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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

Malachy Bloom

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Carleton College - UMN Physics REU - LISA

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  • What is LISA?
  • Why is it cool?

LISA

Stochastic Gravitational Wave Backgrounds with

Anisotropic

Angular Resolution of the Search for

  • What are SGWBs?
  • Can we detect them?
  • Why are they cool?
  • Anisotropies?
  • Using spherical harmonics
  • Characterizing angular resolution
  • (Preliminary) results/conclusions

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

 

LISA = Laser Interferometer Space Antenna ≈ “space LIGO”

  • 2.5 million km arms
  • Orbits/rotates behind Earth
  • Launches in 2030s
  • Why is this cool?

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

(Astronomy: Roen Kelly, after C. Moore, R. Cole, and C. Berry (Institute of Astronomy, Univ. of Cambridge)

LIGO

LISA

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

So what is a SGWB?

Cosmological

Astrophysical

  • Inflation
  • Cosmic strings
  • Primordial black holes
  • Other early universe stuff

(Older and probably not realistic)

  • Milky Way Foreground
    • Choir
  • LMC Background
  • A bunch of other backgrounds
  • High energy
  • Origins
  • Models of Universe
  • Dark Matter?
  • Structure of Universe
  • Astronomy
  • Tests of GR
  • Unknowns

Can point at them!

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

 

BLIP = Bayesian LISA Pipeline

Injection

  • Assume model type
  • Set parameters
  • Generate Data

​

Recovery

  • Assume recovery model type
  • Set more parameters
  • Analyze Data
    • (the Bayesian part)

​

 

Data!

Anisotropic Search

Results!!

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

Might typically impose:

 

Anisotropic energy density:

 

 

 

 

 

 

 

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

 

 

 

 

Clebsch-Gordan Decomposition

 

 

  • Corollary:

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

How do we characterize angular resolution?

  • Inject single point source (BLIP)
  • Recover signal + noise

​

 

 

simulate data (with noise)

analyze data

Spot size

?

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

 

 

 

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

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Carleton College - UMN Physics REU - LISA

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Angular Resolution of the Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

Future (current) work

  • More data points
  • Two-point source injections
  • LMC white dwarf background
  • Milky Way white dwarf foreground

 

← LMC

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Carleton College - UMN Physics REU - LISA

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Many thanks to these people!

  • Alexander Criswell and Vuk Mandic
  • BLIP: Sharan Banagiri, Jessica Eberling, Steven Rieck, & Joseph Romano
  • REU & MSI & NSF & Co

​