Related papers: The Galactic Bulge Diffuse Emission in Broad-Band …
The dominant stellar population of the central bulge of the Milky Way is old, with roughly solar metallicity. The age is very similar to that of the old metal rich bulge globular clusters and to 47 Tucanae, which has an age of 13 Gyr.…
Using ROSAT PSPC data, we have performed several tests aimed at understanding the origin of the soft X-ray spectral component detected from the bulge of M31. We find that a significant soft component in the spectrum of the bulge is…
We analyse velocity, chemical abundance and spatial distribution data for some 1500 K- and M- giants in the Galactic Bulge. The bulge has a well-determined linear rotation curve over the range $\rm 700pc \le R \le 3500pc$ with amplitude…
M82 hosts two well-known ultraluminous X-ray sources (ULXs). X-1, an intermediate-mass black hole (IMBH) candidate, and X-2, an ultraluminous X-ray pulsar (ULXP). Here we present a broadband X-ray spectral analysis of both sources based on…
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…
We present a new determination of the metallicity distribution, age, and luminosity function of the Galactic bulge stellar population. By combining near-IR data from the 2MASS survey, from the SOFI imager at ESO NTT and the NICMOS camera on…
The gigaelectronvolt $\gamma$-ray excess observed towards the Galactic centre remains unexplained. While dark matter annihilation has long been considered a leading explanation, an alternative scenario involving a large population of…
The extent of the accretion disk in the low/hard state of stellar mass black hole X-ray binaries remains an open question. There are some evidence suggesting that the inner accretion disk is truncated and replaced by a hot flow, while the…
Recent observations of the Galactic center in high-energy gamma-rays (above 0.1TeV) have opened up new ways to study this region, from understanding the emission source of these high-energy photons to constraining the environment in which…
The vast majority of optically identified active galactic nuclei (AGNs) in the local Universe reside in host galaxies with prominent bulges, supporting the hypothesis that black hole formation and growth is fundamentally connected to the…
Using the Chandra ACIS-I instruments, we have carried out the deepest X-ray observation on a typical Galactic plane region at l 28.5 deg, where no discrete X-ray sources have been known previously. We have detected, as well as strong…
We present results from Chandra and XMM-Newton X-ray observations of NGC 4214, a nearby dwarf starburst galaxy containing several young regions of very active star-formation. Starburst regions are known to be associated with diffuse X-ray…
The unresolved X-ray emission in the cores of 10 globular clusters hosting millisecond pulsars is investigated. Subtraction of the known resolved point sources leads to detectable levels of unresolved emission in the core region of M28, NGC…
The Galactic Center Excess (GCE) is an extended gamma-ray source in the central region of the Galaxy found in Fermi Large Area Telescope data. In recent years it has become apparent that the GCE may not be spherically symmetric, but may be…
Context: The INTEGRAL hard X-ray observatory has revealed an emerging population of highly obscured X-ray binary systems through multi-wavelength observations. Previous studies have shown that many of these sources are high-mass X-ray…
Until recently our knowledge of the Galactic Bulge stellar populations was based on the study of a few low extinction windows. Large photometric and spectroscopic surveys are now underway to map large areas of the bulge. They probe several…
The Chandra X-ray Observatory is finding a surprisingly large number of cavities in the X-ray emitting intracluster medium, produced by the release of radio plasma from active galactic nuclei. In this Letter, we present simple analytic…
We present the first study of the X-ray sources in one of the most metal-rich globular clusters in the Galaxy, NGC 6528. Using relatively deep (66 ksec) archival imaging from the Chandra X-ray Observatory, we identify 18 sources within the…
The origin of the quenching in galaxies is still highly debated. Different scenarios and processes are proposed. We use multi-band (400-1600 nm) bulge-disc decompositions of massive galaxies in the redshift range 0<z<2 to explore the…
Planetary nebulae (PNe) constitute an important tool to study the chemical evolution of the Milky Way and other galaxies, probing the nucleosynthesis processes, abundance gradients and the chemical enrichment of the interstellar medium. In…