Search Publications
X-ray diagnostics of chemical composition of the accretion disc and donor star in UCXBs - II. XMM-Newton observations
Gilfanov, Marat; Bildsten, Lars; Koliopanos, Filippos +1 more
We search for the Fe Kα line in spectra of ultra-compact X-ray binaries (UCXBs). For this purpose we have analysed XMM-Newton observations of five confirmed UCXBs. We find that the object 2S 0918-549 - whose optical spectrum bears tentative signatures of a C/O accretion disc - is devoid of any emission features in the 6-7 keV range, with an upper …
The 2-24 µm source counts from the AKARI North Ecliptic Pole survey
Pearson, C. P.; Goto, T.; Matsuhara, H. +3 more
We present herein galaxy number counts of the nine bands in the 2-24 µm range on the basis of the AKARI North Ecliptic Pole (NEP) surveys. The number counts are derived from NEP-deep and NEP-wide surveys, which cover areas of 0.5 and 5.8 deg2, respectively. To produce reliable number counts, the sources were extracted from recentl…
Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra
D'Avanzo, P.; Campana, S.; Tagliaferri, G. +9 more
We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of gamma-ray burst afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power-law shape with index 2.4. However, for real instruments, this value depends on thei…
Binary pulsars studies with multiwavelength sky surveys - I. Companion star identification
Page, M. J.; Possenti, A.; Corongiu, A. +7 more
The identification of the stellar companions to binary pulsars is key to studying the evolution of the binary system and how this is influenced by the interactions between the two stars. For only a fraction of the known binary pulsars, the stellar companions have been identified. Here, we used 11 source catalogues available from multiwavelength (u…
A multi-wavelength survey of AGN in massive clusters: AGN distribution and host galaxy properties
Sarajedini, Vicki L.; Klesman, Alison J.
We investigate the effect of environment on the presence and fuelling of active galactic nuclei (AGN) by identifying galaxies hosting AGN in massive galaxy clusters and the fields around them. We have identified AGN candidates via optical variability (178), X-ray emission (74), and mid-IR SEDs (64) in multi-wavelength surveys covering regions cent…
X-rays from wind-blown bubbles: an XMM-Newton detection of NGC 2359
Zhekov, Svetozar A.
We present an analysis of the XMM-Newton observation of the wind-blown bubble NGC 2359. This is the first detection of this object in X-rays. The X-ray emission of NGC 2359 is soft and originates from a thermal plasma with a typical temperature of kT ∼ 0.2 keV. A direct comparison between the one-dimensional hydrodynamic model of wind-blown bubble…
The morphological transformation of red sequence galaxies in the distant cluster XMMU J1229+0151
Demarco, R.; Lidman, C.; Huertas-Company, M. +5 more
We present the results of a detailed analysis of galaxy properties along the red sequence in XMMU J1229+0151, an X-ray selected cluster at z = 0.98 drawn from the High Acuity Wide field K-band Imager Cluster Survey. Taking advantage of the broad photometric coverage and the availability of 77 spectra in the cluster field, we fit synthetic spectral…
Red giant branch bump star counts in data and stellar models
Nataf, David M.
We compare model predictions to observations of star counts in the red giant branch bump (RGBB) relative to the number density of first-ascent red giant branch at the magnitude of the RGBB, EWRGBB. The predictions are shown to exceed the data by (5.2 ± 4.3) per cent for the BaSTI models and by (17.1 ± 4.3) per cent for the Dartmouth mod…
Molecular hydrogen from z = 0.0963 DLA towards the QSO J1619+3342
Muzahid, S.; Srianand, R.; Mohan, V. +1 more
We report the detection of H2 in a zabs = 0.0963 Damped Lyman α (DLA) system towards zem = 0.4716 QSO J1619+3342. This DLA has log N(H I) = 20.55 ± 0.10, 18.13 ≤ log N(H2) ≤ 18.40, [S/H] = -0.62 ± 0.13, [Fe/S] = -1.00 ± 0.17 and the molecular fraction - 2.11 ≤ log[f(H2)] ≤ -1.85. The inferred …
The nature of massive black hole binary candidates - II. Spectral energy distribution atlas
Hogg, David W.; Decarli, R.; Lusso, E. +5 more
Recoiling supermassive black holes (SMBHs) are considered one plausible physical mechanism to explain high velocity shifts between narrow and broad emission lines sometimes observed in quasar spectra. If the sphere of influence of the recoiling SMBH is such that only the accretion disc is bound, the dusty torus would be left behind, hence the SED …