ALMA OBSERVATIONS OF Lyα BLOB 1: HALO SUBSTRUCTURE ILLUMINATED FROM WITHIN

• Published in: The Astrophysical journal Vol. 832; no. 1; p. 37
• Main Authors: Geach, J. E., Narayanan, D., Matsuda, Y., Hayes, M., Mas-Ribas, Ll, Dijkstra, M., Steidel, C. C., Chapman, S. C., Feldmann, R., Avison, A., Agertz, O., Ao, Y., Birkinshaw, M., Bremer, M. N., Clements, D. L., Dannerbauer, H., Farrah, D., Harrison, C. M., Kubo, M., Michałowski, M. J., Scott, Douglas, Smith, D. J. B., Spaans, M., Simpson, J. M., Swinbank, A. M., Taniguchi, Y., Werf, P. van der, Verma, A., Yamada, T.
• Format: Journal Article
• Language: English
• Published: Philadelphia IOP Publishing 20.11.2016
• Subjects: Astrophysics; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; Computer simulation; COSMIC DUST; Deposition; EMISSION; FLUX DENSITY; GALAXIES; galaxies: evolution; galaxies: halos; galaxies: high-redshift; Hubble Space Telescope; HYDROGEN; Low mass stars; LYMAN LINES; MASS; Morphology; PHOTONS; RADIANT HEAT TRANSFER; Radiative transfer; Radio telescopes; RED SHIFT; SATELLITES; SIMULATION; SPACE; Space telescopes; SPECTROMETERS; STAR EVOLUTION; Star formation; STARS; Substructures; Surface brightness; TELESCOPES; ULTRAVIOLET RADIATION
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.3847/0004-637X/832/1/37

ABSTRACT We present new Atacama Large Millimeter/Submillimeter Array (ALMA) 850 μ m continuum observations of the original Ly α Blob (LAB) in the SSA22 field at z  = 3.1 (SSA22-LAB01). The ALMA map resolves the previously identified submillimeter source into three components with a total flux density of  S 850  = 1.68 ± 0.06 mJy, corresponding to a star-formation rate of ∼150 M ⊙ yr −1 . The submillimeter sources are associated with several faint ( m ≈ 27 mag) rest-frame ultraviolet sources identified in Hubble Space Telescope Imaging Spectrograph (STIS) clear filter imaging ( λ ≈ 5850 Å). One of these companions is spectroscopically confirmed with the Keck Multi-Object Spectrometer For Infra-Red Exploration to lie within 20 projected kpc and 250 km s −1 of one of the ALMA components. We postulate that some of these STIS sources represent a population of low-mass star-forming satellites surrounding the central submillimeter sources, potentially contributing to their growth and activity through accretion. Using a high-resolution cosmological zoom simulation of a 10 13 M ⊙ halo at z  = 3, including stellar, dust, and Ly α radiative transfer, we can model the ALMA+STIS observations and demonstrate that Ly α photons escaping from the central submillimeter sources are expected to resonantly scatter in neutral hydrogen, the majority of which is predicted to be associated with halo substructure. We show how this process gives rise to extended Ly α emission with similar surface brightness and morphology to observed giant LABs.