Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Heywood, Ian; Camilo, F.; Cotton, W. D.; Yusef‐Zadeh, F.; Abbott, T. D.; Adam, R.; Aldera, M. A.; Bauermeister, E. F.; Booth, R. S.; Botha, A. G.; Botha, D. H.; Brederode, L. R. S.; Brits, Z. B.; Buchner, S.; Burger, J. P.; Chalmers, J. M.; Cheetham, T.; Villiers, Dirk I. L. de; Dikgale-Mahlakoana, M. A.; Toit, L. J. du; Esterhuyse, S. W. P.; Fanaroff, B. L.; Foley, A. R.; Fourie, D.J.; Gamatham, R. R. G.; Goedhart, S.; Gounden, S.; Hlakola, M. J.; Hoek, C. J.; Hokwana, A.; Horn, D. M.; Horrell, Jasper; Hugo, B.; Isaacson, A. R.; Jonas, J. L.; Jordaan, Jacques; Joubert, A. F.; Józsa, G. I. G.; Julie, Roufurd; Kapp, F.; Kenyon, J. S.; Kotzé, P.; Kriel, Herman; Kusel, T. W.; Lehmensiek, Robert; Liebenberg, D. H.; Loots, Anita; Lord, R. T.; Lunsky, B. M.; Macfarlane, Peter S.; Magnus, Lindsay; Magozore, C.; Mahgoub, O.; Main, J. P. L.; Malan, J. A.; Malgas, R. D.; Manley, Jason; Maree, Matthys; Merry, Bruce; Millenaar, Rob; Mnyandu, N.; Moeng, I. P. T.; Monama, T. E.; Mphego, M. C.; New, Wesley; Ngcebetsha, B.; Oozeer, Nadeem; Otto, A. J.; Passmoor, S. S.; Patel, A. A.; Peens-Hough, A.; Perkins, Simon; Ratcliffe, S.; Renil, Rosly; Rust, A.; Salie, S.; Schwardt, Ludwig; Serylak, M.; Siebrits, R.; Sirothia, S. K.; Smirnov, Alexander; Sofeya, L.; Swart, Paul; Tasse, C.; Taylor, Deanna; Theron, I.P.; Thorat, K.; Tiplady, A. J.; Tshongweni, S.; Balla, T. J. van; Byl, A. van der; Merwe, C. van der; Dyk, C. L. van; Rooyen, Ruby van; Tonder, V. van; Wyk, R. Van; Wallace, Bruce; Welz, M. G.; Williams, L. P.

doi:10.1038/s41586-019-1532-5

Cited by 112 publications

(80 citation statements)

References 37 publications

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“…A massive star or pulsar moving through the CMZ with velocity v * ∼ v a can intersect and inject CRs into a magnetic flux tube that has been stretched by the bipolar outflow from the CMZ (Heywood et al 2019). We conjecture that the perpendicular radio harp sizes correspond to the radial flux-tube extents while the regular arrangement of the harp "strings" in Fig.…”

Section: Sources Powering Non-thermal Filamentsmentioning

confidence: 84%

“…Radio observations of the Galactic center region show many isolated, elongated filaments (Lang et al 1999;LaRosa et al 2001;Nord et al 2004;Yusef-Zadeh et al 2004). Recent high-resolution observations with the MeerKAT radio telescope found that the filaments trace bipolar bubbles that are rising from the CMZ near the Galactic center (Heywood et al 2019). The filaments are characterised by a high aspect ratio, a filament-aligned magnetic field (Lang et al 1999), strongly polarized emission (LaRosa et al 2001), and a hard spectral index that steepens away from the geometric center of the filaments (Law et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Probing Cosmic-Ray Transport with Radio Synchrotron Harps in the Galactic Center

Thomas

Pfrommer

Enßlin

2020

ApJL

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Recent observations with the MeerKAT radio telescope reveal a unique population of faint nonthermal filaments pervading the central molecular zone (CMZ). Some of those filaments are organized into groups of almost parallel filaments, seemingly sorted by their length, so that their morphology resembles a harp with radio emitting "strings". We argue that the synchrotron emitting GeV electrons of these radio harps have been consecutively injected by the same source (a massive star or pulsar) into spatially intermittent magnetic fiber bundles within a magnetic flux tube or via time-dependent injection events. After escaping from this source, the propagation of cosmic ray (CR) electrons inside a flux tube is governed by the theory of CR transport. We propose to use observations of radio harp filaments to gain insight into the specifics of CR propagation along magnetic fields of which there are two principle modes: CRs could either stream with self-excited magneto-hydrodynamical waves or diffuse along the magnetic field. To disentangle these possibilities, we conduct hydrodynamical simulations of either purely diffusing or streaming CR electrons and compare the resulting brightness distributions to the observed synchrotron profiles of the radio harps. We find compelling evidence that CR streaming is the dominant propagation mode for GeV CRs in one of the radio harps. Observations at higher angular resolution should detect more radio harps and may help to disentangle projection effects of the possibly three-dimensional flux-tube structure of the other radio harps.

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Section: Sources Powering Non-thermal Filamentsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Probing Cosmic-Ray Transport with Radio Synchrotron Harps in the Galactic Center

Thomas

Pfrommer

Enßlin

2020

ApJL

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“…Krumholz et al, 2017), although feedback from the central supermassive black hole cannot be ruled out. Irrespective of its origin, it is possible that this event contributed to the high CR ionisation rate, especially given its large energy budget of ∼ 7 × 10 52 ergs (Heywood et al, 2019). These CRs may themselves be responsible for the Galactic wind emanating from the CMZ, in the process explaining the origin of the energetic non-thermal filaments throughout the CMZ, as well as their perpendicular orientation relative to the disc plane (Yusef-Zadeh and Wardle, 2019).…”

Section: The Central Molecular Zonementioning

confidence: 99%

Impact of Low-Energy Cosmic Rays on Star Formation

et al. 2020

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In recent years, exciting developments have taken place in the identification of the role of cosmic rays in star-forming environments. Observations from radio to infrared wavelengths and theoretical modelling have shown that lowenergy cosmic rays (< 1 TeV) play a fundamental role in shaping the chemical richness of the interstellar medium, determining the dynamical evolution of molecular clouds. In this review we summarise in a coherent picture the main results obtained by observations and by theoretical models of propagation and generation 2 Marco Padovani et al.of cosmic rays, from the smallest scales of protostars and circumstellar discs, to young stellar clusters, up to Galactic and extragalactic scales. We also discuss the new fields that will be explored in the near future thanks to new generation instruments, such as: CTA, for the γ-ray emission from high-mass protostars; SKA and precursors, for the synchrotron emission at different scales; and ELT/HIRES, JWST, and ARIEL, for the impact of CRs on exoplanetary atmospheres and habitability.

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“…The nature of the radio filaments is generally better known: magnetic structures illuminated by GeV electrons. Based on recent MeerKAT results, the GeV electrons mostly likely come from a bursting event in the vicinity of Sgr A , which drives a bipolar outflow and accelerated electrons at the shock front (Heywood et al 2019), though some radio filaments might be powered by local particle accelerators such as PWNe and SNRs . However, the X-ray filaments seem to show more complex origins.…”

Section: Origin Of Galactic Center Non-thermal Filamentsmentioning

confidence: 99%

“…Dozens of radio filaments as long as tens of parsecs was detected by the Very Large Array within the central ∼ 2 • of the Galaxy, with strong magnetic field (∼ 1 mG) aligning along the major axis of the filaments (Morris & Serabyn 1996;Yusef-Zadeh & Morris 1988). Recent observations of the MeerKAT telescope have revealed more than 100 filaments, which seem to be associated with the newly discovered bi-polar radio bubbles (Heywood et al 2019). Thanks to polarization detection, the emission mechanism of non-thermal radio filaments has been pinned down to synchrotron emission.…”

Section: Introductionmentioning

confidence: 99%

NuSTAR and Chandra Observations of the Galactic Center Nonthermal X-Ray Filament G0.13–0.11: A Pulsar-wind-nebula-driven Magnetic Filament

Zhang

Zhu

et al. 2020

ApJ

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One of the most unique phenomena in the Galactic center region is the existence of numerous long and narrow filamentary structures within a few hundred parsecs of Sgr A . While more than one than one hundred radio filaments have been revealed by MeerKAT, about two dozens X-ray filaments have been discovered so far. In this article, we report our analysis on the deep Chandra and NuSTAR observations of a non-thermal X-ray filament, G0.13-0.11, which is located adjacent to the Radio arc. Chandra revealed a unique morphology of G0.13-0.11, which is an elongated (0.1 pc in width and 3.2 pc in length) structure slightly bended towards the Radio arc. A pulsar candidate (Γ ∼ 1.4) is detected in the middle of the filament, with a tail of diffuse non-thermal X-ray emission on one side of the filament. The filament is detected by NuSTAR up to 79 keV, with the hard X-ray centroid consistent with the pulsar candidate. We found that the X-ray intensity decays along the filament farther away from the pulsar candidate, dropping to half of its peak value at 2.2 pc away. This system is mostly likely a Pulsar Wind Nebula interacting with ambient interstellar magnetic field, where the filaments are kinetic jets from PWN as recently proposed. The nature of this filament adds to complex origin of the X-ray filaments, which serve as powerful tools to probe local and global powerful particle accelerators in the Galactic center.

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Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Cited by 112 publications

References 37 publications

Probing Cosmic-Ray Transport with Radio Synchrotron Harps in the Galactic Center

Probing Cosmic-Ray Transport with Radio Synchrotron Harps in the Galactic Center

Impact of Low-Energy Cosmic Rays on Star Formation

NuSTAR and Chandra Observations of the Galactic Center Nonthermal X-Ray Filament G0.13–0.11: A Pulsar-wind-nebula-driven Magnetic Filament

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