Precision Weak Lensing Pol Gurri A.Prof. Ned Taylor Prof. Chris - - PowerPoint PPT Presentation

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Precision Weak Lensing Pol Gurri A.Prof. Ned Taylor Prof. Chris - - PowerPoint PPT Presentation

Jan 30, 2024 130 likes •477 views

Precision Weak Lensing Pol Gurri A.Prof. Ned Taylor Prof. Chris Fluke Swinburne University of Technology Galaxies live inside dark matter halos But How? Stellar to Halo Mass Relation Abundance Matching Weak Lensing Source

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Precision Weak Lensing

Pol Gurri A.Prof. Ned Taylor


  • Prof. Chris Fluke

Swinburne University of Technology

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Galaxies live inside dark matter halos

But How?

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Stellar to Halo Mass Relation

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Abundance Matching

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Weak Lensing

Lens
 (foreground) Source
 (background)

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Weak Lensing

Lens
 (foreground) Source
 (background)

γ shear

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Weak Lensing

Lens
 (foreground) Source
 (background)

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Overcoming shape noise

Lens
 (foreground) Source
 (background)

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Stellar to Halo Mass Relation

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My Research

Develop and exploit a new high-precision weak lensing technique

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  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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Precision Weak Lensing

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Precision Weak Lensing

Circular shape Circular motion

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Precision Weak Lensing

α

Circular shape Circular motion

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Precision Weak Lensing

Unlensed Lensed

β

α

  • n
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γobs = γtrue + σ sin(2ϕ)

Dynamical Shape noise

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γobs = γtrue + σ sin(2ϕ) γobs < 0 γobs < 0 γobs > 0 γobs > 0

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Data

Target Selection Observations Analysis

z < 0.15 & i < 17.5

γpred > 0.001

+30 nights KOALA (3.9m) + WIFES (2.3m) 100 galaxies Custom Data Reduction Vel with shear modelling 21 useful targets 3000 systems

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Precision Weak Lensing

Gurri et. al. 2020a

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Precision Weak Lensing

⟨γ⟩ = 0.021 ± 0.005

Gurri et. al. 2020a

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  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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SLIDE 23
  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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The Shape of Shear

Dynamical shape noise Dispersion in SHMR

γobs

σ

γobs

ξ

σ ξ

γobs ≠ γpred

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The Shape of Shear

Dynamical shape noise + dispersion in SHMR

γobs ≠ γpred

γobs

γpred

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γobs

σ σ

ξlow

low high

ξhigh

γobs γobs γobs

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The Shape of Shear

Gurri et. al. 2020b

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  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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SLIDE 29
  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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Dispersion in the SHMR

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Dispersion in the SHMR

ξ = 0.4 dex

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Dispersion in the SHMR

γobs

γpred

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  • 1. Can we detect lensing though velocity fjelds?
  • 2. Can we separate noise from lensing?
  • 3. Can we constrain the SHMR’s dispersion & shape?

My Research

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Contribution to Research Area

  • 1. A new methodology to do weak lensing
  • 2. Published the fjrst dataset of weakly lensed vel. fjelds
  • 3. Opened a way to measure the dispersion in the SHMR