| 1. |
- Burillo, S. G., et al.
(författare)
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ALMA resolves the torus of NGC 1068: Continuum and molecular line emission
- 2016
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 823:1, s. Art. no. L12-
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Tidskriftsartikel (refereegranskat)abstract
- We used the Atacama Large Millimeter Array (ALMA) to map the emission of the CO(6-5) molecular line and the 432 mu m continuum emission from the 300 pc sized circumnuclear disk (CND) of the nearby Seyfert 2 galaxy NGC 1068 with a spatial resolution of similar to 4 pc. These observations spatially resolve the CND and, for the first time, image the dust emission, the molecular gas distribution, and the kinematics from a 7-10 pc diameter disk that represents the submillimeter counterpart of the putative torus of NGC 1068. We fitted the nuclear spectral energy distribution of the torus using ALMA and near-and mid-infrared (NIR/MIR) data with CLUMPY torus models. The mass and radius of the best-fit solution for the torus are both consistent with the values derived from the ALMA data alone: M-gas(torus) = (1 +/- 0.3) x 10(5) M-circle dot and R-torus = 3.5 +/- 0.5 pc. The dynamics of the molecular gas in the torus show strong non-circular motions and enhanced turbulence superposed on a surprisingly slow rotation pattern of the disk. By contrast with the nearly edge-on orientation of the H2O megamaser disk, we found evidence suggesting that the molecular torus is less inclined (i = 34 degrees-66 degrees) at larger radii. The lopsided morphology and complex kinematics of the torus could be the signature of the Papaloizou-Pringle instability, long predicted to likely drive the dynamical evolution of active galactic nuclei tori.
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| 2. |
- Koprowski, M. P., et al.
(författare)
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A resolved map of the infrared excess in a Lyman Break Galaxy at z= 3
- 2016
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 828:2
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Tidskriftsartikel (refereegranskat)abstract
- We have observed the dust continuum of 10 z = 3.1 Lyman break galaxies with the Atacama Large Millimeter/submillimeter Array at similar to 450 mas resolution in Band 7. We detect and resolve the 870 mu m emission in one of the targets with a flux density of S-870 = 192 +/- 57 mu Jy, and measure a stacked 3 sigma signal of S-870 = 67 +/- 23 mu Jy for the remaining nine. The total infrared luminosities are L8-1000 = (8.4 +/- 2.3) x 10(10) L-circle dot for the detection and L8-1000 = (2.9 +/- 0.9) x 10(10) L-circle dot for the stack. With Hubble Space Telescope Advanced Camera for Surveys I-band imaging we map the rest-frame UV emission on the same scale as the dust, effectively resolving the "infrared excess" (IRX = L-FIR/L-UV) in a normal galaxy at z = 3. Integrated over the galaxy we measure IRX = 0.56 +/- 0.15, and the galaxy-averaged UV slope is beta = -1.25 +/- 0.03. This puts the galaxy a factor of similar to 10 below the IRX-beta relation for local starburst nuclei of Meurer et al. However, IRX varies by more than a factor of 3 across the galaxy, and we conclude that the complex relative morphology of the dust relative to UV emission is largely responsible for the scatter in the IRX-beta relation at high-z. A naive application of a Meurer-like dust correction based on the UV slope would dramatically overestimate the total star formation rate, and our results support growing evidence that when integrated over the galaxy, the typical conditions in high-z star-forming galaxies are not analogous to those in the local starburst nuclei used to establish the Meurer relation.
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