2,946 research outputs found
Constraints on the radio loud/radio quiet dichotomy from the fundamental plane
The fundamental plane for black hole activity constitutes a tight correlation
between jet power, X-ray luminosity, and black hole mass. Under the assumption
that a Blandford-Znajek-type mechanism, which relies on black hole spin,
contributes non-negligibly to jet production, the sufficiently small scatter in
the fundamental plane shows that black hole spin differences of
a1 are not typical among the active galactic nuclei
population. If as it seems radio loud and radio quiet objects are both
faithful to the fundamental plane, models of black hole accretion in which the
radio loud/radio quiet dichotomy is based on a spin dichotomy of
a1/a0, respectively, are difficult to reconcile with the
observations.
We show how recent theoretical work based on differences in accretion flow
orientation between retrograde and prograde, accommodates a small scatter in
the fundamental plane for objects that do have non-negligible differences in
black hole spin values. We also show that the dichotomy in spin between the
most radio loud and the most radio quiet involves a0. And, finally, we show how the picture that produces compatibility
with the fundamental plane, also allows one to interpret other otherwise
puzzling observations of jets across the mass scale including 1) the recently
observed inverse relation between radio and X-rays at higher Eddington ratios
in both black hole X-ray binaries as well as active galactic nuclei and 2) the
apparent contradiction between jet power and black hole spin observed in X-ray
hard and transitory burst states in X-ray binaries.Comment: 8 pages, 1 figure, accepted in MNRA
Constraints of the Radio-loud/Radio-quiet Dichotomy from the Fundamental Plane
The Fundamental Plane for black hole activity constitutes a tight correlation between jet power, X-ray luminosity, and black hole mass. Under the assumption that a Blandford–Znajek-type mechanism, which relies on black hole spin, contributes non-negligibly to jet production, the sufficiently small scatter in the Fundamental Plane shows that black hole spin differences of |Δa| ∼ 1 are not typical among the active galactic nuclei population. If – as it seems – radio-loud and radio-quiet objects are both faithful to the Fundamental Plane, models of black hole accretion in which the radio-loud/radio-quiet dichotomy is based on a spin dichotomy of a∼1/a∼0, respectively, are difficult to reconcile with the observations. We show how recent theoretical work based on differences in accretion flow orientation between retrograde and prograde, accommodates a small scatter in the Fundamental Plane for objects that do have non-negligible differences in black hole spin values. We also show that the dichotomy in spin between the most radio loud and the most radio quiet involves |Δa| ≈ 0. And, finally, we show how the picture that produces compatibility with the Fundamental Plane, also allows one to interpret other otherwise puzzling observations of jets across the mass scale including (1) the recently observed inverse relation between radio and X-rays at higher Eddington ratios in both black hole X-ray binaries as well as active galactic nuclei and (2) the apparent contradiction between jet power and black hole spin observed in X-ray hard and transitory burst states in X-ray binaries
Possible Evolution of Supermassive Black Holes from FRI quasars
We explore the question of the rapid buildup of black hole mass in the early
universe employing a growing black hole mass-based determination of both jet
and disk powers predicted in recent theoretical work on black hole accretion
and jet formation. Despite simplified, even artificial assumptions about
accretion and mergers, we identify an interesting low probability channel for
the growth of one billion solar mass black holes within hundreds of millions of
years of the Big Bang without appealing to super Eddington accretion. This
result is made more compelling by the recognition of a connection between this
channel and an end product involving active galaxies with FRI radio morphology
but weaker jet powers in mildly sub-Eddington accretion regimes. While FRI
quasars have already been shown to occupy a small region of the available
parameter space for black hole feedback in the paradigm, we further suggest
that the observational dearth of FRI quasars is also related to their
connection to the most massive black hole growth due to both these FRIs high
redshifts and relative weakness. Our results also allow us to construct the AGN
luminosity function at high redshift, that agree with recent studies. In short,
we produce a connection between the unexplained paucity of a given family of
active galactic nuclei and the rapid growth of supermassive black holes, two
heretofore seemingly unrelated aspects of the physics of active galactic
nuclei.Comment: Accepted for publication in MNRAS on 12-May-2016., 27 pages, 7
figures, 1 tabl
Reconciling AG-star Formation, the Soltan Argument, and Meier\u27s Paradox
We provide a theoretical context for understanding the recent work of Kalfountzou et al. showing that star formation is enhanced at lower optical luminosity in radio-loud quasars. Our proposal for coupling the assumption of collimated FRII quasar-jet-induced star formation with lower accretion optical luminosity also explains the observed jet power peak in active galaxies at higher redshift compared to the peak in accretion power, doing so in a way that predicts the existence of a family of radio-quiet active galactic nuclei associated with rapidly spinning supermassive black holes at low redshift, as mounting observations suggest. The relevance of this work lies in its promise to explain the observed cosmological evolution of accretion power, jet power, and star formation in a way that is both compatible with the Soltan argument and resolves the so-called Meier Paradox
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale Event
We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for
which the lensing-induced brightening of the source star lasted for 2 seasons.
We determine the lens mass from the combined measurements of the microlens
parallax \pie and angular Einstein radius \thetae. The measured mass
indicates that the lens is a binary composed of M dwarfs with masses of
and . The measured relative
lens-source proper motion of is smaller
than of typical Galactic lensing events, while
the estimated angular Einstein radius of \thetae\sim 1.2~{\rm mas} is
substantially greater than the typical value of .
Therefore, it turns out that the long time scale of the event is caused by the
combination of the slow and large \thetae rather than the heavy mass of
the lens. From the simulation of Galactic lensing events with very long time
scales ( days), we find that the probabilities that long
time-scale events are produced by lenses with masses and
are and 2.6\%, respectively, indicating that
events produced by heavy lenses comprise a minor fraction of long time-scale
events. The results indicate that it is essential to determine lens masses by
measuring both \pie and \thetae in order to firmly identify heavy stellar
remnants such as neutron stars and black holes.Comment: 9 pages, 11 figure
Intrinsic Genomic Differences Between African American and White Patients With Clear Cell Renal Cell Carcinoma
There are well-documented racial disparities in outcomes for African American patients with clear cell renal cell carcinoma (ccRCC). Despite a dramatic improvement in overall survival in white patients since the advent of targeted therapy, survival for African Americans with advanced ccRCC has not changed. There is little known about potential racial differences in tumor biology of ccRCC
Quasiparticles in the 111 state and its compressible ancestors
We investigate the relationship of the spontaneously inter-layer coherent
``111''state of quantum Hall bilayers at total filling factor \nu=1 to
``mutual'' composite fermions, in which vortices in one layer are bound to
electrons in the other. Pairing of the mutual composite fermions leads to the
low-energy properties of the 111 state, as we explicitly demonstrate using
field-theoretic techniques. Interpreting this relationship as a mechanism for
inter-layer coherence leads naturally to two candidate states with
non-quantized Hall conductance: the mutual composite Fermi liquid, and an
inter-layer coherent charge e Wigner crystal. The experimental behavior of the
interlayer tunneling conductance and resistivity tensors are discussed for
these states.Comment: 4 Pages, RevTe
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