A strong magnetic field around the supermassive black hole at the centre of the Galaxy

Eatough, Ralph P.; Falcke, H.; Karuppusamy, R.; Lee, K. J.; Champion, D. J.; Keane, E. F.; Desvignes, G.; Schnitzeler, Dominic; Spitler, Laura; Krämer, M.; Klein, Bernd; Bassa, C. G.; Bower, Geoffrey C.; Brunthaler, A.; Cognard, I.; Deller, Adam T.; Demorest, Paul; Freire, P. C. C.; Kraus, A.; Lyne, A. G.; Noutsos, A.; Stappers, B. W.; Wex, Norbert

doi:10.1038/nature12499

Cited by 444 publications

(507 citation statements)

References 24 publications

(25 reference statements)

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“…However, only for the closest one, PSR J1745−2900, which is only 2 4 from Sgr A * (Bower et al 2015), has a case been made for a physical association (Rea et al 2013;Bower et al 2015). As well as having the highest DM of the eight, it also has a very large rotation measure (Eatough et al 2013;Shannon & Johnston 2013), strengthening the case for a physical association. With only one pulsar, we cannot constrain the form or extent of the ionized gas from the pulsar observations.…”

Section: Galactic Centermentioning

confidence: 99%

“…Table 11 lists 14 pulsars that are associated with SNR or pulsar wind nebulae (PWN) and have a known DM and an estimated distance based on the association. In this table, we also include a pulsar (PSR J0248 +6021) that is believed to lie in or near the H II region W5 (Theureau et al 2011) and the magnetar PSR J1745−2900 that is believed to lie close to the Galactic Center (Eatough et al 2013;Rea et al 2013). …”

Section: Association With Nebulaementioning

confidence: 99%

See 1 more Smart Citation

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

Yao¹,

Manchester²,

Wang³

2017

ApJ

1,021

997

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We present a new model for the distribution of free electrons in the Galaxy, the Magellanic Clouds, and the intergalactic medium (IGM) that can be used to estimate distances to real or simulated pulsars and fast radio bursts (FRBs) based on their dispersion measure (DM). The Galactic model has an extended thick disk representing the so-called warm interstellar medium, a thin disk representing the Galactic molecular ring, spiral arms based on a recent fit to Galactic H II regions, a Galactic Center disk, and seven local features including the Gum Nebula, Galactic Loop I, and the Local Bubble. An offset of the Sun from the Galactic plane and a warp of the outer Galactic disk are included in the model. Parameters of the Galactic model are determined by fitting to 189 pulsars with independently determined distances and DMs. Simple models are used for the Magellanic Clouds and the IGM. Galactic model distances are within the uncertainty range for 86 of the 189 independently determined distances and within 20% of the nearest limit for a further 38 pulsars. We estimate that 95% of predicted Galactic pulsar distances will have a relative error of less than a factor of 0.9. The predictions of YMW16 are compared to those of the TC93 and NE2001 models showing that YMW16 performs significantly better on all measures. Timescales for pulse broadening due to interstellar scattering are estimated for (real or simulated) Galactic and Magellanic Cloud pulsars and FRBs.

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Section: Galactic Centermentioning

confidence: 99%

Section: Association With Nebulaementioning

confidence: 99%

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

Yao¹,

Manchester²,

Wang³

2017

ApJ

1,021

997

View full text Add to dashboard Cite

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“…In general, studies of radio pulsars ⋆ E-mail: plazarus@mpifr-bonn.mpg.de have also been used to probe the interstellar medium (e.g. Bhat et al 1998;Berkhuijsen & Müller 2008;Eatough et al 2013). Furthermore, collections of MSPs are being observed regularly as part of so-called pulsar timing array (PTA) projects, which have the ultimate goal of detecting lowfrequency gravitational waves, possibly arising from the cosmic population of super-massive black-hole binaries (e.g.…”

Section: Introductionmentioning

confidence: 99%

Prospects for high-precision pulsar timing with the new Effelsberg PSRIX backend

Lazarus¹,

Karuppusamy²,

Graikou³

et al. 2016

Mon. Not. R. Astron. Soc.

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138

112

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The PSRIX backend is the primary pulsar timing instrument of the Effelsberg 100-m radio telescope since early 2011. This new ROACH-based system enables bandwidths up to 500 MHz to be recorded, significantly more than what was possible with its predecessor, the Effelsberg-Berkeley Pulsar Processor (EBPP). We review the first four years of PSRIX timing data for 33 pulsars collected as part of the monthly European Pulsar Timing Array (EPTA) observations. We describe the automated data analysis pipeline, CoastGuard, that we developed to reduce these observations. We also introduce TOASTER, the EPTA timing database used to store timing results, processing information and observation metadata. Using these new tools, we measure the phase-averaged flux densities at 1.4 GHz of all 33 pulsars. For 7 of these pulsars, our flux density measurements are the first values ever reported. For the other 26 pulsars, we compare our flux density measurements with previously published values. By comparing PSRIX data with EBPP data, we find an improvement of ∼2-5 times in signal-to-noise ratio achievable, which translates to an increase of ∼2-5 times in pulse time-of-arrival (TOA) precision. We show that such an improvement in TOA precision will improve the sensitivity to the stochastic gravitational wave background. Finally, we showcase the flexibility of the new PSRIX backend by observing several millisecond-period pulsars (MSPs) at 5 and 9 GHz. Motivated by our detections, we discuss the potential for complementing existing pulsar timing array data sets with MSP monitoring campaigns at these frequencies.

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“…TDE jets provide again a unique tool to probe the magnetic field structure which is generally very difficult to be studied except for the nuclei of the Milky Way and possibly a few nearby galaxies (e.g., Marrone et al 2007;Eatough et al 2013;Johnson et al 2015;Han 2013). The rotation measure of the radio-MM emission from the TDE jets when they propagate in the CNM can be used to probe the magnetic field structure in the host nuclei (Marrone et al 2007;Eatough et al 2013;Li, Yuan & Wang 2015). The Faraday rotation angle is strongly wavelength dependent (∝ λ 2 ).…”

Section: Magnetic Field In the Cnmmentioning

confidence: 99%

“…The Faraday rotation angle is strongly wavelength dependent (∝ λ 2 ). For a typical rotation measurement of ∼ 10 5 rad m −2 (Marrone et al 2007;Eatough et al 2013), MM polarization observations can be used to give an unambiguous measure of the rotation angle of the orders of tens of degrees. Such measurements are important for determining the intrinsic polarization angles of the jets, as well as the magnetic field structure of the CNM.…”

Section: Magnetic Field In the Cnmmentioning

confidence: 99%

Catching jetted tidal disruption events early in millimetre

Yuan

Wang

Lei

et al. 2016

Mon. Not. R. Astron. Soc.

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Relativistic jets can form from at least some tidal disruption events (TDEs) of (sub-)stellar objects around supermassive black holes. We detect the millimeter (MM) emission of IGR J12580+0134 -the nearest TDE known in the galaxy NGC 4845 at the distance of only 17 Mpc, based on Planck all-sky survey data. The data show significant flux jumps after the event, followed by substantial declines, in all six high frequency Planck bands from 100 GHz to 857 GHz. We further show that the evolution of the MM flux densities are well consistent with our model prediction from an off-axis jet, as was initially suggested from radio and X-ray observations. This detection represents the second TDE with MM detections; the other is Sw J1644+57, an on-axis jetted TDE at redshift of 0.35. Using the on-and off-axis jet models developed for these two TDEs as templates, we estimate the detection potential of similar events with the Large Millimeter Telescope (LMT) and the Atacama Large Millimeter/submillimeter Array (ALMA). Assuming an exposure of one hour, we find that the LMT (ALMA) can detect jetted TDEs up to redshifts z ∼ 1 (2), for a typical disrupted star mass of ∼ 1 M ⊙ . The detection rates of on-and off-axis TDEs can be as high as ∼ 0.6 (13) and 10 (220) per year, respectively, for the LMT (ALMA). We briefly discuss how such observations, together with follow-up radio monitoring, may lead to major advances in understanding the jetted TDEs themselves and the ambient environment of the CNM.

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A strong magnetic field around the supermassive black hole at the centre of the Galaxy

Cited by 444 publications

References 24 publications

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

Prospects for high-precision pulsar timing with the new Effelsberg PSRIX backend

Catching jetted tidal disruption events early in millimetre

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