Status of the NIKA2 Cosmology Legacy Survey (N2CLS)
More than half of the photons emitted by stars across cosmic times have been absorbed by cosmic dust and re-emitted in the far-infrared and millimeter wavelength domain. Herschel and ALMA revealed that very massive and very dusty galaxies already exist in the early Universe (up to z~7). These objects are one of the keys to understand the formation of the most massive galaxies. However, these objects are rare and significant volumes need to be probed to perform a census of the obscured star formation at z>3. ALMA is inefficient to map large area, while the previous generation of single-dish instruments were not enough sensitive.
The NIKA2 camera is perfectly suited to fill the gap between these two types of instruments. Thanks to a new technology of detectors (the KIDs for Kinetic Inductance Detectors), we reach mapping speeds competitive with ALMA at 1.2 and 2 millimeter for a much smaller operational cost. The N2CLS is performing a confusion-limited survey in GOODS-N and a 0.4 deg2 deep mapping in the COSMOS field. We expect to obtain a volume- and SFR-complete sample of tens of star-forming sources above z=4. I will present the updated goal and status of the large program and the expected outcome of N2CLS.