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

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 
 (background) Lens 
 (foreground)

Weak Lensing γ shear Source 
 (background) Lens 
 (foreground)

Weak Lensing Source 
 (background) Lens 
 (foreground)

Overcoming shape noise Source 
 (background) Lens 
 (foreground)

Stellar to Halo Mass Relation

My Research Develop and exploit a new high-precision weak lensing technique

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

Precision Weak Lensing

Precision Weak Lensing Circular shape Circular motion

Precision Weak Lensing Circular shape Circular motion α

Precision Weak Lensing Unlensed Lensed on α β

Dynamical Shape noise σ γ obs = γ true + sin (2 ϕ )

γ obs > 0 σ γ obs = γ true + γ obs < 0 γ obs < 0 sin (2 ϕ ) γ obs > 0

Data Target Selection Observations Analysis z < 0.15 & i < 17.5 +30 nights Custom Data Reduction γ pred > 0.001 KOALA (3.9m) + WIFES (2.3m) Vel with shear modelling 3000 systems 100 galaxies 21 useful targets

Precision Weak Lensing Gurri et. al. 2020a

Precision Weak Lensing ⟨ γ ⟩ = 0.021 ± 0.005 Gurri et. al. 2020a

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

The Shape of Shear γ obs ≠ γ pred σ ξ Dynamical shape noise Dispersion in SHMR γ obs γ obs ξ σ

The Shape of Shear γ obs ≠ γ pred Dynamical shape noise + dispersion in SHMR γ obs γ pred

ξ high ξ low σ γ obs γ obs low σ high γ obs γ obs 0 0 0

The Shape of Shear Gurri et. al. 2020b

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

Dispersion in the SHMR

Dispersion in the SHMR ξ = 0.4 dex

Dispersion in the SHMR γ obs γ pred

My Research 1. Can we detect lensing though velocity fj elds? 2. Can we separate noise from lensing? 3. Can we constrain the SHMR’s dispersion & shape?

Contribution to Research Area 1. A new methodology to do weak lensing 2. Published the fj rst dataset of weakly lensed vel. fj elds 3. Opened a way to measure the dispersion in the SHMR