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American Astronomical Society, Astrophysical Journal, 1(813), p. 41, 2015

DOI: 10.1088/0004-637x/813/1/41

American Astronomical Society, Astrophysical Journal, 1(813), p. 39, 2015

DOI: 10.1088/0004-637x/813/1/39

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Searches for continuous gravitational waves from nine young supernova remnants

Journal article published in 2014 by A.~A A. van Veggel, M. V. van der Sluys, C. van den Broeck, J.~F.~J F. J. van den Brand, N. van Bakel, Joris van Heijningen, M. van Beuzekom, J. Aasi, Bp P. Abbott, R. Abbott, T. and Abernathy M. R. Abbott, Mr R. Abernathy, F. Acernese, K. Ackley, C. Adams and other authors.
This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

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Abstract

We present new results from the Disks@EVLA program for two young stars: CY Tau and DoAr 25. We trace continuum emission arising from their circusmtellar disks from spatially resolved observations, down to tens of AU scales, at {λ} = 0.9, 2.8, 8.0, and 9.8 mm for DoAr25 and at {λ} = 1.3, 2.8, and 7.1 mm for CY Tau. Additionally, we constrain the amount of emission whose origin is different from thermal dust emission from 5 cm observations. Directly from interferometric data, we find that observations at 7 mm and 1 cm trace emission from a compact disk while millimeter-wave observations trace an extended disk structure. From a physical disk model, where we characterize the disk structure of CY Tau and DoAr 25 at wavelengths shorter than 5 cm, we find that (1) dust continuum emission is optically thin at the observed wavelengths and over the spatial scales studied, (2) a constant value of the dust opacity is not warranted by our observations, and (3) a high-significance radial gradient of the dust opacity spectral index, {β}, is consistent with the observed dust emission in both disks, with low-{β} in the inner disk and high-{β} in the outer disk. Assuming that changes in dust properties arise solely due to changes in the maximum particle size (amax), we constrain radial variations of amax in both disks, from cm-sized particles in the inner disk (R 80 AU). These observational constraints agree with theoretical predictions of the radial-drift barrier, however, fragmentation of dust grains could explain our amax(R) constraints if these disks have lower turbulence and/or if dust can survive high-velocity collisions. ; Comment: 18 pages, 15 figures, accepted for publication at ApJ