Results 21 to 30 of about 200 (175)
Symposium - International Astronomical Union, 1982 Observations of sample of Markarian Seyferts with the VLA indicate that a large fraction possess linear radio structure on a scale of a few hundred parsecs to a few kiloparsecs. The radio components generally straddle the optical nucleus and several sources are simple doubles.
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Symposium - International Astronomical Union, 1972 The four Seyfert galaxies with systemic velocities of less than 2000 km s−1 have been observed at 21 cm with the Jodrell Bank 250-ft telescope and a 5 MHz overall bandwidth setting of the 256 channel auto-correlation spectrometer. Relatively strong signals of 0.5 f.u.
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Seyfert Galaxies Astrophysics [PDF]
Universe, 2020 Looking back in time, it is somehow surprising to see the enormous advancement made by astrophysics in just about one century [...]
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Polarization and variability of compact sources measured in [PDF]
, 2023 This paper introduces a new Planck Catalog of Polarized and Variable Compact Sources (PCCS-PV) comprising 153 sources, the majority of which are extragalactic.
Rocha, G. +23 more
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X-ray timing analysis of the quasar PG 1211+143 [PDF]
, 2016 We report on a timing analysis of a new ~630?ks XMM–Newton observation of the quasar, PG 1211+143. We find a well-defined X-ray power spectrum with a well-detected bend at ~7 × 10-5?Hz, consistent with the established tbend–MBH correlation for luminous ...
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The Global Implications of the Hard Excess II: Analysis of the Local population of Radio Quiet AGN [PDF]
, 2016 Active galactic nuclei (AGN) show evidence for reprocessing gas, outflowing from the accreting black hole. The combined effects of absorption and scattering from the circumnuclear material likely explains the `hard excess' of X-ray emission above 20 keV,
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The Astrophysical Journal, 2001 It is known that the spectral energy distribution (SED) of the nuclear radiation of narrow-line Seyfert 1 galaxies (NLS1s) has different shapes with respect to that of ordinary broad-line Seyfert 1 galaxies (BLS1s), particularly in wavelengths of X-ray.
Nagao, T., Murayama, T., Taniguchi, Y.
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Microvariability in Seyfert Galaxies
The Astronomical Journal, 2003 We present the results of a search for microvariability in a sample of eight Seyfert galaxies. Microvariability (i.e., variations occurring on timescales of tens of minutes to hours) has been conclusively demonstrated to exist in the class of active galactic nuclei (AGNs) known as blazars. Its existence in other classes of AGNs is far less certain.
M. T. Carini, J. C. Noble, H. R. Miller
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Galaxy Interaction and the Starburst‐Seyfert Connection [PDF]
The Astrophysical Journal, 2004 28 pages, to appear in The Astrophysical ...
Mouri, H., Taniguchi, Y.
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Grandeurs spectrophotométriques concernant des galaxies Seyfert
, 1976 Le calcul des grandeurs spectrophotométriques : gradients (Φ0, 40,Φ0, 50), pentes (G0, 40 G0, 50) et différences des log10 des densités de flux (Δ = log10 F0,50 — log10 F0,40) a été fait pour 66 galaxies Seyfert et a conduit à l'établissement de deux ...
Edgard Vandekerkhove +1 more
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