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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

Coutens, A. ; Liu, H. B. ; Jiménez-Serra, I. ; Bourke, T. L. ; Forbrich, J. ; Hoare, M. ; Loinard, L. ; Testi, L. ; Audard, M. and Caselli, P. , et al. (2019) In Astronomy and Astrophysics 631.
Abstract

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... (More)

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.

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keywords
Protoplanetary disks, Radio continuum: stars, Stars: activity, Stars: formation
in
Astronomy and Astrophysics
volume
631
article number
A58
publisher
EDP Sciences
external identifiers
  • scopus:85074453310
ISSN
0004-6361
DOI
10.1051/0004-6361/201935340
language
English
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yes
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79572d6c-cba3-4f03-a397-276a2866d808
date added to LUP
2019-11-20 12:01:05
date last changed
2019-11-21 01:54:33
@article{79572d6c-cba3-4f03-a397-276a2866d808,
  abstract     = {<p>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 θ<sub>maj</sub> ×θ<sub>min</sub> ∼ 0.′′4 × 0.′′2. We achieved a 5 μJy beam<sup>-1</sup> 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.</p>},
  author       = {Coutens, A. and Liu, H. B. and Jiménez-Serra, I. and Bourke, T. L. and Forbrich, J. and Hoare, M. and Loinard, L. and Testi, L. and Audard, M. and Caselli, P. and Chacón-Tanarro, A. and Codella, C. and Di Francesco, J. and Fontani, F. and Hogerheijde, M. and Johansen, A. and Johnstone, D. and Maddison, S. and Panić, O. and Pérez, L. M. and Podio, L. and Punanova, A. and Rawlings, J. M.C. and Semenov, D. and Tazzari, M. and Tobin, J. J. and Van Der Wiel, M. H.D. and Van Langevelde, H. J. and Vlemmings, W. and Walsh, C. and Wilner, D.},
  issn         = {0004-6361},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {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},
  url          = {http://dx.doi.org/10.1051/0004-6361/201935340},
  doi          = {10.1051/0004-6361/201935340},
  volume       = {631},
  year         = {2019},
}