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THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW
Partnership, ALMA,Fomalont, E. B.,Vlahakis, C.,Corder, S.,Remijan, A.,Barkats, D.,Lucas, R.,Hunter, T. R.,Brogan, C. L.,Asaki, Y.,Matsushita, S.,Dent, W. R. F.,Hills, R. E.,Phillips, N.,Richards, A. M IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.808 No.1
THE 2014 ALMA LONG BASELINE CAMPAIGN: OBSERVATIONS OF ASTEROID 3 JUNO AT 60 KILOMETER RESOLUTION
Hunter, T. R.,Kneissl, R.,Moullet, A.,Brogan, C. L.,Fomalont, E. B.,Vlahakis, C.,Asaki, Y.,Barkats, D.,Dent, W. R. F.,Hills, R. E.,Hirota, A.,Hodge, J. A.,Impellizzeri, C. M. V.,Liuzzo, E.,Lucas, R.,M IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.808 No.1
<P>We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum images of the asteroid 3 Juno obtained with an angular resolution of 0 ''.042 (60 km at 1.97 AU). The data were obtained over a single 4.4 hr interval, which covers 60% of the 7.2 hr rotation period, approximately centered on local transit. A sequence of 10 consecutive images reveals continuous changes in the asteroid's profile and apparent shape, in good agreement with the sky projection of the three-dimensional model of the Database of Asteroid Models from Inversion Techniques. We measure a geometric mean diameter of 259 +/- 4 km, in good agreement with past estimates from a variety of techniques and wavelengths. Due to the viewing angle and inclination of the rotational pole, the southern hemisphere dominates all of the images. The median peak brightness temperature is 215 +/- 13 K, while the median over the whole surface is 197 +/- 15 K. With the unprecedented resolution of ALMA, we find that the brightness temperature varies across the surface with higher values correlated to the subsolar point and afternoon areas and lower values beyond the evening terminator. The dominance of the subsolar point is accentuated in the final four images, suggesting a reduction in the thermal inertia of the regolith at the corresponding longitudes, which are possibly correlated to the location of the putative large impact crater. These results demonstrate ALMA's potential to resolve thermal emission from the surface of main belt asteroids and to measure accurately their position, geometric shape, rotational period, and soil characteristics.</P>
Vlahakis, C.,Hunter, T. R.,Hodge, J. A.,Pé,rez, L. M.,Andreani, P.,Brogan, C. L.,Cox, P.,Martin, S.,Zwaan, M.,Matsushita, S.,Dent, W. R. F.,Impellizzeri, C. M. V.,Fomalont, E. B.,Asaki, Y.,Barka IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.808 No.1
<P>We present initial results of very high resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the z = 3.042 gravitationally lensed submillimeter galaxy HATLAS J090311.6+003906 (SDP. 81). These observations were carried out using a very extended configuration as part of Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines of up to similar to 15 km. We present continuum imaging at 151, 236, and 290 GHz at unprecedented angular resolutions as fine as 23 mas, corresponding to an unmagnified spatial scale of similar to 180 pc at z = 3.042. The ALMA images clearly show two main gravitational arc components of an Einstein ring, with emission tracing a radius of similar to 1 ''.5. We also present imaging of CO J = 10 - 9, J = 8 - 7, and J = 5 - 4 and H2O (202-111) line emission. The CO emission, at an angular resolution of similar to 170 mas, is found to broadly trace the gravitational arc structures but with differing morphologies between the CO transitions and compared to the dust continuum. Our detection of H2O line emission, using only the shortest baselines, provides the most resolved detection to date of thermal H2O emission in an extragalactic source. The ALMA continuum and spectral line fluxes are consistent with previous Plateau de Bure Interferometer and Submillimeter Array observations despite the impressive increase in angular resolution. Finally, we detect weak unresolved continuum emission from a position that is spatially coincident with the center of the lens, with a spectral index that is consistent with emission from the core of the foreground lensing galaxy.</P>