The Cosmological Spacetime (2009)
Melia, Fulvio, Abdelqader, Majd
We present here the transformations required to recast the Robertson-Walker metric and Friedmann-Robertson-Walker equations in terms of observer-dependent coordinates for several commonly assumed...
X-ray and Radio Variability of M31*, The Andromeda Galaxy Nuclear Supermassive Black Hole (2009)
Garcia, Michael R., Hextall, Richard, Baganoff, Frederick K., Galache, Jose, Melia, Fulvio, Murray, Stephen S., ...
We confirm our earlier tentative detection of M31* in X-rays and measure its light-curve and spectrum. Observations in 2004-2005 find M31* rather quiescent in the X-ray and radio. However, X-ray...
Star Formation at the Galactic Center (2009)
Molecular clouds at the Galactic center (GC) have environments considerably different from their disk counterparts. The GC may therefore provide important clues about how the environment affects star...
Constraints on Dark Energy from the Observed Expansion of our Cosmic Horizon (2008)
Within the context of standard cosmology, an accelerating universe requires the presence of a third `dark' component of energy, beyond matter and radiation. The available data, however, are still...
Neutrinos and Gamma Rays from Galaxy Clusters (2008)
Wolfe, Brandon, Melia, Fulvio, Crocker, Roland M., Volkas, Raymond R.
The next generation of neutrino and gamma-ray detectors should provide new insights into the creation and propagation of high-energy protons within galaxy clusters, probing both the particle physics...
Decaying Dark Matter and the Deficit of Dwarf Haloes (2008)
Abdelqader, Majd, Melia, Fulvio
The hierarchical clustering inherent in Lambda-CDM cosmology seems to produce many of the observed characteristics of large-scale structure. But some glaring problems still remain, including the...
Diffuse TeV Emission at the Galactic Centre (2008)
Wommer, Elizabeth, Melia, Fulvio, Fatuzzo, Marco
The High-Energy Stereoscopic System (HESS) has detected intense diffuse TeV emission correlated with the distribution of molecular gas along the galactic ridge at the centre of our Galaxy. Earlier...
Neutrinos and gamma rays from galaxy clusters (2008)
Wolfe, Brandon, Melia, Fulvio, Crocker, Roland Murley, Volkas, Raymond Robert
Copyright © 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.
Neutrinos and gamma rays from galaxy clusters (2008)
Wolfe, Brandon, Melia, Fulvio, Crocker, Roland Murley, Volkas, Raymond Robert
Copyright © 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.
The Broadband Spectrum of Galaxy Clusters (2007)
We examine whether nonthermal protons energized during a cluster merger are simultaneously responsible for the Coma cluster's diffuse radio flux (via secondary decay) and the departure of its...
Dark Energy in Light of the Cosmic Horizon (2007)
Based on dramatic observations of the CMB with WMAP and of Type Ia supernovae with the Hubble Space Telescope and ground-based facilities, it is now generally believed that the Universe's expansion...
The cosmological principle, promoting the view that the universe is homogeneous and isotropic, is embodied within the mathematical structure of the Robertson-Walker (RW) metric. The equations derived...
Richard Schilizzi, Stuart Vogel, Francesco Paresce, Martin Elvis, Heino Falcke, Peter L. Biermann, ...
Sgr A*: observations, models, and imaging of the event horizon with VLBI
Sgr A, Robert Coker, Fulvio Melia, Heino Falcke
In the first paper of this series, using analytic tools, we examined how the evolution and structure of a massive accretion disk may be influenced significantly by the deposition of mass and angular...
Particle Cascades in Sgr A*: The Possibility of Observing Their gamma-Ray Signature (2007)
Sera Markoff, Fulvio Melia, Ina Sarcevic
tween 40 \Gamma 120 r g (Babul & Ostriker, 1988), which may accelerate a fraction of the particles (mostly ionized hydrogen) to very high energy. The relativistic protons are injected through the...
Accretion Disk Evolution with Wind Infall I. General Solution and Application to Sgr A* (2007)
The evolution of an accretion disk can be influenced significantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass influx impacts the long-term behavior...
High-Energy Emission from Relativistic Particles in Sgr A* (2007)
Sera Markoff, Fulvio Melia, Ina Sarcevic
EGRET onboard the Compton GRO has recently detected a high-energy source at the Galactic center. However, it is not yet clear whether the fl-rays are produced by the hypothesized massive black hole,...
The Supermassive Black Hole at the Galactic Center (2007)
The inner few parsecs at the Galactic Center have come under intense scrutiny in recent years, in part due to the exciting broad-band observations of this region, but also because of the growing...
Radio Synchrotron Emission from Secondary Leptons in the Vicinity of Sgr A* (2007)
Crocker, Roland M., Jones, David, Ballantyne, David R., Melia, Fulvio
A point-like source of ~TeV gamma-rays has recently been seen towards the Galactic center by HESS and other air Cerenkov telescopes. In recent work (Ballantyne et al. 2007), we demonstrated that...
Supermassive Black Holes (2007)
Supermassive black holes have generally been recognized as the most destructive force in nature. But in recent years, they have undergone a dramatic shift in paradigm. These objects may have been...
General Relativistic Flux Modulations from Disk Instabilities in Sagittarius A* (2007)
Falanga, Maurizio, Melia, Fulvio, Tagger, Michel, Goldwurm, Andrea, Belanger, Guillaume
Near-IR and X-ray flares have been detected from the supermassive black hole Sgr A* at the center of our Galaxy with a (quasi)-period of ~17-20 minutes, suggesting an emission region only a few...
The Cosmic Ray Distribution in Sagittarius B (2007)
Crocker, Roland M., Jones, David, Protheroe, Raymond J., Ott, Juergen, Ekers, Ron, Melia, Fulvio, ...
The HESS instrument has observed a diffuse flux of ~ TeV gamma rays from a large solid angle around the Galactic center (GC). This emission is correlated with the distribution of gas in the region...
A Possible Link Between the Galactic Center HESS Source and Sgr A* (2007)
Ballantyne, D. R., Melia, Fulvio, Liu, Siming, Crocker, Roland M.
Recently, HESS and other air Cerenkov telescopes have detected a source of TeV gamma-rays coincident with the Galactic center. It is not yet clear whether the gamma-rays are produced via leptonic or...
A possible link between the Galactic center HESS source and Sagittarius A* (2007)
Ballantyne, D. R., Melia, Fulvio, Liu, Siming, Crocker, Roland Murley
Copyright © 2007. The American Astronomical Society
A possible link between the Galactic center HESS source and Sagittarius A* (2007)
Ballantyne, D. R., Melia, Fulvio, Liu, Siming, Crocker, Roland Murley
Copyright © 2007. The American Astronomical Society
The cosmic ray distribution in Sagittarius B (2007)
Crocker, Roland Murley, Jones, David, Protheroe, Raymond John, Ott, Jurgen, Ekers, Ronald David, Melia, Fulvio, ...
Copyright © 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A.
Radio synchrotron emission from secondary leptons in the vicinity of Sagittarius A* (2007)
Crocker, Roland Murley, Jones, David Sydney, Ballantyne, D. R., Melia, Fulvio
© 2007. The American Astronomical Society. All rights reserved.
The cosmic ray distribution in Sagittarius B (2007)
Crocker, Roland Murley, Jones, David, Protheroe, Raymond John, Ott, Jurgen, Ekers, Ronald David, Melia, Fulvio, ...
Copyright © 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A.
Radio synchrotron emission from secondary leptons in the vicinity of Sagittarius A* (2007)
Crocker, Roland Murley, Jones, David Sydney, Ballantyne, D. R., Melia, Fulvio
© 2007. The American Astronomical Society. All rights reserved.
Chan, Chi-kwan, Liu, Siming, Fryer, Christopher L., Psaltis, Dimitrios, Ozel, Feryal, Rockefeller, Gabriel, ...
High resolution observations of Sgr A* have revealed a wide variety of phenomena, ranging from intense rapid flares to quasi-periodic oscillations, making this object an ideal system to study the...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio, Terrier, Regis
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
A Testable the Stochastic Acceleration Model for Flares in Sagittarius A* (2006)
Liu, Siming, Petrosian, Vahe, Melia, Fulvio, Fryer, Christopher L.
The near-IR and X-ray flares in Sagittarius A* are believed to be produced by relativistic electrons via synchrotron and synchrotron self-Comptonization, respectively. These electrons are likely...
Stochastic Acceleration in the Galactic Center HESS Source (2006)
Liu, Siming, Melia, Fulvio, Petrosian, Vahe, Fatuzzo, Marco
Stochastic acceleration of electrons interacting resonantly with a turbulent magnetic field in a small accretion torus appears to be the likely mechanism responsible for much of Sagittarius A*'s...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Fatuzzo, Marco, Melia, Fulvio, Crocker, Roland Murley
In recent years, apparent anisotropies in the ~EeV cosmic ray (CR) flux arriving at Earth from the general direction of the galactic center have been reported from the analysis of AGASA and SUGAR...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
Fatuzzo, Marco, Melia, Fulvio, Crocker, Roland Murley
In recent years, apparent anisotropies in the ~EeV cosmic ray (CR) flux arriving at Earth from the general direction of the galactic center have been reported from the analysis of AGASA and SUGAR...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Periodic Modulations in an X-ray Flare from Sagittarius A* (2006)
Belanger, Guillaume, Terrier, Regis, De Jager, Okkie, Goldwurm, Andrea, Melia, Fulvio
We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which...
A Possible Rossby Wave Instability Origin for the Flares in Sagittarius A* (2005)
In recent years, near-IR and X-ray flares have been detected from the Galaxy's central radio point source, Sagittarius A* (Sgr A*), believed to be a \~3.10^6 solar masses supermassive black hole. In...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Belanger, Guillaume, Goldwurm, Andrea, Renaud, Matthieu, Terrier, Regis, Melia, Fulvio, Lund, Niels, ...
The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a...
Spin-Induced Disk Precession in Sagittarius A* (2005)
Rockefeller, Gabriel, Fryer, Christopher L., Melia, Fulvio
In Sgr A* at the Galactic center, by far the closest and easiest supermassive black hole we can study, the observational evidence is increasingly pointing to the presence of a compact, hot,...
The X-ray Ridge Surrounding Sgr A* at the Galactic Center (2005)
Rockefeller, Gabriel, Fryer, Christopher L., Baganoff, Frederick K., Melia, Fulvio
We present the first detailed simulation of the interaction between the supernova explosion that produced Sgr A East and the wind-swept inner ~ 2-pc region at the Galactic center. The passage of the...
Stochastic Electron Acceleration During the NIR and X-ray Flares in Sagittarius A* (2005)
Liu, Siming, Melia, Fulvio, Petrosian, Vahe
Recent near-IR (NIR) and X-ray observations of Sagittarius A*'s spectrum have yielded several strong constraints on the transient energization mechanism, justifying a re-examination of the stochastic...
Long-Term Radio Modulation in Sagittarius A* from Spin-Induced Disk Precession (2005)
Prescher, Martin, Melia, Fulvio
There is some evidence, though yet unconfirmed, that Sagittarius A*--the supermassive black hole at the Galactic center--emits its radio waves modulated with a ~100-day period. What is intriguing...
Transrelativistic Synchrotron Emissivity, Cross-Section, and Polarization (2005)
The spectrum and polarization produced by particles spiraling in a magnetic field undergo dramatic changes as the emitters transition from nonrelativistic to relativistic energies. However, none of...
Covariant Kinetic Theory with an Application to the Coma Cluster (2005)
In this paper, we introduce a novel solution to the covariant Landau equation for a pure electron plasma. The method conserves energy and particle number, and reduces smoothly to the Rosenbluth...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Repeated X-ray Flaring Activity in Sagittarius A* (2005)
Belanger, Guillaume, Goldwurm, Andrea, Melia, Fulvio, Yusef-Zadeh, Farah, Ferrando, Philippe, Porquet, Delphine, ...
Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms...
Primary Versus Secondary Leptons in the EGRET SNR's (2004)
The EGRET supernova remnants (SNR's) are all expanding into nearby dense molecular clouds, powering a shock at the interface where protons and electrons accelerate to relativistic energies. A viable...
Neutrinos from the Galactic Center in the Light of its Gamma-Ray Detection at TeV Energy (2004)
Crocker, Roland M., Melia, Fulvio, Volkas, Raymond R.
We re-evaluate the event rate expected in km^3-scale detectors for neutrinos from the direction of the Galactic Center (GC) in light of recent spectral measurements obtained by the HESS instrument...
Diffuse X-rays from the Arches and Quintuplet clusters (2004)
Rockefeller, Gabriel, Fryer, Chris L., Melia, Fulvio, Wang, Q. Daniel
The origin and initial mass function of young stellar clusters near the Galactic center are still poorly understood. Two of the more prominent ones, the Arches and Quintuplet clusters, may have...
Crocker, Roland M., Fatuzzo, Marco, Jokipii, Randy, Melia, Fulvio, Volkas, Raymond R.
Recent analysis of data sets from two extensive air shower cosmic ray detectors shows tantalizing evidence of an anisotropic overabundance of cosmic rays towards the Galactic Center (GC) that ``turns...
Electron Acceleration around the Supermassive Black Hole at the Galactic Center (2004)
Liu, Siming, Petrosian, Vahe', Melia, Fulvio
The recent detection of variable infrared emission from Sagittarius A*, combined with its previously observed flare activity in X-rays, provides compelling evidence that at least a portion of this...
Diffuse X-Rays from the Inner 3 Parsecs of the Galaxy (2003)
Rockefeller, Gabriel, Fryer, Chris L., Melia, Fulvio, Warren, Michael S.
Recent observations with the Chandra X-ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within...
Fromerth, Michael J., Melia, Fulvio
We here estimate the mass M of the central object in five active galactic nuclei (AGNs), using the most recent reverberation data obtained by the AGN Watch Consortium. The cross-correlation function...
A Relativistic Disk in Sagittarius A* (2003)
The detection of a mm/Sub-mm ``bump'' in Sgr A*'s radio spectrum suggests that at least a portion of its overall emission is produced within a compact accretion torus. This inference is strengthened...
Shadowing of the Nascent Jet in NGC 4261 by a Line-Emitting Supersonic Accretion Disk (2003)
Liu, Siming, Fromerth, Michael J., Melia, Fulvio
NGC 4261 (3C 270) is a low-luminosity radio galaxy with two symmetric kiloparsec-scale jets. Earlier Hubble Space Telescope observations indicated the presence of a hundred-parsec scale disk of cool...
A Kinship between the EGRET SNR's and Sgr A East (2003)
Sgr A East appears to be a single, mixed morphology 10,000 year-old supernova remnant (SNR) at the Galactic Center. It also appears to belong to a class of remnants that have been observed and...
The Black Hole at the Center of our Galaxy (2003)
Descubrimiento del astrofísico Fulvio Melia en la constelación de sagitario de un punto oscuro (agujero negro), que está en el centro de nuestra galaxia. Hallazgo que piensa puede ser el...
Spin-Induced Disk Precession in the Supermassive Black Hole at the Galactic Center (2002)
Sgr A* is a compact radio source at the Galactic Center, thought to be the radiative manifestation of a $2.6\times 10^6 M_\odot$ supermassive black hole. At least a portion of its spectrum--notably...
Polarimetric imaging of the massive black hole in the galactic center (2002)
Bromley, Benjamin C., Melia, Fulvio; Liu, Siming
The radio source Sagittarius A* in the Galactic center emits a polarized spectrum at millimeter and submillimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive...
Polarimetric imaging of the massive black hole in the galactic center (2002)
Bromley, Benjamin C., Melia, Fulvio; Liu, Siming
The radio source Sagittarius A* in the Galactic center emits a polarized spectrum at millimeter and submillimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive...
Is Thermal Expansion Driving the Initial Gas Ejection in NGC 6251? (2001)
Melia, Fulvio, Liu, Siming, Fatuzzo, Marco
In this paper, we explore the possibility that the radiative properties of the most compact region in NGC 6251* may be understood in the same sense as Sgr A*, though with some telling differences...
New Constraints on the Nature of Radio Emission in Sagittarius A* (2001)
The mm to sub-mm spectrum of Sgr A* at the Galactic center, as well as its polarization characteristics, are consistent with the inner 10 Schwarzschild radii of a tight Keplerian emitting region of...
An Accretion-Induced X-ray Flare in Sgr A* (2001)
The recent detection of a three-hour X-ray flare from Sgr A* by Chandra provides very strong evidence for a compact emitting region near this supermassive black hole at the Galactic center. Sgr A*'s...
Line Emission from Cooling Accretion Flows in the Nucleus of M31 (2001)
Liu, Siming, Fromerth, Michael J., Melia, Fulvio
The recent Chandra X-ray observations of the nucleus of M31, combined with earlier VLA radio and HST UV spectral measurements, provide the strictest constraints on the nature of accretion onto the...
Polarimetric Imaging of the Massive Black Hole at the Galactic Center (2001)
Bromley, Benjamin C., Melia, Fulvio, Liu, Siming
The radio source Sgr A* in the Galactic center emits a polarized spectrum at millimeter and sub-millimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive black...
The Supermassive Black Hole at the Galactic Center (2001)
The inner few parsecs at the Galactic Center have come under intense scrutiny in recent years, in part due to the exciting broad-band observations of this region, but also because of the growing...
Crocker, Roland M., Melia, Fulvio, Volkas, Raymond R.
We investigate the muon neutrino event rate in km$^3$ neutrino telescopes due to a number of galactic supernova remnants expected on the basis of these objects' known $\gamma$-ray signals. We...
Measuring the Black Hole Spin in Sgr A* (2001)
Melia, Fulvio, Bromley, Benjamin C., Liu, Siming, Walker, K.
The polarized mm/sub-mm radiation from Sgr A* is apparently produced by a Keplerian structure whose peak emission occurs within several Schwarzschild radii (r_S=2GM/c^2) of the black hole. The...
Accretion Processes in the Nucleus of M31 (2001)
The hypothesized supermassive black hole in the nucleus of M31 (which we shall hereafter call M31*) has many features in common with Sgr A* at the Galactic Center, yet they differ in several...
Contenido: Introducción; Campos independientes del tiempo; Propiedades generales de las ecuaciones de Maxwell; Ondas electromagnéticas y radiación; Necesidad de la teoría especial de la...
Electrodynamics / F. Melia. (2001)
Contenido: Introducción; Campos independientes del tiempo; Propiedades generales de las ecuaciones de Maxwell; Ondas electromagnéticas y radiación; Necesidad de la teoría especial de la...
Correlated Sub-mm and X-ray Variability in Sgr A* (2000)
Melia, Fulvio, Liu, Siming, Fatuzzo, Marco
PAPER WITHDRAWN. The recent detection of Sgr A* in the X-ray band, together with the radio polarization measurements conducted over the past few years, offer the best constraints yet for...
A Magnetic Dynamo Origin For The Sub-mm Excess In Sgr A* (2000)
Melia, Fulvio, Liu, Siming, Coker, Robert
The sub-mm bump observed in the spectrum of Sgr A* appears to indicate the existence of a compact emitting component within several Schwarzschild radii, $r_S$, of the nucleus at the Galactic Center....
Polarized mm And sub-mm Emission From Sgr A* At The Galactic Center (2000)
Melia, Fulvio, Liu, Siming, Coker, Robert
The recent detection of significant linear polarization at mm and sub-mm wavelengths in the spectrum of Sgr A* (if confirmed) will be a useful probe of the conditions within several Schwarzschild...
Electron Positron Annihilation Radiation from SgrA East at the Galactic Center (2000)
Fatuzzo, Marco, Melia, Fulvio, Rafelski, Johann
Maps of the Galactic electron-positron annihilation radiation show evidence for three distinct and significant features: (1) a central bulge source, (2) emission in the Galactic plane, and (3) an...
Viewing The Shadow Of The Black Hole At The Galactic Center (2000)
Heino Falcke, Fulvio Melia, Eric Agol
In recent years, the evidence for the existence of an ultra-compact concentration of dark mass associated with the radio source Sgr A* in the Galactic Center has become very strong. However, an...
Viewing the Shadow of the Black Hole at the Galactic Center (1999)
Falcke, Heino, Melia, Fulvio, Agol, Eric
In recent years, the evidence for the existence of an ultra-compact concentration of dark mass associated with the radio source Sgr A* in the Galactic Center has become very strong. However, an...
The Role of Magnetic Field Dissipation in the Black Hole Candidate Sgr A* (1999)
Coker, Robert F., Melia, Fulvio
The compact, nonthermal radio source Sgr A* at the Galactic Center appears to be coincident with a 2.6 million solar mass point-like object. Its energy source may be the release of gravitational...
Time-Dependent Disk Models for the Microquasar GRS1915+105 (1999)
Nayakshin, Sergei, Rappaport, Saul, Melia, Fulvio
We investigate different accretion disk models and viscosity prescriptions in order to provide a basic explanation for the exotic temporal behavior in GRS 1915+105. Based on the fact that the overall...
Coker, Robert F., Melia, Fulvio, Falcke, Heino
In the first paper of this series, using analytic tools, we examined how the evolution and structure of a massive accretion disk may be influenced by the deposition of mass and angular momentum by an...
The Shadow of the Black Hole at the Galactic Center (1999)
Heino Falcke, Fulvio Melia, Eric Agol
. We show that perhaps already with the next generation of long-baseline interferometers at submm-wavelengths we will able to image the shadow of the black hole in the Galactic Center. To a distant...
The Hard X-Ray to Gamma-ray Spectrum in the EGRET AGNs (1998)
EGRET (20 MeV to 30 GeV) on board the Compton GRO has observed high-energy emission from about 40-50 Active Galactic Nuclei. Theoretical models of this emission based on the upscattering of thermal...
Melia, Fulvio, Yusef-Zadeh, Farhad, Fatuzzo, Marco
Continuum low-frequency radio observations of the Galactic Center reveal the presence of two prominent radio sources, Sgr A East and its surrounding Halo, containing non-thermal particle...
Stellar Gas Flows Into A Dark Cluster Potential At The Galactic Center (1998)
The evidence for the presence of a concentration of dark matter at the Galactic center is now very compelling. There is no question that the stellar and gas kinematics within 0.01 pc is dominated by...
Magnetic Flares and State Transitions in Galactic Black Hole and Neutron Star Systems (1997)
Nayakshin, Sergei, Melia, Fulvio
We here examine the conditions of the two-phase disk model under which magnetic flares arise above the cold accretion disk due to magnetic buoyancy and produce X-rays via Comptonization of the disk's...
X-rays From Magnetic Flares In Cygnus X-1: A Unified Model With Seyfert Galaxies (1997)
Nayakshin, Sergei, Melia, Fulvio
Some recent work has shown that the spectrum of Seyfert 1 Galaxies is very similar to that of several Galactic Black Hole Candidates (GBHCs) in their hard state. However, the smallness of the...
Magnetic Flares and the Observed Optical Depth in Seyfert Galaxies (1997)
Nayakshin, Sergei, Melia, Fulvio
We here consider the pressure equilibrium during an intense magnetic flare above the surface of a cold accretion disk. Under the assumption that the heating source for the plasma trapped within the...
Physical Constraints on, and a Model for, the Active Regions in Seyfert Galaxies (1997)
Nayakshin, Sergei, Melia, Fulvio
We discuss several physical constraints on the nature of the Active Regions (AR) in Seyfert 1 Galaxies, and show that a plausible model consistent with these constraints is one in which the ARs are...
Self-Consistent Fokker-Planck Treatment Of Particle Distributions in Astrophysical Plasmas (1997)
Nayakshin, Sergei, Melia, Fulvio
High-energy, multi-component plasmas in which pair creation and annihilation, lepton-lepton scattering, lepton-proton scattering, and Comptonization all contribute to establishing the particle and...
Accretion Disk Evolution With Wind Infall I. General Solution and Application to Sgr A* (1996)
The evolution of an accretion disk can be influenced significantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass influx impacts the long-term behavior...
It is well known that Gamma-ray Burst spectra often display a break at energies $\simless 400$ keV, with some exceptions extending to several MeV.\ \ Modeling of a cosmological source population is...
A Self-Consistent Model For The Long-Term Gamma-Ray Spectral Variability of Cygnus X-1 (1993)
The long-term transitions of the black hole candidate Cygnus X-1 (between the states gamma_1, gamma_2, and gamma_3) include the occasional appearance of a strong ~ MeV bump (gamma_1), whose strength...
Neutron stars and cosmic bursts of X-radiation / (1985)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1985.
Solutions of the classical Yang-Mills equations (1978)
Typescript (photocopy) Includes bibliographical references.