Disk-Magnetosphere Interaction and Outflows: Conical Winds and Axial Jets

Romanova, M. M.; Ustyugova, G. V.; Koldoba, A. V.; Lovelace, R. V. E.

doi:10.1007/978-3-642-00576-3_19

Cited by 9 publications

(12 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Machida et al 2006;Hawley 2009;Romanova et al 2009;Mignone et al 2010, and references therein) have apparently shown that jet formation and acceleration is due to one of two types of physical mechanisms: plasma gun/magnetic towers, as proposed by Contopoulos (1995)/Lynden-Bell (1996, or centrifugal driving, as proposed by Blandford & Payne (1982). What is most important, however, is that these simulations demostrate that at the origin of jet formation and acceleration lies a large-scale magnetic field that threads the central "driving engine" (the central compact object and the surrounding innermost accretion disk).…”

Section: Jet Formation and Destructionmentioning

confidence: 99%

Formation and destruction of jets in X-ray binaries

Kylafis

Contopoulos

Kazanas

et al. 2012

A&A

View full text Add to dashboard Cite

Context. Neutron-star and black-hole X-ray binaries (XRBs) exhibit radio jets, whose properties depend on the X-ray spectral state and history of the source. In particular, black-hole XRBs emit compact, steady radio jets when they are in the so-called hard state. These jets become eruptive as the sources move toward the soft state, disappear in the soft state, and then re-appear when the sources return to the hard state. The jets from neutron-star X-ray binaries are typically weaker radio emitters than the black-hole ones at the same X-ray luminosity and in some cases radio emission is detected in the soft state. Aims. Significant phenomenology has been developed to describe the spectral states of neutron-star and black-hole XRBs, and there is general agreement about the type of the accretion disk around the compact object in the various spectral states. We investigate whether the phenomenology describing the X-ray emission on one hand and the jet appearance and disappearance on the other can be put together in a consistent physical picture. Methods. We consider the so-called Poynting-Robertson cosmic battery (PRCB), which has been shown to explain in a natural way the formation of magnetic fields in the disks of AGNs and the ejection of jets. We investigate whether the PRCB can also explain the formation, destruction, and variability of jets in XRBs. Results. We find excellent agreement between the conditions under which the PRCB is efficient (i.e., the type of the accretion disk) and the emission or destruction of the radio jet. Conclusions. The disk-jet connection in XRBs can be explained in a natural way using the PRCB.

show abstract

Section: Jet Formation and Destructionmentioning

confidence: 99%

Formation and destruction of jets in X-ray binaries

Kylafis

Contopoulos

Kazanas

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…Three-dimensional magnetohydrodynamic simulations (Machida et al 2006;Hawley 2009;Romanova et al 2009;Mignone et al 2010) have shown that there are two mechanisms for jet formation, both requiring a strong large-scale magnetic field: plasma gun/magnetic tower (Contopoulos 1995;LyndenBell 1996), and centrifugal driving (Blandford & Payne 1982). Such a magnetic field can originate from a large distance and the advecting flow carries it to the inner region and amplifies it (Igumenshchev 2008;Lovelace et al 2009;Tchekhovskoy et al 2011).…”

Section: Quiescent Statementioning

confidence: 99%

Accretion and ejection in black-hole X-ray transients

Kylafis

Belloni

2015

A&A

View full text Add to dashboard Cite

Context. A rich phenomenology has been accumulated over the years regarding accretion and ejection in black-hole X-ray transients (BHTs) and it needs an interpretation. Aims. Here we summarize the current observational picture of the outbursts of BHTs, based on the evolution traced in a hardnessluminosity diagram (HLD), and we offer a physical interpretation. Methods. The basic ingredient in our interpretation is the Poynting-Robertson cosmic battery (PRCB), which provides locally the poloidal magnetic field needed for the ejection of the jet. In addition, we make two assumptions, easily justifiable. The first is that the mass-accretion rate to the black hole in a BHT outburst has a generic bell-shaped form, whose characteristic time scale is much longer than the dynamical or the cooling ones. This is guaranteed by the observational fact that all BHTs start their outburst and end it at the quiescent state, i.e., at very low accretion rate, and that state transitions take place over long time scales (hours to days). The second assumption is that at low accretion rates the accretion flow is geometrically thick, ADAF-like, while at high accretion rates it is geometrically thin. Last, but not least, we demonstrate that the previous history of the system is absolutely necessary for the interpretation of the HLD. Results. Both, at the beginning and the end of an outburst, the PRCB establishes a strong poloidal magnetic field in the ADAF-like part of the accretion flow, and this explains naturally why a jet is always present in the right part of the HLD. In the left part of the HLD, the accretion flow is in the form of a thin disk, and such a disk cannot sustain a strong poloidal magnetic filed. Thus, no jet is expected in this part of the HLD. Finally, the counterclockwise traversal of the HLD is explained as follows: all outbursts start from the quiescent state, in which the inner part of the accretion flow is ADAF-like, threaded by a poloidal magnetic field. As the accretion rate increases and the source moves to the hard state, the poloidal magnetic field in the ADAF forces the flow to remain ADAF and the source to move upwards in the HLD rather than to turn left. Thus, the history of the system determines the counterclockwise traversal of the HLD. As a result, no BHT is expected to ever traverse the entire HLD curve in the clockwise direction. Conclusions. We offer a physical interpretation of accretion and ejection in BHTs with only one parameter, the mass transfer rate, plus the history of the system.

show abstract

“…On average, FUor outbursts should occur (or recur) about five times per star formed in the local region of the Milky Way (Hartmann & Kenyon 1996); there have been ∼10 FUors observed within a distance of 1.5 kpc in the last 80 years, compared with the star-formation rate in the same volume (about three per 50 years). These bursts also modify the protoplanetary disk chemistry and require a very different model than simple magnetospheric accretion (e.g., Green et al 2006;Quanz et al 2007;Zhu et al 2007;Romanova et al 2009;Cieza et al 2016), usually invoked for accreting young stars. If FUors represent a short-duration stage that all young stars undergo, then understanding their properties is vital to models of planet formation and the evolution of protoplanetary gas-rich disks.…”

Section: Introductionmentioning

confidence: 99%

The Mid-Infrared Evolution of the Fu Orionis Disk

Green

Jones

Keller

et al. 2016

ApJ

View full text Add to dashboard Cite

We present new SOFIA-FORCAST observations obtained in 2016 February of the archetypal outbursting lowmassyoung stellar object FU Orionis, and wecompare the continuum, solid-state, and gas properties with midinfrareddata obtained at the same wavelengths in 2004 with Spitzer-IRS. In this study, we conduct the first midinfraredspectroscopic comparison of an FUor over a long time period. Over a 12-year period, UBVR monitoring indicates that FU Orionis has continued its steady decrease in overall brightness by ∼14%. We find that this decrease in luminosity occurs only at wavelengths 20 μm. In particular, the continuum shortward of the silicate emission complex at 10 μm exhibits a ∼12% (∼3σ) drop in flux densitybut no apparent change in slope; both the Spitzer and SOFIA spectra are consistent with a 7200 K blackbody. Additionally, the detection of water absorption is consistent with the Spitzer spectrum. The silicate emission feature at 10 μm continues to be consistent with unprocessed grains, unchanged over 12 years. We conclude that either the accretion rate in FU Orionis has decreased by ∼12-14% over this time baselineorthe inner disk has cooled, but the accretion disk remains in a superheated state outside the innermost region.

show abstract

Disk-Magnetosphere Interaction and Outflows: Conical Winds and Axial Jets

Cited by 9 publications

References 29 publications

Formation and destruction of jets in X-ray binaries

Formation and destruction of jets in X-ray binaries

Accretion and ejection in black-hole X-ray transients

The Mid-Infrared Evolution of the Fu Orionis Disk

Contact Info

Product

Resources

About