Polarimetry imprints of exotic compact objects: solitonic boson stars

Fuente: arXiv
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Autori principali: Rosa, João Luís, Aimar, Nicolas, Tamm, Hanna Liis
Natura: Preprint
Pubblicazione: 2025
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author Rosa, João Luís
Aimar, Nicolas
Tamm, Hanna Liis
author_facet Rosa, João Luís
Aimar, Nicolas
Tamm, Hanna Liis
contents In this work we analyze the polarization observational properties of solitonic boson stars orbited by spherical hot-spots emitting synchrotron radiation from a thermal distribution of electrons. We consider three boson star configurations with different compacticities ranging from a dilute model with a large radius to an ultra-compact model capable of holding null bound orbits. We observe that the polarimetric imprints of the primary images for all models are comparable to those of the Schwarzschild spacetime, and thus any potentially distinguishable differences must arise from the additional structure of secondary and plunge-through images. For low inclination ($20^\circ$) observations we find that the two QU-loops of the least compact model are in contradiction with the current ALMA and GRAVITY observations and effectively excludes the possibility of Sgr A* being a dilute solitonic boson star. For high inclination ($80^\circ$) observations, both the Electric Vector Position Angle (EVPA) and the QU-loops present large qualitative deviations from the Schwarzschild black-hole for all models analyzed. Our results emphasize the suitability of polarimetry as a framework to test the nature of supermassive compact objects with future observations, especially at high inclination.
format Preprint
id arxiv_https___arxiv_org_abs_2504_02472
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Polarimetry imprints of exotic compact objects: solitonic boson stars
Rosa, João Luís
Aimar, Nicolas
Tamm, Hanna Liis
General Relativity and Quantum Cosmology
In this work we analyze the polarization observational properties of solitonic boson stars orbited by spherical hot-spots emitting synchrotron radiation from a thermal distribution of electrons. We consider three boson star configurations with different compacticities ranging from a dilute model with a large radius to an ultra-compact model capable of holding null bound orbits. We observe that the polarimetric imprints of the primary images for all models are comparable to those of the Schwarzschild spacetime, and thus any potentially distinguishable differences must arise from the additional structure of secondary and plunge-through images. For low inclination ($20^\circ$) observations we find that the two QU-loops of the least compact model are in contradiction with the current ALMA and GRAVITY observations and effectively excludes the possibility of Sgr A* being a dilute solitonic boson star. For high inclination ($80^\circ$) observations, both the Electric Vector Position Angle (EVPA) and the QU-loops present large qualitative deviations from the Schwarzschild black-hole for all models analyzed. Our results emphasize the suitability of polarimetry as a framework to test the nature of supermassive compact objects with future observations, especially at high inclination.
title Polarimetry imprints of exotic compact objects: solitonic boson stars
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2504.02472