Related papers: Radio background and IGM heating due to Pop III su…
I re-examine the brightness temperature problem in PKS 0405-385 which is an extreme intra-day variable radio quasar with an inferred brightness temperature of $\sim 5 \times 10^{14}$ K at 5 GHz, well above the Compton catastrophe limit of…
Recent observations of excess radiation at extreme ultraviolet and hard X-ray energies straddling the well known thermal soft X-ray emission have provided new tools and puzzles for investigation of the acceleration of nonthermal particles…
The warm-hot intergalactic medium (warm-hot IGM, or WHIM) pervades the filaments of the Cosmic Web and harbours half of the Universe's baryons. The WHIM's thermodynamic properties are notoriously hard to measure. Here we estimate a galaxy…
Tidal Disruption Events (TDEs) release enormous amounts of energy, offering a promising avenue for detecting Population III (Pop III) stars. However, the radiative properties of TDEs of Pop III stars have so far been studied only…
Recently the ARCADE 2 experiment measured the cosmic radio background (CRB) and found the brightness temperature of the CRB at 1.4 GHz to be ~480 mK. Integrating the flux density from the observed 1.4 GHz radio source count produces a…
Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS1830-211. Obtaining average radial velocities and performing Large Velocity Gradient…
We use data on extreme radio scintillation to demonstrate that this phenomenon is associated with hot stars in the solar neighbourhood. The ionized gas responsible for the scattering is found at distances up to 1.75pc from the host star,…
We present results from a {\em Chandra} observation of the cluster gas associated with the FR II radio galaxy 3C 438. This radio galaxy is embedded within a massive cluster with gas temperature $\sim$17 keV and bolometric luminosity of…
The Cosmic Microwave Background radiation is a fundamental prediction of Hot Big Bang cosmology. The temperature of its black-body spectrum has been measured at the present time, $T_{\rm CMBR,0}$ = 2.726$\pm$ 0.010 K, and is predicted to…
The power spectra of the redshifted 21-cm signal from the Epoch of Reionization (EoR) contain information about the ionization and thermal states of the intergalactic medium (IGM), and depend on the properties of the EoR sources. Recently,…
Recent measurements of the cosmic X-ray and radio backgrounds (CXB/CRB, respectively) obtained with Chandra and ARCADE2 report signals in excess of those expected from known sources, suggesting the presence of a yet undiscovered population…
Matter in neutron star collisions can reach densities up to few times the nuclear saturation threshold and temperatures up to one hundred MeV. Understanding the structure and composition of such matter requires many-body nonperturbative…
The Galactic disc is opaque to radio waves from extragalactic sources with frequencies nu less than ~3 MHz. However, radio waves with kHz, Hz, and even lower frequencies may propagate through the intergalactic medium (IGM). I argue that the…
We calculate the contribution to the cosmic infrared background from very massive metal-free stars at high redshift. We explore two plausible star-formation models and two limiting cases for the reprocessing of the ionizing stellar…
Massive stars form in dense and massive molecular cores. The exact formation mechanism is unclear, but it is possible that some massive stars are formed by processes similar to those that produce the low-mass stars, with accretion/ejection…
We used the IRAM Interferometer to obtain sub-arcsecond resolution observations of the high-mass star-forming region W3(OH) and its surroundings at a frequency of 220 GHz. With the improved angular resolution, we distinguish 3 peaks in the…
We present results on the heating of the inter-cluster medium (ICM) by gravitational potential energy from in-falling satellites. We calculate the available excess energy of baryons once they are stripped from their satellite and added to…
The H atoms inside minihalos (i.e. halos with virial temperatures T_vir < 10^4 K, in the mass range roughly from 10^4 M_sun to 10^8 M_sun) during the cosmic dark ages in a LCDM universe produce a redshifted background of…
Observations of the 21 cm line from neutral hydrogen indicate that an Epoch of Heating (EoH) might have preceded the later Epoch of Reionization (EoR). Here we study the effects on the ionization state and the thermal history of the…
Supernovae (SN) generate hot gas in the interstellar medium (ISM), help setting the ISM structure and support the driving of outflows. It is important to resolve the hot gas generation for galaxy formation simulations at solar mass and…