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
Date Issued
2019
Author(s)
Coutens, A.
•
Liu, H. B.
•
Jiménez-Serra, I.
•
Bourke, T. L.
•
Forbrich, J.
•
Hoare, M.
•
Loinard, L.
•
•
Audard, M.
•
Caselli, P.
•
Chacón-Tanarro, A.
•
•
Di Francesco, J.
•
•
Hogerheijde, M.
•
Johansen, A.
•
Johnstone, D.
•
Maddison, S.
•
Panić, O.
•
Pérez, L. M.
•
•
Punanova, A.
•
Rawlings, J. M. C.
•
Semenov, D.
•
Tazzari, M.
•
Tobin, J. J.
•
van der Wiel, M. H. D.
•
van Langevelde, H. J.
•
Vlemmings, W.
•
Walsh, C.
•
Wilner, D.
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 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.
The mosaic image is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A58
Volume
631
Start page
A58
Issn Identifier
0004-6361
Ads BibCode
2019A&A...631A..58C
Rights
open.access
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
aa35340-19.pdf
Description
pdf editoriale
Size
1.46 MB
Format
Adobe PDF
Checksum (MD5)
448688f71a8359a4249e4f7b0000e8ca
Loading...
Name
1909.03515.pdf
Description
preprint
Size
1.79 MB
Format
Adobe PDF
Checksum (MD5)
eb194ce4c85a8fccde219bca19aed906