4MOST Consortium Survey 10: The Time-Domain Extragalactic Survey (TiDES)

TL;DR

The TiDES survey aims to spectroscopically follow up on extragalactic transients and variable sources from upcoming large sky surveys, enabling classification, redshift measurement, and reverberation mapping over five years.

Contribution

This paper introduces the TiDES survey, detailing its three sub-surveys and its capabilities for classifying transients, measuring redshifts, and monitoring active galactic nuclei.

Findings

Spectroscopic classification of transients down to r=22.5 mag.

Spectra for up to 30,000 transients over five years.

Redshift measurements for up to 50,000 host galaxies.

Abstract

The Time-Domain Extragalactic Survey (TiDES) is focused on the spectroscopic follow-up of extragalactic optical transients and variable sources selected from forthcoming large sky surveys such as that from the Large Synoptic Survey Telescope (LSST). TiDES contains three sub-surveys: (i) spectroscopic observations of supernova-like transients; (ii) comprehensive follow-up of transient host galaxies to obtain redshift measurements for cosmological applications; and (iii) repeat spectroscopic observations to enable the reverberation mapping of active galactic nuclei. Our simulations predict we will be able to classify transients down to $r = 22.5$ magnitudes (AB) and, over five years of 4MOST operations, obtain spectra for up to 30,000 live transients to redshift $z \sim 0.5$, measure redshifts for up to 50,000 transient host galaxies to $z \sim 1$ and monitor around 700 active galactic nuclei to $z \sim 2.5$.