An Intrinsic Short-Term Radio Variability Observed in PKS 1510−089

Kadota, Akiko; Fujisawa, Kenta; Sawada-Satoh, Satoko; Wajima, Kiyoaki; Doi, Akira

doi:10.1093/pasj/64.5.109

Cited by 8 publications

(4 citation statements)

References 31 publications

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“…The apparent speed in the ultrarelativistic jet of PKS 1510-089 has been observed to be upto 46c (Jorstad et al 2005) which suggests that the Doppler factor could be very high for this source. From equation ( 6) for t var = 1.30 hr, δ = 47 (Kadota et al 2012), we get an emission region of radius R ∼ 4.85 × 10 15 cm. A less extreme Doppler factor of 10 would imply an emission region of radius R ∼ 1.03 × 10 15 cm.…”

Section: Spectral Energy Distributions Of Flaresmentioning

confidence: 96%

Long-Term Study of the Light Curve of PKS 1510-089 in GeV energies

Prince

Majumdar

Gupta

2017

Proceedings of 7th International Fermi Symposium — PoS(IFS2017)

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We have analyzed data from the Flat Spectrum Radio Quasar PKS 1510-089 collected over a period of 8 years from August 2008 to December 2016 with the Fermi-LAT. We have identified several flares of this highly variable source, studied their temporal and spectral properties in detail and compared with previous works on flares of PKS 1510-089. Five major flares and few sub-flares/sub-structures have been identified in our study. The fastest variability time is found to be 1.30±0.18 hr between MJD 55852.063 and 55852.188 where we estimate the minimum size of the emission region to be 4.85 × 10 15 cm. In most of the flares the spectral energy distributions are better fitted with Logparabolic distribution compared to simple Power law or Power law with exponential cut-offs. This has strong physics implications regarding the nature of the high energy gamma-ray emission region.

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Section: Spectral Energy Distributions Of Flaresmentioning

confidence: 96%

Long-Term Study of the Light Curve of PKS 1510-089 in GeV energies

Prince

Majumdar

Gupta

2017

Proceedings of 7th International Fermi Symposium — PoS(IFS2017)

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“…We employed the 'Z-scan' method to remove both the gain and atmospheric fluctuations, and the pointing offsets. The detailed procedure of the observation and data reduction of the method is described by Kadota et al (2012). The flux density of 1H 0323+342 was measured by comparing the total received power with that of a strong, nearby radio source 3C 123 (9.310 Jy; Ott et al 1994).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Short-Term Radio Variability and Parsec-Scale Structure in a Gamma-Ray Narrow-Line Seyfert 1 Galaxy 1H 0323+342

Wajima,

Fujisawa,

Hayashida

et al. 2013

Preprint

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We made simultaneous single-dish and very long baseline interferometer (VLBI) observations of a narrow-line Seyfert 1 galaxy (NLS1) 1H 0323+342, showing gamma-ray activity revealed by Fermi/LAT observations. We found significant variation of the total flux density at 8 GHz on the time scale of one month by the single-dish monitoring. The total flux density varied by 5.5% in 32 days, which is comparable to the gamma-ray variability time scale, corresponding to the variability brightness temperature of 7.0 × 10 11 K. The source consists of central and southeastern components on the parsec (pc) scale. The flux of only the central component decreased in the same way as the total flux density, indicating that the short-term radio variability, and probably the gammaray emitting region, is associated with this component. From the VLBI observations we obtained the brightness temperatures of greater than (5.2 ± 0.3) × 10 10 K, and derived the equipartition Doppler factor of greater than 1.7, the variability Doppler factor of 2.2, and the 8 GHz radio power of 10 24.6 W Hz −1 . Combining them we conclude that acceleration of radio jets and creation of high-energy particles are ongoing in the central engine, and that the apparent very radio-loud feature of the source is due to the Doppler-boosting effect, resulting in the intrinsic radio loudness to be an order of magnitude smaller than the observed values. We also conclude that the pc-scale jet represents recurrent activity from the the spectral fitting and the estimated kinematic age of pc-and kpc-scale extended components with different position angle.

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“…Agudo et al (2011 also suggested that the γ-ray emitting site is located at a distance > 14 pc from the central engine. The time scale of the radio flux variability seen in AGNs is often shorter than one month (Lazio et al, 2001;Kadota et al, 2012), and therefore it is important to carry out frequent VLBI monitoring observations on a time intervals of weeks.…”

Section: Introductionmentioning

confidence: 99%