SIMBAD references

2017MNRAS.467.3642S - Mon. Not. R. Astron. Soc., 467, 3642-3647 (2017/May-3)

A single H II region model of the strong interstellar scattering towards Sgr A*.

SICHENEDER E. and DEXTER J.

Abstract (from CDS):

Until recently, the strong interstellar scattering observed towards the Galactic centre (GC) black hole, Sgr A*, was thought to come from dense gas within the GC region. The pulse broadening towards the transient magnetar SGR J1745-2900 near Sgr A* has shown that the source of the scattering is instead located much closer to Earth, possibly in a nearby spiral arm. We show that a single H II region along the line of sight, 1.5-4.8 kpc away from Earth with density ne of a few ≃100 cm–3 and radius R ≃ 1.8-3.2 pc can explain the observed angular broadening of Sgr A*. Clouds closer to the GC overproduce the observed disperson measure, providing an independent location constraint that agrees with that from the magnetar pulse broadening. Our model predicts that sources within <=10 pc should show the same scattering origin as the magnetar and Sgr A*, while the nearest known pulsars with separations >20 pc should not. The radio spectrum of Sgr A* should show a cut-off from free-free absorption at 0.2 <= ν <= 1 GHz. For a magnetic field strength B ≃ 15-70 µG, the H II region could produce the rotation measure of the magnetar, the largest of any known pulsar, without requiring the gas near Sgr A* to be strongly magnetized.

Abstract Copyright: © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): scattering - pulsars: individual: (J745-2900) - H ii regions - Galaxy: centre - Galaxy: centre

Simbad objects: 4

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