English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We report ALMA Band 3 observations of CO(6-5), CO(7-6), and [CI](2-1) inB14-65666 (``Big Three Dragons''), one of the brightest Lyman-Break Galaxies at$z>7$ in the rest-frame ultraviolet continuum, far-infrared continuum, andemission lines of [OIII] 88 $\mu$m and [CII] 158 $\mu$m. CO(6-5), CO(7-6), and[CI](2-1), whose $3\sigma$ upper limits on the luminosities are approximately40 times fainter than the [CII] luminosity, are all not detected. The $L_{\rm[CII]}$/$L_{\rm CO(6-5)}$ and $L_{\rm [CII]}$/$L_{\rm CO(7-6)}$ ratios arehigher than the typical ratios obtained in dusty star-forming galaxies orquasar host galaxies at similar redshifts, and they may suggest a lower gasdensity in the photodissociated region in B14-65666. By using the (1) [CII]luminosity, (2) dust mass-to-gas mass ratio, and (3) a dynamical mass estimate,we find that the molecular gas mass ($M_{\rm{mol}}$) is$(0.05-11)\times10^{10}$ $M_{\rm \odot}$. This value is consistent with theupper limit inferred from the nondetection of mid-$J$ CO and [CI](2-1). Despitethe large uncertauinty in $M_{\rm mol}$, we estimate a molecular gas-to-stellarmass ratio ($\mu_{\rm{gas}}$) of $0.65-140$ and a gas depletion time($\tau_{\rm dep}$) of $2.5-550$ Myr; these values are broadly consistent withthose of other high-redshift galaxies. B14-65666 could be an ancestor of apassive galaxy at $z\gtrsim4$ if no gas is fueled from outside the galaxy.

Big Three Dragons: Molecular Gas in a Bright Lyman-Break Galaxy at $z=7.15$