Kiloparsec-scale dust disks in high-redshift luminous submillimeter galaxies
- Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
- Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom)
- Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)
- Max-Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
- Argelander-Institute of Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany)
- European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching (Germany)
- Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States)
- Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS B3H 4R2 (Canada)
- Department of Physics, McGill University, 3600 Rue University, Montreal, QC H3A 2T8 (Canada)
- Joint ALMA Observatory—ESO, Av. Alonso de Cordova, 3104, Santiago (Chile)
- Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205, La Laguna, Tenerife (Spain)
- University College London, Department of Physics and Astronomy, Gower Street, London, WC1E 6BT (United Kingdom)
We present high-resolution (0.″16) 870 μm Atacama Large Millimeter/submillimeter Array (ALMA) imaging of 16 luminous (L{sub IR}∼4×10{sup 12} L{sub ⊙}) submillimeter galaxies (SMGs) from the ALESS survey of the Extended Chandra Deep Field South. This dust imaging traces the dust-obscured star formation in these z∼2.5 galaxies on ∼1.3 kpc scales. The emission has a median effective radius of R {sub e} = 0.″24 ± 0.″02, corresponding to a typical physical size of R{sub e}= 1.8 ± 0.2 kpc. We derive a median Sérsic index of n = 0.9 ± 0.2, implying that the dust emission is remarkably disk-like at the current resolution and sensitivity. We use different weighting schemes with the visibilities to search for clumps on 0.″12 (∼1.0 kpc) scales, but we find no significant evidence for clumping in the majority of cases. Indeed, we demonstrate using simulations that the observed morphologies are generally consistent with smooth exponential disks, suggesting that caution should be exercised when identifying candidate clumps in even moderate signal-to-noise ratio interferometric data. We compare our maps to comparable-resolution Hubble Space Telescope H{sub 160}-band images, finding that the stellar morphologies appear significantly more extended and disturbed, and suggesting that major mergers may be responsible for driving the formation of the compact dust disks we observe. The stark contrast between the obscured and unobscured morphologies may also have implications for SED fitting routines that assume the dust is co-located with the optical/near-IR continuum emission. Finally, we discuss the potential of the current bursts of star formation to transform the observed galaxy sizes and light profiles, showing that the z∼0 descendants of these SMGs are expected to have stellar masses, effective radii, and gas surface densities consistent with the most compact massive (M{sub ∗} ∼ 1–2 × 10{sup 11} M{sub ⊙}) early-type galaxies observed locally.
- OSTI ID:
- 22868342
- Journal Information:
- Astrophysical Journal, Vol. 833, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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