PKS 0405−385: The Smallest Radio Quasar?

Kedziora-Chudczer, Lucyna; Jauncey, D. L.; Wieringa, M.; Walker, Mark A.; Nicolson, G. D.; Reynolds, John E.; Tzioumis, A. K.

doi:10.1086/311001

Cited by 153 publications

(166 citation statements)

References 18 publications

Supporting

Mentioning

162

Contrasting

Order By: Relevance

“…a handful discovered so far (Kedziora-Chudczer et al 1997;Dennett-Thorpe & de Bruyn 2000;Bignall et al 2003). Only 1 of the MASIV Survey sources (J1819+345) displayed such extreme scintillation at 5 GHz.…”

Section: Appendix B: Ruling Out Interpretation As Correlated 5 Ghz Anmentioning

confidence: 98%

The MASIV Survey – IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs

Koay

Macquart

Jauncey

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We investigate the relationship between 5 GHz interstellar scintillation (ISS) and 15 GHz intrinsic variability of compact, radio-selected AGNs drawn from the Microarcsecond Scintillation-Induced Variability (MASIV) Survey and the Owens Valley Radio Observatory (OVRO) blazar monitoring program. We discover that the strongest scintillators at 5 GHz (modulation index, m 5 ≥ 0.02) all exhibit strong 15 GHz intrinsic variability (m 15 ≥ 0.1). This relationship can be attributed mainly to the mutual dependence of intrinsic variability and ISS amplitudes on radio core compactness at ∼ 100 µas scales, and to a lesser extent, on their mutual dependences on source flux density, arcsec-scale core dominance and redshift. However, not all sources displaying strong intrinsic variations show high amplitude scintillation, since ISS is also strongly dependent on Galactic line-of-sight scattering properties. This observed relationship between intrinsic variability and ISS highlights the importance of optimizing the observing frequency, cadence, timespan and sky coverage of future radio variability surveys, such that these two effects can be better distinguished to study the underlying physics. For the full MASIV sample, we find that Fermi-detected gamma-ray loud sources exhibit significantly higher 5 GHz ISS amplitudes than gamma-ray quiet sources. This relationship is weaker than the known correlation between gamma-ray loudness and the 15 GHz variability amplitudes, most likely due to jet opacity effects.

show abstract

Section: Appendix B: Ruling Out Interpretation As Correlated 5 Ghz Anmentioning

confidence: 98%

The MASIV Survey – IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs

Koay

Macquart

Jauncey

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The Lorentz factor γ ≡ 1/ 1 − v 2 /c 2 of these jets ranges from mildly relativistic: γ ∼ 2.55 for GRS 1915+105 (Mirabel & Rodriguez 1994, to quite relativistic: γ = O (10) for typical quasars (e.g. Ghisellini et al 1993), and even to highly relativistic: γ ∼ 10 3 for PKS 0405−385 (Kedziora-Chudczer et al 1997). These jets are not continuous streams of matter, but consist of individual blobs, or "cannonballs".…”

Section: Relativistic Jets In Astrophysicsmentioning

confidence: 99%

On the optical and X-ray afterglows of gamma ray bursts

Dado

Dar

Rújula

2002

A&A

256

View full text Add to dashboard Cite

Abstract. We severely criticize the consuetudinary analysis of the afterglows of gamma-ray bursts (GRBs) in the conical-ejection fireball scenarios. We argue that, instead, recent observations imply that the long-duration GRBs and their afterglows are produced by highly relativistic jets of cannonballs (CBs) emitted in supernova explosions. The CBs are heated by their collision with the supernova shell. The GRB is the boosted surface radiation the CBs emit as they reach the transparent outskirts of the shell. The exiting CBs further decelerate by sweeping up interstellar matter (ISM). The early X-ray afterglow is dominated by thermal bremsstrahlung from the cooling CBs, the optical afterglow by synchrotron radiation from the ISM electrons swept up by the CBs. We show that this model fits simply and remarkably well all the measured optical afterglows of the 15 GRBs with known redshift, including that of GRB 990123, for which unusually prompt data are available. We demonstrate that GRB 980425 was a normal GRB produced by SN1998bw, with standard X-ray and optical afterglows. We find that the very peculiar afterglow of GRB 970508 can be explained if its CBs encountered a significant jump in density as they moved through the ISM. The afterglows of the nearest 8 of the known-redshift GRBs show various degrees of evidence for an association with a supernova akin to SN1998bw. In all other cases such an association, even if present, would have been undetectable with the best current photometric sensitivities. This gives strong support to the proposition that most, maybe all, of the long-duration GRBs are associated with supernovae. Although our emphasis is on optical afterglows, we also provide an excellent description of X-ray afterglows.

show abstract

“…Since its discovery, two main explanations for the very short time scale variability have been proposed, one is that the IDV is intrinsic to the sources, but this frequently leads to a very high brightness temperature of the emitting components (Qian et al 1991) that far exceeds the inverseCompton limit (10 12 K, see Kellermann & Pauliny-Toth 1969). Another explanation is that the IDV is caused by propagation effects, namely by interstellar scintillation (ISS) in our galaxy (see Kedziora-Chudczer et al 1997;Dennett-Thorpe & de Bruyn 2000;Bignall et al 2003). For the "classical" type-II IDV sources (variability time scales <0.5-2 days), however, the origin of the variability is not completely understood (e.g.…”

Section: Introductionmentioning

confidence: 98%

Intra-day variability observations of S5 0716+714 over 4.5 years at 4.8 GHz

Liu

Song

Marchili

et al. 2012

A&A

View full text Add to dashboard Cite

Aims. We aim to search for evidence of annual modulation in the time scales of the BL Lac object S5 0716+714. Methods. The intra-day variability (IDV) observations were carried out monthly from 2005 to 2009, with the Urumqi 25 m radio telescope at 4.8 GHz.Results. The source has shown prominent IDV as well as long-term flux variations. The IDV time scale does show evidence in favor of an annual modulation, suggesting that the IDV of 0716+714 is dominated by interstellar scintillation. The source underwent a strong outburst phase between mid-2008 and mid-2009; a second intense flare was observed in late 2009, but no correlation between the total flux density and the IDV time scale is found, implying that the flaring state of the source does not have serious implications for the general characteristics of its intra-day variability. However, we find that the inner-jet position angle is changing throughout the years, which could result in an annual modulation noise in the anisotropic ISS model fit. There is also an indication that the lowest IDV amplitudes (rms in flux density) correspond to the slowest time scales of IDV, which would be consistent with an ISS origin of the IDV of 0716+714.

show abstract

PKS 0405−385: The Smallest Radio Quasar?

Cited by 153 publications

References 18 publications

The MASIV Survey – IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs

The MASIV Survey – IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs

On the optical and X-ray afterglows of gamma ray bursts

Intra-day variability observations of S5 0716+714 over 4.5 years at 4.8 GHz

Contact Info

Product

Resources

About