VLA cm-wave survey of young stellar objects in the Oph A cluster: Constraining extreme UV- And X-ray-driven disk photoevaporation: A pathfinder for Square Kilometre Array studies
Journal article, 2019
Observations of young stellar objects (YSOs) in centimeter bands can probe the continuum emission from growing dust grains, ionized winds, and magnetospheric activity that are intimately connected to the evolution of protoplanetary disks and the formation of planets. We carried out sensitive continuum observations toward the Ophiuchus A star-forming region, using the Karl G. Jansky Very Large Array (VLA) at 10 GHz over a field-of-view of 6′ and with a spatial resolution of θmaj ×θmin ∼ 0.′′4 × 0.′′2. We achieved a 5 μJy beam-1 rms noise level at the center of our mosaic field of view. Among the 18 sources we detected, 16 were YSOs (three Class 0, five Class I, six Class II, and two Class III) and two were extragalactic candidates. We find that thermal dust emission generally contributed less than 30% of the emission at 10 GHz. The radio emission is dominated by other types of emission, such as gyro-synchrotron radiation from active magnetospheres, free-free emission from thermal jets, free-free emission from the outflowing photoevaporated disk material, and synchrotron emission from accelerated cosmic-rays in jet or protostellar surface shocks. These different types of emission could not be clearly disentangled. Our non-detections for Class II/III disks suggest that extreme UV-driven photoevaporation is insufficient to explain disk dispersal, assuming that the contribution of UV photoevaporating stellar winds to radio flux does not evolve over time. The sensitivity of our data cannot exclude photoevaporation due to the role of X-ray photons as an efficient mechanism for disk dispersal. Deeper surveys using the Square Kilometre Array (SKA) will have the capacity to provide significant constraints to disk photoevaporation.
Stars: formation
Protoplanetary disks
Radio continuum: stars
Stars: activity
Author
A. Coutens
University of Bordeaux
H. B. Liu
European Southern Observatory (ESO)
I. Jimenez-Serra
Queen Mary University of London
T. L. Bourke
SKA Organisation
J. Forbrich
University of Hertfordshire
M. G. Hoare
University of Leeds
L. Loinard
Universidad Nacional Autónoma de México
L. Testi
Arcetri Astrophysical Observatory
European Southern Observatory (ESO)
M. Audard
University of Geneva
P. Caselli
Max Planck Society
A. Chacón-Tanarro
Spanish National Observatory (OAN)
C. Codella
Grenoble Alpes University
Arcetri Astrophysical Observatory
J. Di Francesco
National Research Council Canada
University of Victoria
Francesco Fontani
Arcetri Astrophysical Observatory
M. Hogerheijde
Leiden University
University of Amsterdam
A. Johansen
Lund University
D. Johnstone
National Research Council Canada
University of Victoria
S. Maddison
Swinburne University of Technology
O. Panić
University of Leeds
L. Perez
University of Chile (UCH)
L. Podio
Arcetri Astrophysical Observatory
A. Punanova
Ural Federal University
J. M.C. Rawlings
University College London (UCL)
D. Semenov
Ludwig Maximilian University of Munich (LMU)
Max Planck Society
M. Tazzari
University of Cambridge
J. J. Tobin
National Radio Astronomy Observatory
M. H. D. van der Wiel
Netherlands Institute for Radio Astronomy (ASTRON)
H. J. van Langevelde
Joint Institute for VLBI in Europe (JIVE)
University of Victoria
Wouter Vlemmings
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
C. Walsh
University of Leeds
D. J. Wilner
Harvard-Smithsonian Center for Astrophysics
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 631 A58Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Fusion, Plasma and Space Physics
Infrastructure
Onsala Space Observatory
DOI
10.1051/0004-6361/201935340