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We discuss the rationale for the energy cuts used in the previous study of directional correlation of the five highest energy cosmic ray events with compact, radio quasars. We check the consistency of the next three most energetic events…

Astrophysics · Physics 2009-10-31 Glennys R. Farrar , Peter L. Biermann

Some proposals to account for the highest energy cosmic rays predict that they should point to their sources. We study the five highest energy events (E>10^20 eV) and find they are all aligned with compact, radio-loud quasars. The…

Astrophysics · Physics 2009-10-30 Glennys R. Farrar , Peter L. Biermann

Angular correlations of ultra-high energy cosmic rays with cosmologically distant sources may provide clues to these mysterious events. We compare cosmic ray tracks with energies above $ 10^{20}eV$ to a compilation of radio-loud compact QSO…

We study the correlation between compact radio quasars or 3EG gamma-ray blazars and the arrival directions of cosmic rays above 10^19 eV using an updated list of air shower detections. Our Monte Carlo simulations reveal no significant…

Astrophysics · Physics 2009-12-31 Guenter Sigl , Diego Torres , Luis Anchordoqui , Gustavo Romero

We examine the correlation between compact radio quasars (redshifts in the range $z = 0.3 - 2.2$) and the arrival direction of ultrahigh energy cosmic rays forming clusters. Our Monte Carlo simulation reveals a statistically significant…

The narrow emission line luminosities of radio-loud AGN are well-correlated with their low-frequency radio luminosities. This correlation is linear and extends over at least four orders of magnitude. The correlation is discussed in terms of…

Astrophysics · Physics 2007-05-23 Chris J. Willott

Radio emission is a good indicator of the jet power of radio-loud quasars, while the emission in broad-line can well represent the accretion disc radiation in quasars. We compile a sample of all sources of which the broad-line fluxes are…

Astrophysics · Physics 2009-10-31 Xinwu Cao , D. R. Jiang

The ubiquitous and tight correlation between the radio continuum emission and the far-infrared emission is also found to hold true for starburst galaxies and Ultra Luminous Infrared Galaxies wherein most of the emission is from compact…

Astrophysics · Physics 2007-05-23 T. N. Rengarajan

Using complete samples of steep-spectrum quasars, we present evidence for a correlation between radio and optical luminosity which is not caused by selection effects, nor caused by an orientation dependence (such as relativistic beaming),…

Anisotropy in arrival directions of ultrahigh energy cosmic rays offers the most direct way to search for the sources of these particles. We present estimates of the angular correlation in the HiRes sample of stereo events above 10 EeV, and…

Astrophysics · Physics 2019-08-15 Chad Finley

The present situation with regard to experimental data on ultra high-energy cosmic rays is briefly reviewed. Whilst detailed knowledge of the shape of the energy spectrum is still lacking, it is clear that events above 10^20 eV do exist.…

Astrophysics · Physics 2017-08-23 A. A. Watson

Very recently, a possible clustering of a subset of observed ultrahigh energy cosmic rays above about 40EeV (4x10^19eV) in pairs near the supergalactic plane was reported. We show that a confirmation of this effect would provide information…

Astrophysics · Physics 2009-10-28 Guenter Sigl , David N. Schramm , Sangjin Lee , Paolo Coppi , Christopher T. Hill

We explore the relationship between the extended radio and line emission for a radio-loud quasar sample including both core-dominated and lobe-dominated quasars. A strong correlation is present between the extended radio and broad-line…

Astrophysics · Physics 2009-10-31 Xinwu Cao , D. R. Jiang

A key argument in favor of orientation based unification schemes is the finding that among the most powerful 3CRR radio sources the (apparent) median linear size of quasars is smaller than that of radio galaxies, which supports the idea…

Astrophysics · Physics 2009-10-28 Gopal-Krishna , Vasant Kulkarni , Paul J. Wiita

We investigate whether ultra--high energy cosmic rays (UHECR) may be preferentially produced in massive galaxy clusters, by looking for correlations between UHECR directions and those of x-ray clusters. We find an excess-above-random of…

Astrophysics · Physics 2007-05-23 Elena Pierpaoli , Glennys Farrar

(Abridged) We present a systematic study of the X-ray and multiwavelength properties of a sample of 17 highly radio-loud quasars (HRLQs) at z > 4 with sensitive X-ray coverage from new Chandra and archival Chandra, XMM-Newton, and Swift…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-31 Jianfeng Wu , W. N. Brandt , Brendan P. Miller , Gordon P. Garmire , Donald P. Schneider , Cristian Vignali

In this paper, the correlation between the gamma-ray and the radio bands is investigated. The results show that there is a closer correlation between the gamma-ray emission and the high frequency (1.3mm, 230GHz) radio emission for maximum…

Astrophysics · Physics 2007-05-23 J. H. Fan , G. Adam , G. Z. Xie , S. L. Cao , R. G. Lin , Y. Copin

Quasars and microquasars both contain accreting black holes and power nonthermal radio sources but differ in more than their scales: Quasars are proportionally much more efficient accelerators of energetic electrons. The radio luminosity of…

High Energy Astrophysical Phenomena · Physics 2024-03-06 J. I. Katz

In a series of papers we have found statistically significant correlations between arrival directions of ultra-high energy cosmic rays and BL Lacertae objects. Recently, our calculations were partly repeated by Evans, Ferrer and Sarkar with…

Astrophysics · Physics 2008-11-26 P. Tinyakov , I. Tkachev

Surveys have shown radio-loud (RL) quasars constitute $10 \%$-$15 \%$ of the total quasar population. However, it is unknown if the radio-loud fraction (RL quasars/Total quasars) remains consistent among different parameter spaces. This…

Astrophysics of Galaxies · Physics 2021-03-31 Avinanda Chakraborty , Anirban Bhattacharjee
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