completeness corrections and the small scale issues of the Milky Way - - PowerPoint PPT Presentation

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completeness corrections and the small scale issues of the Milky Way - - PowerPoint PPT Presentation

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completeness corrections and the small scale issues of the Milky Way Stacy Kim Small Galaxies, Cosmic Questions | Durham, UK | July 29, 2019 GAIA DR1 sky map Two fundamental predictions of CDM 1 DM halos are cuspy in their centers, i.e.

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Stacy Kim

completeness corrections

GAIA DR1 sky map

and the small scale issues of the Milky Way

Small Galaxies, Cosmic Questions | Durham, UK | July 29, 2019

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SLIDE 2

1

Two fundamental predictions of CDM

DM halos are cuspy in their centers, i.e.

density radius

  • bserved

(“cored”) CDM (“cuspy”)

Nearly scale-free hierarchy of DM halos

to Earth-mass scales!

cusp-core problem missing satellites problem

2

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Garrison-Kimmel+ 2017

a fundamental prediction of CDM

substructure

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SLIDE 4

DM only simulations of the Milky Way

O(100) satellites

Garrison-Kimmel+ 2017

a fundamental prediction of CDM

substructure

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LMC SMC Fornax Sculptor Draco Ursa Minor Carina GAIA DR1 sky map

  • bserved

~10 satellites!

Sextans Sagittarius Leo I Leo II

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SLIDE 6

LMC SMC Fornax Sculptor Draco Ursa Minor Carina GAIA DR1 sky map

  • bserved

~10 satellites!

missing satellites problem

Sextans Sagittarius Leo I Leo II

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SLIDE 7

LMC SMC Fornax Sculptor Draco Ursa Minor Carina GAIA DR1 sky map

  • bserved

~27 post-SDSS

Sextans Leo I Leo II Sagittarius

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SLIDE 8

LMC SMC Fornax Sculptor Draco Ursa Minor Carina GAIA DR1 sky map

  • bserved

~44 with DES

Sextans Leo I Leo II Sagittarius

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SLIDE 9

LMC SMC Fornax Sculptor Draco Ursa Minor Carina GAIA DR1 sky map

  • bserved

~50 with DES

+ a few others

Sextans Leo I Leo II Sagittarius

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SLIDE 10

Tollerud+ 2008

where’s the rest?

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SLIDE 11

Tollerud+ 2008

where’s the rest?

Milk ilky y Way y radiu ius

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SLIDE 12

Tollerud+ 2008

where’s the rest?

visib isible le

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SLIDE 13

Tollerud+ 2008

where’s the rest?

in invisib isible le visib isible le

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SLIDE 14

Tollerud+ 2008

where’s the rest?

in invisib isible le visib isible le

MW sa satellit ellites es we e ca can’t see see

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SLIDE 15

completeness corrections

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completeness corrections

r (kpc) percent

  • bserved

within r 1 radial distribution

(plotted as a CDF)

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SLIDE 17

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 radial distribution

(plotted as a CDF)

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SLIDE 18

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f radial distribution

(plotted as a CDF)

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SLIDE 19

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f 1 1 f total dwarfs radial distribution

(plotted as a CDF)

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SLIDE 20

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f 1 1 f total dwarfs

radial completeness correction

radial distribution

(plotted as a CDF)

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SLIDE 21

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f total dwarfs 1 1 f survey area Asky A

area completeness correction radial completeness correction

radial distribution

(plotted as a CDF)

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SLIDE 22

completeness corrections

for each dwarf observed, with brightness MV,

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f survey area Asky A

area completeness correction total dwarfs with MV

1 1 f Asky A

=

total dwarfs 1 1 f

radial completeness correction

radial distribution

(plotted as a CDF)

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SLIDE 23

completeness corrections

for each dwarf observed, with brightness MV, sum for each dwarf, MW total

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f survey area Asky A

area completeness correction total dwarfs with MV

1 1 f Asky A

=

total dwarfs 1 1 f

radial completeness correction

radial distribution

(plotted as a CDF)

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SLIDE 24

completeness corrections

for each dwarf observed, with brightness MV, sum for each dwarf, MW total

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f survey area Asky A

area completeness correction total dwarfs with MV

1 1 f Asky A

=

total dwarfs 1 1 f

radial completeness correction

radial distribution

(plotted as a CDF)

No missing satellites! (Kim+ 2018)

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SLIDE 25

completeness corrections

sum for each dwarf, MW total

completeness radius R(MV) r (kpc) percent

  • bserved

within r 1 f survey area Asky A

area completeness correction total dwarfs with σ*

1 1 f Asky A

=

total dwarfs 1 1 f

radial completeness correction

radial distribution

(plotted as a CDF)

for each dwarf observed, with brightness MV, dispersion σ*,

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101 102 r (kpc) 10−3 10−2 10−1 100 N(<r)/Ntotal Segue I NFW SIS ELVIS, stripped D17 DMO + gal DMO + gal + GK17 stripping

radial distributions

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corrected velocity function

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predictions from simulations

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predictions from simulations

to capture suppresion in MF in hydrodynamic simulations

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predictions from simulations

luminous subhalos

galaxies unsuppressed by reionization

Dooley+ 2017, Barber+ 2014

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predictions from simulations

converting Mhalo σ*

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predictions from simulations

converting Mhalo σ*

⟨σ2

∗⟩ = G

4 M(< r1/2) R1/2

Wolf+ 2010 mass estimator

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SLIDE 33

predictions from simulations

converting Mhalo σ*

⟨σ2

∗⟩ = G

4 M(< r1/2) R1/2

Wolf+ 2010 mass estimator

Danielli+ 2018

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predictions from simulations

converting Mhalo σ*

⟨σ2

∗⟩ = G

4 M(< r1/2) R1/2

Wolf+ 2010 mass estimator

Danielli+ 2018

calculate for different density profiles

density radius cored cuspy r1/2

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theory vs. observations

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theory vs. observations

added effect of tidal stripping

Penarrubia+ 2010

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theory vs. observations

requires cusps to explain velocity function!

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theory vs. observations

requires cusps to explain velocity function! too many satellites if severity of disk stripping to be believed!

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implications for SIDM

suggests SIDM constraints

  • f σ*/m ~ 0.3 cm2/g!
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corrected velocity function

transition from cores to cusps at 1010 M¤

Read+2016, Robles+ 2017

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  • bservational uncertainties
  • lder velocity measurements for

the satellite galaxy Boo II

10.5 ± 7.4 km/s --> 4.4 ± 1.1 km/s

Geha+, private communication

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SLIDE 42
  • bservational uncertainties

Geha+, private communication

reducing uncertainties on velocity measurements by a factor of 2

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SLIDE 43
  • bservational uncertainties

Geha+, private communication

reducing uncertainties on velocity measurements by a factor of 2 shape of the velocity function sensitive to uncertainties!

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velocity functions: a summary

CDM with baryons does a decent job explaining satellite kinematics

but too many satellites with disk stripping

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SLIDE 45

velocity functions: a summary

SIDM with σ*/m > 0.3 cm2/g disfavored CDM with baryons does a decent job explaining satellite kinematics

but too many satellites with disk stripping

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SLIDE 46

velocity functions: a summary

shape of corrected velocity function strongly dependent velocity uncertainties more precise measurements needed! CDM with baryons does a decent job explaining satellite kinematics

but too many satellites with disk stripping

SIDM with σ*/m > 0.3 cm2/g disfavored

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SLIDE 47

EXTRAS: MSP

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103 104 105 106 107 108 109 M⇤ (M) 100 101 102 103 Nsats > M⇤

  • bserved
  • bserved + area cor.

NFW SIS ELVIS, stripped D17 DMO + gal DMO + gal + GK17 stripping Behroozi+ 2013 Moster+ 2013 Brook+ 2014 Behroozi+ 2013 Moster+ 2013 Brook+ 2014

corrected luminosity function

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103 104 105 106 107 108 109 M⇤ (M) 100 101 102 103 Nsats > M⇤

  • bserved
  • bserved + area cor.

NFW SIS ELVIS, stripped D17 DMO + gal DMO + gal + GK17 stripping zre = 9.3 zre = 11.3 zre = 14.4 zre = 9.3 zre = 11.3 zre = 14.4

corrected luminosity function

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SLIDE 50

100 101 102 103 cumulative number of satellites < Minfall 107 108 109 1010 1011 infall mass (M)

Brook+ 2014 Moster+ 2013 Behroozi+ 2013

CDM WDM, 8.0 keV WDM, 4.0 keV WDM, 2.0 keV WDM, 1.0 keV

dependence on reionization redshift

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106 107 108 109 Lowest mass galaxy halo (Minfall/M) NFW SIS ELVIS, stripped DMO + gal DMO + gal, GK17 stripping MSP not enough subhalos 106 107 108 hMz=0i/M

mass of Segue I

z = 9.3

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106 107 108 109 Lowest mass galaxy halo (Minfall/M) NFW SIS ELVIS, stripped DMO + gal DMO + gal, GK17 stripping MSP not enough subhalos 106 107 108 hMz=0i/M

mass of Segue I

z = 11.3

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106 107 108 109 Lowest mass galaxy halo (Minfall/M) NFW SIS ELVIS, stripped DMO + gal DMO + gal, GK17 stripping MSP not enough subhalos 106 107 108 hMz=0i/M

mass of Segue I

z = 14.4

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velocity dispersions, σ*

less massive subhalo more massive subhalo

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velocity dispersions, σ*

less massive subhalo more massive subhalo

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velocity dispersions, σ*

less massive subhalo more massive subhalo

Stars in more massive subhalos orbit faster (to counteract gravity), thus velocities a proxy for mass!

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velocity dispersions, σ*

less massive subhalo more massive subhalo

Stars in more massive subhalos orbit faster (to counteract gravity), thus velocities a proxy for central mass! Stars typically live in the centers of subhalos, and thus are sensitive to the presence of central cores vs. cups!