The NOEMA observations of GN-z11: constraining the neutral interstellar medium and dust formation in the heart of cosmic reionization at <i>z</i> = 10.6
Yoshinobu Fudamoto, Pascal A. Oesch, Fabian Walter, Roberto Decarli, C. L. Carilli, Andrea Ferrara, Laia Barrufet, R. J. Bouwens, M. Dessauges‐Zavadsky, Erica J. Nelson, H. Dannerbauer, G. D. Illingworth, Akio Inoue, R. Marques-Chaves, I. Pérez‐Fournon, Dominik A. Riechers, D. Schaerer, Renske Smit, Yuma Sugahara, P. van der Werf
Abstract
ABSTRACT We present results of dust continuum and [C ii]$\, 158\, {\rm \mu m}$ emission line observations of a remarkably UV luminous (MUV = −21.6) galaxy at z = 10.603: GN-z11. Using the Northern Extended Millimeter Array (NOEMA), observations have been carried out over multiple observing cycles. We achieved a high sensitivity resulting in a $\lambda _{\rm rest}=160\, {\rm \mu m}$ continuum $1\, \sigma$ sensitivity of $13.0\, \rm {\mu Jy \, beam}^{ -1}$ and a [C ii] emission line $1\, \sigma$ sensitivity of $31\, \rm {mJy\, beam^{ -1}\, km \, s}^{ -1}$ using $50\, \rm {km \, s}^{ -1}$ binning with a $\sim 2\, {\rm arcsec}$ synthesized beam. Neither dust continuum nor [C ii]$\, 158\, {\rm \mu m}$ line emission are detected at the expected frequency of ν[C ii]$= 163.791\, \rm {GHz}$ and the sky location of GN-z11. The upper limits show that GN-z11 is neither luminous in LIR nor L[C ii], with a dust mass $3\, \sigma$ limit of ${\rm log}\, (M_{\rm dust}/{\rm {\rm M}_{\odot }}) \, \lt\, 6.5-6.9$ and with a [C ii] based molecular gas mass $3\, \sigma$ limit of log (Mmol, [C ii]$/{\rm {\rm M}_{\odot }}) \, \lt \, 9.3$. Together with radiative transfer calculations, we also investigated the possible cause of the dust poor nature of the GN-z11 showed by the blue colour in the UV continuum of GN-z11 (βUV = −2.4), and found that ≳3 × deeper observations are crucial to study dust production at very high-redshift. Nevertheless, our observations show the crucial role of deep mm/submm observations of very high-redshift galaxies to constrain multiple phases in the interstellar medium.