A Jet Source of Event Horizon Telescope Correlated Flux in M87

Punsly, Brian

doi:10.3847/1538-4357/aa960a

Cited by 3 publications

(8 citation statements)

References 44 publications

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“…This connection is provided by the fact that synchrotron radiation from the core region of M 87 at short millimeter wavelengths originates from the vicinity of its central BH (Hada et al 2011). In this regard, a peak frequency higher than 100 GHz supports the broadly investigated idea about a jet dominated by magnetic energy that is launched at the base of the M 87 jet (Broderick & Loeb 2009;Kino et al 2015;Punsly 2017). The underlying flat spectrum in the intermediate frequency range (∼ 15 − 86 GHz) is also interesting.…”

Section: Comparison With Theoretical Predictionsmentioning

confidence: 66%

“…In particular, a stronger magnetic field helps effective jet formation (see Yuan & Narayan 2014 for a review). These models prefer a significantly inverted or at least flat synchrotron spectrum up to > 100 GHz (Broderick & Loeb 2009;Kino et al 2015;Punsly 2017). A high turn-over frequency like this would imply a strong magnetic field strength B ∼ 100 G in the jet base (Kino et al 2015).…”

Section: Introductionmentioning

confidence: 97%

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Long-term millimeter VLBI monitoring of M 87 with KVN at milliarcsecond resolution: nuclear spectrum

Kim

Lee

Hodgson

et al. 2018

A&A

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We study the centimeter-to millimeter-wavelength synchrotron spectrum of the core of the radio galaxy M 87 at 0.8 mas ∼ 110R s spatial scales using four years of fully simultaneous, multi-frequency VLBI data obtained by the Korean VLBI Network (KVN). We find a core spectral index α of −0.37 (S ∝ ν +α ) between 22 GHz and 129 GHz. By combining resolution-matched flux measurements from the Very Long Baseline Array (VLBA) at 15 GHz and taking the Event Horizon Telescope (EHT) 230 GHz core flux measurements in epochs 2009 and 2012 as lower limits, we find evidence of a nearly flat core spectrum across 15 GHz and 129 GHz, which could naturally connect the 230 GHz VLBI core flux. The extremely flat spectrum is a strong indication that the jet base does not consist of a simple homogeneous plasma, but of inhomogeneous multi-energy components, with at least one component with the turn-over frequency 100 GHz. The spectral shape can be qualitatively explained if both the strongly (compact, optically thick at >100 GHz) and the relatively weakly magnetized (more extended, optically thin at <100 GHz) plasma components are colocated in the footprint of the relativistic jet.

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Section: Comparison With Theoretical Predictionsmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 97%

Long-term millimeter VLBI monitoring of M 87 with KVN at milliarcsecond resolution: nuclear spectrum

Kim

Lee

Hodgson

et al. 2018

A&A

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“…It should be noted that in general (more realistically) there would be a bivariate distribution of field strengths and filling fractions. In the example of M87, as noted above, for a/M = 0.99 the broadband spectrum and jet power was fit in Punsly (2017) with an inner accretion disk field strength of 8-15 G. For a filling factor, f ∼ 50%, this corresponds to B P ∼ 15-30 G in order to reproduce the jet power.…”

Section: Resultsmentioning

confidence: 99%

“…The new EHM solution is particularly relevant in the context of recent models of hollow jets emanating from the inner regions of an accretion flow that can describe a very wide range of plausible broadband spectra (mm wavelengths to UV) of the base of the jet in M87 on scales ∼ 15 − 30µas. In addition to explaining broadband emission from the region that produces the correlated 230 GHz flux detected by the Event Horizon Telescope (EHT), the jet base has sufficient power to energize the entire jet out to kiloparsec scales (Punsly 2017). There is no need to invoke a powerful invisible spine jet driven by the EHM in order to power the jet (Moscibrodzka et al 2016).…”

Section: Introductionmentioning

confidence: 99%

A new solution to the plasma starved event horizon magnetosphere

Punsly

Hardcastle

Hada

2018

A&A

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Very Long Baseline Interferometry observations at 86 GHz reveal an almost hollow jet in M87 with a forked morphology. The detailed analysis presented here indicates that the spectral luminosity of the central spine of the jet in M87 is a few percent of that of the surrounding hollow jet 200-400 µ as from the central black hole. Furthermore, recent jet models indicate that a hollow "tubular" jet can explain a wide range of plausible broadband spectra originating from jetted plasma located within ∼30 µ as of the central black hole, including the 230 GHz correlated flux detected by the Event Horizon Telescope. Most importantly, these hollow jets from the inner accretion flow have an intrinsic power capable of energizing the global jet out to kiloparsec scales. Thus motivated, this paper considers new models of the event horizon magnetosphere (EHM) in low luminosity accretion systems. Contrary to some models, the spine is not an invisible powerful jet. It is an intrinsically weak jet. In the new EHM solution, the accreted poloidal magnetic flux is weak and the background photon field is weak. It is shown how this accretion scenario naturally results in the dissipation of the accreted poloidal magnetic flux in the EHM not the accumulation of poloidal flux required for a powerful jet. The new solution indicates less large scale poloidal magnetic flux (and jet power) in the EHM than in the surrounding accretion flow and cannot support significant EHM driven jets.

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“…The discrepancy that was found is not an issue of time variability, it occurred with different telescopes and different frequencies over a ∼ 10 year period (t > 10 4 M). Model parameters such as the treatment of the polar axis, disk size and tilt, funnel magnetization and the jet launching region can affect the jet width (Dibi et al 2012;Sadowksi et al 2013;Punsly 2017). It is not clear, nor claimed, that Figures 2 and 3 capture the widest, most edge dominated possible simulated jets for z < 0.35 mas.…”

Section: Discussionmentioning

confidence: 99%

Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87

Punsly

2019

ApJL

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Jet models of Event Horizon Telescope (EHT) data should also conform to the observed jet profiles just downstream. This study evaluates conformance of models of black hole jets to images of the innermost jet of M87. This is a basic test that should be passed before using them to perform a physical interpretation of EHT data. Recent 86 GHz Very Long Baseline Interferometry observations of M87 have revealed the morphology and size of the jet near its source (< 65 M, or 0.06 lt-yrs after correcting for line of sight to the jet, where M is the black hole mass in geometrized units) for the first time. Current transverse resolution indicates that this region is dominated by flux emanating from the edge of the jet. The observed inner jet profiles are compared to all existing published synthetic radio images constructed from "state of the art" 3-D numerical simulations of the black hole accretion system in M87. Despite efforts to produce the characteristic wide, edge dominated jet, these models are too narrow (by a factor of ∼ 2) in the region 0.06 -0.32 lt-yrs from the source, even though the jets (spine and/or sheath) in the image plane might appear conformant farther downstream. Furthermore, the synthetic radio images are not edge dominated 0.06 -0.32 lt-yrs from the source, but spine dominated. Analyses that implement these models as physical diagnostics of EHT visibility amplitudes are therefore suspect. Thus, these inner jet characteristics are important considerations before applying simulations to the EHT data.

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A Jet Source of Event Horizon Telescope Correlated Flux in M87

Cited by 3 publications

References 44 publications

Long-term millimeter VLBI monitoring of M 87 with KVN at milliarcsecond resolution: nuclear spectrum

Long-term millimeter VLBI monitoring of M 87 with KVN at milliarcsecond resolution: nuclear spectrum

A new solution to the plasma starved event horizon magnetosphere

Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87

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