BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Neutron stars as dark matter probes DTSTART:20251015T143000Z DTEND:20251015T160000Z DTSTAMP:20260804T210109Z UID:5345f97c-bbae-490c-9df2-e185f2d94c2a SEQUENCE:3 CREATED:20251003T132724Z DESCRIPTION:Compact stars\, due to their enormous gravitational field\, ca n accumulate a sizable amount of dark matter in their interior. Depending on its nature\, accumulated dark matter may affect the properties of neutr on stars in quite different ways. I will give an overview of the impact of dark matter on various observable properties of neutron stars\, i.e.\, th e mass-radius relation\, tidal deformability\, merger dynamics\, gravitati onal waveform\, thermal evolution\, etc. For two scenarios\, asymmetric fe rmionic and bosonic dark matter\, the conditions under which dark matter p articles tend to condense in the core of the star or create an extended ha lo will be presented. I will show how dark matter condensed in a core tend s to decrease the total gravitational mass and tidal deformability compare d to a pure baryonic star\, which appears as an effective softening of the equation of state. On the other hand\, the presence of a dark matter halo has the opposite effect\, causing an increase in those observable quantit ies. Thus\, observational data on compact stars could be affected by accum ulated dark matter and\, consequently\, constraints we put on the strongly interacting matter at high densities. While neutron stars provide a compe lling testing ground for gravity\, nuclear physics\, and physics beyond th e Standard Model\, the possible degeneracy between the effect of dark matt er or gravity beyond GR and dense matter properties could lead to misleadi ng conclusions while analyzing the observational data. We will discuss how the joint efforts of multi-messenger observations of neutron stars\, alon g with experimental and theoretical subatomic physics\, are pivotal for br eaking a possible degeneracy and shedding light on the neutron star intern al composition. In addition\, I will review the effect of dark matter on b inary neutron star mergers and emitted gravitational wave signals. I will present the numerical-relativity simulations of compact stars admixed with the dark matter component and discuss how the present and next-generation gravitational wave telescopes could shed light on dark matter-admixed com pact stars and constrain the dark matter properties. LAST-MODIFIED:20251009T110039Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/neutron-stars-as-dark-matt er-probes/ X-ALT-DESC;FMTTYPE=text/html:

Compact stars\, due to their enormous gravitational field\, can accumulate a sizable amount o f dark matter in their interior. Depending on its nature\, accumulated dar k matter may affect the properties of neutron stars in quite different way s. I will give an overview of the impact of dark matter on various observa ble properties of neutron stars\, i.e.\, the mass-radius relation\, tidal deformability\, merger dynamics\, gravitational waveform\, thermal evoluti on\, etc. For two scenarios\, asymmetric fermionic and bosonic dark matter \, the conditions under which dark matter particles tend to condense in th e core of the star or create an extended halo will be presented.

I will show how dark matter condensed in a core tends to decrease the tot al gravitational mass and tidal deformability compared to a pure baryonic star\, which appears as an effective softening of the equation of state. O n the other hand\, the presence of a dark matter halo has the opposite eff ect\, causing an increase in those observable quantities. Thus\, observati onal data on compact stars could be affected by accumulated dark matter an d\, consequently\, constraints we put on the strongly interacting matter a t high densities.

While neutron stars provide a compelling testi ng ground for gravity\, nuclear physics\, and physics beyond the Standard Model\, the possible degeneracy between the effect of dark matter or gravi ty beyond GR and dense matter properties could lead to misleading conclusi ons while analyzing the observational data.

We will discuss how the joint efforts of multi-messenger observations of neutron stars\, along with experimental and theoretical subatomic physics\, are pivotal for bre aking a possible degeneracy and shedding light on the neutron star interna l composition. In addition\, I will review the effect of dark matter on bi nary neutron star mergers and emitted gravitational wave signals. I will p resent the numerical-relativity simulations of compact stars admixed with the dark matter component and discuss how the present and next-generation gravitational wave telescopes could shed light on dark matter-admixed comp act stars and constrain the dark matter properties.

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