{"id":19,"date":"2025-07-16T19:49:31","date_gmt":"2025-07-16T17:49:31","guid":{"rendered":"https:\/\/web.infn.it\/GravitySirens\/?page_id=19"},"modified":"2026-01-20T23:52:19","modified_gmt":"2026-01-20T22:52:19","slug":"research","status":"publish","type":"page","link":"https:\/\/web.infn.it\/GravitySirens\/research\/","title":{"rendered":"Our research"},"content":{"rendered":"

Our research<\/h1>\n\n\n
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For 20 years, measurements of the Universe expansion rate from close-by and far sources have been in tension, hinting at the presence of new physics. Our struggle to study the Universe’s expansion is due to the difficulty of observing cosmological sources for which the distance is known. Gravitational Waves (GWs) from compact binary coalescences (CBCs) are emergent cosmological probes that provide the distance of the source, thus taking the name of Standard Sirens. Unfortunately, they do not provide the other ingredient to measure the Universe’s expansion: the redshift.<\/p>\n\n\n\n

GravitySirens<\/mark> is an ambitious project aiming to measure the cosmic expansion with CBCs and exploit their link with the astrophysical environment to obtain implicit redshift information. GravitySirens will focus on the population and astrophysical properties of GW sources that can allow a more precise measure of the cosmic expansion. We are active on several research lines for GW cosmology.<\/p>\n<\/div>\n<\/div>\n\n\n\n

Bright siren cosmology<\/h2>\n\n\n\n
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Clashing binary neutron stars, or a neutron star and a black hole, might also emit light coming from the mass ejecta. The identification of an associated gamma-ray burst of a kilonova would allow us to perfectly pinpoint the host galaxy. GW170817 is the only bright siren so far. These sources are a golden siren for cosmology, but they are difficult to detect. <\/p>\n\n\n\n

Dark siren cosmology<\/h2>\n\n\n\n
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Most of the gravitational wave sources, such as binary black holes, are not accompanied by any electromagnetic emission. For these sources, observed with only gravitational waves, we can still infer the redshift on a population level by using cross-correlations with galaxy catalogues and large-scale structure tracers or the redshifting of their very same mass in the gravitational wave signal by the Universe expansion.<\/p>\n\n\n\n

Modified gravity <\/h2>\n\n\n\n
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The universe is still full of unsolved puzzles. Some of the proposed solutions to open questions involve a modification of gravity at either cosmological scales or at the black hole horizon level. We use populations of gravitational waves to explore this possibility.<\/p>\n\n\n\n

Bayesian statistics, machine learning and computing<\/h2>\n\n\n\n
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The common tool to make sense out of this plethora of data is the use of an innovative technique for data analysis. We develop Bayesian methods, code infrastructures and machine learning tools to enhance our ability to analyse, to the best of our capabilities, gravitational wave data.<\/p>\n","protected":false},"excerpt":{"rendered":"

For 20 years, measurements of the Universe expansion rate from close-by and far sources have been in tension, hinting at the presence of new physics. Our struggle to study the Universe’s expansion is due to the difficulty of observing cosmological sources for which the distance is known. Gravitational Waves (GWs) from compact binary coalescences (CBCs) […]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-no-title","meta":{"footnotes":""},"class_list":["post-19","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/pages\/19","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/comments?post=19"}],"version-history":[{"count":10,"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/pages\/19\/revisions"}],"predecessor-version":[{"id":328,"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/pages\/19\/revisions\/328"}],"wp:attachment":[{"href":"https:\/\/web.infn.it\/GravitySirens\/wp-json\/wp\/v2\/media?parent=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}