Obscured star formation in Lyα blobs at z = 3.1
We present results from the AzTEC/ASTE 1.1-mm imaging survey of 35 Lyα blobs (LABs) found in the SSA22 protocluster at z = 3.1. These 1.1-mm data reach an rms noise level of 0.7–1 mJy beam⁻¹, making this the largest millimetre-wave survey of LABs to date. While one (or possibly two) out of 35 LABs m...
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2013 |
| País: | México |
| Institución: | Instituto Nacional de Astrofísica, Óptica y Electrónica |
| Repositorio: | Repositorio Institucional del INAOE |
| Idioma: | inglés |
| OAI Identifier: | oai:inaoe.repositorioinstitucional.mx:1009/2270 |
| Acceso en línea: | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/2270 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Inspec/Galaxies: evolution info:eu-repo/classification/Inspec/Galaxies: formation info:eu-repo/classification/Inspec/Galaxies: high-redshift info:eu-repo/classification/Inspec/Galaxies: starburst info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/21 |
| Sumario: | We present results from the AzTEC/ASTE 1.1-mm imaging survey of 35 Lyα blobs (LABs) found in the SSA22 protocluster at z = 3.1. These 1.1-mm data reach an rms noise level of 0.7–1 mJy beam⁻¹, making this the largest millimetre-wave survey of LABs to date. While one (or possibly two) out of 35 LABs might be detected at 3σ level, no significant (≥3.5σ) emission is found in any of individual 35 LABs. From this, we estimate 3σ upper limits on the far-infrared luminosity of LFIR < 2 × 10¹² L๏ (the dust temperature of 35K and the emissivity index of 1.5 are assumed). Stacking analysis reveals that the 1.1-mm flux density averaged over the LABs is S₁.₁mm < 0.40 mJy (3σ), which places a constraint of LFIR< 4.5 × 10¹¹ L๏. These data constrain the dust spectral energy distributions of the LABs more tightly than ever if their spectral indices at rest-frame wavelength of ≈ 240 μm are similar to those found in (ultra-)luminous infrared galaxies at 0.2 < z < 0.3. Our results suggest that LABs on average have little ultraluminous obscured star formation, in contrast to a long-believed picture that LABs undergo an intense episode of dusty star formation activities with star formation rates of ∼10³M๏ yr⁻¹. Observations with the Atacama Large Millimeter/submillimeter Array are needed to directly study the obscured part of star formation activity in the LABs. |
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