237 results on '"Charles D. Dermer"'
Search Results
2. Diffuse Galactic Gamma Rays from Shock-Accelerated Cosmic Rays
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Charles D. Dermer
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- 2012
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3. Photopion production in black-hole jets and flat-spectrum radio quasars as PeV neutrino sources
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Charles D. Dermer, Kohta Murase, and Yoshiyuki Inoue
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Ultra-high-energy cosmic rays ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Cosmic ray ,γ-ray bursts ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,IceCube ,symbols.namesake ,γ rays ,Neutrinos ,Blazar ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Astronomy and Astrophysics ,Quasar ,Particle acceleration ,Black hole ,Lorentz factor ,Space and Planetary Science ,symbols ,High Energy Physics::Experiment ,Neutrino ,Gamma-ray burst ,Astrophysics - High Energy Astrophysical Phenomena ,Blazars - Abstract
The IceCube collaboration has reported neutrinos with energies between ~30 TeV and a few PeV that are significantly enhanced over the cosmic-ray induced atmospheric background. Viable high-energy neutrino sources must contain very high-energy and ultra-high energy cosmic rays while efficiently making PeV neutrinos. Gamma-ray Bursts (GRBs) and blazars have been considered as candidate cosmic-ray accelerators. GRBs, including low-luminosity GRBs, can be efficient PeV neutrino emitters for low bulk Lorentz factor outflows, although the photopion production efficiency needs to be tuned to simultaneously explain ultra-high-energy cosmic rays. Photopion production efficiency of cosmic-rays accelerated in the inner jets of flat spectrum radio quasars (FSRQs) is ~1-10% due to interactions with photons of the broad-line region (BLR), whereas BL Lac objects are not effective PeV neutrino sources due to the lack of external radiation fields. Photopion threshold effects with BLR photons suppress neutrino production below ~1 PeV, which imply that neutrinos from other sources would dominate over the diffuse neutrino intensity at sub-PeV energies. Reduction of the >> PeV neutrino flux can be expected when curving cosmic-ray proton distributions are employed. Considering a log-parabolic function to describe the cosmic-ray distribution, we discuss possible implications for particle acceleration in black-hole jets. Our results encourage a search for IceCube PeV neutrino events associated with gamma-ray loud FSRQs using Fermi-LAT data. In our model, as found in our previous work, the neutrino flux is suppressed below 1 PeV, which can be tested with increased IceCube exposure., 14 pages, 7 figures, added treatments of synchrotron self-absorption and optimal neutrino production in jetted sources; accepted for publication in Journal of High Energy Astrophysics
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- 2014
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4. Active galactic nuclei at gamma-ray energies
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Charles D. Dermer, Berrie Giebels, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet ( LLR ), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -École polytechnique ( X ) -Centre National de la Recherche Scientifique ( CNRS )
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Cherenkov Telescope Array ,gamma ray: background ,Radio galaxy ,[ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph] ,torus ,Astrophysics ,01 natural sciences ,Astrophysical jet ,accretion ,Supermassive black holes ,optical ,black hole ,Rayons gamma ,010303 astronomy & astrophysics ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,photon ,General Engineering ,Noyaux actifs de galaxie ,gamma ray: emission ,flow ,Astrophysics - High Energy Astrophysical Phenomena ,BL Lac object ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Energy Engineering and Power Technology ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Trous noirs supermassifs ,blazar ,jet: relativistic ,X-ray ,0103 physical sciences ,synchrotron ,cosmic radiation: UHE ,AGN ,010306 general physics ,Blazar ,Astrophysics::Galaxy Astrophysics ,plasma ,gamma ray: energy ,Supermassive black hole ,Active galactic nuclei ,galaxy: radio wave ,Gamma rays ,Astronomy ,Galaxy ,Cherenkov counter ,spectral ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
Active Galactic Nuclei can be copious extragalactic emitters of MeV-GeV-TeV gamma rays, a phenomenon linked to the presence of relativistic jets powered by a super-massive black hole in the center of the host galaxy. Most of gamma-ray emitting active galactic nuclei, with more than 1500 known at GeV energies, and more than 60 at TeV energies, are called "blazars". The standard blazar paradigm features a jet of relativistic magnetized plasma ejected from the neighborhood of a spinning and accreting super-massive black hole, close to the observer direction. Two classes of blazars are distinguished from observations: the flat-spectrum radio-quasar class (FSRQ) is characterized by strong external radiation fields, emission of broad optical lines, and dust tori. The BL Lac class (from the name of one of its members, BL Lacertae) corresponds to weaker advection-dominated flows with gamma-ray spectra dominated by the inverse Compton effect on synchrotron photons. This paradigm has been very successful for modeling the broadband spectral energy distributions of blazars. However, many fundamental issues remain, including the role of hadronic processes and the rapid variability of those BL Lac objects whose synchrotron spectrum peaks at UV or X-ray frequencies. A class of gamma-ray--emitting radio galaxies, which are thought to be the misaligned counterparts of blazars, has emerged from the results of the Fermi-Large Area Telescope and of ground-based Cherenkov telescopes. Blazars and their misaligned ounterparts make up most of the >100 MeV extragalactic gamma ray background (EGB), and are uspected of being the sources of ultra-high energy cosmic rays. The future "Cherenkov Telescope Array", in synergy with the Fermi-Large Area Telescope and a wide range of telescopes in space and on he ground, will write the next chapter of blazar physics., 27 pages, 28 figures, in a topical review on gamma-ray astronomy above 100 MeV, to be published in Comptes Rendus Physique de l'Acad\'emie des Sciences (CRAS)
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- 2016
5. Theory of high-energy messengers
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Charles D. Dermer
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Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,History ,Active galactic nucleus ,Gravitational wave ,media_common.quotation_subject ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,FOS: Physical sciences ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,LIGO ,Universe ,Computer Science Applications ,Education ,Extragalactic background light ,Intergalactic travel ,Neutrino ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
Knowledge of the distant high-energy universe comes from photons, ultra-high energy cosmic rays (UHECRs), high-energy neutrinos, and gravitational waves. The theory of high-energy messengers reviewed here focuses on the extragalactic background light at all wavelengths, cosmic rays and magnetic fields in intergalactic space, and neutrinos of extragalactic origin. Comparisons are drawn between the intensities of photons and UHECRs in intergalactic space, and the high-energy neutrinos recently detected with IceCube at about the Waxman-Bahcall flux. Source candidates for UHECRs and high-energy neutrinos are reviewed, focusing on star-forming and radio-loud active galaxies. HAWC and Advanced LIGO are just underway, with much anticipation., Comment: 12 pages, 8 figures; invited review for 14th International Congress in Topics in Astroparticle and Underground Physics, Torino, Italy, 7 - 11 September 2015
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- 2016
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6. Electron Acceleration in Pulsar-Wind Termination Shocks: An Application to the Crab Nebula Gamma-Ray Flares
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John J. Kroon, Peter A. Becker, Charles D. Dermer, and Justin D. Finke
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Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Gamma ray ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Synchrotron ,Afterglow ,law.invention ,Particle acceleration ,Acceleration ,Crab Nebula ,Pulsar ,Space and Planetary Science ,law ,0103 physical sciences ,Physics::Accelerator Physics ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics ,Flare - Abstract
The {\gamma}-ray flares from the Crab nebula observed by AGILE and Fermi-LAT reaching GeV energies and lasting several days challenge the standard models for particle acceleration in pulsar wind nebulae, because the radiating electrons have energies exceeding the classical radiation-reaction limit for synchrotron. Previous modeling has suggested that the synchrotron limit can be exceeded if the electrons experience electrostatic acceleration, but the resulting spectra do not agree very well with the data. As a result, there are still some important unanswered questions about the detailed particle acceleration and emission processes occurring during the flares. We revisit the problem using a new analytical approach based on an electron transport equation that includes terms describing electrostatic acceleration, stochastic wave-particle acceleration, shock acceleration, synchrotron losses, and particle escape. An exact solution is obtained for the electron distribution, which is used to compute the associated {\gamma}-ray synchrotron spectrum. We find that in our model the {\gamma}-ray flares are mainly powered by electrostatic acceleration, but the contributions from stochastic and shock acceleration play an important role in producing the observed spectral shapes. Our model can reproduce the spectra of all the Fermi-LAT and AGILE flares from the Crab nebula, using magnetic field strengths in agreement with the multi-wavelength observational constraints. We also compute the spectrum and duration of the synchrotron afterglow created by the accelerated electrons, after they escape into the region on the downstream side of the pulsar wind termination shock. The afterglow is expected to fade over a maximum period of about three weeks after the {\gamma}-ray flare., Comment: Accepted for publication in ApJ
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- 2016
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7. The lag-luminosity relation in the GRB source frame: an investigation with Swift BAT bursts
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P. N. Bhat, J. T. Linnemann, J. P. Norris, U. Abeysekara, N. Gehrels, Kirsten Tollefson, T. N. Ukwatta, L. C. Maximon, T. Sakamoto, Kalvir S. Dhuga, A. Eskandarian, Charles D. Dermer, M. Stamatikos, Eda Sonbas, and William C. Parke
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Swift ,Physics ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Lag ,Isotropy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Redshift ,Luminosity ,Time of arrival ,Space and Planetary Science ,0103 physical sciences ,Gamma-ray burst ,010303 astronomy & astrophysics ,computer ,Energy (signal processing) ,computer.programming_language - Abstract
Spectral lag, which is defined as the difference in time of arrival of high and low energy photons, is a common feature in Gamma-ray Bursts (GRBs). Previous investigations have shown a correlation between this lag and the isotropic peak luminosity for long duration bursts. However, most of the previous investigations used lags extracted in the observer-frame only. In this work (based on a sample of 43 Swift long GRBs with known redshifts), we present an analysis of the lag-luminosity relation in the GRB source-frame. Our analysis indicates a higher degree of correlation -0.82 +/- 0.05 (chance probability of ~ 5.5 x 10^-5) between the spectral lag and the isotropic peak luminosity, Liso, with a best-fit power-law index of -1.2 +/- 0.2, such that Liso proportional to lag^-1.2. In addition, there is an anti-correlation between the source-frame spectral lag and the source-frame peak energy of the burst spectrum, E_pk(1+z).
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- 2011
8. Jet formation in the magnetospheres of supermassive black holes: analytic solutions describing energy loss through Blandford-Znajek processes
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Charles D. Dermer and Govind Menon
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Physics ,Supermassive black hole ,Jet (fluid) ,Rotating black hole ,Space and Planetary Science ,Astrophysics::High Energy Astrophysical Phenomena ,Quantum electrodynamics ,Poynting vector ,Energy flux ,Magnetosphere ,Flux ,Astronomy and Astrophysics ,Magnetohydrodynamics - Abstract
In this paper, we provide exact solutions for the extraction of energy from a rotating black hole via both the electromagnetic Poynting flux and matter currents. By appropriate choice of a radially independent poloidal function Λ(θ), we find solutions where the dominant outward energy flux is along the polar axis, consistent not only with a jet-like collimated outflow, but also with a weaker flux of energy along the equatorial plane. Unlike previously obtained solutions, the magnetosphere is free of magnetic monopoles everywhere.
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- 2011
9. ACCELERATION OF ULTRA-HIGH-ENERGY COSMIC RAYS IN THE COLLIDING SHELLS OF BLAZARS AND GAMMA-RAY BURSTS: CONSTRAINTS FROM THEFERMI GAMMA-RAY SPACE TELESCOPE
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Charles D. Dermer and Soebur Razzaque
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Fermi acceleration ,Quasar ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,Astrophysical jet ,Space and Planetary Science ,Ultra-high-energy cosmic ray ,Astrophysics - High Energy Astrophysical Phenomena ,Blazar ,Astrophysics::Galaxy Astrophysics ,Fermi Gamma-ray Space Telescope - Abstract
Fermi Gamma ray Space Telescope measurements of spectra, variability time scale, and maximum photon energy give lower limits to the apparent jet powers and, through gammagamma opacity arguments, the bulk Lorentz factors of relativistic jets. The maximum cosmic-ray particle energy is limited by these two quantities in Fermi acceleration scenarios. Recent data are used to constrain the maximum energies of cosmic-ray protons and Fe nuclei accelerated in colliding shells of GRBs and blazars. The Fermi results indicate that Fe rather than protons are more likely to be accelerated to ultra-high energies in AGNs, whereas powerful GRBs can accelerate both protons and Fe to >~ 10^{20} eV. Emissivity of nonthermal radiation from radio galaxies and blazars is estimated from the First Fermi AGN Catalog, and shown to favor BL Lac objects and FR1 radio galaxies over flat spectrum radio quasars, FR2 radio galaxies, and long-duration GRBs as the sources of UHECRs., 8 pages, 3 figures, ApJ, in press
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- 2010
10. Synchrotron Radiation from Ultra-High Energy Protons and the Fermi Observations of GRB 080916C~!2010-03-15~!2010-05-15~!2010-08-31~!
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Charles D. Dermer, Soebur Razzaque, and Justin D. Finke
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Gamma ray ,GRB 080916C ,Synchrotron radiation ,Proton Synchrotron ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Synchrotron ,law.invention ,law ,Physics::Accelerator Physics ,Gamma-ray burst ,Fermi Gamma-ray Space Telescope - Abstract
Fermi ! -ray telescope data of GRB 080916C with ~10 55 erg in apparent isotropic ! -ray energy, show a several second delay between the rise of 100 MeV - GeV radiation compared with keV - MeV radiation. Here we show that synchrotron radiation from cosmic ray protons accelerated in GRBs, delayed by the proton synchrotron cooling timescale in a jet of magnetically-dominated shocked plasma moving at highly relativistic speeds with bulk Lorentz factor !~500 , could explain this result. A second generation electron synchrotron component from attenuated proton synchrotron radiation makes enhanced soft X-ray to MeV ! -ray emission. Long GRBs with narrow, energetic jets accelerating particles to ultra-high energies could explain the Auger observations of UHE cosmic rays from sources within 100 Mpc for nano-Gauss intergalactic magnetic fields. The total energy requirements in a proton synchrotron model are !" 16/3 . This model for GRB 080916C is only plausible if Γ< ~ 500 and the jet opening angle is ~1 o .
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- 2010
11. ON THE BREAK IN THEFERMI-LARGE AREA TELESCOPE SPECTRUM OF 3C 454.3
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Justin D. Finke and Charles D. Dermer
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Spectral line ,law.invention ,Telescope ,Black hole ,Spitzer Space Telescope ,Space and Planetary Science ,law ,Spectral energy distribution ,Fermi Gamma-ray Space Telescope - Abstract
Fermi Gamma-ray Space Telescope observations of the flat spectrum radio quasar 3C 454.3 show a spectral-index change ΔΓ 1.2 ± 0.3 at break energy E br 2.4 ± 0.3 GeV. Such a sharp break is inconsistent with a cooling electron distribution and is poorly fit with a synchrotron self-Compton model. We show that a combination of two components, namely, the Compton-scattered disk and broad-line region (BLR) radiations, explains this spectral break and gives a good fit to the quasi-simultaneous radio, optical/UV, X-ray, and γ-ray spectral energy distribution observed in 2008 August. A sharp break can be produced independent of the emitting region's distance from the central black hole if the BLR has a gradient in density R –2, consistent with a wind model for the BLR.
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- 2010
12. MODELING THE EXTRAGALACTIC BACKGROUND LIGHT FROM STARS AND DUST
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Charles D. Dermer, Soebur Razzaque, and Justin D. Finke
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Initial mass function ,Active galactic nucleus ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,Extinction (astronomy) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Luminosity ,Stars ,Extragalactic background light ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The extragalactic background light (EBL) from the far infrared through the visible and extending into the ultraviolet is thought to be dominated by starlight, either through direct emission or through absorption and reradiation by dust. This is the most important energy range for absorbing $\g$-rays from distant sources such as blazars and gamma-ray bursts and producing electron positron pairs. In previous work we presented EBL models in the optical through ultraviolet by consistently taking into account the star formation rate (SFR), initial mass function (IMF) and dust extinction, and treating stars on the main sequence as blackbodies. This technique is extended to include post-main sequence stars and reprocessing of starlight by dust. In our simple model, the total energy absorbed by dust is assumed to be re-emitted as three blackbodies in the infrared, one at 40 K representing warm, large dust grains, one at 70 K representing hot, small dust grains, and one at 450 K representing polycyclic aromatic hydrocarbons. We find our best fit model combining the Hopkins and Beacom SFR using the Cole et al. parameterization with the Baldry and Glazebrook IMF agrees with available luminosity density data at a variety of redshifts. Our resulting EBL energy density is quite close to the lower limits from galaxy counts and in some cases below the lower limits, and agrees fairly well with other recent EBL models shortward of about 5 $\mu$m. Deabsorbing TeV $\g$-ray spectra of various blazars with our EBL model gives results consistent with simple shock acceleration theory. We also find that the universe should be optically thin to $\g$-rays with energies less than 20 GeV., Comment: 13 pages, 10 figures, 3 tables, emulateapj. Version accepted by ApJ
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- 2010
13. GAMMA-RAY STUDIES OF BLAZARS: SYNCHRO-COMPTON ANALYSIS OF FLAT SPECTRUM RADIO QUASARS
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Hannah Krug, Markus Boettcher, Charles D. Dermer, and Justin D. Finke
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Physics ,Photon ,Point source ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Compton scattering ,Gamma ray ,FOS: Physical sciences ,Synchrotron radiation ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Redshift ,Space and Planetary Science ,Blazar - Abstract
We extend a method for modeling synchrotron and synchrotron self-Compton radiations in blazar jets to include external Compton processes. The basic model assumption is that the blazar radio through soft X-ray flux is nonthermal synchrotron radiation emitted by isotropically-distributed electrons in the randomly directed magnetic field of outflowing relativistic blazar jet plasma. Thus the electron distribution is given by the synchrotron spectrum, depending only on the Doppler factor $\delta_{\rm D}$ and mean magnetic field $B$, given that the comoving emission region size scale $R_b^\prime \lesssim c \dD t_v/(1+z)$, where $t_v$ is variability time and $z$ is source redshift. Generalizing the approach of Georganopoulos, Kirk, and Mastichiadis (2001) to arbitrary anisotropic target radiation fields, we use the electron spectrum implied by the synchrotron component to derive accurate Compton-scattered $\gamma$-ray spectra throughout the Thomson and Klein-Nishina regimes for external Compton scattering processes. We derive and calculate accurate $\gamma$-ray spectra produced by relativistic electrons that Compton-scatter (i) a point source of radiation located radially behind the jet, (ii) photons from a thermal Shakura-Sunyaev accretion disk and (iii) target photons from the central source scattered by a spherically-symmetric shell of broad line region (BLR) gas. Calculations of broadband spectral energy distributions from the radio through $\gamma$-ray regimes are presented, which include self-consistent $\gamma\gamma$ absorption on the same radiation fields that provide target photons for Compton scattering. Application of this baseline flat spectrum radio/$\gamma$-ray quasar model is considered in view of data from $\gamma$-ray telescopes and contemporaneous multi-wavelength campaigns., Comment: Accepted by ApJ. 22 pages, 12 figures, 2 tables. Minor revisions to figures and text
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- 2009
14. SUZAKUOBSERVATIONS OF LOCAL ULTRALUMINOUS INFRARED GALAXIES
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Naohisa Anabuki, Andrew S. Wilson, Stacy H. Teng, Charles D. Dermer, Takao Nakagawa, Yuichi Terashima, Christopher S. Reynolds, David B. Sanders, Sylvain Veilleux, and Luigi C. Gallo
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Luminous infrared galaxy ,Physics ,Active galactic nucleus ,galaxies: individual (IRAS F05189-2524, IRAS F08572 + 3915, Mrk 273, PKS 1345 + 12, Arp 220) ,Astrophysics (astro-ph) ,galaxies: active ,FOS: Physical sciences ,Astronomy ,galaxies: starburst ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Spectral line ,Luminosity ,X-rays: galaxies ,Space and Planetary Science ,Ionization ,Equivalent width ,Line (formation) - Abstract
We report the results from our analysis of {\it Suzaku} XIS (0.5-10 keV) and HXD/PIN (15-40 keV) observations of five well-known local ULIRGs: {\em IRAS} F05189-2524, {\em IRAS} F08572+3915, Mrk 273, PKS 1345+12, and Arp 220. The XIS observations of F05189-2524 and Mrk 273 reveal strong iron lines consistent with Fe K$\alpha$ and changes in spectral shapes with respect to previous {\it Chandra} and {\it XMM-Newton} observations. Mrk 273 is also detected by the HXD/PIN at $\sim$1.8-$\sigma$. For F05189-2524, modeling of the data from the different epochs suggests that the change in spectral shape is likely due to the central source switching off, leaving behind a residual reflection spectrum, or an increase in the absorbing column. An increase in the covering fraction of the absorber can describe the spectral variations seen in Mrk 273, although a reduction in the intrinsic AGN luminosity cannot be formally ruled out. The {\it Suzaku} spectra of Mrk 273 are well fit by a ~94% covering fraction model with a column density of $\sim10^{24}$ cm$^{-2}$. The absorption-corrected log[$L_{\rm 2-10 keV}$ / $L_{\rm IR}$] ratio is consistent with those found in PG Quasars. The 0.5-10 keV spectrum of PKS 1345+12 and Arp 220 seem unchanged from previous observations and their hard X-ray emission is not convincingly detected by the HXD/PIN. The large column density derived from CO observations and the large equivalent width of an ionized Fe line in Arp 220 can be reconciled by an ionized reflection model. F08572+3915 is undetected in both the XIS and HXD/PIN, but the analysis of unpublished {\em Chandra} data provides a new measurement at low energies., Comment: 37 pages including 4 tables and 10 figures. Accepted for publication in ApJ. It is tentatively scheduled to appear in the January 20, 2009 issue of ApJ
- Published
- 2009
15. Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT
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A. W. Borgland, W. B. Atwood, S. Germani, Grzegorz Madejski, Nicola Giglietto, A. P. Waite, Denis Bastieri, P. L. Nolan, A. De Luca, A. Reimer, M. N. Lovellette, Jeffrey D. Scargle, P. A. Caraveo, Persis S. Drell, C. Meurer, N. Kawai, R. A. Cameron, P. Fusco, Sylvain Guiriec, Francesco Longo, Carmelo Sgrò, Riccardo Rando, E. Hays, T. H. Burnett, Richard Dubois, Gino Tosti, R. E. Hughes, E. J. Siskind, Joel R. Primack, Claudia Cecchi, Johann Cohen-Tanugi, G.L. Godfrey, Nanda Rea, E. Nuss, P. Giommi, Matthew Kerr, S. J. Fegan, Takaaki Tanaka, Tadayuki Takahashi, W. Mitthumsiri, Paul S. Ray, David Paneque, M. Kuss, S. Rainò, M. S. Strickman, D. J. Thompson, Magnus Axelsson, V. Vasileiou, N. Vilchez, Jonathan F. Ormes, Kent S. Wood, Markus Ackermann, Jean Ballet, M. Lemoine-Goumard, Karen Watters, B. Lott, M. T. Wolff, C. Farnier, H. Tajima, M. Brigida, C. C. Cheung, T. Glanzman, A. Sander, R. Claus, F. Piron, Paul J. Wang, Stefano Ciprini, Jean-Luc Starck, J. M. Casandjian, G. A. Caliandro, A. Brez, Yasunobu Uchiyama, A. van Etten, J. P. Norris, T. Ylinen, Hiromitsu Takahashi, Morihiro Hayashida, Alice K. Harding, P. M. Saz Parkinson, A. Morselli, V. Vitale, A. Chekhtman, Tsunefumi Mizuno, David S. Smith, R. P. Johnson, T. Ohsugi, F. Gargano, Elliott D. Bloom, B. M. Baughman, Nicola Omodei, Luca Latronico, J. Bregeon, L. Guillemot, A. Y. Rodriguez, Brandon Anderson, M. Dormody, C. Monte, A. A. Abdo, E. Orlando, J. E. Grove, Yasushi Fukazawa, P. Spinelli, M. N. Mazziotta, F. Giordano, M. L. Kocian, Stefan Funk, T. A. Porter, Roger W. Romani, M.-H. Grondin, F. de Palma, J. G. Thayer, Seth Digel, Tyrel J. Johnson, A. Makeev, Dario Gasparrini, P. D. Smith, E. Do Couto E Silva, Brian L Winer, M. E. Monzani, P. Lubrano, Luca Baldini, Giovanni F. Bignami, H. F.W. Sadrozinski, Ronaldo Bellazzini, Emanuele Bonamente, M. Pierbattista, I. A. Grenier, Gudlaugur Johannesson, J. Lande, F. Loparco, M. Ziegler, Felix Ryde, A. De Angelis, Jürgen Knödlseder, Y. Hanabata, C. Favuzzi, Gloria Spandre, Guido Barbiellini, B. Giebels, Matthew G. Baring, A. Tramacere, S. Murgia, S. Ritz, Charles D. Dermer, D. Parent, Melissa Pesce-Rollins, O. Tibolla, D. J. Suson, B. Berenji, W. McConville, Pascal Bruel, W. N. Johnson, Peter F. Michelson, Hideaki Katagiri, T. Kamae, Igor V. Moskalenko, Olaf Reimer, Jan Conrad, Diego F. Torres, V. Pelassa, C. Gwon, Julie McEnery, Neil Gehrels, David Sánchez, Marco Ajello, L. Tibaldo, Jun Kataoka, Ö. Çelik, S. Cutini, M. Pepe, D. Dumora, James Chiang, Roger Blandford, M. Marelli, M. Razzano, L.S. Rochester, T. L. Usher, Keith Bechtol, T. Reposeur, Abdo, A. A., Ackermann, M., Ajello, M., Anderson, B., Atwood, W. B., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Bignami, G. F., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Conrad, J., Cutini, S., Dermer, C. D., Angelis, A. d., Luca, A. d., Palma, F. d., Digel, S. W., Dormody, M., Silva, E. D. E., Drell, P. S., Dubois, R., Dumora, D., Farnier, C., Favuzzi, C., Fegan, S. J., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Glanzman, T., Godfrey, G., Grenier, I. A., Grondin, M. H., Grove, J. E., Guillemot, L., Guiriec, S., Gwon, C., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Hughes, R. E., Johannesson, G., Johnson, R. P., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Kerr, M., Knodlseder, J., Kocian, M. L., Kuss, M., Lande, J., Latronico, L., Lemoine Goumard, M., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Makeev, A., Marelli, M., Mazziotta, M. N., Mcconville, W., Mcenery, J. E., Meurer, C., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nolan, P. L., Norris, J. P., Nuss, E., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Parent, D., Pelassa, V., Pepe, M., Pesce Rollins, M., Pierbattista, M., Piron, F., Porter, T. A., Primack, J. R., Raino, S., Rando, R., Ray, P. S., Razzano, M., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rochester, L. S., Rodriguez, A. Y., Romani, R. W., Ryde, F., Sadrozinski, H. F. W., Sanchez, D., Sander, A., Parkinson, P. M. S., Scargle, J. D., Sgro, C., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Starck, J. L., Strickman, M. S., Suson, D. J., Tajima, H., Takahashi, H., Takahashi, T., Tanaka, T., Thayer, J. G., Thompson, D. J., Tibaldo, L., Tibolla, O., Torres, D. F., Tosti, G., Tramacere, A., Uchiyama, Y., Usher, T. L., Etten, A. V., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wang, P., Watters, K., Winer, B. L., Wolff, M. T., Wood, K. S., Ylinen, T., Ziegler, M., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and High Energy Astrophys. & Astropart. Phys (API, FNWI)
- Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Astrophysics::High Energy Astrophysical Phenomena ,Fermi satellite ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,High Energy Gamma-ray Astronomy ,Pulsar ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010306 general physics ,Supernova remnant ,010303 astronomy & astrophysics ,Pulsars ,Astrophysics::Galaxy Astrophysics ,Physics ,Multidisciplinary ,[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Gamma ray ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Astrophysics - Astrophysics of Galaxies ,Neutron star ,Stars ,Supernova ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope ,X-ray pulsar - Abstract
Pulsars are rapidly-rotating, highly-magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently, only seven were observed to pulse in gamma rays and these were all discovered at other wavelengths. The Fermi Large Area Telescope makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics and the energetics of pulsar wind nebulae and supernova remnants., Comment: Corresponding authors: Michael Dormody, Paul S. Ray, Pablo M. Saz Parkinson, Marcus Ziegler
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- 2009
16. Detection of high-energy gamma-ray emission from the globular cluster 47 Tucanae with Fermi
- Author
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I. A. Grenier, Marco Ajello, Francesco Longo, J. B. Thayer, T. H. Burnett, M. Ziegler, A. Sander, N. Kawai, Yasunobu Uchiyama, L. Tibaldo, V. Vasileiou, Kent S. Wood, C. Meurer, Luca Latronico, P. Wang, Hartmut Sadrozinski, Gloria Spandre, Denis Bastieri, N.A. Webb, Alessandro Brez, Gino Tosti, C. C. Cheung, Igor V. Moskalenko, Luca Baldini, R. E. Hughes, Emanuele Bonamente, A. Chekhtman, T. L. Usher, J. Lande, Sylvain Guiriec, Olaf Reimer, D. Horan, Jean Ballet, A. Y. Rodriguez, V. Pelassa, M. Pierbattista, R. Dubois, J. M. Casandjian, P. L. Nolan, L. Guillemot, D. J. Thompson, W. B. Focke, Stefano Ciprini, C. Farnier, B. M. Baughman, Diego F. Torres, P. Spinelli, P. D. Smith, C. Favuzzi, M. Razzano, S. Rainò, Tsunefumi Mizuno, Eric Charles, P. M. Saz Parkinson, C. Monte, T. Ohsugi, D. Parent, S. Murgia, B. Lott, Julie McEnery, Neil Gehrels, Hiromitsu Takahashi, David Sánchez, Elliott D. Bloom, W. B. Atwood, D. J. Suson, F. Piron, Pascal Bruel, Ö. Çelik, A. S. Johnson, S. Cutini, Francesco Giordano, T. Kamae, T. Glanzman, Nicola Giglietto, Jürgen Knödlseder, Nicola Omodei, M. Pepe, W. N. Johnson, W. McConville, Claudia Cecchi, Y. Hanabata, Randall P. Johnson, Carmelo Sgrò, Riccardo Rando, Alice K. Harding, Dario Gasparrini, Peter F. Michelson, M. N. Mazziotta, J. G. Thayer, A. Tramacere, James Chiang, A. A. Abdo, E. Orlando, P. Lubrano, B. Giebels, F. Gargano, Roger Blandford, Roger W. Romani, E. Nuss, G. Godfrey, Sylvain Chaty, M. N. Lovellette, Jean-Luc Starck, T. Reposeur, P. A. Caraveo, J. E. Grove, David Paneque, Takaaki Tanaka, D. Dumora, J. P. Norris, Hideaki Katagiri, A. Morselli, Persis S. Drell, Yasushi Fukazawa, Johann Cohen-Tanugi, Nanda Rea, A. W. Borgland, M. Kuss, J. F. Ormes, M. S. Strickman, V. Vitale, M. Roth, J. Bregeon, E. Hays, Seth Digel, M. Brigida, F. de Palma, F. Kuehn, E. Do Couto E Silva, T. Ylinen, J. H. Panetta, Magnus Axelsson, M. Lemoine-Goumard, Brian L Winer, N. Vilchez, Hiroyasu Tajima, Tyrel J. Johnson, T. A. Porter, Jan Conrad, Markus Ackermann, R. A. Cameron, Morihiro Hayashida, A. A. Moiseev, Keith Bechtol, M. Dormody, R. Claus, P. Fusco, F. Loparco, Gudlaugur Johannesson, A. Makeev, W. Mitthumsiri, Matthew Kerr, Felix Ryde, M. E. Monzani, G. A. Caliandro, S. J. Fegan, Guido Barbiellini, M. Frailis, L. S. Rochester, B. Berenji, Ronaldo Bellazzini, S. Ritz, Charles D. Dermer, David Smith, S. Germani, A. Reimer, Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W. B., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Charles, E., Chaty, S., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Conrad, J., Cutini, S., Dermer, C. D., Palma, F. d., Digel, S. W., Dormody, M., Silva, E. D. E., Drell, P. S., Dubois, R., Dumora, D., Farnier, C., Favuzzi, C., Fegan, S. J., Focke, W. B., Frailis, M., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giebels, B., Giglietto, N., Giordano, F., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Horan, D., Hughes, R. E., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kawai, N., Kerr, M., Knodlseder, J., Kuehn, F., Kuss, M., Lande, J., Latronico, L., Lemoine Goumard, M., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Makeev, A., Mazziotta, M. N., Mcconville, W., Mcenery, J. E., Meurer, C., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nolan, P. L., Norris, J. P., Nuss, E., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pierbattista, M., Piron, F., Porter, T. A., Raino, S., Rando, R., Razzano, M., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rochester, L. S., Rodriguez, A. Y., Romani, R. W., Roth, M., Ryde, F., Sadrozinski, H. F. W., Sanchez, D., Sander, A., Parkinson, P. M. S., Sgro, C., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Starck, J. L., Strickman, M. S., Suson, D. J., Tajima, H., Takahashi, H., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, G., Tramacere, A., Uchiyama, Y., Usher, T. L., Vasileiou, V., Vilchez, N., Vitale, V., Wang, P., Webb, N., Winer, B. L., Wood, K. S., Ylinen, T., Ziegler, M., Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, High Energy Astrophys. & Astropart. Phys (API, FNWI), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,Fermi satellite ,Astrophysics ,01 natural sciences ,High Energy Gamma-ray Astronomy ,Globular Clusters ,Luminosity ,Pulsar ,Millisecond pulsar ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,education.field_of_study ,Multidisciplinary ,010308 nuclear & particles physics ,[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Neutron star ,Star cluster ,Globular cluster ,Fermi Gamma-ray Space Telescope - Abstract
Gamma-Ray Pulsar Bonanza Most of the pulsars we know about were detected through their radio emission; a few are known to pulse gamma rays but were first detected at other wavelengths (see the Perspective by Halpern ). Using the Fermi Gamma-Ray Space Telescope, Abdo et al. (p. 840 , published online 2 July; see the cover) report the detection of 16 previously unknown pulsars based on their gamma-ray emission alone. Thirteen of these coincide with previously unidentified gamma-ray sources, solving the 30-year-old mystery of their identities. Pulsars are fast-rotating neutron stars. With time they slow down and cease to radiate; however, if they are in a binary system, they can have their spin rates increased by mass transfer from their companion stars, starting a new life as millisecond pulsars. In another study, Abdo et al. (p. 845 ) report the detection of gamma-ray emission from the globular cluster 47 Tucanae, which is coming from an ensemble of millisecond pulsars in the cluster's core. The data imply that there are up to 60 millisecond pulsars in 47 Tucanae, twice as many as predicted by radio observations. In a further companion study, Abdo et al. (p. 848 , published online 2 July) searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars outside of stellar clusters, finding gamma-ray pulsations for eight of them. Their properties resemble those of other gamma-ray pulsars, suggesting that they share the same basic emission mechanism. Indeed, both sets of pulsars favor emission models in which the gamma rays are produced in the outer magnetosphere of the neutron star.
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- 2009
17. Synchrotron Self‐Compton Analysis of TeV X‐Ray‐Selected BL Lacertae Objects
- Author
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Markus Boettcher, Charles D. Dermer, and Justin D. Finke
- Subjects
Physics ,Jet (fluid) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Synchrotron radiation ,Astronomy and Astrophysics ,Electron ,Astrophysics ,Synchrotron ,law.invention ,Space and Planetary Science ,law ,Intergalactic travel ,Blazar ,Energy (signal processing) ,Flare - Abstract
We introduce a methodology for analysis of multiwavelength data from X-ray selected BL Lac (XBL) objects detected in the TeV regime. By assuming that the radio--through--X-ray flux from XBLs is nonthermal synchrotron radiation emitted by isotropically-distributed electrons in the randomly oriented magnetic field of a relativistic blazar jet, we obtain the electron spectrum. This spectrum is then used to deduce the synchrotron self-Compton (SSC) spectrum as a function of the Doppler factor, magnetic field, and variability timescale. The variability timescale is used to infer the comoving blob radius from light travel-time arguments, leaving only two parameters. With this approach, we accurately simulate the synchrotron and SSC spectrum of flaring XBLs in the Thomson through Klein-Nishina regimes. Photoabsorption by interactions with internal jet radiation and the intergalactic background light (IBL) is included. Doppler factors, magnetic fields, and absolute jet powers are obtained by fitting the {\em HESS} and {\em Swift} data of the recent giant TeV flare observed from \object{PKS 2155--304}. For the contemporaneous {\em Swift} and {\em HESS} data from 28 and 30 July 2006, respectively, Doppler factors $\gtrsim 60$ and absolute jet powers $\gtrsim 10^{46}$ ergs s$^{-1}$ are required for a synchrotron/SSC model to give a good fit to the data, for a low intensity of the IBL and a ratio of 10 times more energy in hadrons than nonthermal electrons. Fits are also made to a TeV flare observed in 2001 from Mkn 421 which require Doppler factors $\gtrsim 30$ and jet powers $\gtrsim 10^{45}$ erg s$^{-1}$., Comment: 44 pages, 11 figures. Substantial revisions. Accepted by ApJ
- Published
- 2008
18. Nonthermal Synchrotron Radiation from Gamma‐Ray Burst External Shocks and the X‐Ray Flares Observed withSwift
- Author
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Charles D. Dermer
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,X-ray ,Shell (structure) ,FOS: Physical sciences ,Spherical cap ,Synchrotron radiation ,Astronomy and Astrophysics ,Astrophysics ,Light curve ,Afterglow ,Shock (mechanics) ,Space and Planetary Science ,Gamma-ray burst ,Astrophysics::Galaxy Astrophysics - Abstract
An analysis of the interaction between a spherical relativistic blast-wave shell and a stationary cloud with a spherical cap geometry is performed assuming that the cloud width << x, where x is the distance of the cloud from the GRB explosion center. The interaction is divided into three phases: (1) a collision phase with both forward and reverse shocks; (2) a penetration phase when either the reverse shock has crossed the shell while the forward shock continues to cross the cloud, or vice versa; and (3) an expansion phase when, both shocks having crossed the cloud and shell, the shocked fluid expands. Temporally evolving spectral energy distributions (SEDs) are calculated for the problem of the interaction of a blast-wave shell with clouds that subtend large and small angles compared with the Doppler(-cone) angle 1/Gamma_0, where Gamma_0 is the coasting Lorentz factor. The Lorentz factor evolution of the shell/cloud collision is treated in the adiabatic limit. Behavior of the light curves and SEDs on, e.g., Gamma_0, shell-width parameter eta, and properties and locations of the cloud is examined. Short timescale variability (STV) in GRB light curves, including ~100 keV gamma-ray pulses observed with BATSE and delayed ~1 keV X-ray flares found with Swift, can be explained by emissions from an external shock formed by the GRB blast wave colliding with small density inhomogeneities in the "frozen pulse" approximation (eta -> 0, where Delta_0 + eta x/Gamma_0^2 is the blast-wave shell width), and perhaps in the thin-shell approximation (eta ~ 1/Gamma_0), but not when eta ~ 1. If this approximation is valid, then external shock processes could make the dominant prompt and afterglow emissions in GRB light curves, consistent with short delay two-step collapse models for GRBs., 19 pages, 11 figures, ApJ, in press (Aug. 20, 2008); includes revisions
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- 2008
19. The Hard VHE γ-Ray Emission in High-Redshift TeV Blazars: Comptonization of Cosmic Microwave Background Radiation in an Extended Jet?
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Charles D. Dermer, Justin D. Finke, and Markus Boettcher
- Subjects
Physics ,Spectral index ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Cosmic microwave background ,Gamma ray ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Redshift ,Space and Planetary Science ,Intergalactic travel ,High Energy Physics::Experiment ,Blazar ,Background radiation - Abstract
Observations of very-high-energy (VHE, E > 250 GeV) gamma-ray emission from several blazars at z > 0.1 have placed stringent constraints on the elusive spectrum and intensity of the intergalactic infrared background radiation (IIBR). Correcting their observed VHE spectrum for gamma-gamma absorption even by the lowest plausible level of the IIBR provided evidence for a very hard (photon spectral index Gamma_{ph} < 2) intrinsic source spectrum out to TeV energies. Such a hard VHE gamma-ray spectrum poses a serious challenge to the conventional synchrotron-self-Compton interpretation of the VHE emission of TeV blazars and suggests the emergence of a separate emission component beyond a few hundred GeV. Here we propose that such a very hard, slowly variable VHE emission component in TeV blazars may be produced via Compton upscattering of Cosmic Microwave Background (CMB) photons by shock-accelerated electrons in an extended jet. For the case of 1ES 1101-232, this component could dominate the bolometric luminosity of the extended jet if the magnetic fields are of the order of typical intergalactic magnetic fields B ~ 10 micro-Gauss and electrons are still being accelerated out to TeV energies gamma > 4 X 10^6) on kiloparsec scales along the jet., Accepted for publication in ApJ Letters
- Published
- 2008
20. Rapid X‐Ray Declines and Plateaus inSwiftGRB Light Curves Explained by a Highly Radiative Blast Wave
- Author
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Charles D. Dermer
- Subjects
Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Light curve ,Plateau (mathematics) ,Space and Planetary Science ,Radiative transfer ,Adiabatic process ,Gamma-ray burst ,Blast wave ,Fermi Gamma-ray Space Telescope - Abstract
GRB X-ray light curves display rapid declines followed by a gradual steepening or plateau phase in >~ 30% of GRBs in the Swift sample. Treating the standard relativistic blastwave model in a uniform circumburst medium, it is shown that if GRBs accelerate ultra-high energy cosmic rays through a Fermi mechanism, then the hadronic component can be rapidly depleted by means of photopion processes on time scales ~100 - 10^4 s after the GRB explosion. While discharging the hadronic energy in the form of ultra-high energy cosmic ray neutrals and escaping cosmic-ray ions, the blast wave goes through a strongly radiative phase, causing the steep declines observed with Swift. Following the discharge, the blast wave recovers its adiabatic behavior, forming the observed plateaus or slow declines. These effects are illustrated by calculations of model bolometric light curves. The results show that steep X-ray declines and plateau features occur when GRB sources take place in rather dense media, with n >~ 100 cc out to >~ 10^17 cm., 13 pages, 7 figs, minor changes from previous version; accepted for publication in ApJ
- Published
- 2007
21. Statistics of Cosmological Black Hole Jet Sources: Blazar Predictions for theGamma-Ray Large Area Space Telescope
- Author
-
Charles D. Dermer
- Subjects
Physics ,biology ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,biology.organism_classification ,Redshift ,Luminosity ,Lorentz factor ,symbols.namesake ,Space and Planetary Science ,Statistics ,symbols ,Egret ,Blazar ,BL Lac object - Abstract
A study of the statistics of cosmological black-hole jet sources is applied to EGRET blazar data, and predictions are made for GLAST. Black-hole jet sources are modeled as collimated relativistic plasma outflows with radiation beamed along the jet axis due to strong Doppler boosting. The comoving rate density of blazar flares is assumed to follow a blazar formation rate (BFR), modeled by analytic functions based on astronomical observations and fits to EGRET data. The redshift and size distributions of gamma-ray blazars observed with EGRET, separated into BL Lac object (BL) and flat spectrum radio quasar (FSRQ) distributions, are fit with monoparametric functions for the distributions of the jet Lorentz factor \Gamma, comoving directional power l'_e, and spectral slope. A BFR factor ~10 x greater at z ~ 1 than at present is found to fit the FSRQ data. A smaller comoving rate density and greater luminosity of BL flares at early times compared to the present epoch fits the BL data. Based on the EGRET observations, ~1000 blazars consisting of ~800 FSRQs and FR2 radio galaxies and ~200 BL Lacs and FR1 radio galaxies will be detected with GLAST during the first year of the mission. Additional AGN classes, such as hard-spectrum BL Lacs that were mostly missed with EGRET, could add more GLAST sources. The FSRQ and BL contributions to the EGRET gamma-ray background at 1 GeV are estimated at the level of ~10 - 15% and ~2 - 4%, respectively. EGRET and GLAST sensitivities to blazar flares are considered in the optimal case, and a GLAST analysis method for blazar detection is outlined.
- Published
- 2007
22. High-energy cosmology
- Author
-
Charles D. Dermer
- Subjects
Physics ,Luminous infrared galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Cosmology ,Galaxy ,Space and Planetary Science ,Observatory ,Milagro ,Neutrino ,Blazar ,Astrophysics::Galaxy Astrophysics - Abstract
Our knowledge of the high-energy universe is undergoing a period of rapid change as new astronomical detectors of high-energy radiation start to operate at their design sensitivities. Now is a boomtime for high-energy astrophysics, with new discoveries from Swift and HESS, results from MAGIC and VERITAS starting to be reported, the upcoming launches of the gamma-ray space telescopes GLAST and AGILE, and anticipated data releases from IceCube and Auger. A formalism for calculating statistical properties of cosmological gamma-ray sources is presented. Application is made to model calculations of the statistical distributions of gamma-ray and neutrino emission from (i) beamed sources, specifically, long-duration GRBs, blazars, and extagalactic microquasars, and (ii) unbeamed sources, including normal galaxies, starburst galaxies and clusters. Expressions for the integrated intensities of faint beamed and unbeamed high-energy radiation sources are also derived. A toy model for the background intensity of radiation from dark-matter annihilation taking place in the early universe is constructed. Estimates for the gamma-ray fluxes of local group galaxies, starburst, and infrared luminous galaxies are briefly reviewed. Because the brightest extragalactic gamma-ray sources are flaring sources, and these are the best targets for sources of PeV -- EeV neutrinos and ultra-high energy cosmic rays, rapidly slewing all-sky telescopes like MAGIC and an all-sky gamma-ray observatory beyond Milagro will be crucial for optimal science return in the multi-messenger age., 10 pages, 3 figs, accepted for publication in the Barcelona Conference on Multimessenger Astronomy; corrected eq. 27, revised Fig. 3, added 2 refs
- Published
- 2007
23. A class of exact solutions to the force-free, axisymetric, stationary magnetosphere of a Kerr black hole
- Author
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Govind Menon and Charles D. Dermer
- Subjects
Physics ,Angular momentum ,Constraint algorithm ,Exact solutions in general relativity ,Physics and Astronomy (miscellaneous) ,Rotating black hole ,Astrophysics::High Energy Astrophysical Phenomena ,Blandford–Znajek process ,Magnetosphere ,Angular velocity ,Function (mathematics) ,Astrophysics ,Mathematical physics - Abstract
We analyze the constraint equation giving allowed solutions describing fields and currents in a force-free magnetosphere around a rotating black hole. Utilizing the divergence properties of the energy and angular-momentum fluxes for physically allowed solutions, we conclude that poloidal surfaces are independent of the radial coordinate for large values of $r$. Using this fact and the Znajek regularity condition, we explicitly derive all possible exact solutions admitted by the constraint equation for $r$ independent poloidal surfaces, which are given in terms of the electromagnetic angular velocity function $\Omega = 1/a\sin^2\theta$, where $a$ is the angular momentum per unit mass of the black hole.
- Published
- 2007
24. Near-Equipartition Jets with Log-Parabola Electron Energy Distribution and the Blazar Spectral-Index Diagrams
- Author
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Justin D. Finke, Dahai Yan, Charles D. Dermer, Li Zhang, and Benoit Lott
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Spectral index ,Photon ,Astrophysics::High Energy Astrophysical Phenomena ,Isotropy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Synchrotron ,Spectral line ,law.invention ,Space and Planetary Science ,law ,Blazar ,Astrophysics - High Energy Astrophysical Phenomena ,Equipartition theorem ,BL Lac object - Abstract
Fermi-LAT analyses show that the gamma-ray photon spectral indices Gamma_gamma of a large sample of blazars correlate with the vFv peak synchrotron frequency v_s according to the relation Gamma_gamma = d - k log v_s. The same function, with different constants d and k, also describes the relationship between Gamma_gamma and peak Compton frequency v_C. This behavior is derived analytically using an equipartition blazar model with a log-parabola description of the electron energy distribution (EED). In the Thomson regime, k = k_EC = 3b/4 for external Compton processes and k = k_SSC = 9b/16 for synchrotron self-Compton (SSC) processes, where b is the log-parabola width parameter of the EED. The BL Lac object Mrk 501 is fit with a synchrotron/SSC model given by the log-parabola EED, and is best fit away from equipartition. Corrections are made to the spectral-index diagrams for a low-energy power-law EED and departures from equipartition, as constrained by absolute jet power. Analytic expressions are compared with numerical values derived from self-Compton and external Compton scattered gamma-ray spectra from Ly alpha broad-line region and IR target photons. The Gamma_gamma vs. v_s behavior in the model depends strongly on b, with progressively and predictably weaker dependences on gamma-ray detection range, variability time, and isotropic gamma-ray luminosity. Implications for blazar unification and blazars as ultra-high energy cosmic-ray sources are presented. Arguments by Ghisellini et al. (2014) that the jet power exceeds the accretion luminosity depend on the doubtful assumption that we are viewing at the Doppler angle., 13 pages, 9 figures, accepted to ApJ; includes corrections in response to referee report, including consideration of a model with a low-energy power law
- Published
- 2015
25. Impact of Fermi-LAT and AMS-02 results on cosmic-ray astrophysics
- Author
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Charles D. Dermer
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,QC1-999 ,Astrophysics::High Energy Astrophysical Phenomena ,Bremsstrahlung ,FOS: Physical sciences ,Cosmic ray ,Electron ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxy ,Spectral line ,Interstellar medium ,Emissivity ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
This article reviews a few topics relevant to Galactic cosmic-ray astrophysics, focusing on the recent AMS-02 data release and Fermi Large Area Telescope data on the diffuse Galactic gamma-ray emissivity. Calculations are made of the diffuse cosmic-ray induced p+p --> pi^0 --> 2 gamma spectra, normalized to the AMS-02 cosmic-ray proton spectrum at ~ 10 - 100 GV, with and without a hardening in the cosmic-ray proton spectrum at rigidities R >~ 300 GV. A single power-law momentum "shock" spectrum for the local interstellar medium cosmic-ray proton spectrum cannot be ruled out from the gamma-ray emissivity data alone without considering the additional contribution of electron bremsstrahlung. Metallicity corrections are discussed, and a maximal range of nuclear enhancement factors from 1.52 to 1.92 is estimated.Origins of the 300 GV cosmic-ray proton and alpha-particle hardening are discussed., In SuGAR2015, Searching for the sources of Galactic Cosmic Rays, University of Geneva, 21-23 January 2015; eds. E. Prandini & S. Toscano; 6 pages, 3 figures
- Published
- 2015
- Full Text
- View/download PDF
26. Models of Very-High-Energy Gamma-Ray Emission from the Jets of Microquasars: Orbital Modulation
- Author
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Markus Böttcher and Charles D. Dermer
- Subjects
Physics ,Jet (fluid) ,Photon ,Astrophysics::High Energy Astrophysical Phenomena ,Compton scattering ,Gamma ray ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Electron ,Cosmology ,Synchrotron ,law.invention ,Space and Planetary Science ,law ,High Energy Physics::Experiment ,Astrophysics::Earth and Planetary Astrophysics ,Absorption (electromagnetic radiation) ,Astrophysics::Galaxy Astrophysics - Abstract
The recent detection of very-high-energy (GeV — TeV) γ-ray emission from the Galactic black-hole candidate and microquasar LS 5039 has sparked renewed interest in jet models for the high-energy emission in those objects. In this work, we have focused on models in which the high-energy emission results from synchrotron and Compton emission by relativistic electrons in the jet (leptonic jet models). Particular attention has been paid to a possible orbital modulation of the high-energy emission due to azimuthal asymmetries caused by the presence of the companion star. Both orbitalphase dependent γγ absorption and Compton scattering of optical/UV photons from the companion star may lead to an orbital modulation of the gamma-ray emission. We make specific predictions which should be testable with refined data from HESS and the upcoming GLAST mission.
- Published
- 2006
27. Time‐dependent Stochastic Particle Acceleration in Astrophysical Plasmas: Exact Solutions Including Momentum‐dependent Escape
- Author
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Peter A. Becker, Charles D. Dermer, and Truong Le
- Subjects
Physics ,Scattering ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Electron ,Charged particle ,Momentum diffusion ,Particle acceleration ,Momentum ,Acceleration ,Space and Planetary Science ,Quantum electrodynamics ,Magnetohydrodynamics - Abstract
Stochastic acceleration of charged particles due to interactions with magnetohydrodynamic (MHD) plasma waves is the dominant process leading to the formation of the high-energy electron and ion distributions in a variety of astrophysical systems. Collisions with the waves influence both the energization and the spatial transport of the particles, and therefore it is important to treat these two aspects of the problem in a self-consistent manner. We solve the representative Fokker-Planck equation to obtain a new, closed-form solution for the time-dependent Green's function describing the acceleration and escape of relativistic ions interacting with Alfven or fast-mode waves characterized by momentum diffusion coefficient $D(p)\propto p^q$ and mean particle escape timescale $t_esc(p) \propto p^{q-2}$, where $p$ is the particle momentum and $q$ is the power-law index of the MHD wave spectrum. In particular, we obtain solutions for the momentum distribution of the ions in the plasma and also for the momentum distribution of the escaping particles, which may form an energetic outflow. The general features of the solutions are illustrated via examples based on either a Kolmogorov or Kraichnan wave spectrum. The new expressions complement the results obtained by Park and Petrosian, who presented exact solutions for the hard-sphere scattering case ($q=2$) in addition to other scenarios in which the escape timescale has a power-law dependence on the momentum. Our results have direct relevance for models of high-energy radiation and cosmic-ray production in astrophysical environments such as $\gamma$-ray bursts, active galaxies, and magnetized coronae around black holes., Comment: Accepted for publication in ApJ
- Published
- 2006
28. Time‐dependent Synchrotron and Compton Spectra from Jets of Microquasars
- Author
-
Swati Gupta, Markus Boettcher, and Charles D. Dermer
- Subjects
Physics ,Jet (fluid) ,Photon ,Radiative cooling ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Compton scattering ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Synchrotron ,Spectral line ,law.invention ,Space and Planetary Science ,law ,Blazar ,Astrophysics::Galaxy Astrophysics - Abstract
Jet models for the high-energy emission of Galactic X-ray binary sources have regained significant interest with detailed spectral and timing studies of the X-ray emission from microquasars, the recent detection by the HESS collaboration of very-high-energy gamma-rays from the microquasar LS~5039, and the earlier suggestion of jet models for ultraluminous X-ray sources observed in many nearby galaxies. Here we study the synchrotron and Compton signatures of time-dependent electron injection and acceleration, adiabatic and radiative cooling, and different jet geometries in the jets of Galactic microquasars. Synchrotron, synchrotron-self-Compton, and external-Compton radiation processes with soft photons provided by the companion star and the accretion disk are treated. An analytical solution is presented to the electron kinetic equation for general power-law geometries of the jets for Compton scattering in the Thomson regime. We pay particular attention to predictions concerning the rapid flux and spectral variability signatures expected in a variety of scenarios, making specific predictions concerning possible spectral hysteresis, similar to what has been observed in several TeV blazars. Such predictions should be testable with dedicated monitoring observations of Galactic microquasars and ultraluminous X-ray sources using Chandra and/or XMM-Newton., Accepted for publication in ApJ; 37 manuscript pages, including 10 eps figures; uses AASTeX macros
- Published
- 2006
29. Cosmic Rays from Gamma-Ray Bursts in the Galaxy
- Author
-
Charles D. Dermer and Jeremy M. Holmes
- Subjects
Physics ,Scattering ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Magnetic field ,Auger ,Space and Planetary Science ,Observatory ,Irradiation ,Gamma-ray burst - Abstract
The rate of terrestrial irradiation events by galactic gamma-ray bursts (GRBs) is estimated using recent standard-energy results. We assume that GRBs accelerate high-energy cosmic rays, and present results of three-dimensional simulations of cosmic rays moving in the Galactic magnetic field and diffusing through pitch-angle scattering. An on-axis GRB extinction event begins with a powerful prompt gamma-ray and neutron pulse, followed by a longer-lived phase from cosmic-ray protons and neutron-decay protons that diffuse towards Earth. Our results force a reinterpretation of reported ~ 10^{18} eV cosmic-ray anisotropies and offer a rigorous test of the model where high-energy cosmic rays originate from GRBs, which will soon be tested with the Auger Observatory., 9 pages, 4 figures, ApJ Letters, in press. Clarified limit of test-particle approximation, prediction that Auger will not confirm SUGAR source. (Data may not appear onscreen at low magnification.) Simulations at http://heseweb.nrl.navy.mil/gamma/~dermer/invest/sim/index.htm
- Published
- 2005
30. Curvature Effects in Gamma‐Ray Burst Colliding Shells
- Author
-
Charles D. Dermer
- Subjects
Physics ,Jet (fluid) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Energy flux ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Photon energy ,Curvature ,Afterglow ,Lorentz factor ,symbols.namesake ,Space and Planetary Science ,symbols ,Atomic physics ,Gamma-ray burst ,Adiabatic process - Abstract
An elementary kinematic model for emission produced by relativistic spherical colliding shells is studied. The case of a uniform blast-wave shell with jet opening angle $\theta_j \gg 1/\Gamma$ is considered, where $\Gamma$ is the Lorentz factor of the emitting shell. The shell, with comoving width $\Delta r^\prime$, is assumed to be illuminated for a comoving time $\Delta t^\prime$ and to radiate a broken power-law $\nu L_\nu$ spectrum peaking at comoving photon energy $\e_{pk,0}^{\prime}$. Synthetic GRB pulses are calculated, and the relation between energy flux and internal comoving energy density is quantified. Curvature effects dictate that the measured $\nu F_\nu$ flux at the measured peak photon energy $\e_{pk}$ is proportional to $\e^3_{pk}$ in the declining phase of a GRB pulse. Possible reasons for discrepancy with observations are discussed, including adiabatic and radiative cooling processes that extend the decay timescale, a nonuniform jet, or the formation of pulses by external shock processes. A prediction of a correlation between prompt emission properties and times of the optical afterglow beaming breaks is made for a cooling model, which can be tested with Swift., Comment: 13 pages, 5 figures, added back-of-envelope estimate of curvature relation, minor corrections, ApJ, in press, v. 614, 10 Oct 2004
- Published
- 2004
31. Synchrotron versus Compton Interpretations for Extended X‐Ray Jets
- Author
-
A. Atoyan and Charles D. Dermer
- Subjects
Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Cosmic microwave background ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Electron ,Astrophysics ,Synchrotron ,law.invention ,Space and Planetary Science ,law ,Neutrino ,Blazar ,Lepton - Abstract
A widely discussed explanation for the origin of the X-ray emission observed from knots in extended quasar jets with the Chandra X-ray Obseratory is Compton-scattered CMBR by electrons with Lorentz factors $\gamma^\prime \sim 10^2$. This model faces difficulties in terms of total energy requirements, and in explaining the spatial profiles of the radio, optical, and X-ray knots in sources such as PKS 0637-752, 3C 273, or PKS 1127-145. These difficulties can be resolved in the framework of one- and two-component synchrotron models. We propose a model where the broad band radio to X-ray synchrotron emission in quasar jets is powered by collimated beams of ultra-high energy neutrons and gamma-rays formed in the sub-parsec scale jets. The decay of the neutral beam in the intergalactic medium drives relativistic shocks to accelerate nonthermal electrons out of the ambient medium. A second synchrotron component arises from the injection of leptons with Lorentz factors $\gg 10^7$ that appear in the extended jet in the process of decay of ultra-high energy gamma rays. This approach could account for qualitative differences in the extended X-ray jets of FR1 and FR2 galaxies. Detection of high-energy neutrinos from blazars and core-dominated quasars will provide strong evidence for this model., Comment: 12 pages, 2 figures; accepted in ApJ
- Published
- 2004
32. Neutral beam model for the anomalous γ-ray emission component in GRB 941017
- Author
-
Charles D. Dermer and A. Atoyan
- Subjects
Physics ,Photon ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Gamma ray ,FOS: Physical sciences ,Synchrotron radiation ,Astronomy and Astrophysics ,Electron ,Astrophysics ,Radiation ,Space and Planetary Science ,Physics::Accelerator Physics ,Neutron ,Neutrino ,Gamma-ray burst - Abstract
Gonz��lez et al. (2003) have reported the discovery of an anomalous radiation component from ~ 1 -- 200 MeV in GRB 941017. This component varies independently of and contains > 3 times the energy found in the prompt ~ 50 keV -- 1 MeV radiation component that is well described by the relativistic synchrotron-shock model. Acceleration of hadrons to very high energies can give rise to two additional emission components, one produced inside the GRB blast wave and one associated with an escaping beam of ultra-high energy (UHE; > 10^{14} eV) neutrons, gamma rays, and neutrinos. The first component extending to ~ 100 MeV is from a pair-photon cascade induced by photomeson processes with the internal synchrotron photons coincident with the prompt radiation. The outflowing UHE neutral beam can undergo further interactions with external photons from the backscattered photon field to produce a beam of hyper-relativistic electrons that lose most of their energy during a fraction of a gyroperiod in the assumed Gauss-strength magnetic fields of the circumburst medium. The synchrotron radiation of these electrons has a spectrum with vF_v index equal to +1 that can explain the anomalous component in GRB 941017. This interpretation of the spectrum of GRB 941017 requires a high baryon load of the accelerated particles in GRB blast waves. It implies that most of the radiation associated with the anomalous component is released at > 500 MeV, suitable for observations with GLAST, and with a comparable energy fluence in ~100 TeV neutrinos that could be detected with a km-scale neutrino telescope like IceCube., 4 pages, 1 figure, minor corrections, Astronomy and Astrophysics Letters, in press
- Published
- 2004
33. Transformation Properties of External Radiation Fields, Energy‐Loss Rates and Scattered Spectra, and a Model for Blazar Variability
- Author
-
Reinhard Schlickeiser and Charles D. Dermer
- Subjects
Physics ,Soft photon ,Field (physics) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Cosmic microwave background ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Plasma ,Radiation ,Spectral line ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Blazar ,Astrophysics::Galaxy Astrophysics - Abstract
We treat transformation properties of external radiation fields in the proper frame of a plasma moving with constant speed. The specific spectral energy densities of external isotropic and accretion-disk radiation fields are derived in the comoving frame of relativistic outflows, such as those thought to be found near black-hole jet and gamma-ray burst sources. Nonthermal electrons and positrons Compton-scatter this radiation field, and high-energy protons and ions interact with this field through photomeson and photopair production. We revisit the problem of the Compton-scattered spectrum associated with an external accretion-disk radiation field, and clarify a past treatment by the authors. Simple expressions for energy-loss rates and Thomson-scattered spectra are given for ambient soft photon fields consisting either of a surrounding external isotropic monochromatic radiation field, or of an azimuthally symmetric, geometrically thin accretion-disk radiation field. A model for blazar emission is presented that displays a characteristic spectral and variability behavior due to the presence of a direct accretion-disk component. The disk component and distinct flaring behavior can be bright enough to be detected from flat spectrum radio quasars with {\it GLAST}. Spectral states of blazars are characterized by the relative importance of the accretion-disk and scattered radiation fields and, in the extended jet, by the accretion disk, inner jet, and cosmic microwave background radiation fields., Comment: 43 pages, 12 figures, ApJ, in press; includes improvements in response to referee report, added references, section of detectability with GLAST
- Published
- 2002
34. Neutrino, Neutron, and Cosmic‐Ray Production in the External Shock Model of Gamma‐Ray Bursts
- Author
-
Charles D. Dermer
- Subjects
Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Cosmic microwave background ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Radiation ,Luminosity ,Supernova ,Space and Planetary Science ,Neutron ,Neutrino ,Gamma-ray burst ,Astrophysics::Galaxy Astrophysics - Abstract
The hypothesis that ultra-high energy (>~ 10^19 eV) cosmic rays (UHECRs) are accelerated by gamma-ray burst (GRB) blast waves is assumed to be correct. Implications of this assumption are then derived for the external shock model of gamma-ray bursts. The evolving synchrotron radiation spectrum in GRB blast waves provides target photons for the photomeson production of neutrinos and neutrons. Decay characteristics and radiative efficiencies of the neutral particles that escape from the blast wave are calculated. The diffuse high-energy GRB neutrino background and the distribution of high-energy GRB neutrino events are calculated for specific parameter sets, and a scaling relation for the photomeson production efficiency in surroundings with different densities is derived. GRBs provide an intense flux of high-energy neutrons, with neutron-production efficiencies exceeding ~ 1% of the total energy release. The radiative characteristics of the neutron beta-decay electrons from the GRB "neutron bomb" are solved in a special case. Galaxies with GRB activity should be surrounded by radiation halos of ~ 100 kpc extent from the outflowing neutrons, consisting of a nonthermal optical/X-ray synchrotron component and a high-energy gamma-ray component from Compton-scattered microwave background radiation. The luminosity of sources of GRBs and relativistic outflows in L* galaxies such as the Milky Way is at the level of ~10^40+-1 ergs/s. This is sufficient to account for UHECR generation by GRBs. We briefly speculate on the possibility that hadronic cosmic rays originate from the subset of supernovae that collapse to form relativistic outflows and GRBs. (abridged), 53 pages, 8 figures, ApJ, in press, 574, July 20, 2002. Substantial revision, previous Appendix expanded to ApJ, 556, 479; cosmic ray origin speculations to Heidelberg (astro-ph/001054) and Hamburg ICRC (astro-ph/0202254) proceedings
- Published
- 2002
35. Transient Absorption Features in Gamma‐Ray Bursts and Their Implications for Gamma‐Ray Burst Progenitors
- Author
-
M. Boettcher, Charles D. Dermer, and Chris L. Fryer
- Subjects
Physics ,Supernova ,Line-of-sight ,Space and Planetary Science ,Feature (computer vision) ,Ultrafast laser spectroscopy ,Astronomy and Astrophysics ,Observable ,Astrophysics ,Absorption (electromagnetic radiation) ,Ejecta ,Gamma-ray burst - Abstract
The recent detection of a transient absorption feature in the prompt emission of GRB 990705 has sparked multiple attempts to fit this feature in terms of photoelectric absorption or resonance scattering out of the line of sight to the observer. However, the physical conditions required to reproduce the observed absorption feature turn out to be rather extreme compared to the predictions of current GRB progenitor models. In particular, strong clumping of ejecta from the GRB progenitor seems to be required. Using detailed 3D hydrodynamic simulations of supernova explosions as a guideline, we have investigated the dynamics and structure of pre-GRB ejecta predicted in various GRB progenitor models. Based on our results, combined with population synthesis studies relevant to the He-merger model, we estimate the probability of observing X-ray absorption features as seen in GRB 990705 to << 1 %. Alternatively, if the supranova model is capable of producing highly collimated long-duration GRBs, it may be a more promising candidate to produce observable, transient X-ray absorption features.
- Published
- 2002
36. EQUIPARTITION GAMMA-RAY BLAZARS AND THE LOCATION OF THE GAMMA-RAY EMISSION SITE IN 3C 279
- Author
-
Catherine Boisson, Benoit Lott, Matteo Cerruti, Charles D. Dermer, Andreas Zech, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), and Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Luminosity ,symbols.namesake ,0103 physical sciences ,Blazar ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,ComputingMilieux_MISCELLANEOUS ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,[PHYS]Physics [physics] ,010308 nuclear & particles physics ,Gamma ray ,Astronomy and Astrophysics ,Quasar ,Lorentz factor ,13. Climate action ,Space and Planetary Science ,Eddington luminosity ,symbols ,Astrophysics - High Energy Astrophysical Phenomena ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Fermi Gamma-ray Space Telescope - Abstract
Blazar spectral models generally have numerous unconstrained parameters, leading to ambiguous values for physical properties like Doppler factor delta or fluid magnetic field B'. To help remedy this problem, a few modifications of the standard leptonic blazar jet scenario are considered. First, a log-parabola function for the electron distribution is used. Second, analytic expressions relating energy loss and kinematics to blazar luminosity and variability, written in terms of equipartition parameters, imply delta, B', and the principal electron Lorentz factor gamma'_pk. The external radiation field in a blazar is approximated by Ly alpha radiation from the broad line region (BLR) and ~0.1 eV infrared radiation from a dusty torus. When used to model 3C 279 SEDs from 2008 and 2009 reported by Hayashida et al. (2012), we derive delta ~ 20-30, B' ~ few G, and total (IR + BLR) external radiation field energy densities u ~ 0.01 - 0.001 erg/cm^3, implying an origin of the gamma-ray emission site in 3C 279 at the outer edges of the BLR. This is consistent with the gamma-ray emission site being located at a distance R ~ 5 GeV gamma-ray emission observed with Fermi LAT from 3C 279 challenge the model, opening the possibility of hadronic origins of the emission. For low hadronic content, absolute jet powers of ~10% of the Eddington luminosity are calculated., Comment: 17 pages, 8 figures. Accepted from publication in ApJ
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- 2014
37. Fermi large area telescope observations of blazar 3C 279 occultations by the sun
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J. S. Perkins, Nicola Giglietto, A. P. Waite, Igor V. Moskalenko, Brian L Winer, Olaf Reimer, A. A. Moiseev, Soebur Razzaque, M. N. Lovellette, S. Germani, K. S. Wood, P. A. Caraveo, Persis S. Drell, A. W. Borgland, Sylvain Guiriec, C. Favuzzi, E. Hays, C. Romoli, T. L. Usher, Claudia Cecchi, F. Loparco, P. Lubrano, Daniel Sánchez, Hiromitsu Takahashi, M. Hayashida, Alex Drlica-Wagner, S. Murgia, Rodrigo Nemmen, Keith Bechtol, F. D'Ammando, R. Claus, M. E. Monzani, F. Piron, Takaaki Tanaka, E. Orlando, T. Ohsugi, Eleonora Troja, Miranda Jackson, A. Reimer, Daniela Hadasch, T. Jogler, G. Pivato, Nicola Omodei, M. Razzano, Francesco Longo, Paolo Giommi, S. Rainò, A. Morselli, V. Vitale, Tsunefumi Mizuno, L. Tibaldo, J. Bregeon, S. Larsson, M. N. Mazziotta, S. Buson, R. A. Cameron, Steven Ritz, R. E. Hughes, Denis Bastieri, Dario Gasparrini, R. C. G. Chaves, P. Bruel, G. Godfrey, J. E. Grove, Miguel A. Sánchez-Conde, Yasushi Fukazawa, R. Buehler, J. Lande, James Chiang, F. Gargano, Roger Blandford, A. Chekhtman, Peter F. Michelson, Marcello Giroletti, C. C. Cheung, J. Mehault, Justin Vandenbroucke, M. Tinivella, W. B. Focke, P. Spinelli, Guido Barbiellini, Francesco Giordano, C. Monte, Johann Cohen-Tanugi, T. Glanzman, P. Fusco, E. J. Siskind, M. Orienti, G. A. Caliandro, I. A. Grenier, V. Vasileiou, E. Cavazzuti, Seth Digel, Gloria Spandre, D. Prokhorov, Stefano Ciprini, Zhenwei Yang, Carmelo Sgrò, E. Nuss, David Paneque, M. Kuss, E. Do Couto E Silva, A. Franckowiak, A. De Angelis, G. Tosti, Giacomo Vianello, Charles D. Dermer, Jürgen Knödlseder, Ronaldo Bellazzini, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Blandford RD, Borgland AW, Bregeon J, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cavazzuti E, Cecchi C, Chaves RCG, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, DAmmando F, de Angelis A, Dermer CD, Digel SW, Silva EDE, Drell PS, Drlica-Wagner A, Favuzzi C, Focke WB, Franckowiak A, Fukazawa Y, Fusco P, Gargano F, Gasparrini D, Germani S, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guiriec S, Hadasch D, Hayashida M, Hays E, Hughes RE, Jackson MS, Jogler T, Knodlseder J, Kuss M, Lande J, Larsson S, Longo F, Loparco F, Lovellette MN, Lubrano P, Mazziotta MN, Mehault J, Michelson PF, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nemmen R, Nuss E, Ohsugi T, Omodei N, Orienti M, Orlando E, Paneque D, Perkins JS, Piron F, Pivato G, Prokhorov D, Raino S, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Romoli C, Sanchez-Conde M, Sanchez DA, Sgro C, Siskind EJ, Spandre G, Spinelli P, Takahashi H, Tanaka T, Tibaldo L, Tinivella M, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Winer BL, Wood KS, Yang Z, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), BARBIELLINI AMIDEI, Guido, Bastieri, D., Bechtol, K., Bellazzini, R., Blandford, R. D., Borgland, A. W., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Cavazzuti, E., Cecchi, C., Chaves, R. C. G., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., D'Ammando, F., de Angelis, A., Dermer, C. D., Digel, S. W., Silva, E. do Couto e., Drell, P. S., Drlica Wagner, A., Favuzzi, C., Focke, W. B., Franckowiak, A., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Germani, S., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hadasch, D., Hayashida, M., Hays, E., Hughes, R. E., Jackson, M. S., Jogler, T., Knödlseder, J., Kuss, M., Lande, J., Larsson, S., Longo, Francesco, Loparco, F., Lovellette, M. N., Lubrano, P., Mazziotta, M. N., Mehault, J., Michelson, P. F., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nemmen, R., Nuss, E., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Perkins, J. S., Piron, F., Pivato, G., Prokhorov, D., Rainò, S., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Ritz, S., Romoli, C., Sánchez Conde, M., Sanchez, D. A., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Takahashi, H., Tanaka, T., Tibaldo, L., Tinivella, M., Tosti, G., Troja, E., Usher, T. L., Vandenbroucke, J., Vasileiou, V., Vianello, G., Vitale, V., Waite, A. P., Winer, B. L., Wood, K. S., and Yang, Z.
- Subjects
Nuclear and High Energy Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Sun: X-rays, gamma rays ,01 natural sciences ,Article ,law.invention ,quasars: individual (3C 279) ,Telescope ,Spitzer Space Telescope ,law ,0103 physical sciences ,occultations ,individual: 3C 279 [quasars] ,astroparticle physics ,gamma rays: general ,Space and Planetary Science ,Astronomy and Astrophysics ,Astrophysics::Solar and Stellar Astrophysics ,quasars: individual: 3C 279 ,Blazar ,010303 astronomy & astrophysics ,Light dark matter ,Astroparticle physics ,Physics ,010308 nuclear & particles physics ,X-ray [Sun] ,astroparticle physic ,Astronomy ,Quasar ,gamma-rays ,Sun: X-rays ,gamma rays ,occultation ,Halo ,Astrophysics::Earth and Planetary Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,general [gamma rays] ,Fermi Gamma-ray Space Telescope - Abstract
Observations of occultations of bright. gamma-ray sources by the Sun may reveal predicted pair halos around blazars and/or new physics, such as, e.g., hypothetical light dark matter particles-axions. We use Fermi Gamma-Ray Space Telescope (Fermi) data to analyze four occultations of blazar 3C 279 by the Sun on October 8 each year from 2008 to 2011. A combined analysis of the observations of these occultations allows a point-like source at the position of 3C 279 to be detected with significance of approximate to 3 sigma, but does not reveal any significant excess over the flux expected from the quiescent Sun. The likelihood ratio test rules out complete transparency of the Sun to the blazar. gamma-ray emission at a 3s confidence level.
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- 2014
38. Impulsive and long duration high-energy gamma-ray emission from the very bright 2012 march 7 solar flares
- Author
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T. Jogler, Nicola Omodei, Luca Latronico, Charles D. Dermer, M. Tinivella, E. Do Couto E Silva, Denis Bastieri, G. Pivato, Vahé Petrosian, E. J. Siskind, Johann Cohen-Tanugi, Hiromitsu Takahashi, J. Lande, M. E. Monzani, R. J. Murphy, M. Brigida, Elisabetta Bissaldi, R. Buehler, Brian L Winer, E. Orlando, Stefano Ciprini, Jürgen Knödlseder, J. H. Panetta, T. Glanzman, Alice Allafort, Yoshiyuki Inoue, J. S. Perkins, Seth Digel, Dario Gasparrini, W. N. Johnson, F. Piron, A. A. Moiseev, Masanori Ohno, Nicola Giglietto, Ronaldo Bellazzini, Paolo Giommi, J. F. Ormes, André Schulz, Rodrigo Nemmen, T. Ohsugi, Eleonora Troja, Julie McEnery, Miranda Jackson, D. Horan, S. Murgia, Emanuele Bonamente, G. A. Caliandro, I. A. Grenier, A. Reimer, A. Chekhtman, Peter F. Michelson, Marcello Giroletti, S. Larsson, Alex Drlica-Wagner, F. Loparco, Gudlaugur Johannesson, X. Hou, G. Tosti, Daniela Hadasch, W. B. Focke, M. Hayashida, P. Spinelli, F. Gargano, Gloria Spandre, Justin Vandenbroucke, Benoit Lott, M. Roth, M. Mayer, M. Razzano, Giacomo Vianello, Melissa Pesce-Rollins, Filippo D'Ammando, Francesco Giordano, Marco Ajello, R. E. Hughes, Guido Barbiellini, J. B. Thayer, M. N. Lovellette, P. A. Caraveo, R. Desiante, T. J. Brandt, Persis S. Drell, D. L. Wood, L. R. Cominsky, Zhenwei Yang, Igor V. Moskalenko, R. A. Cameron, Francesco Longo, T. Kamae, T. A. Porter, Michael David Werner, E. Hays, M. Orienti, V. Vasileiou, D. Paneque, Olaf Reimer, D. J. Thompson, P. Fusco, P. Bruel, Carmelo Sgrò, Riccardo Rando, Jan Conrad, S. Buson, G. Godfrey, R. Claus, T. L. Usher, A. Morselli, V. Vitale, L. Tibaldo, E. Nuss, C. Monte, C. Favuzzi, J. Bregeon, D. Kocevski, F. de Palma, S. Rainò, Tsunefumi Mizuno, M. Kuss, Takeshi Nakamori, A. S. Johnson, S. Cutini, G. Chiaro, J. E. Grove, Yasushi Fukazawa, Andrea Albert, S. Germani, K. S. Wood, James Chiang, A. Franckowiak, Luca Baldini, J. G. Thayer, M. N. Mazziotta, Sylvain Guiriec, Claudia Cecchi, Eric Charles, P. Lubrano, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Ajello M, Albert A, Allafort A, Baldini L, Barbiellini G, Bastieri D, Bellazzini R, Bissaldi E, Bonamente E, Brandt TJ, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cecchi C, Charles E, Chekhtman A, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Conrad J, Cutini S, DAmmando F, de Palma F, Dermer CD, Desiante R, Digel SW, Silva EDE, Drell PS, Drlica-Wagner A, Favuzzi C, Focke WB, Franckowiak A, Fukazawa Y, Fusco P, Gargano F, Gasparrini D, Germani S, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guiriec S, Hadasch D, Hayashida M, Hays E, Horan D, Hou X, Hughes RE, Inoue Y, Jackson MS, Jogler T, Johannesson G, Johnson AS, Johnson WN, Kamae T, Knodlseder J, Kocevski D, Kuss M, Lande J, Larsson S, Latronico L, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Mayer M, Mazziotta MN, McEnery JE, Michelson PF, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Murphy R, Nakamori T, Nemmen R, Nuss E, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, Ormes JF, Paneque D, Panetta JH, Perkins JS, Pesce-Rollins M, Petrosian V, Piron F, Pivato G, Porter TA, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Roth M, Schulz A, Sgro C, Siskind EJ, Spandre G, Spinelli P, Takahashi H, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Tinivella M, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Werner M, Winer BL, Wood DL, Wood KS, Yang Z, Ajello, M., Albert, A., Allafort, A., Baldini, L., BARBIELLINI AMIDEI, Guido, Bastieri, D., Bellazzini, R., Bissaldi, Elisabetta, Bonamente, E., Brandt, T. J., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Cecchi, C., Charles, E., Chekhtman, A., Chiang, J., Chiaro, G., Ciprini, S., Claus, R., Cohen Tanugi, J., Cominsky, L. R., Conrad, J., Cutini, S., D'Ammando, F., De Palma, F., Dermer, C. D., Desiante, R., Digel, S. W., Do Couto E. Silva, E., Drell, P. S., Drlica Wagner, A., Favuzzi, C., Focke, W. B., Franckowiak, A., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Germani, S., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hadasch, D., Hayashida, M., Hays, E., Horan, D., Hou, X., Hughes, R. E., Inoue, Y., Jackson, M. S., Jogler, T., Jóhannesson, G., Johnson, A. S., Johnson, W. N., Kamae, T., Knödlseder, J., Kocevski, D., Kuss, M., Lande, J., Larsson, S., Latronico, L., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Mayer, M., Mazziotta, M. N., Mcenery, J. E., Michelson, P. F., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Murphy, R., Nakamori, T., Nemmen, R., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Paneque, D., Panetta, J. H., Perkins, J. S., Pesce Rollins, M., Petrosian, V., Piron, F., Pivato, G., Porter, T. A., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Roth, M., Schulz, A., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Takahashi, H., Thayer, J. G., Thayer, J. B., Thompson, D. J., Tibaldo, L., Tinivella, M., Tosti, G., Troja, E., Usher, T. L., Vandenbroucke, J., Vasileiou, V., Vianello, G., Vitale, V., Werner, M., Winer, B. L., Wood, D. L., Wood, K. S., and Yang, Z.
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Sun: flares ,[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Proton ,Astrophysics::High Energy Astrophysical Phenomena ,Hadron ,Astrophysics ,Sun: X-rays, gamma rays ,7. Clean energy ,01 natural sciences ,Power law ,Spectral line ,flares, Sun: X-rays, gamma rays [Sun] ,0103 physical sciences ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Physics ,Sun: flare ,Solar flare ,010308 nuclear & particles physics ,[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Sun: flares, Sun: X-rays, gamma rays ,Gamma ray ,Astronomy and Astrophysics ,gamma rays ,13. Climate action ,Space and Planetary Science ,Physics::Space Physics ,ddc:520 ,Astrophysics - High Energy Astrophysical Phenomena ,Sun: X-rays ,Fermi Gamma-ray Space Telescope - Abstract
The Fermi Large Area Telescope (LAT) observed two bright X-class solar flares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission above 100 MeV lasting for approximately 20 hours. Accurate localization of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with these flares originated. Our analysis of the >100 MeV gamma-ray emission shows a relatively rapid monotonic decrease in flux during the first hour of the impulsive phase, and a much slower, almost monotonic decrease in flux for the next 20 hours. The spectra can be adequately described by a power law with a high energy exponential cutoff, or as resulting from the decay of neutral pions produced by accelerated protons and ions with an isotropic power-law energy distribution. The required proton spectrum has a number index ~3, with minor variations during the impulsive phase, while during the temporally extended phase the spectrum softens monotonically, starting with index ~4. The >30 MeV proton flux and spectra observed near the Earth by the GOES satellites also show a monotonic flux decrease and spectral softening during the extended phase, but with a harder spectrum, with index ~3. Based on the Fermi-LAT and GOES observations of the flux and spectral evolution of these bright flares, we explore the relative merits of prompt and continuous acceleration scenarios, hadronic and leptonic emission processes, and acceleration at the solar corona by the fast Coronal Mass Ejections (CME) as explanations for the observations. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona which penetrate the lower solar atmosphere and produce pions that decay into gamma-rays., Comment: Contact Authors: N. Omodei, M. Pesce-Rollins, V. Petrosian. 14 pages, 5 figures, 4 Tables. Submitted to The Astrophysical Journal
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- 2014
39. Local, Non-Geodesic, Timelike Currents in the Force-Free Magnetosphere of a Kerr Black Hole
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Charles D. Dermer and Govind Menon
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Electromagnetic field ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics and Astronomy (miscellaneous) ,Geodesic ,Magnetosphere ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,General Relativity and Quantum Cosmology ,Rotating black hole ,Flow (mathematics) ,Differential geometry ,Quantum electrodynamics ,Current (fluid) ,Astrophysics - High Energy Astrophysical Phenomena ,Sign (mathematics) - Abstract
In this paper, we use previously developed exact solutions to present some of the curious features of a force-free magnetosphere in a Kerr background. More precisely, we obtain a hitherto unseen timelike current in the force-free magnetosphere that does not flow along a geodesic. The electromagnetic field in this case happens to be magnetically dominated. This too is a feature that has entered the literature for the first time. Changing the sign of a single parameter in our solutions generates a spacelike current that creates an electromagnetic field that is electrically dominated.
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- 2014
- Full Text
- View/download PDF
40. Diffuse Neutrino Intensity from the Inner Jets of Active Galactic Nuclei: Impacts of External Photon Fields and the Blazar Sequence
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Kohta Murase, Yoshiyuki Inoue, and Charles D. Dermer
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Nuclear and High Energy Physics ,Particle physics ,Spectral index ,Active galactic nucleus ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Instrumentation and Methods for Astrophysics ,Spectral density ,FOS: Physical sciences ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Luminosity ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,Astrophysics of Galaxies (astro-ph.GA) ,Production (computer science) ,Neutrino ,Astrophysics - High Energy Astrophysical Phenomena ,Intensity (heat transfer) ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We study high-energy neutrino production in inner jets of radio-loud active galactic nuclei (AGN), taking into account effects of external photon fields and the blazar sequence. We show that the resulting diffuse neutrino intensity is dominated by quasar-hosted blazars, in particular, flat spectrum radio quasars, and that PeV-EeV neutrino production due to photohadronic interactions with broadline and dust radiation is unavoidable if the AGN inner jets are ultrahigh-energy cosmic-ray (UHECR) sources. Their neutrino spectrum has a cutoff feature around PeV energies since target photons are due to Ly$\alpha$ emission. Because of infrared photons provided by the dust torus, neutrino spectra above PeV energies are too hard to be consistent with the IceCube data unless the proton spectral index is steeper than 2.5, or the maximum proton energy is $\lesssim100$ PeV. Thus, the simple model has difficulty in explaining the IceCube data. For the cumulative neutrino intensity from blazars to exceed $\sim{10}^{-8}~{\rm GeV}~{\rm cm}^{-2}~{\rm s}^{-1}~{\rm sr}^{-1}$, their local cosmic-ray energy generation rate would be $\sim10-100$ times larger than the local UHECR emissivity, but is comparable to the averaged gamma-ray blazar emissivity. Interestingly, future detectors such as the Askaryan Radio Array can detect $\sim0.1-1$ EeV neutrinos even in more conservative cases, allowing us to indirectly test the hypothesis that UHECRs are produced in the inner jets. We find that the diffuse neutrino intensity from radio-loud AGN is dominated by blazars with gamma-ray luminosity of $\gtrsim10^{48}~{\rm erg}~{\rm s}^{-1}$, and the arrival directions of their $\sim1-100$ PeV neutrinos correlate with the luminous blazars detected by Fermi., Comment: 17 pages, 16 figures, 3 tables, accepted for publication in PRD, with extended descriptions. Results and conclusions unchanged
- Published
- 2014
- Full Text
- View/download PDF
41. Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A
- Author
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P. A. Jenke, Brian L Winer, Soebur Razzaque, A. A. Moiseev, L. R. Cominsky, Igor V. Moskalenko, Melissa Gibby, Yoshiyuki Inoue, Justin D. Finke, Olaf Reimer, Katsuaki Asano, Robert D. Preece, F. Loparco, E. Moretti, André Schulz, Akira Okumura, George Younes, Matthew G. Baring, D. Byrne, William S. Paciesas, Chryssa Kouveliotou, C. Favuzzi, Judith Racusin, Melissa Pesce-Rollins, Charles A. Meegan, Robert R. Rando, T. Jogler, S. J. Fegan, Luca Baldini, J. G. Thayer, W. B. Focke, P. Spinelli, Sylvain Guiriec, Ryo Yamazaki, P. N. Bhat, Alex Drlica-Wagner, Shuze Zhu, A. von Kienlin, Vandiver Chaplin, Francesco Giordano, Anne M. Diekmann, M. E. Monzani, Jean Ballet, T. A. Porter, Hoi-Fung Yu, A. Franckowiak, J. Michael Burgess, G. Godfrey, W. N. Johnson, W. B. Atwood, Nicola Omodei, S. Rainò, Jeffrey D. Scargle, J. R. Cummings, J. S. Perkins, R. A. Cameron, Tsunefumi Mizuno, R. E. Hughes, Denis Bastieri, Misty Giles, Nicola Giglietto, Rodrigo Nemmen, Shaolin Xiong, Stefano Ciprini, D. Hadasch, S. Germani, K. S. Wood, T. Ohsugi, Eleonora Troja, Stefan Funk, Colleen A. Wilson-Hodge, P. Bruel, G. Chiaro, D. Horan, F. de Palma, A. C. Collazzi, Julie McEnery, V. Pelassa, A. J. van der Horst, Neil Gehrels, L. Di Venere, David Gruber, J. E. Grove, Yasushi Fukazawa, E. J. Siskind, Hiromitsu Takahashi, Valerie Connaughton, A. De Angelis, Adam Goldstein, M. Mayer, V. La Parola, D. J. Thompson, Carmelo Sgrò, G. Tosti, M. N. Lovellette, P. A. Caraveo, Persis S. Drell, M. Roth, Gudlaugur Johannesson, D. Kocevski, V. Vasileiou, Marco Ajello, J. B. Thayer, J. Lande, Jonathan Granot, S. Murgia, P. Fusco, E. Nuss, David Paneque, Sheila McBreen, M. Kuss, T. L. Usher, Francesco Longo, S. Buson, F. Piron, Giacomo Vianello, Masanori Ohno, Felix Ryde, W. H. Cleveland, Emanuele Bonamente, Charles D. Dermer, Magnus Axelsson, Alice K. Harding, I. A. Grenier, Markus Ackermann, Justin Vandenbroucke, Michael S. Briggs, Vahé Petrosian, Luca Latronico, Jürgen Knödlseder, Gloria Spandre, P. M. Saz Parkinson, Ronaldo Bellazzini, Johann Cohen-Tanugi, R. Desiante, T. Kawano, M. Tinivella, Elizabeth C. Ferrara, Guido Barbiellini, Stephen F. Foley, G. A. Caliandro, C. C. Cheung, M. Deklotz, Elisabetta Bissaldi, E. Hays, A. Morselli, F. Gargano, M. Orienti, V. Vitale, J. Bregeon, R. Claus, Alberto Sartori, Y. Hanabata, L. Tibaldo, G. Pivato, A. Reimer, M. Brigida, D. Tierney, M. N. Mazziotta, Eda Sonbas, Arne Rau, Giancarlo Cusumano, Claudia Cecchi, S. Larsson, Diego F. Torres, Gerard Fitzpatrick, S. Cutini, R. M. Kippen, James Chiang, M. Hayashida, Hiroyasu Tajima, Jan Conrad, R. Buehler, Peter F. Michelson, Marcello Giroletti, Eric Charles, Steven Ritz, A. Chekhtman, P. Lubrano, Keith Bechtol, M. Razzano, Filippo D'Ammando, Ackermann M, Ajello M, Asano K, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Bechtol K, Bellazzini R, Bissaldi E, Bonamente E, Bregeon J, Brigida M, Bruel P, Buehler R, Burgess JM, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cecchi C, Chaplin V, Charles E, Chekhtman A, Cheung CC, Chiang J, Chiaro G, Ciprini S, Claus R, Cleveland W, Cohen-Tanugi J, Collazzi A, Cominsky LR, Connaughton V, Conrad J, Cutini S, DAmmando F, de Angelis A, DeKlotz M, de Palma F, Dermer CD, Desiante R, Diekmann A, Di Venere L, Drell PS, Drlica-Wagner A, Favuzzi C, Fegan SJ, Ferrara EC, Finke J, Fitzpatrick G, Focke WB, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gehrels N, Germani S, Gibby M, Giglietto N, Giles M, Giordano F, Giroletti M, Godfrey G, Granot J, Grenier IA, Grove JE, Gruber D, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hays E, Horan D, Hughes RE, Inoue Y, Jogler T, Johannesson G, Johnson WN, Kawano T, Knodlseder J, Kocevski D, Kuss M, Lande J, Larsson S, Latronico L, Longo F, Loparco F, Lovellette MN, Lubrano P, Mayer M, Mazziotta MN, McEnery JE, Michelson PF, Mizuno T, Moiseev AA, Monzani ME, Moretti E, Morselli A, Moskalenko IV, Murgia S, Nemmen R, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orienti M, Paneque D, Pelassa V, Perkins JS, Pesce-Rollins M, Petrosian V, Piron F, Pivato G, Porter TA, Racusin JL, Raino S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Roth M, Ryde F, Sartori A, Parkinson PMS, Scargle JD, Schulz A, Sgro C, Siskind EJ, Sonbas E, Spandre G, Spinelli P, Tajima H, Takahashi H, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Winer BL, Wood KS, Yamazaki R, Younes G, Yu HF, Zhu SJ, Bhat PN, Briggs MS, Byrne D, Foley S, Goldstein A, Jenke P, Kippen RM, Kouveliotou C, McBreen S, Meegan C, Paciesas WS, Preece R, Rau A, Tierney D, van der Horst AJ, von Kienlin A, Wilson-Hodge C, Xiong S, Cusumano G, La Parola V, Cummings JR, M., Ackermann, M., Ajello, K., Asano, W. B., Atwood, M., Axelsson, L., Baldini, J., Ballet, BARBIELLINI AMIDEI, Guido, M. G., Baring, D., Bastieri, K., Bechtol, R., Bellazzini, Bissaldi, Elisabetta, E., Bonamente, J., Bregeon, M., Brigida, P., Bruel, R., Buehler, J. M., Burge, S., Buson, G. A., Caliandro, R. A., Cameron, P. A., Caraveo, C., Cecchi, V., Chaplin, E., Charle, A., Chekhtman, C. C., Cheung, J., Chiang, G., Chiaro, S., Ciprini, R., Clau, W., Cleveland, J., Cohen Tanugi, A., Collazzi, L. R., Cominsky, V., Connaughton, J., Conrad, S., Cutini, F., D'Ammando, A. d., Angeli, M., Deklotz, F. d., Palma, C. D., Dermer, R., Desiante, A., Diekmann, L. D., Venere, P. S., Drell, A., Drlica Wagner, C., Favuzzi, S. J., Fegan, E. C., Ferrara, J., Finke, G., Fitzpatrick, W. B., Focke, A., Franckowiak, Y., Fukazawa, S., Funk, P., Fusco, F., Gargano, N., Gehrel, S., Germani, M., Gibby, N., Giglietto, M., Gile, F., Giordano, M., Giroletti, G., Godfrey, J., Granot, I. A., Grenier, J. E., Grove, D., Gruber, S., Guiriec, D., Hadasch, Y., Hanabata, A. K., Harding, M., Hayashida, E., Hay, D., Horan, R. E., Hughe, Y., Inoue, T., Jogler, G., Johannesson, W. N., Johnson, T., Kawano, J., Knoedlseder, D., Kocevski, M., Ku, J., Lande, S., Larsson, L., Latronico, Longo, Francesco, F., Loparco, M. N., Lovellette, P., Lubrano, M., Mayer, M. N., Mazziotta, J. E., Mcenery, P. F., Michelson, T., Mizuno, A. A., Moiseev, M. E., Monzani, E., Moretti, A., Morselli, I. V., Moskalenko, S., Murgia, R., Nemmen, E., Nu, M., Ohno, T., Ohsugi, A., Okumura, N., Omodei, M., Orienti, D., Paneque, V., Pelassa, J. S., Perkin, M., Pesce Rollin, V., Petrosian, F., Piron, G., Pivato, T. A., Porter, J. L., Racusin, S., Raino, R., Rando, M., Razzano, S., Razzaque, A., Reimer, O., Reimer, S., Ritz, M., Roth, F., Ryde, A., Sartori, P. M., Saz, J. D., Scargle, A., Schulz, C., Sgro, E. J., Siskind, E., Sonba, G., Spandre, P., Spinelli, H., Tajima, H., Takahashi, J. G., Thayer, J. B., Thayer, D. J., Thompson, L., Tibaldo, M., Tinivella, D. F., Torre, G., Tosti, E., Troja, T. L., Usher, J., Vandenbroucke, V., Vasileiou, G., Vianello, V., Vitale, B. L., Winer, K. S., Wood, R., Yamazaki, G., Youne, H. . ., F., S. J., Zhu, P. N., Bhat, M. S., Brigg, D., Byrne, S., Foley, A., Goldstein, P., Jenke, R. M., Kippen, C., Kouveliotou, S., Mcbreen, C., Meegan, W. S., Paciesa, R., Preece, A., Rau, D., Tierney, A. J., Van, A. v., Kienlin, C., Wilson Hodge, S., Xiong, G., Cusumano, V. L., Parola, J. R., Cummings, and High Energy Astrophys. & Astropart. Phys (API, FNWI)
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,SPECTRAL COMPONENT ,Synchrotron radiation ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,LARGE-AREA TELESCOPE ,HIGH-ENERGY EMISSION ,AFTERGLOWS ,PROMPT ,law.invention ,Telescope ,Spitzer Space Telescope ,law ,Astrophysics::Galaxy Astrophysics ,Physics ,Multidisciplinary ,Gamma ray ,GRB 130427A ,Astronomy ,Afterglow ,GRB, Fermi-LAT ,ddc:500 ,Astrophysics - High Energy Astrophysical Phenomena ,Gamma-ray burst ,Fermi Gamma-ray Space Telescope - Abstract
The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of such unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest $\gamma$-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the non-thermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock., Comment: 30 pages, 6 figures. Accepted for publication in Science. Corresponding authors: S. Zhu (sjzhu@umd.edu); J. Chiang (jchiang@slac.stanford.edu); C. Dermer (charles.dermer@nrl.navy.mil); N. Omodei (nicola.omodei@stanford.edu); G. Vianello (giacomov@slac.stanford.edu); S. Xiong (Shaolin.Xiong@uah.edu)
- Published
- 2014
42. Beaming, Baryon Loading, and the Synchrotron Self‐Compton Component in Gamma‐Ray Bursts
- Author
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Kurt Mitman, J. Chiang, and Charles D. Dermer
- Subjects
Physics ,Photon ,Opacity ,Astrophysics::High Energy Astrophysical Phenomena ,GRB 080916C ,Synchrotron radiation ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Redshift ,Space and Planetary Science ,Gamma-ray burst ,Blast wave - Abstract
We present detailed calculations of nonthermal synchrotron and synchrotron self-Compton (SSC) spectra radiated by blast waves that are energized by interactions with a uniform surrounding medium. Radio, optical, X-ray and gamma-ray light curves and spectral indices are calculated for a standard parameter set that yields hard GRB spectra during the prompt emission phase. Because no lateral spreading of the blast-wave is assumed, the calculated temporal breaks represent the sharpest breaks possible from collimated outflows in a uniform surrounding medium. Absence of SSC hardenings in observed GRB X-ray afterglows indicates magnetic field generation toward equipartition as the blast wave evolves. EGRET detections of 100 MeV-GeV photons observed promptly and 90 minutes after GRB 940217 are attributed to nonthermal synchrotron radiation and SSC emission from a decelerating blast wave, respectively. The SSC process will produce prompt TeV emission that could be observed from GRBs with redshifts $z \lesssim 0.1$, provided $\gamma$-$\gamma$ opacity in the source is small. Measurements of the time dependence of the 100 MeV-GeV spectral indices with the planned {\it GLAST} mission will chart the evolution of the SSC component and test the external shock scenario. Transient optical and X-ray emissions from misaligned GRBs are generally much weaker than on-axis emissions produced by dirty and clean fireballs that would themselves not trigger a GRB detector; thus detection of long wavelength transients not associated with GRBs will not unambiguously demonstrate GRB beaming.
- Published
- 2000
43. Variability in blazars
- Author
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Charles D. Dermer
- Subjects
Physics ,Jet (fluid) ,Photon ,Radiative cooling ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Plasmoid ,Astrophysics ,Plasma ,Kinetic energy ,Relativistic plasma ,Blazar - Abstract
The kinetic energy of bulk relativistic plasma ejected from the central engine of blazars is converted into nonthermal particle energy in the comoving frame through a process of sweeping up material from the surrounding medium. The resulting deceleration of the bulk plasma introduces a number of effects which must be included in blazar modeling. For example, the varying Doppler factor means that model fits must employ time integrations appropriate to the observing times of the detectors. We find that the ratio of the peak synchrotron fluxes reached at two different photon energies is largest when viewing along the jet axis, and becomes smaller at large angles to the jet axis. This effect is important in studies of the statistics of jet sources. Variability due either to bulk plasma deceleration or radiative cooling must be distinguished in order to apply recently proposed tests for beaming from correlated X-ray and TeV observations. The blast-wave physics developed to analyze these problems implies that most of the energy injected in the comoving frame is originally in the form of nonthermal hadrons. Because plasmoid deceleration can produce rapid variability due to a changing Doppler factor, arguments against hadronic blazar models related to the long radiative cooling time scale of hadrons are not compelling., 13 pages, 3 figures,Invited talk at VERITAS Workshop on TeV Astrophysics of Extragalactic Sources, Cambridge, MA, Oct. 23-24, 1998. In press, Astroparticle Physics, ed. M. Catanese, J. Quinn, T. Weekes
- Published
- 1999
44. The External Shock Model of Gamma-Ray Bursts: Three Predictions and a Paradox Resolved
- Author
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Charles D. Dermer, Markus Böttcher, and James Chiang
- Subjects
Physics ,Spectral index ,Photon ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Astrophysics ,Radiation ,Photon energy ,Spectral line ,Space and Planetary Science ,Gamma-ray burst ,Blast wave - Abstract
In the external shock model, gamma-ray burst (GRB) emissions are produced by the energization and deceleration of a thin relativistic blast wave due to its interactions with the circumburst medium (CBM). We study the physical properties of an analytic function which describes temporally-evolving GRB spectra in the limit of a smooth CBM with density n(x)\propto x^(-\eta), where x is the radial coordinate. The hard-to-soft spectral evolution and the intensity-hardness correlation of GRB peaks are reproduced. We predict that (1) GRB peaks are aligned at high photon energies and lag at low energies according to a simple rule; that (2) temporal indices at the leading edge of a GRB peak display a well-defined shift with photon energy; and that (3) the change in the spectral index values between the leading and trailing edges of a GRB peak decreases at higher photon energies. The reason that GRBs are usually detected with vF_v peaks in the 50 keV - several MeV range for detectors which trigger on peak flux over a fixed time interval is shown to be a consequence of the inverse correlation of peak flux and duration of the radiation emitted by decelerating blast waves., Comment: 10 pages, 2 figures, accepted for publication in Astrophysical Journal Letters, uses aaspp4.sty, epsf.sty
- Published
- 1999
45. Short-Timescale Variability in the External Shock Model of Gamma-Ray Bursts
- Author
-
Charles D. Dermer and Kurt Mitman
- Subjects
Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Light curve ,Lorentz factor ,symbols.namesake ,Space and Planetary Science ,symbols ,Gamma-ray burst ,Shock model ,Astrophysics::Galaxy Astrophysics ,Blast wave - Abstract
We have developed a computer model to calculate gamma ray burst (GRB) light curves and efficiencies from the interaction of a single, thin blast wave with clouds in the external medium. Large amplitude, spiky variability occurs when the clouds have radii r << R/Gamma, where R is the mean distance of a cloud from the GRB source and Gamma is the blast-wave Lorentz factor. Efficiencies >~ 10% require a large number of small clouds, each with sufficiently large column densities to extract most of the available blast-wave energy in the region of interaction. For such efficiencies, we find that erratic variability persists in the simulated GRB light curves. If GRB sources are surrounded by clouds with such properties, then short timescale variability of GRBs is possible in the external shock model., 10 pages, 2 figures, uses aaspp4.sty, ApJ Letters, in press (1999) Corrections made in response to referee report
- Published
- 1999
46. Gamma-ray burst afterglows from decelerating material: Blast waves and plasmoids
- Author
-
Charles D. Dermer and James Chiang
- Subjects
Physics ,Nuclear and High Energy Physics ,Accretion (meteorology) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics ,Electron ,Kinetic energy ,Atomic and Molecular Physics, and Optics ,Afterglow ,Lorentz factor ,symbols.namesake ,Radiative transfer ,symbols ,Gamma-ray burst ,Blast wave - Abstract
We examine the dynamics and emitted radiation from material with a large initial bulk Lorentz factor which decelerates as it sweeps up ambient matter. The bulk kinetic energy of the material is converted into non-thermal energy of electrons which radiate isotropically in the locally co-moving frame. Self-consistent solutions for the dynamics of the material are computed which account for changes in its bulk relativistic inertia due to accretion and the emitted radiation. Fully radiative and non-radiative solutions are shown to be limiting cases agreeing with standard solutions for spherically expanding blast waves. We have calculated the afterglow synchrotron emission for a variety of parameters and geometries, and we compare a fiducial example to the afterglow behavior observed from recent gamma-ray burst X-ray and optical couterparts.
- Published
- 1999
47. High-energy Gamma Rays from Ultra–high-energy Cosmic-Ray Protons in Gamma-Ray Bursts
- Author
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Markus Böttcher and Charles D. Dermer
- Subjects
Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Gamma ray ,FOS: Physical sciences ,Synchrotron radiation ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Afterglow ,Space and Planetary Science ,GRB 970508 ,Intergalactic travel ,Ultra-high-energy cosmic ray ,Gamma-ray burst - Abstract
It has recently been proposed that ultrahigh energy ($\gtrsim 10^{19}$ eV) cosmic rays (UHECRs) are accelerated by the blast waves associated with GRBs. We calculate the observed synchrotron radiation spectrum from protons and energetic leptons formed in the cascades initiated by photopion production, taking into account $\gamma\gamma$ attenuation at the source. Normalizing to the emission characteristics of GRB~970508, we predict $\sim 10$ MeV - 100 GeV fluxes at a level which may have been observed with EGRET from bright GRBs, and could be detected with the proposed GLAST experiment or with ground-based air \v Cerenkov telescopes having thresholds $\lesssim $ several hundred GeV. The temporal decay of the UHECR-induced high-energy $\gamma$-ray afterglows is significantly slower than that of the lower-energy burst and associated synchrotron self-Compton (SSC) radiation, which provides a direct way to test the hadronic origin of a high-energy GRB afterglow. Besides testing the UHECR origin hypothesis, the short wavelength emission and afterglows can be used to probe the level of the diffuse intergalactic infrared radiation field or constrain redshifts of GRB sources., Comment: Accepted for publication in ApJ Letters
- Published
- 1998
48. Temporal Evolution of Nonthermal Spectra from Supernova Remnants
- Author
-
J. G. Skibo, J. R. Mattox, Charles D. Dermer, and Steven J. Sturner
- Subjects
Physics ,Range (particle radiation) ,Astrophysics::High Energy Astrophysical Phenomena ,Compton scattering ,Bremsstrahlung ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Electron ,Near-Earth supernova ,Interstellar medium ,Supernova ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Supernova remnant ,Astrophysics::Galaxy Astrophysics - Abstract
Assuming that supernova shocks accelerate nonthermal particles, we model the temporally evolving nonthermal particle and photon spectra at different stages in the lifetime of a standard shell-type supernova remnant (SNR). A characteristic νFν spectrum of an SNR consists of a peak at radio through optical energies from nonthermal electron synchrotron emission and another high-energy gamma-ray peak due primarily to secondary pion production, nonthermal electron bremsstrahlung, and Compton scattering. We find that supernova remnants are capable of producing maximum gamma-ray luminosities 1035 ergs s-1 if the density of the local interstellar medium is 10 cm-3. This emission will persist for 105 yr after the supernova explosion because of the long energy loss timescales for electrons with kinetic energy ~1 GeV. This long gamma-ray lifetime implies that SNRs with a wide range of ages could be gamma-ray sources and could constitute some of the unidentified EGRET sources.
- Published
- 1997
49. Annihilation Fountain in the Galactic Center Region
- Author
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Charles D. Dermer and J. G. Skibo
- Subjects
Physics ,Annihilation ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Galactic Center ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galactic plane ,Galaxy ,Galactic halo ,Positron ,Space and Planetary Science ,Annihilation radiation ,Halo ,Astrophysics::Galaxy Astrophysics - Abstract
Two different model-independent mapping techniques have been applied to OSSE, SMM, TGRS and balloon data and reveal a feature in the 0.511 MeV electron-positron annihilation radiation pattern of our galaxy centered roughly at l=-2 deg. and b=10 deg. with a flux of 5x10^(-4) 0.511 MeV ph/cm^2/s. If near the galactic center, then positron sources are producing approximately 10^42 positrons/s which annihilate 1-2 kpc above the galactic plane. A starburst episode within the inner few hundred pc of our galaxy would drive hot pair-laden gas into the halo, with the one-sidedness pointing to the site of initial pressure release at the onset of the starburst activity. Positrons lose energy and annihilate as they are convected upward with the gas flow, and we calculate high-latitude annihilation patterns and fluxes in accord with the observations. Changes in the ionization state when the escaping gas cools could give annihilation radiation substructure. The fountain of hot (10^6-10^7 K) gas rising into the galactic halo would be seen through its enhanced dispersion measure, thermal emission, and recombination radiation., Comment: 11 pages, Latex, requires AASTEX macros and psfig.tex, 2 postscript figures, Submitted to Astrophysical Journal Letters
- Published
- 1997
50. Time Variability Detected in the Gamma-Ray Emission of 3C 273 by OSSE
- Author
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Charles D. Dermer, W. N. Johnson, K. McNaron-Brown, and James D. Kurfess
- Subjects
Physics ,Scintillation ,Spectral index ,Spectrometer ,Astrophysics::High Energy Astrophysical Phenomena ,Gamma ray ,Flux ,Astronomy ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Power law ,Space and Planetary Science ,Observatory - Abstract
We report results of a 3 week observation of the quasar 3C 273 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (CGRO). During the observation between 1994 August 31 and September 20, 3C 273 exhibited variability on timescales as short as 3-4 days in the 0.05-0.15 MeV energy range. This is the shortest measured variability of 3C 273 in this energy range. The measured flux at 100 keV is 2.40 ± 0.06 (×10-2 ph cm-2 s-1 MeV-1), which is the highest recorded flux for 3C 273 by OSSE in 5 years of monitoring and nearly twice as great as the previously recorded peak flux measured in 1991 June. While the flux varied by a factor of 1.7, no significant gamma-ray spectral evolution in the OSSE band was observed throughout the viewing period. The data for the full viewing period are described better with a broken power law than a single power law, with photon spectral index Γ = 1.62 ± 0.08 below a break at 300 ± 100 keV, and with a spectral index change of ΔΓ = 0.9+ 1.6−0.6. This break energy is significantly lower than the 1 MeV break reported by Johnson et al. in 1991 June.
- Published
- 1997
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