Obscured star formation in Ly-alpha blobs at z = 3.1

Abstract

We present results from the AzTEC/ASTE 1.1-mm imaging survey of 35 Ly-alpha blobs (LABs) found in the SSA22 protocluster at z = 3.1. These 1.1-mm data reach an r.m.s. noise level of 0.7-1 mJy/beam, making this the largest millimetre-wave survey of LABs to date. No significant (> 3.5-sigma) emission is found in any of individual 35 LABs, and from this, we estimate 3-sigma upper limits on the far-infrared luminosity of L_FIR < 2e+12 Lsun. Stacking analysis reveals that the 1.1-mm flux density averaged over the LABs is S(1.1mm) < 0.40 mJy (3-sigma), which places a constraint of L_FIR < 4.5e+11 Lsun. This indicates that earlier 850-um measurements of the LABs may have overestimated their flux densities. Our results suggest that LABs on average have little ultra-luminous 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 ~ 10^3 Msun/yr. Observations with ALMA are needed to directly study the obscured part of star-formation activity in the LABs.

7 pages, 4 figures, 1 table, accepted for publication in MNRAS

References in corpus (11)

• SHARC-2 350 Micron Observations of Distant Submillimeter Selected Galaxies
• AzTEC Millimetre Survey of the COSMOS Field: I. Data Reduction and Source Catalogue
• The AzTEC mm-Wavelength Camera
• The Chandra Deep Protocluster Survey: Ly-alpha Blobs are powered by heating, not cooling
• Spatial correlation between submillimetre and Lyman-alpha galaxies in the SSA 22 protocluster
• A Keck/DEIMOS Spectroscopy of Lyman Alpha Blobs at Redshift z=3.1
• Wide-field mid-infrared and millimetre imaging of the high-redshift radio galaxy, 4C41.17
• Deep Spectroscopy of Systematically Surveyed Extended Lyman-alpha Sources at z~3-5
• High-Resolution Submillimeter Imaging of the Ly-alpha Blob1 in SSA 22
• Infrared and millimetre-wavelength evidence for cold accretion within a z = 2.83 Lyman-alpha blob
• Submillimeter observations of the J2142-4423 Lya protocluster at z = 2.38

Cited by in corpus (15)

• AzTEC/ASTE 1.1 mm survey of SSA22: Counterpart identification and photometric redshift survey of submillimeter galaxies
• The Formation of the massive galaxies in the SSA22 z=3.1 protocluster
• Overturning the Case for Gravitational Powering in the Prototypical Cooling Lyman-alpha Nebula
• ALMA Deep Field in SSA22: Survey Design and Source Catalog of a 20 arcmin^2 Survey at 1.1mm
• An extremely dense group of massive galaxies at the centre of the protocluster at z = 3.09 in the SSA22 field
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• About AGN ionization echoes, thermal echoes, and ionization deficits in low redshift Lyman-alpha blobs
• A submillimeter galaxy illuminating its circumgalactic medium: Ly-alpha scattering in a cold, clumpy outflow
• An Extragalactic Spectroscopic Survey of the SSA22 Field
• Deep submillimeter and radio observations in the SSA22 field. I. Powering sources and Lyα escape fraction of Lyα blobs
• ALMA observations of a z~3.1 Protocluster: Star Formation from Active Galactic Nuclei and Lyman-Alpha Blobs in an Overdense Environment
• Pinpointing the Molecular Gas within a Lyman Alpha Blob at z ~ 2.7
• ALMA Observations of Lyman-alpha Blob 1: Multiple major-mergers and widely distributed interstellar media
• The average submillimetre properties of Lyman-alpha Blobs at z=3
• A high dust emissivity index beta for a CO-faint galaxy in a filamentary Lyman-alpha nebula at z=3.1