Search Publications
IRAS 22150+6109 - a young B-type star with a large disc
Zakhozhay, Olga V.; Manset, Nadine; Miroshnichenko, Anatoly S. +4 more
We present the results of a spectroscopic analysis and spectral energy distribution (SED) modelling of the optical counterpart of the infrared source IRAS 22150+6109. The source was suggested to be a Herbig Be star located in the star-forming region L 1188. Absorption lines in the optical spectrum indicate a spectral type B3, while weak Balmer emi…
NuSTAR view of the central region of M31
Stiele, H.; Kong, A. K. H.
Our neighbouring large spiral galaxy, the Andromeda galaxy (M31 or NGC 224), is an ideal target to study the X-ray source population of a nearby galaxy. NuSTAR observed the central region of M31 in 2015 and allows studying the population of X-ray point sources at energies higher than 10 keV. Based on the source catalogue of the large XMM-Newton su…
Milky Way globular cluster metallicity and low-mass X-ray binaries: the red giant influence
Barmby, P.; Vulic, N.; Gallagher, S. C.
Galactic and extragalactic studies have shown that metal-rich globular clusters (GCs) are approximately three times more likely to host bright low-mass X-ray binaries (LMXBs) than metal-poor GCs. There is no satisfactory explanation for this metallicity effect. We tested the hypothesis that the number density of red giant branch (RGB) stars is lar…
Large-scale properties of the clump mass function
Elia, D.; Schisano, E.; Molinari, S. +1 more
The mass function of molecular cloud clumps and cores is widely used to compare the results of numerical simulations with the observations adopting different prescriptions for star formation. However, our ability to test different theories relies critically on our ability to measure it accurately and interpret it confidently. From an observational…
A physical process of the radial acceleration of disc galaxies
Wilhelm, Klaus; Dwivedi, Bhola N.
An impact model of gravity designed to emulate Newton's law of gravitation is applied to the radial acceleration of disc galaxies. Based on this model (Wilhelm et al. 2013), the rotation velocity curves can be understood without the need to postulate any dark matter contribution. The increased acceleration in the plane of the disc is a consequence…
An XMM-Newton observation of the symbiotic star AG Peg: the X-ray emission after the end of its 2015 outburst
Zhekov, Svetozar A.; Tomov, Toma V.
We present an analysis of the XMM-Newton observation of the symbiotic star AG Peg, obtained after the end of its 2015 outburst. The X-ray emission of AG Peg is soft and of thermal origin. AG Peg is an X-ray source of class β of the X-ray sources among the symbiotic stars, whose X-ray spectrum is well matched by a two-temperature optically thin pla…
Northern Galactic molecular cloud clumps in Hi-GAL: dense gas map and environmental trends
Rosolowsky, Erik; Zetterlund, Erika; Glenn, Jason
In the quest to understand high-mass star formation, it is necessary to understand that from which the high-mass stars will form - dense molecular gas clouds and clumps. The Herschel Infrared Galactic Plane Survey (Hi-GAL) is a comprehensive survey of thermal dust emission that can be used to characterize the properties and Galactic distribution o…
Is there really a debris disc around ζ2 Reticuli?
Hales, A.; Casassus, S.; Bayo, A. +10 more
The presence of a debris disc around the Gyr-old solar-type star ζ ^2 Reticuli was suggested by the Spitzer infrared excess detection. Follow-up observations with Herschel/PACS revealed a double-lobed feature that displayed asymmetries both in brightness and position. Therefore, the disc was thought to be edge-on and significantly eccentric. Here …
The first detection of neutral hydrogen in emission in a strong spiral lens
Heiles, Carl; Blandford, Roger; Chakrabarti, Sukanya +7 more
We report H I observations of eight spiral galaxies that are strongly lensing background sources. Our targets were selected from the Sloan WFC (Wide Field Camera) Edge-on Late-type Lens Survey (SWELLS) using the Arecibo, Karl G. Jansky Very Large Array, and Green Bank telescopes. We securely detect J1703+2451 at z = 0.063 with a signal-to-noise ra…
SAFARI - I. A SPHERE discovery of a super metal-rich M-dwarf companion to the star HD 86006
Jones, M. I.; Girard, J. H.; Vigan, A. +3 more
We report the direct detection of a fully convective, early-to-mid M-dwarf companion orbiting the star HD 86006, using ESO-SPHERE during Science Verification as part of the SAFARI program. HARPS+CORALIE radial velocity measurements first indicated a possible companion. Such work highlights the synergies that are now possible between these two obse…