Credit: Alex Drlica-Wagner and DES
The Southern Stellar Stream Spectroscopic Survey (S5) and Beyond
Ting LiLeon Lederman Fellow, Fermilab
KICP Associated Fellow, the University of Chicago
Massively multiplexed spectroscopy with MSE, 26-28 February, 2019, Tucson, AZ
Field of Streams in the Dark Energy Survey (DES) Footprint
Shipp et al. (2018)w/ TSL(DES Collaboration)
The Southern Stellar Stream Spectroscopic Survey (S5) and Beyond
Ting LiLeon Lederman Fellow, Fermilab
KICP Associated Fellow, the University of Chicago
S5 Collaboration
• DES Milky Way• Ting Li* (co-PI)• Kyler Kuehn*• Nora Shipp• Andrew Pace• Alex Drlica-Wagner• Vasily Belokurov• Jennifer Marshall• Sahar Allam• Douglas Tucker• Eduardo Balbinot• Keith Bechtol• Kathy Vivas• Risa Wechsler• Brian Yanny
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• Australians• Daniel Zucker* (co-PI)• Geraint Lewis*• Jeffrey Simpson• Gary Da Costa• Dougal Mackey• Sarah Martell• Gayandhi De Silva• Zhen Wan• Jeremy Mould• Andrew Casey• Joss Bland-Hawthorn• Ken Freeman• Prajwal Kafle• Sanjib Sharma• Helmut Jerjen
• DES external collaborators• Denis Erkal• Sergey Koposov• Marla Geha• Josh Simon• Yao-Yuan Mao• Alexander Ji
* S5 Leadership
S5 is an international collaboration of ~30 members
Introduction
• Why Stellar Streams?• Formation of Galactic Halo• Milky Way’s Gravitational Potential• Dark Matter Subhalo Distribution
• Modern imaging surveys have discovered 50+ streams in the Milky Way (e.g., Mateu et al. 2018, Shipp et al. 2018)
• ~7 streams has been followed up spectroscopically.
• Spectroscopic follow-up observations• important;• but extremely difficult 4
High Multiplexity, wide FOV: AAT/2df+AAOmega
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AAT: Anglo-Australian Telescope (4 meter) at
Siding Spring Observatory
2df: 2-deg (in diameter) field fiber positioner w/ 400 fibers
Large Field-of-View, High Multiplexity= An Ideal Instrument for Stellar Streams Follow-ups
AAOmega: a dual-arm optical
spectrograph
• Started in August 2018• Goals: S5 + Gaia + DES =
6D + [Fe/H] for 14 DES streams
• ~25 nights in 2018B• 10 DES streams fully
mapped; 8 streams are reduced and confirmed
• Expand beyond DES footprint in 2019 for a total of 20 streams
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S5 : Overview and Status
Already double the number of streams with
6D info.
Li et al. in prep
Credit: Nora Shipp
• Line-of-sight velocities
• Proper motions (Gaia DR2)
• Metallicities• Orbits• Chemical
Abundance (high-resolution follow-up)
• Progenitors• ….
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Example: ATLAS Stream (w/ 12 AAT pointings)
Li et al. in prep
Orphan Stream inferred from RR Lyraes in Gaia DR2
Perturbation from LMC
Koposov et al. 2019 (w/ TSL), 1812.08172Erkal et al. 2019 (w/ TSL), 1812.08192(The OATs: Orphan Aspen Treasury Collaboration)
Perturbation from LMC
• Most Southern Streams were affected by LMC
• Simultaneous fit with multiple streams can infer the 3D profile of LMCCredit: Denis Erkal
Preliminary
Summary
S5 is a Spectroscopic Survey of the Southern Stellar Streams; a collaboration of ~30 scientists.Goals:
•Measure 6D + metallicity•Characterize stream progenitors•Constrain the Milky Way mass•Assess the influence of the LMC
Current Status:•25 AAT nights in 2018B•10 DES streams observed, w/ 8 reduced & confirmed•Accomplish a total of 20 streams w/ Dec < +30 deg by the end of 2019
Auxiliary Programs:•S5-Halo Survey (RR Lyrae, BHB, metal-poor stars, white dwarfs, etc.)•S5 -LOWZ Survey (dwarf galaxies at z < 0.05)•High resolution spectroscopy w/ Magellan/MIKE
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Looking Forward
Stream at 10-30 kpc:• Discovery: DES (4m), w/ MSTO stars at g < 22.5• Proper Motion: Gaia DR2, w/ RGB at g < 19.5• RV+FeH: S5 (AAT, 4m), w/ RGB at g < 19.5• Chemical abundance: S5 (Magellan, 6.5m), w/ TRGB at g < 18
Streams at 40-100 kpc:• Discovery: LSST (8m), w/ MSTO stars at g < 25.5• Proper Motion: Gaia (5yr)/WFIRST/LSST, w/RGB at g < 22.5• RV+FeH: MSE (11.25m), w/ RGB at g < 22.5• Chemical abundance: MSE/GMT/TMT, w/ TRGB at g < 20
Looking Forward
Stream at 10-30 kpc:• Discovery: DES (4m), w/ MSTO stars at g < 22.5• Proper Motion: Gaia DR2, w/ RGB at g < 19.5• RV+FeH: S5 (AAT, 4m), w/ RGB at g < 19.5• Chemical abundance: S5 (Magellan, 6.5m), w/ TRGB at g < 18• RV+FeH: MSE, w/ MSTO at g < 22.5• Chemical abundance: MSE, w/ RGBs at g < 20
Streams at 40-100 kpc:• Discovery: LSST (8m), w/ MSTO stars at g < 25.5• Proper Motion: Gaia (5yr)/WFIRST/LSST, w/RGB at g < 22.5• RV+FeH: MSE (11.25m), w/ RGB at g < 22.5• Chemical abundance: MSE/GMT/TMT, w/ TRGB at g < 20
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backup slides
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• Started in August 2018
• Goals: S5 + Gaia = 6D + [Fe/H] for all DES streams
• Targets with 15 < g < 20• photometry: DES DR1 • proper motion: Gaia DR2
• RV precision ~ 1km/s at high S/N• ~2hr exposure per field, with S/N ~ 5
at g ~ 18.5 in the red
S5 Overview
S5 is more than a stream survey!
• S5 - Stream (150/400)• S5 - Halo (150/400)
• Blue Horizontal Branch Stars• RR Lyrae Stars• Metal-Poor Stars• Low Proper Motion Stars
• S5 - LowZ (100/400)• Dwarf Galaxies in Low Redshift (z < 0.05)• w/ color and morphology selection
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Perturbation from LMC
Offsets between the tracks and the proper motions of the streams.
Shipp et al. in prep
Preliminary
• Most Southern Streams were affected by LMC