相关论文: Diffuse X-ray emission in globular cluster cores

We study the gamma-ray emission from millisecond pulsars within the Milky Way's globular cluster system in order to measure the luminosity function of this source population. We find that these pulsars have a mean luminosity of $\langle…

(Abridged) We present the results of M31 globular cluster (GC) X-ray source survey, based on the data of XMM-Newton and Chandra observations covering ~6100 sq.arcmin of M31. We detected 43 X-ray sources coincident with globular cluster…

We have searched for optical identifications for 39 Chandra X-ray sources that lie within the 1.9 arcmin half-mass radius of the nearby (d = 4.0 kpc), core-collapsed globular cluster, NGC 6752, using deep Hubble Space Telescope ACS/WFC…

Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where 5 +/- 3 of these sources are likely to be related to the cluster. Using differential optical photometry, we have…

Evidence is emerging that the luminous X-ray sources in the cores of globular clusters may often consist of, or perhaps even as a class be dominated by, ultracompact (P < 1 hr) binary stars. To the two such systems already known, in NGC…

We analyse 8 years of PASS 8 Fermi-LAT data, in the 60 MeV - 300 GeV energy range, from 30 high Galactic latitude globular clusters. Six of these globular clusters are detected with a TS > 25, with NGC 6254 being detected as gamma-ray…

We found several extranuclear (r >~ 3") X-ray nebulae within 40" (6.3 kpc at 32.5 Mpc) of the nucleus of the Seyfert galaxy NGC 2992. The net X-ray luminosity from the extranuclear sources is ~2-3 E39 erg/s (0.3-8.0 keV). The X-ray core…

Chandra observations of the X-ray faint elliptical galaxy NGC 4697 resolve much of the X-ray emission (61% within one effective radius) into ~80 point sources, of which most are low mass X-ray binaries (LMXBs). These LMXBs provide the bulk…

I review recent work on X-ray sources in Galactic globular clusters, identified with low-mass X-ray binaries (LMXBs), cataclysmic variables (CVs), millisecond pulsars (MSPs) and coronally active binaries by Chandra. Faint transient LMXBs…

The dynamical production of low-mass X-ray binaries and brighter cataclysmic variables (CVs) in dense globular clusters is well-established. We investigate how the X-ray emissivity of fainter X-ray binaries (principally CVs and coronally…

Chandra has resolved the starburst nuclear region of the face-on grand-design spiral M83. Eighty-one point sources are detected above 3.5 sigma in the ACIS S3 image, and 15 of them are within the inner 16-arcsec region of the galaxy. A…

We have monitored a sample of 27 nearby globular clusters in the hard X-ray band (20-120 keV) for approximately 1400 days using the BATSE instrument on board the Compton Gamma-Ray Observatory. Globular clusters may contain a large number of…

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 exploit XMM-Newton archival data in a study of the extended X-ray emission emanating from the Galactic Centre (GC) region. EPIC-pn and EPIC-MOS observations, with a total exposure approaching 0.5 and 1 Ms respectively, were used to…

Using archival spectral-imaging data with a total exposure of $\sim144$ ks obtained by {\it Chandra}, 43 X-ray sources are detected within the half-light radius of globular cluster M62 (NGC6266). Based on the X-ray colour-luminosity diagram…

We analyzed deep Chandra observations of the Galactic plane region centered at l=28.55, b=-0.03 with the aim to obtain the best possible constraints on the contribution of weak point sources to the Galactic ridge X-ray emission (GRXE) in…

A subset of galaxies have dense nuclei, and when these galaxies are accreted and tidally stripped, the nuclei can masquerade as globular clusters in the halos of large galaxies. If these nuclei contain massive central black holes, some may…

We use deep Chandra observations to measure the emissivity of the unresolved X-ray emission in the elliptical galaxy NGC 3379. After elimination of bright, low-mass X-ray binaries with luminosities >10^{36 erg/sec, we find that the…

We explore the nature of unresolved X-ray emission in a broad sample of galaxies of all morphological types based on archival Chandra data. After removing bright compact sources, we study L_X/L_K luminosity ratios of unresolved emission,…

We present a Chandra X-ray Observatory investigation of the millisecond pulsars (MSPs) in the globular cluster M28 (NGC 6626). In what is one of the deepest X-ray observations of a globular cluster, we firmly detect seven and possibly…