` of Dark Matter with the Milky Way Satellite Galaxies Ting Li - - PowerPoint PPT Presentation

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` of Dark Matter with the Milky Way Satellite Galaxies Ting Li - - PowerPoint PPT Presentation

Jan 28, 2023 157 likes •489 views

Constraining the Nature ` of Dark Matter with the Milky Way Satellite Galaxies Ting Li Lederman Fellow Fermi National Accelerator Laboratory DPF 2017 Jul 31st, 2017 1 Credit: Reidar Hahn, Yuanyuan Zhang Why Studying the Milky Way Dwarf

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Credit: Reidar Hahn, Yuanyuan Zhang

Ting Li

Lederman Fellow Fermi National Accelerator Laboratory DPF 2017 Jul 31st, 2017

Constraining the Nature

  • f Dark Matter with the

Milky Way Satellite Galaxies

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SLIDE 2

Why Studying the Milky Way Dwarf Galaxies

  • Milky Way Satellites are Most Dark-Matter-Dominated Galaxies.
  • Milky Way Satellites are Good Testbeds for 𝚳CDM Paradigm
  • Missing Satellites Problem?
  • Cusp-Core Problem?
  • Cold vs. Warm vs. Decay vs. Self-interacting?
  • Milky Way Satellites Are Important to Understand Galaxy Formation
  • Dwarf Galaxies vs. Star Clusters
  • Star Formation History
  • Reionization of the Universe
  • Milky Way Satellites Are Good Sites for Dark Matter Search
  • MACHO: Massive compact halo object
  • WIMP: Weakly interacting massive particles

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SLIDE 3
  • Milky Way satellites are good testbeds for 𝚳CDM paradigm
  • Milky Way satellites are important to understand galaxy formation
  • Milky Way satellites are good site for dark matter search

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Discovery

Imaging/CTIO/Blanco/4m

Spectroscopic Follow-up on Milky Way Dwarf Galaxies in DES

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SLIDE 4

Are these DES candidates dark matter dominated dwarf galaxies? What is the star formation history of these dwarf galaxies? What is the dark matter masses of these dwarf galaxy candidates?

  • Milky Way satellites are good testbeds for 𝚳CDM paradigm
  • Milky Way satellites are important to understand galaxy formation
  • Milky Way satellites are good site for dark matter search

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Discovery

Imaging/CTIO/Blanco/4m

Spectroscopic Follow-up on Milky Way Dwarf Galaxies in DES

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SLIDE 5

Are these DES candidates dark matter dominated dwarf galaxies? What is the star formation history of these dwarf galaxies? What is the dark matter masses of these dwarf galaxy candidates?

  • Milky Way satellites are good testbeds for 𝚳CDM paradigm
  • Milky Way satellites are important to understand galaxy formation
  • Milky Way satellites are good site for dark matter search

3

Discovery

Imaging/CTIO/Blanco/4m

Spectroscopic Follow-up on Milky Way Dwarf Galaxies in DES

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SLIDE 6

Are these DES candidates dark matter dominated dwarf galaxies? What is the star formation history of these dwarf galaxies? What is the dark matter masses of these dwarf galaxy candidates?

  • Milky Way satellites are good testbeds for 𝚳CDM paradigm
  • Milky Way satellites are important to understand galaxy formation
  • Milky Way satellites are good site for dark matter search

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Discovery Characterization

Imaging/CTIO/Blanco/4m Spectroscopy/LCO/Magellan/6.5m

Spectroscopic Follow-up on Milky Way Dwarf Galaxies in DES

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SLIDE 7

Dwarf Galaxy Candidates Discovered in 2015

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Drlica-Wagner et al. 2015 (DES Collaboration)

Blue = Known prior to 2015 Red triangles = DES Y2Q1 candidates Red circles = DES Y1A1 candidates Green = Other new candidates Galactic Coordinates

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SLIDE 8

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Classical Dwarfs Ultra-Faint Dwarfs DES Dwarfs

DES Dwarf Galaxy Candidates

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Classical Dwarfs Ultra-Faint Dwarfs DES Dwarfs

DES Dwarf Galaxy Candidates

Reticulum II Reticulum II Simon et al. (2015) Walker et al. (2015) Koposov et al. (2015) Ji et al. (2015) Roederer et al. (2015)

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Farthest: Eridanus II (370 kpc)

Li et al. (2017) arxiv: 1611.05052

Eridanus II Classical Dwarfs Ultra-Faint Dwarfs DES Dwarfs

DES Dwarf Galaxy Candidates

Tucana III Nearest: Tucana III (25 kpc)

Simon, Li et al. (2017), arxiv: 1610.05301

Reticulum II

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SLIDE 11

Spectra

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2D Spectra 1D Spectra

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SLIDE 12

Spectra

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2D Spectra

Geha et al. 2009

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Eridanus II

  • Dwarf galaxy candidate discovered in DES Year 1 data
  • Distant : ~370 kpc (beyond the virial radius of MW)
  • One of the farthest dwarf galaxies in Milky Way
  • Smallest star-forming galaxy?
  • Important for understanding the quenching of dwarf galaxies
  • Smallest galaxy possessing a central star cluster
  • Provide constraints on MACHO dark matter

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Koposov et al. (2015) Bechtol et al. (2015)

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Eridanus II: Dark Matter Content

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28 members identified

Li et al. (2017)

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Eridanus II: Dark Matter Content

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28 members identified

Li et al. (2017)

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Eridanus II: Dark Matter Content

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28 members identified

Li et al. (2017)

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SLIDE 17

Eridanus II: Dark Matter Content

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28 members identified

Li et al. (2017)

Eridanus II is dark matter dominated dwarf galaxy

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Eridanus II: Star Formation

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Koposov et al. (2015)

Smallest star-forming galaxy?

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SLIDE 19

Eridanus II: Star Formation

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No sign of recently forming stars.

Koposov et al. (2015)

Smallest star-forming galaxy?

Li et al. (2017)

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SLIDE 20

MACHO Constraints

MACHO:Massive Astrophysical Compact Halo Object

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MACHO Constraints

MACHO:Massive Astrophysical Compact Halo Object

  • Eri II possesses a central star cluster
  • MACHO will dynamically heat the cluster until it dissolves (Brandt 2016)
  • The survival of the central cluster place strong constrains on MACHO

abundance

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DECam/DES

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MACHO Constraints

MACHO:Massive Astrophysical Compact Halo Object

  • Eri II possesses a central star cluster
  • MACHO will dynamically heat the cluster until it dissolves (Brandt 2016)
  • The survival of the central cluster place strong constrains on MACHO

abundance

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DECam/DES

Li et al. (2017)

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SLIDE 23

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Eridanus II DES Dwarfs

DES Dwarf Galaxy Candidates

Reticulum II

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Eridanus II DES Dwarfs

DES Dwarf Galaxy Candidates

Reticulum II Tucana III Nearest: Tucana III (25 kpc)

Simon, Li et al. (2017), arxiv: 1610.05301

Dwarf galaxy candidates discovered in Year 2 data

  • Distant to Sun: 25 kpc
  • One of the nearest dwarf galaxy in Milky Way
  • Likely a good candidate for indirect dark

matter search

  • Linear Structure around Tuc III
  • An ultra-faint dwarf galaxy under tidal

disruption?

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SLIDE 25

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Eridanus II DES Dwarfs

DES Dwarf Galaxy Candidates

Reticulum II Tucana III Nearest: Tucana III (25 kpc)

Simon, Li et al. (2017), arxiv: 1610.05301

Dwarf galaxy candidates discovered in Year 2 data

  • Distant to Sun: 25 kpc
  • One of the nearest dwarf galaxy in Milky Way
  • Likely a good candidate for indirect dark

matter search

  • Linear Structure around Tuc III
  • An ultra-faint dwarf galaxy under tidal

disruption?

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SLIDE 26

Tucana III: Dark Matter Content

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26 members identified

Velocity dispersion is NOT resolved

Simon, Li et al. (2017)

Velocity Dispersion Velocity

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Tucana III: Dark Matter Content

14

26 members identified

Velocity dispersion is NOT resolved

Simon, Li et al. (2017)

Velocity Dispersion Velocity

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SLIDE 28

Tucana III: Dark Matter Content

14

26 members identified

Velocity dispersion is NOT resolved

Simon, Li et al. (2017)

Velocity Dispersion Velocity

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Tucana III: Classification

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  • Globular cluster is possible, but more likely to be a dwarf galaxy
  • Large radius
  • Low metallicity

Simon, Li et al. (2017)

If it is a dwarf galaxy, it will be one of the known dwarf galaxy with lowest mass. Not ideal for indirect dark matter search.

Globular Clusters Dwarf Galaxies

Eridanus II Tucana III

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SLIDE 30

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Eridanus II DES Dwarfs

Summary and Future

Reticulum II Tucana III

  • Farthest dwarf galaxy
  • No recent star

formation history

  • MACHO constraints
  • Nearest dwarf galaxy
  • Velocity dispersion

not resolved

  • Classification

uncertain

  • Lowest mass dwarf?

LMC SMC

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SLIDE 31

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Eridanus II DES Dwarfs

Summary and Future

Reticulum II Tucana III

Tucana IV, Tucana V, Grus II Satellites from MagLiteS, BLISS….

  • Farthest dwarf galaxy
  • No recent star

formation history

  • MACHO constraints
  • Nearest dwarf galaxy
  • Velocity dispersion

not resolved

  • Classification

uncertain

  • Lowest mass dwarf?

LMC SMC