New H.E.S.S. diffuse emission from the Galactic center

Lacroix et al. (2016) show that the newly detected H.E.S.S. (High Energy Stereoscopic System) gamma-ray diffuse emission from the Galactic center below 0.45 deg can be accounted for by inverse Compton emission from millisecond pulsars and heavy (~ 100 TeV) dark matter annihilating to electrons or muons with a thermal or sub-thermal cross-section, provided that the dark matter density profile features a supermassive black hole-induced spike on sub-pc scales.

Image: Center of our Galaxy. Credit: NASA, ESA, SSC, CXC, and STScI

They discuss the impact of the interstellar radiation field, magnetic field and diffusion set-up on the spectral and spatial morphology of the resulting emission. For well-motivated parameters, they show that the DM-induced emission reproduces the spatial morphology of the H.E.S.S. signal above ~ 10 TeV, while they obtain a more extended component from pulsars at lower energies, which could be used as a prediction for future H.E.S.S. observations.

Lacroix et al. 2016 (preprint) - New H.E.S.S. diffuse emission from the Galactic center: a combination of heavy dark matter and millisecond pulsars? (arXiv)

Comments

ORBITAL PERIODS OF THE PLANETS

For orbital period generally we refer to the sidereal period, that is the temporal cycle that it takes an object to make a full orbit, relative to the stars. This is the orbital period in an inertial (non-rotating) frame of reference (365,25 days for the earth).

Astrophysics collection (March 11, 2016)

Latest astrophysics news Rotation curves of galaxies as a test of MOND? Galaxies are rotating with such speed that the gravity generated by their observable matter could not possibly hold them together. In a recent paper ( Haghi et al. 2016 ) the authors test the Modified Newtonian Dynamics (MOND). Read>> A binary origin for a central compact object (CCO)? Doroshenko et al. 2016 investigate the possible binary origin of the CCO XMMUJ173203.3-344518 . Read>> Rapidly rotating pulsars as possible sources of fast radio bursts (FRB) In a recent paper ( Lyutikov et al. 2016 ) the authors discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars. Read>> Supernovae from WD-WD direct collisions In recent years it was suggested that WD-WD direct collisions (probably extremely rare and occurring only in dense stellar clusters) provide an additional channel for supernova...

A BINARY ORIGIN FOR A CENTRAL COMPACT OBJECT (CCO)?

Figure: False-Colour X-ray and infrared emission image from the core of the infrared shell. The RGB colours correspond to Chandra X-ray 0.2-10 keV (blue), IRAC infrared 8 μm (green), and HPACS 70 μm (red) data. The intensity scale is logarithmic for all channels. Overlaid are equal brightness levels from the MIPS 24 μm band. Note that around the CCO the infrared emission is suppressed in the 70 μm band and enhanced in the 24 μm band suggesting higher dust temperature. Credit: Doroshenko et al 2016 Central compact objects (CCOs) are thought to be young isolated neutron stars that were born during the preceding core-collapse supernova explosion.

SpaceTime

Search This Blog