A disk origin for inner stellar halo structures around the Milky Way - - PowerPoint PPT Presentation

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A disk origin for inner stellar halo structures around the Milky Way - - PowerPoint PPT Presentation

May 04, 2023 248 likes •684 views

A disk origin for inner stellar halo structures around the Milky Way Adrian Price-Whelan (Princeton University) adrn adrianprw Kathryn Johnston , Allyson Sheffield, Chervin Laporte , Maria Bergemann, Branimir Sesar, Ting Li, Chris Hayes,

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SLIDE 1

A disk origin for inner stellar halo structures around the Milky Way

Adrian Price-Whelan

(Princeton University)

adrn

adrianprw

Kathryn Johnston, Allyson Sheffield, Chervin Laporte, Maria Bergemann, Branimir Sesar, Ting Li, Chris Hayes, Steve Majewski, Rachael Beaton, Judy Cohen, Andy Tzanidakis

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SLIDE 2

Streams vs. “structures”

Grillmair & Carlin 2016

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SLIDE 3

Streams vs. “structures”

  • C. Slater
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SLIDE 4

Streams vs. “structures”

Monoceros, Anticenter Stream (ACS) Eastern Banded Structure (EBS) Triangulum-Andromeda (TriAnd)

  • C. Slater
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SLIDE 5

Anticenter Stream (ACS) Eastern Banded Structure (EBS) Monoceros / Giant Anticenter Stellar Stream (GASS) / Low Latitude Stream (LLS) Triangulum-Andromeda A13 Hercules-Aquila cloud Virgo over-density Eridanus-Phoenix

“Structures” / clouds / shells

d ~ 8 kpc d ~ 10 kpc d ~ 8–12 kpc d ~ 15–30 kpc d ~ 12–15 kpc d ~ 10–20 kpc d ~ 6–20 kpc d ~ 16 kpc

(heliocentric)

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SLIDE 6

Kicked out of disk? Accreted debris?

  • A. Tzanidakis & C. Laporte
  • D. Hendel
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SLIDE 7

Kicked out of disk? Accreted debris?

  • A. Tzanidakis & C. Laporte
  • D. Hendel
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SLIDE 8

the Triangulum-Andromeda region

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SLIDE 9

the Triangulum-Andromeda region

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SLIDE 10

g − i i

20 22 24 1 2

“Annoying Milky Way Foreground”

Martin+2007

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SLIDE 11

g − i i

20 22 24 1 2

Monoceros Triand 1 & 2

d⊙ ∼ 20 − 30 kpc

“Annoying Milky Way Foreground”

Martin+2007

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SLIDE 12

Sheffield+2014

As an accretion event:

Size + metallicity of TriAnd would imply ≳Sgr-mass progenitor

  • 2 -1.5 -1

[Fe/H]

  • 0.5

0.5

Triand 1

Triand 2

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SLIDE 13

APOGEE survey

Sagittarius dsph metallicity distribution

(RGB stars)

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SLIDE 14

TriAnd

RR Lyrae from Catalina Sky Survey

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SLIDE 15

−150 −100 −50 50 100 150

vGSR [km s−1]

(M-giants)

P > 0.8 P ≤ 0.8 M-giants

100 110 120 130 140 150 160

l [deg]

−150 −100 −50 50 100 150

vGSR [km s−1]

(RR Lyrae)

10 25 40

N

M-giants RR Lyrae

Price-Whelan+2015

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SLIDE 16

Monoceros & A13

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SLIDE 17

Monoceros/GASS A13 TriAnd

RR Lyrae from Catalina Sky Survey

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SLIDE 18

Sheffield, Price-Whelan+2018

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TriAnd, Monoceros, A13 have many K/M giants, few (if any) RR Lyrae: suggests a stellar population unlike any of the dwarf satellites of the Milky Way The Milky Way disk is metal rich: few RR Lyrae, many K/M giants

  • could these features have originated in the disk?
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SLIDE 20

but…very far from disk

Johnston, Price-Whelan+2017

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SLIDE 21

Detailed chemistry of A13 & TriAnd

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SLIDE 22

Bergemann,…,Price-Whelan+2018

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SLIDE 23

Bergemann,…,Price-Whelan+2018

[Fe/H]

  • 2
  • 1

1

  • 3

[Na/Fe]

  • 1
  • 0.5

0.0 0.5

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SLIDE 24

Bergemann,…,Price-Whelan+2018

[Fe/H]

  • 2
  • 1

1

  • 3

[Na/Fe]

  • 1
  • 0.5

0.0 0.5

MW disk Outer disk

  • pen clusters
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SLIDE 25

Bergemann,…,Price-Whelan+2018

[Fe/H]

  • 2
  • 1

1

  • 3

[Na/Fe]

  • 1
  • 0.5

0.0 0.5

MW disk Outer disk

  • pen clusters

Sgr Fornax

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Bergemann,…,Price-Whelan+2018

[Fe/H]

  • 2
  • 1

1

  • 3

[Na/Fe]

  • 1
  • 0.5

0.0 0.5

MW disk Outer disk

  • pen clusters

Sgr Fornax TriAnd / A13

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SLIDE 27

3D kinematics with Gaia

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SLIDE 28

TriAnd stars Rotating with the disk, slightly slower than solar circular velocity

σvR = σvz = 25 km s−1 | ¯ vϕ| = 185 km s−1 σvϕ ≈ 50 km s−1

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SLIDE 29

Summary

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SLIDE 30

Summary

Many of the “structures” identified as streams, clouds, or halo over- densities are associated with or originate from the Galactic disk, but now at extreme radii/heights above disk

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SLIDE 31

Eastern Banded Structure (EBS) Anticenter Stream (ACS) Monoceros / GASS TriAnd A13 Hercules-Aquila Eri-Phoenix (?) Virgo (?)

Disk Accretion

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SLIDE 32

Eastern Banded Structure (EBS) Anticenter Stream (ACS) Monoceros / GASS TriAnd A13 Hercules-Aquila Eri-Phoenix (?) Virgo (?)

Disk Accretion

This talk Talk by Chervin Laporte

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Summary

Many of the “structures” identified as streams, clouds, or halo over- densities are associated with or originate from the Galactic disk, but now at extreme radii/heights above disk These stars could have been “kicked out” as a result of interactions with Sagittarius and the LMC

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SLIDE 34

Laporte+2017

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Summary

Many of the “structures” identified as streams, clouds, or halo over- densities are associated with or originate from the Galactic disk, but now at extreme radii/heights above disk These stars could have been “kicked out” as a result of interactions with Sagittarius and the LMC These features are tracers of dark matter in the outer disk, and will constrain interaction history of the Milky Way and Sagittarius

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SLIDE 36

Some relevant work:

Newberg+2002 Martin+2007, 2014 Sheffield, Johnston+2014 Xu, Newberg+2015 Price-Whelan, Johnston, Sheffield+2015 Li, Sheffield+2017 Laporte+2017 Johnston, Price-Whelan+2017 Bergemann, Sesar+2018 Sheffield, Price-Whelan+2018 Hayes+2018

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Extra slides

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Kirby+2013 Sgr LMC SMC

TriAnd

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SLIDE 39

Kirby+2013

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RR Lyrae K/M Giants

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SLIDE 41

[Fe/H]

  • 2
  • 1

1

  • 3

[Mg/Fe]

  • 0.4

0.0 0.4 0.8

Bergemann,…,Price-Whelan+2018

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SLIDE 42

Bergemann,…,Price-Whelan+2018