- ONDE GRAVITAZIONALI - ALLA SCOPERTA DI UN UNIVERSO ... · Buchi neri in collisione: come far...

Monica ColpiDipartimento di Fisica G. Occhialini

Università di Milano Bicocca

LA RELATIVITÀ GENERALE DI EINSTEIN COMPIE 100 ANNI6 Novembre 2015

- ONDE GRAVITAZIONALI - ALLA SCOPERTA DI UN UNIVERSO INVISIBILE

Buchi neri in collisione: come far vibrare la gravità e creare i suoi messagggeri

Friday, November 20, 15

ONDE GRAVITAZIONALI ?

DISTURBI NELLA CURVATURA DELLO SPAZIO TEMPO CAUSATI DAL MOTO DI

GRANDI MASSE

OSCILLAZIONI CHE SI PROPAGANO ALLA VELOCITÀ DELLA LUCE

IN REALTÀNON VIAGGIANO ATTRAVERSO LO SPAZIO

ma è LA TESSITURA DELLA

SPAZIO TEMPO STESSO CHE OSCILLA


• sono state rivelate?

• si! indirettamete

• “double neutron star binaries”

• Nobel - HULSE & TAYLOR 1993

• (3.5 m/year)


stelle di neutroni binarie in coalescenza


• ma i buchi neri sono i buchi neri?


Extreme mass ratio inspirals

tomografia dello spazio tempo attorno a un buco nero


III: ONDE GRAVTAZIONALI DALL’UNIVERSO:

BUCO NERO IN CADUTA SU UN

BUCO NERO SUPERMASSIVO ORBITA ECCENTRICA

DALLA FORMA DELL’ONDA SI DETERMINANO MASSA E SPIN

DEI BUCHI NERI IN COALESCENZA


inventario di forme d’onda emesse da buchi neri in coalescenza


4

FIG. 3. Waveform polarizations h+ (blue) and h⇥ (orange) in a sky direction parallel to the initial orbital plane of eachsimulation. All plots have the same horizontal scale, with each tick representing a time interval of 2000M (equal to 0.2 s for a20M� BBH).

vious studies consider only aligned spins [47, 104, 105]and at best either 15–20 orbits [39, 49] or a few orbits atvery large separation [106]. With the longer waveformsin this catalog, these studies can extend to the earlierpart of the inspiral, where PN theory is expected to bemore accurate, and to include a larger region of parame-ter space.

Independent validation of existing analytical waveform

models: Many waveform models [86, 107–111] are cali-brated against numerical relativity simulations—but usu-ally only with a small number of simulations, which arecomparatively short (typically < 10 orbits). The newsimulations here enable tests of these models at di↵erentpoints in parameter space and covering more cycles.

Detection sensitivity: Following the approach taken inthe NINJA projects [42, 98, 112], our waveforms canbe injected into GW detector noise to study the e�-ciency of GW data-analysis pipelines. Injections of pre-cessing and/or eccentric waveforms from this catalog canquantify the impact of precession and eccentricity on thedetection sensitivity of current searches using circular,aligned-spin templates. The new waveforms will also helpassess the performance of searches with precessing wave-form templates.

Systematic errors in parameter estimation: Parame-ter estimation methods [5] currently use inspiral-only PNwaveforms. Applying parameter estimation methods to

the waveforms in this catalog will enable the systematicerrors of this approach to be quantified.Construction of precessing inspiral-merger-ringdown

waveform models: This catalog will enable the construc-tion of sophisticated phenomenological or e↵ective-one-body waveform models for precessing binaries, extendingthe first such e↵ort [113].Periastron advance can be studied in aligned spin bi-

naries and generic binaries [114, 115].While this catalog will enable pioneering studies, ma-

jor challenges remain for future work. First, for a wave-form to be most useful for data analysis, it must be con-nected to a PN waveform from the early inspiral, forminga hybrid waveform [42] that spans the entire frequencyrange of a GW detector. This is di�cult for precessingconfigurations, because of both the complexity of pre-cessing PN waveforms and ambiguities in connecting PNbinary parameters with the numerical binary parame-ters [88].Second, most of the parameter space remains unex-

plored. Only 24 configurations have mass ratio q > 3(cf. Fig. 1); of these, only 5 are precessing, and almostnone have a spinning smaller black hole. Spinning BBHsystems for 5 <⇠ q <⇠ 10 are particularly interesting be-cause they serve as accurate proxies for BH-NS binaries.Furthermore, the catalog contains only three simulations(the only three to date [47, 94]) with spins � � 0.93 (i.e.,

inventario di forme d’onda emesse da buchi neri in coalescenza


h+

h⇥

come rivelare un’onda gravitazionale?


ESA COSMIC VISION .... 2025eLISA/NGO

LASER INTERFEROMETER SPACE ANTENNA1 MILIONI DI CHILOMETRI


MODELLO STANDARD RELATIVITÀ GENERALE


- ONDE GRAVITAZIONALI - ALLA SCOPERTA DI UN UNIVERSO ... · Buchi neri in collisione: come far...

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