Almost 50 years after “Introducing the Black Hole” 1, we are witnessing the clear evidence on the discovery of the moment of formation of the Black Hole in GRB 190114C. I am very happy to present ...these results at the 4th Zeldovich virtual meeting.
It has been thought for decades that rotating black holes (BHs) power the energetic gamma-ray bursts (GRBs) and active galactic nuclei (AGNs), but the mechanism that extracts the BH energy has ...remained elusive. We here show that the solution to this problem arises when the BH is immersed in an external magnetic field and ionized low-density matter. For a magnetic field parallel to the BH spin, the induced electric field accelerates electrons outward and protons inward in a conical region, centered on the BH rotation axis, and of semi-aperture angle
θ
≈
60
∘
from the BH rotation axis. For an antiparallel magnetic field, protons and electrons exchange their roles. The particles that are accelerated outward radiate off energy and angular momentum to infinity. The BH powers the process by reducing its energy and angular momentum by capturing polar protons and equatorial electrons with net negative energy and angular momentum. The electric potential allows for negative energy states outside the BH ergosphere, so the latter does not play any role in this electrodynamical BH energy extraction process.
The blackholic quantum Rueda, J. A.; Ruffini, R.
The European physical journal. C, Particles and fields,
04/2020, Volume:
80, Issue:
4
Journal Article
Peer reviewed
Open access
We show that the high-energy emission of GRBs originates in the
inner engine
: a Kerr black hole (BH) surrounded by matter and a magnetic field
B
0
. It radiates a sequence of discrete events of ...particle acceleration, each of energy
E
=
ħ
Ω
eff
, the
blackholic quantum
, where
Ω
eff
=
4
(
m
Pl
/
m
n
)
8
(
c
a
/
G
M
)
(
B
0
2
/
ρ
Pl
)
Ω
+
. Here
M
,
a
=
J
/
M
,
Ω
+
=
c
2
∂
M
/
∂
J
=
(
c
2
/
G
)
a
/
(
2
M
r
+
)
and
r
+
are the BH mass, angular momentum per unit mass, angular velocity and horizon;
m
n
is the neutron mass,
m
Pl
,
λ
Pl
=
ħ
/
(
m
Pl
c
)
and
ρ
Pl
=
m
Pl
c
2
/
λ
Pl
3
, are the Planck mass, length and energy density. Here and in the following use CGS-Gaussian units. The timescale of each process is
τ
el
∼
Ω
+
-
1
, along the rotation axis, while it is much shorter off-axis owing to energy losses such as synchrotron radiation. We show an analogy with the Zeeman and Stark effects, properly scaled from microphysics to macrophysics, that allows us to define the
BH magneton
,
μ
BH
=
(
m
Pl
/
m
n
)
4
(
c
a
/
G
M
)
e
ħ
/
(
M
c
)
. We give quantitative estimates for GRB 130427A adopting
M
=
2.3
M
⊙
,
c
a
/
(
G
M
)
=
0.47
and
B
0
=
3.5
×
10
10
G. Each emitted
quantum
,
E
∼
10
37
erg, extracts only
10
-
16
times the BH rotational energy, guaranteeing that the process can be repeated for thousands of years. The
inner engine
can also work in AGN as we here exemplified for the supermassive BH at the center of M87.
Abstract
We show that the gravitomagnetic interaction of a Kerr black hole (BH) with a surrounding magnetic field induces an electric field that accelerates charged particles to ultra-relativistic ...energies in the vicinity of the BH. Along the BH rotation axis, these electrons/protons can reach energies of even thousands of petaelectronvolts, so stellar-mass BHs in long gamma-ray bursts (GRBs) and supermassive BHs in active galactic nuclei can contribute to the ultrahigh-energy cosmic rays thorough this mechanism. At off-axis latitudes, the particles accelerate to energies of hundreds of gigaelectronvolts and emit synchrotron radiation at gigaelectronvolt energies. This process occurs within 60° around the BH rotation axis, and due to the equatorial symmetry, it forms a double-cone emission. We outline the theoretical framework describing these acceleration and radiation processes, how they extract the rotational energy of the Kerr BH and the consequences for the astrophysics of GRBs.
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 × 10
6
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 ⟨
χ
̄
2
⟩
S2,RAR
≈ 3.1 and ⟨
χ
̄
2
⟩
S2,BH
≈ 3.3 for S2 and ⟨
χ
̄
2
⟩
G2,RAR
≈ 20 and ⟨
χ
̄
2
⟩
G2,BH
≈ 41 for G2. The fit of the corresponding
z
data shows that while for S2 we find comparable fits, that is,
χ
̄
2
z,RAR
≈ 1.28 and
χ
̄
2
z,BH
≈ 1.04, for G2 the RAR model alone can produce an excellent fit of the data, that is,
χ
̄
2
z,RAR
≈ 1.0 and
χ
̄
2
z,BH
≈ 26. In addition, the critical mass for gravitational collapse of a degenerate 56 keV-fermion DM core into a BH is ∼ 10
8
M
⊙
. This result may provide the initial seed for the formation of the observed central supermassive BH in active galaxies, such as M 87.
We investigate charged particles’ circular motion in the gravitational field of a charged mass distribution described by the Reissner–Nordström spacetime. We introduce a set of independent parameters ...completely characterizing the different spatial regions in which circular motion is allowed. We provide a most complete classification of circular orbits for different sets of particle and source charge-to-mass ratios. We study both black holes and naked singularities and show that the behavior of charged particles depend drastically on the type of source. Our analysis shows in an alternative manner that the behavior of circular orbits can in principle be used to distinguish between black holes and naked singularities. From this analysis, special limiting values for the dimensionless charge of black hole and naked singularity emerge, namely, Q/M
=
1/2,
Q
/
M
=
13
/
5
and
Q
/
M
=
2
/
3
for the black hole case and Q/M
=
1,
Q
/
M
=
5
/
(
2
6
)
,
Q
/
M
=
3
6
/
7
, and finally
Q
/
M
=
9
/
8
for the naked singularity case. Similarly and surprisingly, analogous limits emerge for the orbiting particles charge-to-mass ratio
ϵ
, for positive charges
ϵ
=
1
,
ϵ
=
2
and
ϵ
=
M
/
Q
. These limits play an important role in the study of the coupled electromagnetic and gravitational interactions, and the investigation of the role of the charge in the gravitational collapse of compact objects.
A multi-decade theoretical effort has been devoted to finding an efficient mechanism to use the rotational and electrodynamical extractable energy of a Kerr-Newman black hole (BH), to power the most ...energetic astrophysical sources such as gamma-ray bursts (GRBs) and active galactic nuclei. We show an efficient general relativistic electrodynamical process which occurs in the “inner engine” of a binary driven hypernova. The inner engine is composed of a rotating Kerr BH of mass
M
and dimensionless spin parameter
α
, a magnetic field of strength
B
0
aligned and parallel to the rotation axis, and a very low-density ionized plasma. Here, we show that the gravitomagnetic interaction between the BH and the magnetic field induces an electric field that accelerates electrons and protons from the environment to ultrarelativistic energies emitting synchrotron radiation. We show that in GRB 190114C the BH of mass
M
= 4.4
M
⊙
,
α
= 0.4, and
B
0
≈ 4 × 10
10
G can lead to a high-energy (≳GeV) luminosity of 10
51
erg s
−1
. The inner engine parameters are determined by requiring (1) that the BH extractable energy explains the GeV and ultrahigh-energy emission energetics, (2) that the emitted photons are not subjected to magnetic-pair production, and (3) that the synchrotron radiation timescale agrees with the observed high-energy timescale. We find for GRB 190114C a clear jetted emission of GeV energies with a semi-aperture angle of approximately 60° with respect to the BH rotation axis.
On 2018 July 28, GRB 180728A triggered Swift satellites and, soon after the determination of the redshift, we identified this source as a type II binary-driven hypernova (BdHN II) in our model. ...Consequently, we predicted the appearance time of its associated supernova (SN), which was later confirmed as SN 2018fip. A BdHN II originates in a binary composed of a carbon-oxygen core (COcore) undergoing SN, and the SN ejecta hypercritically accrete onto a companion neutron star (NS). From the time of the SN shock breakout to the time when the hypercritical accretion starts, we infer the binary separation 3 × 1010 cm. The accretion explains the prompt emission of isotropic energy 3 × 1051 erg, lasting ∼10 s, and the accompanying observed blackbody emission from a thermal convective instability bubble. The new neutron star ( NS) originating from the SN powers the late afterglow from which a NS initial spin of 2.5 ms is inferred. We compare GRB 180728A with GRB 130427A, a type I binary-driven hypernova (BdHN I) with isotropic energy >1054 erg. For GRB 130427A we have inferred an initially closer binary separation of 1010 cm, implying a higher accretion rate leading to the collapse of the NS companion with consequent black hole formation, and a faster, 1 ms spinning NS. In both cases, the optical spectra of the SNe are similar, and not correlated to the energy of the gamma-ray burst. We present three-dimensional smoothed-particle-hydrodynamic simulations and visualizations of the BdHNe I and II.
Abstract
Nonlinear structure formation for fermionic dark matter particles leads to dark matter density profiles with a degenerate compact core surrounded by a diluted halo. For a given fermion mass, ...the core has a critical mass that collapses into a supermassive black hole (SMBH). Galactic dynamics constraints suggest a ∼100 keV/
c
2
fermion, which leads to ∼10
7
M
⊙
critical core mass. Here, we show that baryonic (ordinary) matter accretion drives an initially stable dark matter core to SMBH formation and determines the accreted mass threshold that induces it. Baryonic gas density
ρ
b
and velocity
v
b
inferred from cosmological hydrosimulations and observations produce sub-Eddington accretion rates triggering the baryon-induced collapse in less than 1 Gyr. This process produces active galactic nuclei in galaxy mergers and the high-redshift Universe. For TXS 2116–077, merging with a nearby galaxy, the observed 3 × 10
7
M
⊙
SMBH, for
Q
b
=
ρ
b
/
v
b
3
=
0.125
M
⊙
/
(
100
km
s
−
1
pc
)
3
, forms in ≈0.6 Gyr, consistent with the 0.5–2 Gyr merger timescale and younger jet. For the farthest central SMBH detected by the Chandra X-ray satellite in the
z
= 10.3 UHZ1 galaxy observed by the James Webb Space Telescope (JWST), the mechanism leads to a 4 × 10
7
M
⊙
SMBH in 87–187 Myr, starting the accretion at
z
= 12–15. The baryon-induced collapse can also explain the ≈10
7
–10
8
M
⊙
SMBHs revealed by JWST at
z
≈ 4–6. After its formation, the SMBH can grow to a few 10
9
M
⊙
in timescales shorter than 1 Gyr via sub-Eddington baryonic mass accretion.
Abstract
Binary-driven hypernova (BdHN) models have been adopted to explain the observed properties of long gamma-ray bursts (GRBs). Here, we perform a comprehensive data analysis (temporal and ...spectral analysis, GeV emission, and afterglow) on GRB 130427A, GRB 160509A, and GRB 160625B. We identify three specific episodes characterized by different observational signatures and show that these episodes can be explained and predicted to occur within the framework of the BdHNe I model, as first observed in GRB 190114C and reported in an accompanying paper. Episode 1 includes the “SN-rise” with the characteristic cutoff power-law spectrum; Episode 2 is initiated by the moment of formation of the black hole, coincident with the onset of the GeV emission and the ultrarelativistic prompt emission phase, and is characterized by a cutoff power law and blackbody spectra; Episode 3 is the “cavity,” with its characteristic featureless spectrum.
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