Introduction to X Ray Excess

The afterglow emission from the kilonova/macronova ejecta may explain the X-ray excess but exceeds the radio observations if the spectrum is the same.

66, thus supports (with caveats) an accretion-powered origin for the X-ray excess in GW170817.

No conventional astrophysical explanation of the magnificent seven hard x-ray excess exists at present.

Equally, we also compute the x-ray excess emission resulting from the conversion of axions back to photons in the presence of a strong magnetic field in the envelope of these stars.

The spectral energy distributions (SEDs) of some blazars exhibit an ultraviolet (UV) and/or soft X-ray excess that can be modeled with different radiation mechanisms.

The origin of the Soft X-ray excess in the spectra of several nearby active galactic nucleus is still highly debated.

Soft and hard X-ray excesses, compared to the continuum power-law shape between ∼2-10 keV, are common features observed in the spectra of active galactic nuclei (AGN) and are associated with the accretion disc-corona system around the supermassive black hole.

The average spectrum over the entire duration exhibits a strong soft X-ray excess above the power law continuum.

, the head) at ∼48 kpc west of the X-ray peak, a split cold gas tail that extends eastward to ∼163 kpc, and a plume of spiral-like X-ray excess (within about 81–324 kpc northeast of the cluster core) that connects to the end of the tail.

The joint X-ray spectral analyses of five sets of Soft X-ray Telescope and Large Area X-ray Proportional Counter spectral data reveal a soft X-ray excess component, a narrow iron line (with no indication of a significant Compton hump), and a steepening power law (ΔΓ ∼ 0.

The extreme ultraviolet (EUV) continuum, and the ‘soft X-ray excess’, can be explained with a ‘warm Comptonisation’ component.

The soft X-ray excess in ESO 511–G030 can be described either as the thermal Comptonization of disk seed photons by a warm ( ), optically thick ( ), and compact ( ) corona or as the blurred reflection from an untruncated and moderate to highly ionized accretion disk.

It may be responsible for Soft X-ray excess seen in accreting sources.

The warm phase has kT (where T is the temperature and k is the Boltzmann constant) of about 120 electronvolts, reminiscent of the typical soft-X-ray excess, an almost universal thermal-like feature in the X-ray spectra of luminous active nuclei6–8.

Different approaches are known for the derivation of X-ray excess ionization, varying from classic approach1 to huge Monte Carlo simulations.

The soft X-ray excess - the excess of X-rays below 2 keV with respect to the extrapolation of the hard X-ray spectral continuum model - is a very common feature among type 1 active galactic nuclei (AGN); yet the nature of the soft X-ray excess is still poorly understood and hotly debated.

We report significant hard X-ray excesses in the energy range 2-8 keV for two nearby isolated neutron stars RX J1856.

At the same time, IAXO will have enough sensitivity to detect lower mass axions invoked to explain: 1) the origin of the anomalous “transparency” of the Universe to gamma-rays, 2) the observed soft X-ray excess from galaxy clusters or 3) some inflationary models.

The broad-band high-energy data agree with an accretion flow model consisting of two phases: an outer standard accretion disc with a warm upper layer, responsible for the optical--UV emission and the soft X-ray excess, and an inner slim JED playing the role of a hard X-ray emitting hot corona.

In this work, we test the CAB model that is put forward to explain the soft X-ray excess in the Coma cluster due to CAB ALPs conversion into photons using the M87 jet environment.

We assume that the flow is radially stratified, with an outer standard disc, an inner hot Comptonising region and an intermediate warm Comptonising region to produce the soft X-ray excess.

No significant X-ray excesses are found inside or to the west of the radio lobe.