A network of filaments detected by Herschel in the Serpens core

A laboratory to test simulations of low-mass star formation^⋆,⋆⋆

¹ Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679 München, Germany
e-mail: vrocca@usm.uni-muenchen.de
² Excellence Cluster “Universe”, Boltzmannstr. 2, 85748 Garching bei München, Germany
³ Institute for Physics/IGAM, NAWI Graz, Karl-Franzens-Universität, Universitätsplatz 5/II, 8010 Graz, Austria
⁴ ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
⁵ INAF–Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
⁶ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁷ Max Planck International Research School for Astronomy and Cosmology, 69117 Heidelberg, Germany
⁸ SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
⁹ Departamento de Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain

Received: 31 October 2014
Accepted: 20 August 2015

Abstract

Context. Filaments represent a key structure during the early stages of the star formation process. Simulations show that filamentary structures commonly formed before and during the formation of cores.

Aims. The Serpens core is an ideal laboratory for testing the state of the art of simulations of turbulent giant molecular clouds.

Methods. We used Herschel observations of the Serpens core to compute temperature and column density maps of the region. We selected the early stages of a recent simulation of star-formation, before stellar feedback was initiated, with similar total mass and physical size as the Serpens core. We also derived temperature and column density maps from the simulations. The observed distribution of column densities of the filaments was analyzed, first including and then masking the cores. The same analysis was performed on the simulations as well.

Results. A radial network of filaments was detected in the Serpens core. The analyzed simulation shows a striking morphological resemblance to the observed structures. The column density distribution of simulated filaments without cores shows only a log-normal distribution, while the observed filaments show a power-law tail. The power-law tail becomes evident in the simulation if the focus is only the column density distribution of the cores. In contrast, the observed cores show a flat distribution.

Conclusions. Even though the simulated and observed filaments are subjectively similar-looking, we find that they behave in very different ways. The simulated filaments are turbulence-dominated regions; the observed filaments are instead self-gravitating structures that will probably fragment into cores.