Probing the Early and Late Universe with the Gravitational-Wave - PowerPoint PPT Presentation

Probing the Early and Late Universe with the Gravitational-Wave Background Alexander C. Jenkins GW4FP Workshop, Amsterdam 13 November 2019

The Stochastic Gravitational-Wave Background 1 Cosmic Strings 2 Compact Binary Coalescences 3

Stochastic gravitational-wave background (SGWB) faint/numerous sources astrophysical and cosmological incoherent, persistent, correlated GW density parameter: 1 d ρ GW Ω GW ( f ) = ρ crit d(ln f ) alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 1 / 16

LIGO upper limits (isotropic) scales as √ ∼ 1 / obs time (as well as number and sensitivity of detectors) note that Ω GW ≪ Ω CMB ≈ 10 − 5 , so detection is hard LIGO/Virgo ’19 PRD, arXiv:1903.02886 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 2 / 16

Angular power spectrum CMB � d 2 ˆ C ℓ = n P ℓ (cos θ ) � δ T δ T � θ SGWB � d 2 ˆ C ℓ = n P ℓ (cos θ ) � δ Ω GW δ Ω GW � θ Images: Planck collaboration alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 3 / 16

LIGO upper limits (directional) results depend on GW frequency spectrum Ω GW = Ω ref ( f / f ref ) α LIGO/Virgo ’19 PRD, arXiv:1903.08844 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 4 / 16

The Stochastic Gravitational-Wave Background 1 Cosmic Strings 2 Compact Binary Coalescences 3

Cosmic string network O (1) long string → many loops one parameter: string tension G µ = mass length � 2 � new physics scale ∼ Planck scale generically produced in many BSM theories Ringeval, Sakellariadou, & Bouchet ’07 JCAP, arXiv:astro-ph/0511646 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 5 / 16

GW bursts from loops Cusp Kink h ( t ) Cusp − 0 . 4 − 0 . 2 0 . 0 0 . 2 0 . 4 Kink t/ s alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 6 / 16

Did LIGO/Virgo just see its first cosmic string??? alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 7 / 16

Cosmic string SGWB LIGO O2 constraint: G µ � 10 − 14 (10 9 TeV) with LISA/ET: G µ � 10 − 17 (10 7 . 5 TeV ) what does this mean for HEP? alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 8 / 16

Cosmic strings beyond Λ CDM SGWB spectrum depends on thermal history Auclair+ (inc. ACJ) ’19, arXiv:1909.00819 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 9 / 16

Cosmic strings beyond Λ CDM SGWB spectrum depends on relativistic degrees of freedom Auclair+ (inc. ACJ) ’19, arXiv:1909.00819 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 10 / 16

Anisotropies from cosmic strings stronger for smaller G µ could this help detection? ACJ & Sakellariadou ’18 PRD, arXiv:1802.06046 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 11 / 16

The Stochastic Gravitational-Wave Background 1 Cosmic Strings 2 Compact Binary Coalescences 3

Compact binary SGWB: a new probe of large-scale structure CBCs expected to be loudest component of SGWB BHs and NSs live in galaxies ∴ galaxies trace out LSS Springel+ ’05 Nature, arXiv:astro-ph/0504097 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 12 / 16

Simulating the compact binary SGWB get galaxies from Millennium N-body simulation compute rate for each galaxy superimpose → SGWB map ACJ+ ’18 PRD, arXiv:1806.01718 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 13 / 16

Probing LSS with LIGO/Virgo? will close the gap over time, and with more detectors signal could be larger if we find new populations (e.g. BHNS) can we boost the signal by cross-correlating with galaxy surveys? (see talk by Omar Contigiani) alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 14 / 16

Projection effects can enhance the signal at large scales Bertacca+ (inc. ACJ) ’19, arXiv:1909.11627 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 15 / 16

Summary the stochastic GW background will soon be a vital probe of cosmology and fundamental physics searches for new physics with GWs from cosmic strings new probe of large-scale structure with clustering of compact binaries alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 16 / 16

Extra slides alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 16 / 16

Cosmic star formation history alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 16 / 16

CBC population models input from LIGO/Virgo: local rate mass distribution p ( m 1 ) ∝ m − α m 1 p ( m 2 ) = uniform m min ≤ m 2 ≤ m 1 ≤ m max ACJ+ ’18 PRL, arXiv:1810.13435 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 16 / 16

Shot noise, and how to beat it ACJ & Sakellariadou ’19 PRD, arXiv:1902.07719 ACJ, Romano, & Sakellariadou ’19 PRD, arXiv:1907.06642 alexander.jenkins@kcl.ac.uk Probing the Universe with the GW Background GW4FP, 13 November 2019 16 / 16