S5 is a spectroscopic survey that began in 2018 using the 2dF/AAOmega spectrograph on the 3.9-metre Anglo-Australian Telescope at Siding Spring Observatory. The aim is to map the kinematics and chemistry of stellar streams in the Southern Hemisphere. The initial focus has been on recently identified streams within the footprint of the Dark Energy Survey (DES), with the eventual goal of surveying the entire southern sky.
The streams represent material tidally striped from dwarf galaxies and globular clusters and hence are essential dynamical probes of the dark matter distribution of the Milky Way, as well as providing a detailed snapshot of its accretion history.
The 350 science fibres of the 2dF fibre positioner, the precise photometry of DES DR1, and the superb proper motions from Gaia DR2 allow us to conduct an efficient spectroscopic survey to map these DES streams. In addition to the stream survey, we use spare fibres on each pointing to undertake a Milky Way halo survey, and a low-redshift galaxy survey.
The main survey. The goal is to measure radial velocities and metallicities of stream members. S5 has mapped over 20 streams both inside and outside of DES footprint. We were the first spectroscopic observations of the DES streams.
We use about a third of our fibres for a Milky Way halo survey. This has the aim of observing interesting objects in the halo such as hyper-velocity stars, extremely metal-poor stars, RR Lyraes, and white dwarfs.
Nearby faint galaxies are difficult to distinguish from the far more numerous background galaxy population via photometry alone. The goal of including low-redshift (low-z) galaxy targets in S5 is to increase the number of spectroscopically confirmed low-z galaxies in order to better train photometric selection algorithms, and help build a statistic sample of very low-z galaxies.
We are also using Magellan/MIKE to obtain high-resolution spectra of bright stream members in order to derive stellar parameters and precise elemental abundances. These will enable us to understand the stream progenitors and chemical evolution.
The First Public Data Release of the Southern Stellar Stream Spectroscopic Survey was on April 24, 2021. S5 DR1 contains data derived from all observations taken between 2018-2019. For details on target selection, data reduction, survey validation see Li et al. (2019) and see this PDF for documenation and column descriptions of S5 DR1.
be downloaded from zenodo. There are two versions of the
s5_pdr1.fits which contains all columns;
s5_pdr1_light.fits which only contains the
small subset with the most frequently used columns.
If any data from this release is used for publication, please cite Li et al. (2019) for reference and include the following text in your acknowledgments:
Based on data acquired at the Anglo-Australian Telescope. We acknowledge the traditional owners of the land on which the AAT stands, the Gamilaraay people, and pay our respects to elders past and present.
We provide machine-readable versions of large tables published in our papers.
If you are interested in the S5 reduced spectra, please contact Ting Li.
S5 is a collaboration between the members of the DES Milky Way Working Group and a group of Australian astronomers.
If you are interested in getting involved in S5, please contact Ting Li or other members in the S5 leadership team.
S5 leadership team helps to coordinate the operational and scientific efforts of the collaboration.
S5 Dynamical modeling coordinator
S5 HIRES coordinator
S5 Data release coordinator
S5 Proper motion coordinator
S5 Website coordinator
Sahar Allam, Eduardo Balbinot, Keith Bechtol, Vasily Belokurov, Andrew Casey, Lara Cullinane, Gary Da Costa, Gayandhi De Silva, Alex Drlica-Wagner, Marla Geha, Dougal Mackey, Sarah Martell, Andrew Pace, Sanjib Sharma, Josh Simon, Douglas Tucker, Kathy Vivas, Zhen Wan, Risa Wechsler, Brian Yanny