), Alfonso XII 3, 28014 Madrid, Spain SRON Netherlands Institute for Space Research, PO Box 800, 9700 AV Groningen, The Netherlands Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
The original calculation of the fraction of the total integrated intensity in each component type presented in Table 4 of Mottram et al (2014) did not correctly take into account the different distance corrections for the cavity shock compared to the spot shock and envelope components
For the cavity shock components a correction of (d/200 pc) was used, assuming that the emission is extended along the outflow axis but point-like perpendicular to it, while for the other components (d/200 pc)2 was used, assuming that both are point-like

Summary

Introduction

2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 3 Max Planck Institut für Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Germany 4 Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042, USA 5 Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125

Results

Conclusion