نتایج جستجو برای: ray emission
تعداد نتایج: 447481 فیلتر نتایج به سال:
The Knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of BF3/nano-γ-Al2O3 at room temperature in ethanol. This catalyst is characterized by powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and energy-disper...
We have for the first time detected X-ray emission associated with a protostellar jet, on the jet emanating from the L1551 IRS5 protostar. The IRS5 protostar is hidden behind a very large absorbing column density, making the direct observation of the jet’s emission possible. The observed X-ray emission is likely associated with the shock “working surface”, i.e. the interface between the jet and...
The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Kα line emission at 6.4 keV from material that is neutral or in a low ionization state can be produced either by X-ray photoionization or by cosmic-ray...
We use the observed optical-UV and X-ray emission spectrum of Cen X-4 during quiescence to constrain models for the accretion flow in this system. We argue that the optical-UV emission is not due to an optically-thick quiescent accretion disk, nor due to synchrotron emission from an Advection-Dominated Accretion Flow (ADAF). Emission from the bright spot could account for the observed optical-U...
X-ray images and spectra of 5 cataloged supernova remnants (SNRs), G12.0−0.1, G346.6−0.2, G348.5+0.1, G348.7+0.3, and G355.6−0.0, observed in the ASCA galactic plane survey are presented. The sizes of X-ray emission from G12.0−0.1, G348.5+0.1, G348.7+0.3, and G355.6−0.0 are comparable to their radio structures, while that of G346.6−0.2 is smaller than the radio structure. The X-ray spectra of a...
The X-ray colors and X-ray–to–optical luminosity ratios (LX/LB) of 61 early-type galaxies observed with the ROSAT PSPC are determined. The colors indicate that the X-ray spectral properties of galaxies vary as a function of LX/LB. The brightest X-ray galaxies have colors consistent with thermal emission from hot gas with roughly the same metallicity of 50% solar. The spatial variation of the co...
We analyze observations obtained with the Chandra X-ray Observatory of bright Compton thick active galactic nuclei (AGNs), those with column densities in excess of 1.5 × 10 cm along the lines of sight. We therefore view the powerful central engines only indirectly, even at X-ray energies. Using high spatial resolution and considering only galaxies that do not contain circumnuclear starbursts, w...
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