Inside the Bondi radius of M87

Abstract

Chandra X-ray observations of the nearby brightest cluster galaxy M87 resolve the hot gas structure across the Bondi accretion radius of the central supermassive black hole, a measurement possible in only a handful of systems but complicated by the bright nucleus and jet emission. By stacking only short frame-time observations to limit pileup, and after subtracting the nuclear PSF, we analysed the X-ray gas properties within the Bondi radius at 0.12 − 0.22 kpc (1.5 − 2.8 arcsec), depending on the black hole mass. Within 2 kpc radius, we detect two significant temperature components, which are consistent with constant values of 2 keV and 0.9 keV down to 0.15 kpc radius. No evidence was found for the expected temperature increase within ∼ 0.25 kpc due to the influence of the SMBH. Within the Bondi radius, the density profile is consistent with ρ∝r −1 . The lack of a temperature increase inside the Bondi radius suggests that the hot gas structure is not dictated by the SMBH's potential and, together with the shallow density profile, shows that the classical Bondi rate may not reflect the accretion rate onto the SMBH. If this density profile extends in towards the SMBH, the mass accretion rate onto the SMBH could be at least two orders of magnitude less than the Bondi rate, which agrees with Faraday rotation measurements for M87. We discuss the evidence for outflow from the hot gas and the cold gas disk and for cold feedback, where gas cooling rapidly from the hot atmosphere could feed the cirumnuclear disk and fuel the SMBH. At 0.2 kpc radius, the cooler X-ray temperature component represents ∼ 20% of the total Xray gas mass and, by losing angular momentum to the hot gas component, could provide a fuel source of cold clouds within the Bondi radius.

DISCOVERY OF AN OUTFLOW FROM RADIO OBSERVATIONS OF THE TIDAL DISRUPTION EVENT ASASSN-14li

“…The inferred profile is steeper than the R R 3 2 ( ) r µ -profile expected for Bondi accretion in the circumnuclear regions of low accretion rate systems (Bondi 1952), and from the R R 1 ( ) r µ -profile inferred within the Bondi radius of Sgr A* and the AGN in M87 (Baganoff et al 2003;Russell et al 2015). The circumnuclear density profile inferred from radio observations of the relativistic TDE Sw J1644+57 is consistent with R R 3 2 ( ) r µ -but shows a hint of a steeper slope at R  0.05 pc, the smallest radius probed (Berger et al 2012).…”

A new bound on axion-like particles

“…The cluster background accounts for up to 10% of the emission within the region covered by the nuclear point spread function. Reference [29] showed that the cluster surface brightness increases towards the nucleus in M87, therefore a background spectrum extracted in a surrounding annulus will likely underestimate the true background. Following [29], we have therefore used a ChaRT/marx PSF simulation to subtract the nuclear emission and evaluate the effect of the observed increase in the background cluster surface brightness.…”

“…Reference [29] showed that the cluster surface brightness increases towards the nucleus in M87, therefore a background spectrum extracted in a surrounding annulus will likely underestimate the true background. Following [29], we have therefore used a ChaRT/marx PSF simulation to subtract the nuclear emission and evaluate the effect of the observed increase in the background cluster surface brightness. The stellar population and unresolved low mass X-ray binaries contribute at most a few per cent of this background and are not considered further [36].…”

Accretion of rotating fluids onto stationary solutions

“…These conditions are easily met in astrophysics and atmospheric motion. The presence of a gradient of pressure, which is a sort of fluid group self force, renders the accretion motion non-geodesic.In accretion motion back reaction effects are taken into consideration in numerical and simulation analyses [1][2][3]. Full analytical treatments [4-8] drop back reaction effects for simplicity and cognitive treatments [9-15] may include emission effects and neglect back reaction too.…”

“…In accretion motion back reaction effects are taken into consideration in numerical and simulation analyses [1][2][3]. Full analytical treatments [4][5][6][7][8] drop back reaction effects for simplicity and cognitive treatments [9][10][11][12][13][14][15] may include emission effects and neglect back reaction too.…”