Results 61 to 70 of about 8,827 (222)

Eötvös experiments with supermassive black holes [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 2016
By examining the locations of central black holes in two elliptical galaxies, M\,32 and M\,87, we derive constraints on the violation of the strong equivalence principle for purely gravitational objects, i.e. black holes, of less than about two-thirds, $η_N<0.68$ from the gravitational interaction of M\,87 with its neighbours in the Virgo cluster ...
Asvathaman, Asha   +2 more
openaire   +1 more source

Axion Black Hole Solution in Non‐Metricity Gravity

open access: yesFortschritte der Physik, Volume 74, Issue 2, February 2026.
Abstract A static, spherically symmetric black hole solution in symmetric teleparallel (non‐metricity) gravity sourced by an axion field is constructed. Starting from the modified field equations, exact configurations are obtained characterized by the mass M$M$ and an axion–geometry coupling β$\beta$, with temporal metric function A(r)=1−2Mr+βr$A(r)=1-\
A. Eid, G.G.L. Nashed
wiley   +1 more source

Star cluster black hole, 2013 [PDF]

open access: yes, 2013
Image of star cluster black hole. Scientists had believed that supermassive black holes, located at the centres of galaxies, increased their mass in step with the growth of their host galaxy.
Alister W. Graham, Gabriel Perez Diaz
core  

Testing the Weak Cosmic Censorship Conjecture via Test Particle–Induced Overcharging/Overspinning of Kerr–Newman–Modified Gravity Black Hole

open access: yesAdvances in Astronomy, Volume 2026, Issue 1, 2026.
We examine the weak cosmic censorship conjecture (WCCC) violation by throwing a charged and rotating test particle into a Kerr–Newman–modified gravity black hole (KN–MOG BH). The result depends on several factors, such as the relative sign of the particle’s charge and its direction of rotation with respect to black hole (BH).
Waqar Ahmad   +2 more
wiley   +1 more source

The Black Hole Spin Controversy [PDF]

open access: yes, 2012
Astrophysical black holes are the simplest possible objects. They are completely described by only two parameters in general relativity, their mass and the specific angular momentum, spin.
KOLEHMAINEN, MARI,JOHANNA   +1 more
core  

Braneworld black holes and black strings [PDF]

open access: yes, 2008
This thesis involves the study of strong and weak gravity phenomenology within the braneworld paradigm. We begin with a general overview of the hypothesised concept of extra spatial dimensions and explain why they are so interesting.
Mistry, Bina
core  

From Nuclear Star Clusters to Little Red Dots: Black Hole Growth, Mergers, and Tidal Disruptions

open access: yesThe Astrophysical Journal
Little Red Dots, discovered by the James Webb Space Telescope, are hypothesized to be active galactic nuclei containing a supermassive black hole, possibly surrounded by a dense stellar cluster, large amounts of gas, and likely by a population of stellar-
Konstantinos Kritos, Joseph Silk
doaj   +1 more source

The GLEAMing of the first supermassive black holes

open access: yesPublications of the Astronomical Society of Australia, 2020
AbstractWe present the results of a new selection technique to identify powerful ($L_{\rm 500\,MHz} \gt 10^{27}\,\text{WHz}^{-1}$) radio galaxies towards the end of the Epoch of Reionisation. Our method is based on the selection of bright radio sources showing radio spectral curvature at the lowest frequency (${\sim}100\,\text{MHz}$) combined with the ...
Guillaume Drouart   +9 more
openaire   +5 more sources

Supermassive black holes in the early Universe [PDF]

open access: yesProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2015
The recent discovery of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.3 has exacerbated the time compression problem implied by the appearance of supermassive black holes only approximately 900 Myr after the big bang, and only approximately 500 Myr beyond the formation of Pop II and III stars. Aside from heralding
F. Melia, T. M. McClintock
openaire   +2 more sources

Deep Space Network Radio Science and Ground‐Based Planetary Radar in the Next Decade

open access: yesRadio Science, Volume 60, Issue 7, July 2025.
Abstract The Deep Space Network (DSN) has been a core operational element of NASA's crewed and robotic exploration of the Solar System since the early 1960s. The primary role of the DSN has been to acquire telemetry and navigation data, but over the years, its radiometric and radar capabilities have expanded to form a system for obtaining unique ...
R. S. Park   +13 more
wiley   +1 more source

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