On Black Hole Detection with the OWL/Airwatch Telescope

In scenarios with large extra dimensions and TeV scale gravity ultrahigh energy neutrinos produce black holes in their interactions with the nucleons. We show that ICECUBE and OWL may observe large number of black hole events and provide valuable information about the fundamental Planck scale and the number of extra dimensions. OWL is especially well suited to observe black hole events produced by neutrinos from the interactions of cosmic rays with the 3 K background radiation. Depending on the parameters of the scenario of large extra dimensions and on the flux model, as many as 28 events per year are expected for a Planck scale of 3 TeV.Comment: 8 pages, including 7 color figures, three figure captions corrected, minor changes for clarification, one reference adde

Binary black hole detection rates in inspiral gravitational wave searches

The signal-to-noise ratios (SNRs) for quasi-circular binary black hole inspirals computed from restricted post-Newtonian waveforms are compared with those attained by more complete post-Newtonian signals, which are superpositions of amplitude-corrected harmonics of the orbital phase. It is shown that if one were to use the best available amplitude-corrected waveforms for detection templates, one should expect SNRs in actual searches to be significantly lower than those suggested by simulations based purely on restricted waveforms.Comment: 9 pages, 1 figur

Microscopic black hole detection in UHECR: the double bang signature

According to recent conjectures on the existence of large extra dimensions in our universe, black holes may be produced during the interaction of Ultra High Energy Cosmic Rays with the atmosphere. However, and so far, the proposed signatures are based on statistical effects, not allowing identification on an event by event basis, and may lead to large uncertainties. In this note, events with a double bang topology, where the production and instantaneous decay of a microscopic black hole (first bang) is followed, at a measurable distance, by the decay of an energetic tau lepton (second bang) are proposed as an almost background free signature. The characteristics of these events and the capability of large cosmic ray experiments to detect them are discussed.Comment: revised version, 5 figure

Intelligent black hole detection in mobile AdHoc networks

Security is a critical and challenging issue in MANET due to its open-nature characteristics such as: mobility, wireless communications, self-organizing and dynamic topology. MANETs are commonly the target of black hole attacks. These are launched by malicious nodes that join the network to sabotage and drain it of its resources. Black hole nodes intercept exchanged data packets and simply drop them. The black hole node uses vulnerabilities in the routing protocol of MANETS to declare itself as the closest relay node to any destination. This work proposed two detection protocols based on the collected dataset, namely: the BDD-AODV and Hybrid protocols. Both protocols were built on top of the original AODV. The BDD-AODV protocol depends on the features collected for the prevention and detection of black hole attack techniques. On the other hand, the Hybrid protocol is a combination of both the MI-AODV and the proposed BDD-AODV protocols. Extensive simulation experiments were conducted to evaluate the performance of the proposed algorithms. Simulation results show that the proposed protocols improved the detection and prevention of black hole nodes, and hence, the network achieved a higher packet delivery ratio, lower dropped packets ratio, and lower overhead. However, this improvement led to a slight increase in the end-to-end delay

The Murmur of the Sleeping Black Hole: Detection of Nuclear Ultraviolet Variability in LINER Galaxies

LINER nuclei, which are present in many nearby galactic bulges, may be the manifestation of low-rate or low-radiative-efficiency accretion onto supermassive central black holes. However, it has been unclear whether the compact UV nuclear sources present in many LINERs are clusters of massive stars, rather than being directly related to the accretion process. We have used HST to monitor the UV variability of a sample of 17 galaxies with LINER nuclei and compact nuclear UV sources. Fifteen of the 17 galaxies were observed more than once, with two to five epochs per galaxy, spanning up to a year. We detect significant variability in most of the sample, with peak-to-peak amplitudes from a few percent to 50%. In most cases, correlated variations are seen in two independent bands (F250W and F330W). Comparison to previous UV measurements indicates, for many objects, long-term variations by factors of a few over decade timescales. Variability is detected in LINERs with and without detected compact radio cores, in LINERs that have broad H-alpha wings detected in their optical spectra (``LINER 1's''), and in those that do not (``LINER 2s''). This variability demonstrates the existence of a non-stellar component in the UV continuum of all types, and sets a lower limit to the luminosity of this component. We note a trend in the UV color (F250W/F330W) with spectral type - LINER 1s tend to be bluer than LINER 2s. This trend may indicate a link between the shape of the nonstellar continuum and the presence or the visibility of a broad-line region. In one target, the post-starburst galaxy NGC 4736, we detect variability in a previously noted UV source that is offset by 2.5" (60 pc in projection) from the nucleus. This may be the nearest example of a binary active nucleus, and of the process leading to black hole merging.Comment: accepted to Ap

Black hole particle emission in higher-dimensional spacetimes

In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross-sections, the relative emissivities and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in models with extra dimensions and black hole detection in particle colliders.Comment: 4 pages, RevTeX 4. v3: Misprints in Tables correcte

The Supermassive Black Hole and Dark Matter Halo of NGC 4649 (M60)

We apply the axisymmetric orbit superposition modeling to estimate the mass of the supermassive black hole and dark matter halo profile of NGC 4649. We have included data sets from the Hubble Space Telescope, stellar, and globular cluster observations. Our modeling gives the black hole mass = 4.5 \pm 1.0 10^9 \Msun and M/L = 8.7 \pm 1.0 (or 8.0 \pm 0.9 after foreground Galactic extinction is corrected). We confirm the presence of a dark matter halo, but the stellar mass dominates inside the effective radius. The parameters of the dark halo are less constrained due to the sparse globular cluster data at large radii. We find that in NGC 4649 the dynamical mass profile from our modeling is consistently larger than that derived from the X-ray data over most of the radial range by roughly 60% to 80%. It implies that either some forms of non-thermal pressure need to be included, the assumed hydrostatic equilibrium may not be a good approximation in the X-ray modelings of NGC 4649, or our assumptions used in the dynamical models are biased. Our new black hole mass is about two times larger than the previous published value; the earlier model did not adequately sample the orbits required to match the large tangential anisotropy in the galaxy center. If we assume that there is no dark matter, the results on the black hole mass and M/L do not change significantly, which we attribute to the inclusion of HST spectra, the sparse globular cluster kinematics, and a diffuse dark matter halo. Without the HST data, the significance of the black hole detection is greatly reduced.Comment: Accepted for publication in ApJ. emulateapj format. 11 page