A survey for high optical polarization in quasars with core-dominant radio structure - Is there a beamed optical continuum?

Wills, Beverley J.; Wills, D.; Breger, M.; Antonucci, Robert; Barvainis, Richard

doi:10.1086/171869

Cited by 203 publications

(219 citation statements)

References 0 publications

Supporting

Mentioning

208

Contrasting

Unclassified

Order By: Relevance

“…Wardle & Homan 2003). Since beamed synchrotron radiation can also explain the high optical linear polarization observed in HPQs and contribute significantly to the optical continuum (Impey & Tapia 1990;Wills et al 1992), a similar origin to both the optical and the radio circular polarizations appears likely although they most probably arise from different regions. Since Faraday conversion is inefficient at visible wavelengths, the detected optical circular polarization should be caused by synchrotron emission.…”

Section: Detection Of Optical Circular Polarization and Implication Fmentioning

confidence: 97%

“…Unless indicated otherwise, these measurements were obtained in white light, i.e., in the 3200-8800 Å or 4000-8800 Å spectral ranges, which Landstreet & Angel (1972); (b) Moore & Stockman (1981); (c) Stockman et al (1984); (d) ; (e) Impey & Tapia (1990); ( f ) Wills et al (1992); (g) Valtaoja et al (1993); (h) Takalo & Sillanpää (1993); (i) Impey et al (1995); ( j) Tommasi et al (2001a); (k) Tommasi et al (2001b).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical circular polarization in quasars

Hutsemékers

Borguet

Sluse

et al. 2010

A&A

127

View full text Add to dashboard Cite

We present new optical circular polarization measurements with typical uncertainties <0.1% for a sample of 21 quasars. All but two objects have null circular polarization. We use this result to constrain the polarization due to photon-pseudoscalar mixing along the line of sight. We detect significant (>3σ) circular polarization in two blazars with high linear polarization and discuss the implications of this result for quasar physics. In particular, the recorded polarization degrees may be indicative of magnetic fields as strong as 1 kG or a significant contribution of inverse Compton scattering to the optical continuum.

show abstract

Section: Detection Of Optical Circular Polarization and Implication Fmentioning

confidence: 97%

Section: Observations and Data Reductionmentioning

confidence: 99%

Optical circular polarization in quasars

Hutsemékers

Borguet

Sluse

et al. 2010

A&A

127

View full text Add to dashboard Cite

show abstract

“…Except for 4C 34.47, the spectral indices of polarized Ñux of the radio-optical aligned quasars are consistent with the opticalÈnear-UV range measured for blazars (e.g., Landau et al 1986), and a synchrotron component with moderately strong polarization (P D 10%) that provides of the total continuum Ñux would account [10% for the observed levels of polarization. The canonical benchmark for a highly polarized quasar has been that the broadband optical polarization exceed P \ 3% (e.g., Moore & Stockman 1981 ;Stockman et al 1984 ;Wills et al 1992). This criterion was based on the bimodal distribution of polarization observed among survey QSOs (Stockman 1978), a fact that suggested di †erent polarizing mechanisms dominate in the two regimes.…”

Section: Fig 7èas Inmentioning

confidence: 99%

“…The synchrotron components proposed here would be much more stable than those of classical blazars, and this is qualitatively consistent with jets viewed at larger angles to the ejection axis. A strong link between the existence of a beamed optical component and core-dominant radio structure is well established (e.g., Impey & Tapia 1988 ;Wills et al 1992), and strong optical polarization is almost always seen in superluminal sources. It is therefore interesting that the most core dominant of our targets, 4C 34.47, with lies in the range where a majority of log (F core /F tot ) B [0.3, sources would show high polarization (Impey et al 1989).…”

Section: Fig 7èas Inmentioning

confidence: 99%

Evidence for Polarized Synchrotron Components in Radio‐Optical Aligned Quasars

Schmidt

Smith

2000

ApJ

View full text Add to dashboard Cite

A tendency for the axes of double-lobed radio quasars to be aligned with the electric vectors of optical polarization in the active galactic nuclei is well known. However, the origin of the polarization and reason behind its correlation with radio morphology is not yet established. From accurate spectropolarimetry of seven quasars that show this alignment e †ect, we Ðnd that the polarization is universally conÐned to the continuum and not shared by the line emission or 3000 bump. Over the observed A region, 4000È8000 the spectral indices of polarized Ñux, are consistent with uniform polariza-A , P ] F j , tion applied to the light of the big blue bump or with synchrotron emission. However, electron scattering from an optically thick, geometrically thin, accretion disk is well known to give rise to a polarization position angle that is perpendicular to the disk axis. Optical synchrotron emission akin to that shown to exist in the miniblazar 3C 273 is a more attractive explanation, and supporting evidence can be found for some of the targets in the form of polarimetric variability over intervals of years. Properties of the most strongly polarized radio-optical aligned quasars can be explained by misdirected blazar core components that have net polarizations of P D 10% and provide D10% of the total optical light.

show abstract

“…There is evidence that the beamed synchrotron emission from the base of the radio jet extends to visible wavelengths in BL Lacs and quasars (Wills et al 1992). Several authors (Hardcastle & Worrall 2000;Chiaberge et al 2002;Kharb & Shastri 2004) investigated the correlations between the radio and optical regimes for radio-loud FRI-FRII radio galaxies with the sample size < ∼ 65 objects.…”

Section: Introductionmentioning

confidence: 99%

Radio-optical scrutiny of compact AGN: correlations between properties of pc-scale jets and optical nuclear emission

Arshakian¹,

Torrealba

Chavushyan

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. We study the correlations between the VLBA (Very Long Baseline Array) radio emission at 15 GHz, extended emission at 151 MHz, and optical nuclear emission at 5100 Å for a complete sample of 135 compact jets. Methods. We use the partial Kendall's tau correlation analysis to check the link between radio properties of parsec-scale jets and optical nuclear luminosities of host active galactic nuclei (AGN). Results. We find a significant positive correlation for 99 quasars between optical nuclear luminosities and total radio (VLBA) luminosities of unresolved cores at 15 GHz originated at milliarcseconds scales. For 18 BL Lacs, the optical continuum emission correlates with the radio emission of the jet at 15 GHz. We suggest that the radio and optical emission are beamed and originate in the innermost part of the sub-parsec-scale jet in quasars. Analysis of the relation between the apparent speed of the jet and the optical nuclear luminosity at 5100 Å supports the relativistic beaming model for the optical emission generated in the jet, and allows the peak values of the intrinsic optical luminosity of the jet and its Lorentz factor to be estimated for the populations of quasars (2 × 10 20 W Hz −1 and γ = 52), BL Lacs (9 × 10 21 W Hz −1 and γ = 20), and radio galaxies (1.5 × 10 21 W Hz −1 and γ = 9). The radio-loudness of quasars (the ratio of 15 GHz flux density and optical nuclear flux at 5100 Å) is found to increase at high redshifts, which is interpreted as progressively higher Doppler factors in radio regime compared to those in optical. A strong positive correlation is found between the intrinsic kinetic power of the jet (measured from the flux density at 151 MHz) and the apparent luminosities of the total and the unresolved core emission of the jet at 15 GHz. This correlation is interpreted in terms of an intrinsically more luminous parsec-scale jet producing more luminous extended structure, which is detectable at low radio frequencies, 151 MHz. A possibility that the low frequency radio emission is relativistically beamed in superluminal sources and therefore correlates with radio luminosity of the jet at 15 GHz cannot be ruled out. Monitoring of superluminal AGN in a wide range of frequencies is required to check the contribution of each effect.

show abstract

A survey for high optical polarization in quasars with core-dominant radio structure - Is there a beamed optical continuum?

Cited by 203 publications

References 0 publications

Optical circular polarization in quasars

Optical circular polarization in quasars

Evidence for Polarized Synchrotron Components in Radio‐Optical Aligned Quasars

Radio-optical scrutiny of compact AGN: correlations between properties of pc-scale jets and optical nuclear emission

Contact Info

Product

Resources

About