Can fermionic dark matter mimic supermassive black holes?

Argüelles, Carlos; Krut, A.; Rueda, J. A.; Ruffini, Remo

doi:10.1142/s021827181943003x

Cited by 11 publications

(11 citation statements)

References 16 publications

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“…Our results provide strong observational support to the quantum-core hypothesis as an alternative to the massive BH hypothesis in Sgr A* (Argüelles et al 2019b(Argüelles et al , 2018, and also to the fermionic nature of DM. In this line, it is desirable to further test the presence of fermionic DM concentrations in our galactic core from existing luminosity constraints on the variability of the compact radio source Sgr A*, in addition to the dynamical constraints.…”

Section: Discussionsupporting

confidence: 73%

“…As was explicitly shown in Argüelles et al (2019bArgüelles et al ( ,a, 2018, this type of dense core -diluted halo density profile suggests that the DM might explain the mass of the dark compact object in Sgr A* as well as the halo mass. It applies not only to the Milky Way, but also to other galactic structures from dwarfs and ellipticals to galaxy clusters (Argüelles et al 2019a).…”

Section: Ruffini-argüelles-rueda Model Of Dark Mattersupporting

confidence: 64%

“…In the work here, this motivation is twofold. First, it has recently been shown (Argüelles et al 2019b(Argüelles et al ,a, 2018 . Theoretical and observed orbit of G2 around Sgr A*.…”

Section: Discussionmentioning

confidence: 99%

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Geodesic motion of S2 and G2 as a test of the fermionic dark matter nature of our Galactic core

Becerra-Vergara

Argüelles

Krut

et al. 2020

A&A

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116

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The motion of S-stars around the Galactic center implies that the central gravitational potential is dominated by a compact source, Sagittarius A* (Sgr A*), which has a mass of about 4 × 106 M⊙ and is traditionally assumed to be a massive black hole (BH). The explanation of the multiyear accurate astrometric data of the S2 star around Sgr A*, including the relativistic redshift that has recently been verified, is particularly important for this hypothesis and for any alternative model. Another relevant object is G2, whose most recent observational data challenge the scenario of a massive BH: its post-pericenter radial velocity is lower than expected from a Keplerian orbit around the putative massive BH. This scenario has traditionally been reconciled by introducing a drag force on G2 by an accretion flow. As an alternative to the central BH scenario, we here demonstrate that the observed motion of both S2 and G2 is explained in terms of the dense core – diluted halo fermionic dark matter (DM) profile, obtained from the fully relativistic Ruffini-Argüelles-Rueda (RAR) model. It has previously been shown that for fermion masses 48−345 keV, the RAR-DM profile accurately fits the rotation curves of the Milky Way halo. We here show that the solely gravitational potential of such a DM profile for a fermion mass of 56 keV explains (1) all the available time-dependent data of the position (orbit) and line-of-sight radial velocity (redshift function z) of S2, (2) the combination of the special and general relativistic redshift measured for S2, (3) the currently available data on the orbit and z of G2, and (4) its post-pericenter passage deceleration without introducing a drag force. For both objects, we find that the RAR model fits the data better than the BH scenario: the mean of reduced chi-squares of the time-dependent orbit and z data are ⟨χ̄2⟩S2,RAR ≈ 3.1 and ⟨χ̄2⟩S2,BH ≈ 3.3 for S2 and ⟨χ̄2⟩G2,RAR ≈ 20 and ⟨χ̄2⟩G2,BH ≈ 41 for G2. The fit of the corresponding z data shows that while for S2 we find comparable fits, that is, χ̄2z,RAR ≈ 1.28 and χ̄2z,BH ≈ 1.04, for G2 the RAR model alone can produce an excellent fit of the data, that is, χ̄2z,RAR ≈ 1.0 and χ̄2z,BH ≈ 26. In addition, the critical mass for gravitational collapse of a degenerate 56 keV-fermion DM core into a BH is ∼ 108 M⊙. This result may provide the initial seed for the formation of the observed central supermassive BH in active galaxies, such as M 87.

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Section: Discussionsupporting

confidence: 73%

Section: Ruffini-argüelles-rueda Model Of Dark Mattersupporting

confidence: 64%

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Geodesic motion of S2 and G2 as a test of the fermionic dark matter nature of our Galactic core

Becerra-Vergara

Argüelles

Krut

et al. 2020

A&A

Self Cite

116

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“…( 18) is thus solved numerically with a Levenberg-Marquardt least square minimization method, implying a large iterative process (taking ∼ few 10 1 hours of standard desktop CPU-time). below), since it is similar to that of a Milky-Way RAR DM halo for 𝑚𝑐 2 = 48 keV, shown to perfectly fit the rotation curve data (Argüelles et al 2018(Argüelles et al , 2019bBecerra-Vergara et al 2020). This is a remarkable result, since for the first time a core-halo solution like (3) known to be of astrophysical applicability, has now been proven to fall inside the meta-stable branch while being extremely long-lived (as calculated in appendix A) and thus reachable in Nature.…”

Section: Tidally Truncated Dm Halosmentioning

confidence: 64%

“…We believe this is not a coincidence: i.e. the fact that in Argüelles et al (2018Argüelles et al ( , 2019b; Becerra-Vergara et al (2020) it was shown the existence of a DM core-halo profile where the core can mimic a massive BH while the outer halo can explain the rotation curve, was already a smoking gun for its plausibility in Nature. (iii) There is a full family of solutions in the second stable branch between (b) and (c) (corresponding to 𝜃 0 ≈ 31.5 and 𝛽 0 ∈ [3.3 × 10 −5 , 5 × 10 −5 ]), which are found to be of astrophysical interest: that is, they lie within the allowed DM surface density Σ obs 0D strip as shown in fig.…”

Section: Tidally Truncated Dm Halosmentioning

confidence: 95%

On the formation and stability of fermionic dark matter halos in a cosmological framework

Argüelles,

Díaz,

Krut

et al. 2020

Preprint

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The formation and stability of collisionless self-gravitating systems is a long standing problem, which dates back to the work of D. Lynden-Bell on violent relaxation, and extends to the issue of virialization of dark matter (DM) halos. An important prediction of such a relaxation process is that spherical equilibrium states can be described by a Fermi-Dirac phase-space distribution, when the extremization of a coarse-grained entropy is reached. In the case of DM fermions, the most general solution develops a degenerate compact core surrounded by a diluted halo. As shown recently, the latter is able to explain the galaxy rotation curves while the DM core can mimic the central black hole. A yet open problem is whether this kind of astrophysical core-halo configurations can form at all, and if they remain stable within cosmological timescales. We assess these issues by performing a thermodynamic stability analysis in the microcanonical ensemble for solutions with given particle number at halo virialization in a cosmological framework. For the first time we demonstrate that the above core-halo DM profiles are stable (i.e. maxima of entropy) and extremely long lived. We find the existence of a critical point at the onset of instability of the core-halo solutions, where the fermion-core collapses towards a supermassive black hole. For particle masses in the keV range, the core-collapse can only occur for 𝑀 vir 10 9 M starting at 𝑧 vir ≈ 10 in the given cosmological framework. Our results prove that DM halos with a core-halo morphology are a very plausible outcome within nonlinear stages of structure formation.

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Experimental studies of black holes: status and future prospects

Genzel,

Eisenhauer,

Gillessen

2024

Astron Astrophys Rev

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More than a century ago, Albert Einstein presented his general theory of gravitation (GR) to the Prussian Academy of Sciences. One of the predictions of the theory is that not only particles and objects with mass, but also the quanta of light, photons, are tied to the curvature of space-time, and thus to gravity. There must be a critical compactness, above which photons cannot escape. These are black holes (henceforth BH). It took 50 years after the theory was announced before possible candidate objects were identified by observational astronomy. And another 50 years have passed, until we finally have in hand detailed and credible experimental evidence that BHs of 10 to $$10^{10}$$ 10 10 times the mass of the Sun exist in the Universe. Three very different experimental techniques, but all based on Michelson interferometry or Fourier-inversion spatial interferometry have enabled the critical experimental breakthroughs. It has now become possible to investigate the space-time structure in the vicinity of the event horizons of BHs. We briefly summarize these interferometric techniques, and discuss the spectacular recent improvements achieved with all three techniques. Finally, we sketch where the path of exploration and inquiry may go on in the next decades.

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Can fermionic dark matter mimic supermassive black holes?

Cited by 11 publications

References 16 publications

Geodesic motion of S2 and G2 as a test of the fermionic dark matter nature of our Galactic core

Geodesic motion of S2 and G2 as a test of the fermionic dark matter nature of our Galactic core

On the formation and stability of fermionic dark matter halos in a cosmological framework

Experimental studies of black holes: status and future prospects

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