Future gravitational wave detector in space could uncover secrets of the Universe

Date:
February 10, 2022
Source:
University of Nottingham
Summary:
New research has shown that future gravitational wave detections
from space will be capable of finding new fundamental fields and
potentially shed new light on unexplained aspects of the Universe.



FULL STORY ==========================================================================
New research has shown that future gravitational wave detections from
space will be capable of finding new fundamental fields and potentially
shed new light on unexplained aspects of the Universe.


========================================================================== Professor Thomas Sotiriou from the University of Nottingham's Centre
of Gravity and Andrea Maselli, researcher at GSSI and INFN associate,
together with researchers from SISSA, and La Sapienza of Rome, showed
the unprecedented accuracy with which gravitational wave observations
by the space interferometer LISA (Laser Interferometer Space Antenna),
will be able to detect new fundamental fields. The research has been
published in Nature Astronomy.

In this new study researchers suggest that LISA, the space-based
gravitational- wave (GW) detector which is expected to be launched
by ESA in 2037 will open up new possibilities for the exploration of
the Universe.

Professor Thomas Sotiriou, Director of the Nottingham Centre of Gravity explains: "New fundamental fields, and in particular scalars, have been suggested in a variety of scenarios: as explanations for dark matter,
as the cause for the accelerated expansion of the Universe, or as
low-energy manifestations of a consistent and complete description of
gravity and elementary particles. We have now shown that LISA will offer unprecedented capabilities in detecting scalar fields and this offers
exciting opportunities for testing these scenarios." Observations of astrophysical objects with weak gravitational fields and small spacetime curvature have provided no evidence of such fields so far. However,
there is reason to expect that deviations from General Relativity, or interactions between gravity and new fields, will be more prominent at
large curvatures. For this reason, the detection of GWs -- which opened
a novel window on the strong-field regime of gravity -- represents an
unique opportunity to detect these fields.

Extreme Mass Ratio Inspirals (EMRI) in which a stellar-mass compact
object, either a black hole or a neutron star, inspirals into black hole
up to millions of times the mass of the Sun, are among the target sources
of LISA, and provide a golden arena to probe the strong-field regime of gravity. The smaller body performs tens of thousands of orbital cycles
before it plunges into the supermassive black hole and this leads to
long signals that can allow us to detect even the smallest deviations
from the predictions of Einstein's theory and the Standard Model of
Particle Physics.

The researchers have developed a new approach for modelling the signal
and performed for the first time a rigorous estimate of LISA's capability
to detect the existence of scalar fields coupled with the gravitational interaction, and to measure how much scalar field is carried by the
small body of the EMRI.

Remarkably, this approach is theory-agnostic, since it does not depend on
the origin of the charge itself, or on the nature of the small body. The analysis also shows that such measurement can be mapped to strong bounds
on the theoretical parameters that mark deviations from General Relativity
or the Standard Model.

LISA will be devoted to detect gravitational waves by astrophysical
sources, will operate in a constellation of three satellites,orbiting
around the Sun millions of kilometers far away each other. LISA will
observe gravitational waves emitted at low frequency, within a band
not available to terrestrial interferometers due to environmental
noise. The visible spectrum for LISA will allow to study new families of astrophysical sources, different from those observed by Virgo and LIGO,
as the EMRIs, opening a new window on the evolution of compact objects
in a large variety of environments of our Universe.

========================================================================== Story Source: Materials provided by University_of_Nottingham. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Andrea Maselli, Nicola Franchini, Leonardo Gualtieri, Thomas
P. Sotiriou,
Susanna Barsanti, Paolo Pani. Detecting fundamental fields with
LISA observations of gravitational waves from extreme mass-ratio
inspirals.

Nature Astronomy, 2022; DOI: 10.1038/s41550-021-01589-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220210125823.htm

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