Intracluster Light: a luminous tracer for dark matter in clusters of - - PowerPoint PPT Presentation

ICL Mireia Montes

July 5th, 2018

Intracluster Light:

a luminous tracer for dark matter in clusters of galaxies

Mireia Montes

In collaboration with: Ignacio Trujillo, Sarah Brough

ICL Mireia Montes

• History of the assembly of the galaxy cluster

When?

Age of the stars

Who?

Metallicity of the stars

• Properties of the underlying dark matter halo

Shape and extent

What does the ICL tell us?

ICL Mireia Montes

In previous episodes… MACS J0717.5+3745

• 6 galaxy clusters observed with

HST (Lotz et al. 2017, 140 orbits/ cluster)

• Redshift range 0.3 < z < 0.55
• Multiwavelength observations

(F435W, F606W, F814W, F105W, F125W,

F140W, F160W)

~31 mag/arcsec2 (3x3 arcsec2, 3σ)

ICL Mireia Montes

In previous episodes…

MACSJ1149.5+2223

Montes & Trujillo 2014, 2018

• [Fe/H]ICL=-0.5 to -0.3 (0.3-0.4 Z☉)
• M = 109.5 - 1010 M☉
• Ages between 2-6 Gyr younger than the

BCG(s)

• z<1

Consistent with being formed by

ICL Mireia Montes

In previous episodes…

ICL Mireia Montes

Pillepich+2014, 2018

Slope of the stellar mass density profile of the halo (3D) correlates with the total halo mass

In previous episodes… ICL as a tracer of DM?

Montes & Trujillo 2018 3D Slope of stellar mass density

M200

“ …with power-law slopes

• f the radial mass density

distribution as shallow as the dark matter’s”

Pillepich+2018

IllustrisTNG

ICL Mireia Montes

ICL as a tracer of DM? Gravitational lensing Detailed DM distribution within clusters!!

Total mass (Stellar + DM)

Jauzac et al. (2014, 2015a)

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ICL as a tracer of DM!

A2744 M0416

50 75 100 125 140 kpc ICL

MASS

X-rays

M0416

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Modified Hausdorff distance (MHD) Hausdorff distance: Modified Hausdorff distance:

It gives us the mean difference in distance between the tracer and the model, in kpc

Huttenlocher et al. (1993)

maximum distance among two sets of points

More robust to outliers!!

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Montes & Trujillo 2018 (in prep)

Modified Hausdorff distance (MHD)

ICL vs. Circle (R)

Different lens inversion techniques => uncertainties in the mass maps

10"= 45.4 kpc

A2744

ICL Mireia Montes

Merging or recently merged clusters X-rays do not follow the potential of the cluster A2744 ICL as a tracer of DM!

Montes & Trujillo 2018 (in prep) X-rays vs. Mass

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ICL as a tracer of DM. Surprising? Massive halos tend to accrete more and more luminous

satellites (Gao+2004) Those satellites tend to deposit their stars at large radii

(Cooper+2015)

Less concentrated stellar radial profiles!

NO! A n d n

• w

a l s

• i

n 2

• D

!

Hey! Remember…

ICL Mireia Montes

ICL: luminous tracer of DM in clusters of galaxies

10"= 49.2 kpc

AS1063

ICL Mireia Montes

• Study the ICL in the SAMI clusters with HSC@ Subaru
• Large survey of 3000 galaxies (8 clusters)
• Integral-field spectroscopy providing stellar populations

and dynamics of the whole galaxy in 2D!!

Ho et al. 2016

We need to reduce the data carefully!!

+ ICL For the future…

Thanks

ICL Mireia Montes

Montes & Trujillo 2018

For discussion

SB cut? But it has some problems

Evolution of the fraction driven by passive evolution of stellar populations (B band vs V band)

Difference in depths

BCG + ICL fit?

B V V

Fraction of light in ICL