A Radio Reference Frame

Johnston, K. J.; Fey, A. L.; Zacharias, N.; Russell, J. L.; Ma, C.; Vegt, C. de; Reynolds, J. E.; Jauncey, D. L.; Archinal, B. A.; Carter, M. S.; Corbin, T. E.; Eubanks, T. M.; Florkowski, D. R.; Hall, David; McCarthy, Dennis D.; McCulloch, P. M.; King, E. A.; Nicolson, G.; Shaffer, D. B.

doi:10.1086/117571

Cited by 140 publications

(66 citation statements)

References 1 publication

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“…b Uncertainty radius of the best-fit gtfindsrc position at 68% and 95% confidence level in degrees. c Uncertainty on the radio position in arcseconds (Johnston et al 1995).…”

Section: Gamma-ray Source Associationmentioning

confidence: 99%

First Detection in Gamma-Rays of a Young Radio Galaxy: Fermi-Lat Observations of the Compact Symmetric Object PKS 1718−649

Migliori

Siemiginowska

Sobolewska

et al. 2016

ApJL

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We report the γ-ray detection of a young radio galaxy, PKS 1718−649, belonging to the class of compact symmetric objects (CSOs), with the Large Area Telescope (LAT) on board the Fermi satellite. The third Fermi Gamma-ray LAT catalog (3FGL) includes an unassociated γ-ray source, 3FGL J1728.0−6446, located close to PKS 1718−649. Using the latest Pass 8 calibration, we confirm that the best-fit 1σ position of the γ-ray source is compatible with the radio location of PKS 1718−649. Cross-matching of the γ-ray source position with the positions of blazar sources from several catalogs yields negative results. Thus, we conclude that PKS 1718−649 is the most likely counterpart to the unassociated LAT source. We obtain a detection test statistics TS ∼ 36 (>5σ) with a best-fit photon spectral index Γ = 2.9 ± 0.3 and a 0.1-100 GeV photon flux density F 0.1−100 GeV = (11.5 ± 0.3) × 10 −9 ph cm −2 s −1 . We argue that the linear size (∼2 pc), the kinematic age (∼100 years), and the source distance (z = 0.014) make PKS 1718−649 an ideal candidate for γ-ray detection in the framework of the model proposing that the most compact and the youngest CSOs can efficiently produce GeV radiation via inverseCompton scattering of the ambient photon fields by the radio lobe non-thermal electrons. Thus, our detection of the source in γ-rays establishes young radio galaxies as a distinct class of extragalactic high-energy emitters and yields a unique insight on the physical conditions in compact radio lobes interacting with the interstellar medium of the host galaxy.

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“…b Uncertainty radius of the best-fit gtfindsrc position at 68% and 95% confidence level in degrees. c Uncertainty on the radio position in arcseconds (Johnston et al 1995).…”

Section: Gamma-ray Source Associationmentioning

confidence: 99%

First Detection in Gamma-Rays of a Young Radio Galaxy: Fermi-Lat Observations of the Compact Symmetric Object PKS 1718−649

Migliori

Siemiginowska

Sobolewska

et al. 2016

ApJL

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“…• 22 19.6 , Johnston et al 1995) and further extract the spectrum and light curve, using the reflected-region method (Berge et al 2007) to estimate the background contamination. With 1133 on-source events, 9042 off-source events and an onoff normalization of α = 0.10, the significance of the 218 γ rays excess is 6.6σ (standard deviations, Li & Ma 1983).…”

Section: Hess Observationsmentioning

confidence: 99%

The high-energyγ-ray emission of AP Librae

Abramowski¹,

Aharonian²,

Benkhali³

et al. 2014

A&A

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The γ-ray spectrum of the low-frequency-peaked BL Lac (LBL) object AP Librae is studied, following the discovery of very-high-energy (VHE; E > 100 GeV) γ-ray emission up to the TeV range by the H.E.S.S. experiment. This makes AP Librae one of the few VHE emitters of the LBL type. The measured spectrum yields a flux of (8.8 ± 1.5 stat ± 1.8 sys ) × 10 −12 cm −2 s −1 above 130 GeV and a spectral index of Γ = 2.65±0.19 stat ± 0.20 sys . This study also makes use of Fermi-LAT observations in the high energy (HE, E > 100 MeV) range, providing the longest continuous light curve (5 years) ever published on this source. The source underwent a flaring event between MJD 56 306-56 376 in the HE range, with a flux increase of a factor of 3.5 in the 14 day bin light curve and no significant variation in spectral shape with respect to the low-flux state. While the H.E.S.S. and (low state) Fermi-LAT fluxes are in good agreement where they overlap, a spectral curvature between the steep VHE spectrum and the Fermi-LAT spectrum is observed. The maximum of the γ-ray emission in the spectral energy distribution is located below the GeV energy range.

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“…It is located at α J2000 = 20 h 09 m 25.39 s , δ J2000 = −48 • 49 53.7 (Johnston et al 1995) and has a redshift of z = 0.071 (Falomo et al 1987).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

Abramowski

Acero

Aharonian

et al. 2011

A&A

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The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E > 100 GeV) spectrum measured with H.E.S.S.Supported by CAPES Foundation, Ministry of Education of Brazil.Article published by EDP Sciences A110, page 1 of 9 A&A 533, A110 (2011) with a peak energy between ∼5 and 500 GeV. Compared to observations with contemporaneous coverage in the VHE and X-ray bands in 2004, the X-ray flux was ∼50 times higher during the 2009 campaign while the TeV γ-ray flux shows marginal variation over the years. The spectral energy distribution during this multi-wavelength campaign was fit by a one zone synchrotron self-Compton model with a well determined cutoff in X-rays. The parameters of a one zone SSC model are inconsistent with variability time scales. The variability behaviour over years with the large changes in synchrotron emission and small changes in the inverse Compton emission does not warrant an interpretation within a one-zone SSC model despite an apparently satisfying fit to the broadband data in 2009.

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A Radio Reference Frame

Cited by 140 publications

References 1 publication

First Detection in Gamma-Rays of a Young Radio Galaxy: Fermi-Lat Observations of the Compact Symmetric Object PKS 1718−649

First Detection in Gamma-Rays of a Young Radio Galaxy: Fermi-Lat Observations of the Compact Symmetric Object PKS 1718−649

The high-energyγ-ray emission of AP Librae

Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

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