Related papers: Stellar contributors to the hard X-ray background?
Despite the plethora of deep (sub-mJy) radio surveys there remains considerable doubt as to the exact nature of the galaxies contributing to the source counts. Current evidence suggests that starformation in moderately luminous 'normal'…
We have performed 23 GHz VLA observations of 7 compact, luminous infrared galaxies, selected to have evidence of starburst activity. New and published multi-frequency data are combined to obtain the spectral energy distributions of all 7…
The total extragalactic $\gamma$-ray flux provides a powerful probe into the origin and evolution of the highest energy processes in our universe. An important component of this emission is the isotropic $\gamma$-ray background (IGRB),…
The star formation activity of the host galaxies of active galactic nuclei (AGNs) provides valuable insights into the complex interconnections between black hole growth and galaxy evolution. A major obstacle arises from the difficulty of…
In this chapter we review some aspects of X-ray binaries, particularly those presenting steady jets, i.e. microquasars. Because of their proximity and similarities with active galactic nuclei (AGN), galactic jet sources are unique…
Recent observational results obtained with SCUBA, COBE and ISO have greatly improved our knowledge of the infrared and sub-mm background radiation. These limits become constraining given the realization that most AGNs are heavily obscured…
X-ray binaries, powered by black holes, neutron stars, or white dwarfs accreting matter from a companion star, are among the brightest beacons in galaxies, outshining the Sun by a factor of millions. Most emit primarily above 0.3 keV in…
For over a century, the identification of high-energy cosmic ray (CR) sources remains an open question. For Galactic CRs with energy up to $10^{15}$ eV, supernova remnants (SNRs) have traditionally been thought the main candidate source.…
Aims. The synthesis of the cosmic X-ray background (CXB) requires a large population of Compton-thick active galactic nuclei that have not been detected so far. We probe whether bright infrared galaxies could harbor a population of…
Based on recent work on spectral decomposition of the emission of star-forming galaxies, we assess whether the integrated 2-10 keV emission from high-mass X-ray binaries (HMXBs), L_{2-10}^{HMXB}, can be used as a reliable estimator of…
Observations of high-z galaxies and gamma-ray bursts now allow for empirical studies during reionization. However, even deep surveys see only the brightest galaxies at any epoch and must extrapolate to arbitrary lower limits to estimate the…
We use deep Chandra imaging and an extensive optical spectroscopy campaign on the Keck 10-m telescopes to study the properties of X-ray point sources in five large-scale structures at redshifts of z ~ 0.7-0.9. We first study X-ray point…
With recent Chandra observations, at least 60% of the 2-10 keV background is now resolved into discrete sources. Here we present deep optical, NIR, submm, and 20 cm (radio) images, as well as high-quality optical spectra, of a complete…
There is growing evidence supporting the coeval growth of galaxies and their resident SMBH. Most studies also claim a correlation between the activity of the SMBH and the star-formation of the host galaxy. It is unclear, though, whether…
A preponderance of evidence links long-duration, soft-spectrum gamma-ray bursts (GRBs) with the death of massive stars. The observations of the GRB-supernova (SN) connection present the most direct evidence of this physical link. We…
It was once common to regard Seyfert and starburst galaxies as completely different types of object, but there is growing recognition that these classifications refer to the extremes of a continuous spectrum of galaxy types. In a previous…
We present the X-ray source number counts in two energy bands (0.5-2 and 2-10 keV) from a very large source sample: we combine data of six different surveys, both shallow wide field and deep pencil beam, performed with three different…
The super-massive black-holes in the centers of Active Galactic Nuclei (AGNs) are surrounded by obscuring matter that can block the nuclear radiation. Depending on the amount of blocked radiation, the flux from the AGN can be too faint to…
The disks of Active Galactic Nuclei (AGNs) have emerged as rich environments for the production and capture of stars and the compact objects that they leave behind. These stars produce long Gamma-Ray Bursts (LGRBs) at their deaths, while…
Recent months have witnessed dramatic progress in our understanding of SGRBs. There is now general agreement that SGRBs can produce directed outflows of relativistic matter with a kinetic luminosity exceeding by many millions that of AGN.…