A deep search for CO J=2-1 emission from a Lyman-Alpha blob at z~6.595

Abstract

We have used the Green Bank Telescope to carry out a deep search for redshifted CO J=2-1 line emission from an extended (>17 kpc) Ly-Alpha blob (LAB), "Himiko", at z~6.595. Our non-detection of CO J=2-1 emission places the strong 3-sigma upper limit of L'_CO < 1.8x10^10 x sqrt(dV/250) K km/s pc^2 on the CO line luminosity. This is comparable to the best current limits on the CO line luminosity in LABs at z~3 and lower-luminosity Lyman-Alpha emitters (LAEs) at z>~6.5. High-z LABs appear to have lower CO line luminosities than the host galaxies of luminous quasars and sub-mm galaxies at similar redshifts, despite their high stellar mass. Although the CO-to-H2 conversion factor is uncertain for galaxies in the early Universe, we assume X_CO = 0.8 Msun (K km/s pc^2)^-1 to obtain the limit M(H_2) < 1.4 x 10^10 Msun on Himiko's molecular gas mass; this is a factor of >2.5 lower than the stellar mass in the z~6.595 LAB.

11 pages, 1 Figure; Accepted for publication in ApJ Letters

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Cited by in corpus (10)

• Cool Gas in High Redshift Galaxies
• ALMA Observation of 158 micron [CII] Line and Dust Continuum of a z=7 Normally Star-forming Galaxy in the Epoch of Reionization
• CO line emission from galaxies in the Epoch of Reionization
• FIR line emission from high redshift galaxies
• A search for CII-158$\mu$m line emission in HCM\,6A, a Lyman-$\alpha$ emitter at $z=6.56$
• Constraining dust formation in high-redshift young galaxies
• Deep rest-frame far-UV spectroscopy of the giant Lyman-alpha emitter 'Himiko'
• A gas-rich AGN near the centre of a galaxy cluster at z ~ 1.4
• Pinpointing the Molecular Gas within a Lyman Alpha Blob at z ~ 2.7
• Discovery of a protocluster core associated with an enormous Ly$\alpha$ Nebula at $z=2.3$