Search Publications
Modelling the observed stellar mass function and its radial variation in galactic globular clusters
Vesperini, Enrico; Dalessandro, Emanuele; Ferraro, Francesco R. +3 more
We measure how the slope α of the stellar mass function (MF) changes as a function of clustercentric distance r in five Galactic globular clusters and compare α(r) to predictions from direct N-body star cluster simulations. Theoretical studies predict that α(r) (which traces the degree of mass segregation in a cluster) should steepen with time as …
Study of orbital and superorbital variability of LSI +61° 303 with X-ray data
Tsygankov, S.; Takahashi, H.; Babyk, Iu. +4 more
LSI +61° 303 is one of the few X-ray binaries with a Be star companion from which radio, X-rays and high-energy gamma-ray (GeV and TeV) emission have been observed. The nature of the high-energy activity of the system is not yet fully understood, but it is widely believed that it is generated due to the interaction of the relativistic electrons le…
An extinction-free AGN selection by 18-band SED fitting in mid-infrared in the AKARI NEP deep field
Hashimoto, Tetsuya; Goto, Tomotsugu; Matsuhara, Hideo +2 more
We have developed an efficient active galactic nucleus (AGN) selection method using 18-band spectral energy distribution (SED) fitting in mid-infrared (mid-IR). AGNs are often obscured by gas and dust, and those obscured AGNs tend to be missed in optical, UV and soft X-ray observations. Mid-IR light can help us to recover them in an obscuration-fr…
SCUBA-2 follow-up of Herschel-SPIRE observed Planck overdensities
Clements, David L.; Lagache, Guilaine; Scott, Douglas +11 more
We present SCUBA-2 follow-up of 61 candidate high-redshift Planck sources. Of these, 10 are confirmed strong gravitational lenses and comprise some of the brightest such submm sources on the observed sky, while 51 are candidate proto-cluster fields undergoing massive starburst events. With the accompanying Herschel-Spectral and Photometric Imaging…
The extremely metal-poor galaxy DDO 68: the luminous blue variable, Hα shells and the most luminous stars
Moiseev, A. V.; Makarova, L. N.; Makarov, D. I. +2 more
This paper presents new results from the ongoing study of the unusual Lynx-Cancer void galaxy DDO 68, which has star-forming regions of record low metallicity [12+log (O/H) ∼7.14]. The results include the following. (I) A new spectrum and photometry have been obtained with the 6-m SAO RAS telescope (BTA) for the luminous blue variable (LBV = DDO68…
Investigating the X-ray counterparts to unidentified sources in the 1000-orbit INTEGRAL/IBIS catalogue
Bird, A. J.; Fiocchi, M.; Ubertini, P. +6 more
The latest INTEGRAL/IBIS all-sky survey lists 219 hard X-ray sources whose nature is still unknown. We report on our ongoing campaign aimed at identifying these high-energy emitters by exploiting the focusing capabilities of the X-ray Telescope (XRT, 0.2-10 keV) onboard Swift, which allow an enhancement of the source localization to arcsec level, …
X-ray flaring in PDS 456 observed in a high-flux state
Turner, T. J.; Reeves, J. N.; Braito, V. +3 more
We present an analysis of a 190 ks (net exposure) Suzaku observation, carried out in 2007, of the nearby (z = 0.184) luminous (Lbol ∼ 1047 erg s-1) quasar PDS 456. In this observation, the intrinsically steep bare continuum is revealed compared to subsequent observations, carried out in 2011 and 2013, where the sou…
XMM-Newton observation of MV Lyr and the sandwiched model confirmation
Ness, J. -U.; Dobrotka, A.; Nucita, A. A. +1 more
We present spectral and timing analyses of simultaneous X-ray and UV observations of the VY Scl system MV Lyr taken by XMM-Newton, containing the longest continuous X-ray + UV light curve and highest signal-to-noise X-ray (EPIC) spectrum to date. The RGS spectrum displays emission lines plus continuum, confirming model approaches to be based on th…
HD 164492C: a rapidly rotating, Hα-bright, magnetic early B star associated with a 12.5 d spectroscopic binary
Rivinius, Th.; Wade, G. A.; Alecian, E. +6 more
We employ high-resolution spectroscopy and spectropolarimetry to derive the physical properties and magnetic characteristics of the multiple system HD 164492C, located in the young open cluster M20. The spectrum reveals evidence of three components: a broad-lined early B star (HD 164492C1), a narrow-lined early B star (HD 164492C2) and a late B st…
The dependence of halo mass on galaxy size at fixed stellar mass using weak lensing
Hudson, Michael J.; Balogh, Michael L.; Charlton, Paul J. L. +1 more
Stellar mass has been shown to correlate with halo mass, with non-negligible scatter. The stellar mass-size and luminosity-size relationships of galaxies also show significant scatter in galaxy size at fixed stellar mass. It is possible that, at fixed stellar mass and galaxy colour, the halo mass is correlated with galaxy size. Galaxy-galaxy lensi…