Discovery of 0.5 MK Gas in the Center of the Virgo Cluster

Lieu, Richard; Mittaz, Jonathan P. D.; Bowyer, Stuart; Lockman, Felix J.; Hwang, Chorng-Yuan; Schmitt, J. H. M. M.

doi:10.1086/309908

Cited by 141 publications

(115 citation statements)

References 17 publications

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“…This causes a drastic modulation in the electron synchrotron spectrum, especially for Cen A, which is responsible for the whole emission in the broadband range ∼10 −5 −10 7 eV. In the case of M 87, this type of absorption has a minor impact, since the column density is much less (N H = 2 × 10 20 cm −2 , Lieu et al 1996). The internal absorption of gamma-rays is also taken into account, being important only within the injection zone, where the synchrotron emission of primary electrons provide an important absorbing target.…”

Section: Discussionmentioning

confidence: 99%

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Reynoso

Medina

Romero

2011

A&A

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Context. The well known radiogalaxy Cen A has been recently detected as a source of very high energy (VHE) γ-rays by the HESS experiment just before Fermi/LAT detected it at high energies (HE). The detection, together with that of M 87, established radiogalaxies as VHE γ-ray emitters. Aims. The aim of this work is to present a lepto-hadronic model for the VHE emission from the relativistic jets in FR I radiogalaxies. Methods. We consider that protons and electrons are accelerated in a compact region near the base of the jet, and they cool emitting multi wavelength radiation as propagating along the jet. The proton and electron distributions are obtained through steady-state transport equation taking into account acceleration, radiative and non-radiative cooling processes, as well as particle transport by convection. Results. Considering the effects of photon absorption at different wavelengths, we calculate the radiation emitted by the primary protons and electrons, as well as the contribution of secondaries particles (e ± , πs and μs). The expected high-energy neutrino signal is also obtained and the possibility of detections with KM3NeT and IceCube is discussed. Conclusions. The spectral energy distribution obtained in our model with an appropriate set of parameters for an extended emission zone can account for much of the observed spectra for both AGNs.

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Section: Discussionmentioning

confidence: 99%

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Reynoso

Medina

Romero

2011

A&A

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“…The EUV excess in the 0.07 to 0.14 keV range was first detected by the Extreme Ultraviolet Explorer from Coma (Lieu et al 1996) and some other clusters. There are claimed detections of similar excess emissions in the 0.1 to 0.4 keV band by Rosat, BeppoSAX and XMM-Newton.…”

Section: Euv Emissionmentioning

confidence: 94%

Nonthermal Radiation Mechanisms

2008

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In this paper we review the possible radiation mechanisms for the observed non-thermal emission in clusters of galaxies, with a primary focus on the radio and hard X-ray emission. We show that the difficulty with the non-thermal, non-relativisitic Bremsstrahlung model for the hard X-ray emission, first pointed out by Petrosian (2001) using a cold target approximation, is somewhat alleviated when one treats the problem more exactly by including the fact that the background plasma particle energies are on average a factor of 10 below the energy of the non-thermal particles. This increases the lifetime of the non-thermal particles, and as a result decreases the extreme energy requirement, but at most by a factor of three. We then review the synchrotron and so-called inverse Compton emission by relativistic electrons, which when compared with observations can constrain the value of the magnetic field and energy of relativistic electrons. This model requires a low value of the magnetic field which is far from the equipartition value. We briefly review the possibilities of gammaray emission and prospects for GLAST observations. We also present a toy model of the non-thermal electron spectra that are produced by the acceleration mechanisms discussed in an accompanying paper.

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“…Soft X-ray excess radiation in clusters has been detected in observations by the Extreme Ultraviolet Explorer (EUVE), ROSAT and XMM-Newton (Lieu et al 1996;Bonamente et al 2001;Finoguenov et al 2003;see Durret et al 2008-Chap. 4, this issue for an overview).…”

Section: Soft X-ray Excess Radiation In Galaxy Clustersmentioning

confidence: 99%

Numerical Simulations of the Warm-Hot Intergalactic Medium

2008

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In this paper we review the current predictions of numerical simulations for the origin and observability of the warm hot intergalactic medium (WHIM), the diffuse gas that contains up to 50 per cent of the baryons at z ∼ 0. During structure formation, gravitational accretion shocks emerging from collapsing regions gradually heat the intergalactic medium (IGM) to temperatures in the range T ∼ 10 5 -10 7 K. The WHIM is predicted to radiate most of its energy in the ultraviolet (UV) and X-ray bands and to contribute a significant fraction of the soft X-ray background emission. While O VI and C IV absorption systems arising in the cooler fraction of the WHIM with T ∼ 10 5 -10 5.5 K are seen in FUSE and Hubble Space Telescope observations, models agree that current X-ray telescopes such as Chandra and XMM-Newton do not have enough sensitivity to detect the hotter WHIM. However, future missions such as Constellation-X and XEUS might be able to detect both emission lines and absorption systems from highly ionised atoms such as O VII, O VIII and Fe XVII.

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Discovery of 0.5 MK Gas in the Center of the Virgo Cluster

Cited by 141 publications

References 17 publications

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Nonthermal Radiation Mechanisms

Numerical Simulations of the Warm-Hot Intergalactic Medium

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