Related papers: X-ray Shadowing Experiments Toward Infrared Dark C…
To characterize the initial conditions for intermediate- to high-mass star formation, we observed two Infrared Dark Clouds (IRDCs) that remain absorption features up to 70mum wavelength, with the PdBI in the 3.23mm dust continuum as well as…
Long arcs in clusters of galaxies, produced by gravitational lensing, can be used to estimate the mass interior to the arcs and therefore, constrain the cluster mass distribution. The radial density distribution of the intracluster gas…
Interstellar dust permeates our Galaxy and plays an important role in many physical processes in the diffuse and dense regions of the interstellar medium. High-resolution X-ray spectroscopy, coupled with modelling based on laboratory dust…
It is currently assumed that infrared dark clouds (IRDCs) represent the earliest evolutionary stages of high-mass stars ($>$ 8 M$_{\odot}$). Submillimeter and millimeter-wave studies performed over the past 15 years show that IRDCs possess…
X-ray photons scattered by the interstellar medium carry information about dust distribution, dust grain model, scattering cross section, and the distance of the source; they also take longer time than unscattered photons to reach the…
Lada et al. (1994) have described a method for studying the distribution of dust in dark clouds using infrared imaging surveys. In particular they show that the method provides some information about the structure of the gas (dust) on…
We present a multi-wavelength study of seven AGN at spectroscopic redshift >2.5 in the 7 Ms Chandra Deep Field South, selected to have good FIR/sub-mm detections. Our aim is to investigate the possibility that the obscuration observed in…
The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6$\mu m$ IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old…
The dust-to-gas ratios in three different samples of luminous, ultraluminous, and hyperluminous infrared galaxies are calculated by modelling their radio to soft X-ray spectral energy distributions using composite models which account for…
Recent observations with the Chandra X-ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within the inner 10'' of the Galaxy. The hot…
We studied the X-ray dust scattering halos around 17 bright X-ray point sources using {\it Chandra} data. We use an iterative method to resolve the halos at small scattering angles from the zeroth order data in CC-mode or the first order…
The earliest phases of massive star formation are found in cold and dense infrared dark clouds (IRDCs). Since the detection method of IRDCs is very sensitive to the local properties of the background emission, we present here an alternative…
We aim to explore the capabilities of dust emission and rays for probing the properties of the interstellar medium in the nearby anti-centre region, using gamma-ray observations with the Fermi Large Area Telescope (LAT), and the thermal…
Bright clusters of galaxies can be seen out to cosmological distances, and thus they can be used to derive cosmological parameters. Although the continuum X-ray emission from the intra-cluster gas is optically thin, the optical depth of…
Identified as extinction features against the bright Galactic mid-infrared background, infrared dark clouds (IRDCs) are thought to harbor the very earliest stages of star and cluster formation. In order to better characterize the properties…
Galactic interstellar dust has a profound impact not only on our observations of objects throughout the Universe, but also on the morphology, star formation, and chemical evolution of the Galaxy. The advent of massive imaging and…
Galactic and extra-galactic sources produce X-rays that are often absorbed by molecules and atoms in giant molecular clouds (GMCs), which provides valuable information about their composition and physical state. We mimic this phenomenon…
Archival Chandra observations are used to study the X-ray emission associated with star formation in the central region of the nearby SAB(s)cd galaxy NGC 2403. The distribution of X-ray emission is compared to the morphology visible at…
To understand the conditions under which dense, molecular gas is able to form within a galaxy, we post-process a series of three-dimensional galactic-disk-scale simulations with ray-tracing based radiative transfer and chemical network…
To study the fragmentation and gravitational collapse of dense cores in infrared dark clouds (IRDCs), we have obtained submillimeter continuum and spectral line data as well as multiple inversion transitions of NH3 and H2O maser data of…