Many similar phenomena occur in astrophysical systems with spatial and mass scales different by many orders of magnitudes. For examples, collimated outflows are produced from the Sun, proto-stellar systems, gamma-ray bursts, neutron star and black hole X-ray binaries, and supermassive black holes; various kinds of flares occur from the Sun, stellar coronae, X-ray binaries and active galactic nu...

Our Galaxy harbours a large population of X-ray sources of intermediate to low X-ray luminosity (typically LX from 1027 to 1034 erg s−1). At energies below 2 keV, active coronae completely dominate the X-ray landscape. However, the nature and the properties of the Galactic sources detected at energies >∼ 2 keV is much less constrained. Optical follow-up spectroscopic observations show that in a...

We use archival Chandra X-Ray Observatory data to investigate X-ray emission from early-type galaxies in the rich z = 0.06 cluster Abell 3128. By combining the X-ray count-rates from an input list of optically-selected galaxies, we obtain a statistical detection of X-ray flux, unbiased by X-ray selection limits. Using 87 galaxies with reliable Chandra data, X-ray emission is detected for galaxi...

We report on a campaign to identify the counterparts to the population of X-ray sources discovered at the centre of our Galaxy by Wang et al. [7] using Chandra. We have used deep, near infrared images obtained on VLT/ISAAC to identify candidate counterparts as astrometric matches to the X-ray positions. Follow up KS-band spectroscopic observations of the candidate counterparts are used to searc...

As part of our campaign to determine the nature of the various source populations of the low-luminosity globular cluster X-ray sources, we have obtained a Chandra X-ray Observatory ACIS-S3 image of the globular cluster NGC 6440. We detect 24 sources to a limiting luminosity of ∼2×1031 erg s−1 (0.5–2.5 keV) inside the cluster’s half-mass radius, all of which lie within ∼2 core radii of the clust...

It has been suggested that most Be/X-ray binaries are low X-ray luminosity nearby objects, containing white dwarfs (Chevalier & Ilovaisky 1998). We show that existing evidence indicates that all known Be/X-ray binaries are relatively bright X-ray sources containing neutron stars and that the spectral distribution of this group differs considerably from that of isolated Be stars. We suggest that...