Radio spectral index distribution of SDSS-FIRST sources across optical diagnostic diagrams

Zajaček, Michal; Busch, G.; Valencia-S., M.; Eckart, A.; Britzen, S.; Fuhrmann, L.; Schneeloch, Jana; Fazeli, Nastaran; Harrington, Kevin; Zensus, J. A.

doi:10.1051/0004-6361/201833388

Cited by 36 publications

(37 citation statements)

References 83 publications

(114 reference statements)

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“…We investigate the jet hypothesis further by determining the spectral index of the mmcontinuum emission of HS 0810+2554. Typically, non-thermal synchrotron emission from jets dominates their SED at frequencies 10 GHz (Gioia, Gregorini & Klein 1982;Duric, Bourneuf & Gregory 1988;Zajaček et al 2019) and thermal emission from dust in the disc begins to dominate at mm-wavelengths. The nonthermal synchrotron spectra of jets are often fit with power-law models of the form S ν ∝ ν α , where α is the spectral index.…”

Section: E N S I N G a Na Ly S I Smentioning

confidence: 99%

Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554

Chartas

Davidson

Brusa³

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the quadruply lensed z = 1.51 quasar HS 0810+2554 which provide useful insight on the kinematics and morphology of the CO molecular gas and the ∼ 2 mm-continuum emission in the quasar host galaxy. Lens modelling of the mm-continuum and the spectrally integrated CO(J = 3→2) images indicates that the source of the mm-continuum has an eccentricity of e ∼ 0.9 with a size of ∼1.6 kpc and the source of line emission has an eccentricity of e ∼ 0.7 with a size of ∼1 kpc. The spatially integrated emission of the CO(J = 2→1) and CO(J = 3→2) lines shows a triple peak structure with the outer peaks separated by Δv21 = 220 ± 19 km s−1 and Δv32 = 245 ± 28 km s−1, respectively, suggesting the presence of rotating molecular CO line emitting gas. Lensing inversion of the high spatial resolution images confirms the presence of rotation of the line emitting gas. Assuming a conversion factor of αCO = 0.8 M⊙ (K km s−1 pc2)−1 we find the molecular gas mass of HS 0810+2554 to be MMol = (5.2 ± 1.5)/μ32 × 1010 M⊙, where μ32 is the magnification of the CO(J = 3→2) emission. We report the possible detection, at the 3.0–4.7σ confidence level, of shifted CO(J = 3→2) emission lines of high-velocity clumps of CO emission with velocities up to 1702 km s−1. We find that the momentum boost of the large-scale molecular wind is below the value predicted for an energy-conserving outflow given the momentum flux observed in the small-scale ultrafast outflow.

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Section: E N S I N G a Na Ly S I Smentioning

confidence: 99%

Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554

Chartas

Davidson

Brusa³

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Both cases represent optically thick synchrotron emission, S ∝ ν 0.5−1.5 , typical of radio cores; -We increased the value of ξ to 3.0, which corresponds to α = 1 for the cylindrical geometry (optically thin synchtrotron emission, S ∝ ν −1 , typical of older radio lobes) or α = 0 for discrete emission components (flat spectrum). With these two values of the Doppler boosting exponent, we essentially cover the whole range of the radio-spectral indices that were found within optical diagnostic diagrams of galaxies (see Zajaček et al 2019, for details). The blazars that are usually associated with LINERs having lower line-ratio log ([O iii]/Hβ), typically have flat to inverted radio spectra with an offset in the radio-spectral index distribution with respect to Seyfert galaxies (Zajaček et al 2019).…”

Section: Modeling the Precessing Inner Jetmentioning

confidence: 99%

“…With these two values of the Doppler boosting exponent, we essentially cover the whole range of the radio-spectral indices that were found within optical diagnostic diagrams of galaxies (see Zajaček et al 2019, for details). The blazars that are usually associated with LINERs having lower line-ratio log ([O iii]/Hβ), typically have flat to inverted radio spectra with an offset in the radio-spectral index distribution with respect to Seyfert galaxies (Zajaček et al 2019).…”

Section: Modeling the Precessing Inner Jetmentioning

confidence: 99%

A cosmic collider: Was the IceCube neutrino generated in a precessing jet-jet interaction in TXS 0506+056?

Britzen

Fendt

Böttcher

et al. 2019

A&A

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Context. The neutrino event IceCube−170922A appears to originate from the BL Lac object TXS 0506+056. To understand the neutrino creation process and to localize the emission site, we studied the radio images of the jet at 15 GHz. Aims. Other BL Lac objects show properties similar to those of TXS 0506+056, such as multiwavelength variability or a curved jet. However, to date only TXS 0506+056 has been identified as neutrino emitter. The aim of this paper is to determine what makes the parsec-scale jet of TXS 0506+056 specific in this respect. Methods. We reanalyzed and remodeled 16 VLBA 15 GHz observations between 2009 and 2018. We thoroughly examined the jet kinematics and flux-density evolution of individual jet components during the time of enhanced neutrino activity between September 2014 and March 2015, and in particular before and after the neutrino event. Results. Our results suggest that the jet is very strongly curved and most likely observable under a special viewing angle of close to zero. We may observe the interaction between jet features that cross each other’s paths. We find subsequent flux-density flaring of six components passing the likely collision site. In addition, we find a strong indication for precession of the inner jet, and model a precession period of about 10 yr via the Lense-Thirring effect. We discuss an alternative scenario, which is the interpretation of observing the signature of two jets within TXS 0506+056, again hinting toward a collision of jetted material. We essentially suggest that the neutrino emission may result from the interaction of jetted material in combination with a special viewing angle and jet precession. Conclusions. We propose that the enhanced neutrino activity during the neutrino flare in 2014–2015 and the single EHE neutrino IceCube-170922A could have been generated by a cosmic collision within TXS 0506+056. Our findings seem capable of explaining the neutrino generation at the time of a low gamma-ray flux and also indicate that TXS 0506+056 might be an atypical blazar. It seems to be the first time that a potential collision of two jets on parsec scales has been reported and that the detection of a cosmic neutrino might be traced back to a cosmic jet-collision.

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“…Another property that should be taken into consideration is the potential contribution of the jet and its components to the optical luminosity, which can affect the positioning of the source within R Hβ − L 5100 relation in terms of the luminosity. In particular, correlations have been found between the radio spectral slope, radio loudness, the luminosity of [OIII] line and the strength of FeII line (Zajaček et al, 2019;Laor et al, 2019). More refined results will be presented in the near future.…”

Section: Pos(multif2019)010mentioning

confidence: 85%

Quasars from LSST as dark energy tracers: first steps

Aldama¹,

Panda²,

Czerny³

2020

Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)

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In the near future, new surveys promise a significant increase in the number of quasars (QSO) at large redshifts. This will help to constrain the dark energy models using quasars. The Large Synoptic Survey Telescope (LSST) will cover over 10 million QSO in six photometric bands during its 10-year run. QSO will be monitored and subsequently analyzed using the photometric reverberation mapping (RM) technique. In low-redshift quasars, the combination of reverberation-mapped and spectroscopic results have provided important progress. However, there are still some facts which have to be taken into account for future results. It has been found that super-Eddington sources show time delays shorter than the expected from the well-known Radius-Luminosity (R Hβ − L 5100) relation. Using a sample of 117 Hβ reverberation-mapped AGN with 0.02 < z < 0.9, we propose a correction by the accretion rate effect recovering the classical R Hβ − L 5100 relation. We determined the cosmological constants, which are in agreement with Λ-Cold Dark Matter model within 2σ confidence level, which is still not suitable for testing possible departures from the standard model. Upcoming LSST data will decrease the uncertainties in the dark energy determination using reverberation-mapped sources, particularly at high redshifts. We show the first steps in the modeling of the expected light curves for Hβ and Mg II.

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Radio spectral index distribution of SDSS-FIRST sources across optical diagnostic diagrams

Cited by 36 publications

References 83 publications

Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554

Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554

A cosmic collider: Was the IceCube neutrino generated in a precessing jet-jet interaction in TXS 0506+056?

Quasars from LSST as dark energy tracers: first steps

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