SIMBAD references

2014ApJ...791...41H - Astrophys. J., 791, 41 (2014/August-2)

The origin of the X-ray emission from the high-velocity cloud MS30.7-81.4-118.


Abstract (from CDS):

A soft X-ray enhancement has recently been reported toward the high-velocity cloud MS30.7-81.4-118 (MS30.7), a constituent of the Magellanic Stream. In order to investigate the origin of this enhancement, we have analyzed two overlapping XMM-Newton observations of this cloud. We find that the X-ray enhancement is ∼6' or ∼100 pc across, and is concentrated to the north and west of the densest part of the cloud. We modeled the X-ray enhancement with a variety of spectral models. A single-temperature equilibrium plasma model yields a temperature of (3.69–0.44+0.47) x 106K and a 0.4-2.0 keV luminosity of 7.9x1033 erg/s. However, this model underpredicts the on-enhancement emission around 1 keV, which may indicate the additional presence of hotter plasma (T ≳ 107 K), or that recombination emission is important. We examined several different physical models for the origin of the X-ray enhancement. We find that turbulent mixing of cold cloud material with hot ambient material, compression or shock heating of a hot ambient medium, and charge exchange reactions between cloud atoms and ions in a hot ambient medium all lead to emission that is too faint. In addition, shock heating in a cool or warm medium leads to emission that is too soft (for reasonable cloud speeds). We find that magnetic reconnection could plausibly power the observed X-ray emission, but resistive magnetohydrodynamical simulations are needed to test this hypothesis. If magnetic reconnection is responsible for the X-ray enhancement, the observed spectral properties could potentially constrain the magnetic field in the vicinity of the Magellanic Stream.

Abstract Copyright:

Journal keyword(s): Galaxy: halo - ISM: clouds - ISM: individual: MS30.7-81.4-118 - X-rays: ISM

Simbad objects: 11

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