# 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.

## Key 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 $z \sim 2.5$.

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Source: https://tomesphere.com/paper/1903.02476