ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Search for [CII] line and dust emission in 6<z<8 galaxies

Understand

We present a search for [CII] line and dust continuum emission from optical dropout galaxies at $z>6$ using ASPECS, our ALMA Spectroscopic Survey in the Hubble Ultra-Deep Field (UDF).

• Our observations, which cover the frequency range $212-272$ GHz, encompass approximately the range $6<z<8$ for [CII] line emission and reach a limiting luminosity of L$_{\rm [CII]}\sim$(1.6-2.5)$\times$10$^{8}$ L$_{\odot}$.
• We identify fourteen [CII] line emitting candidates in this redshift range with significances $>$4.5 $\sigma$, two of which correspond to blind detections with no optical counterparts.
• At this significance level, our statistical analysis shows that about 60\% of our candidates are expected to be spurious.