Search Publications
On the relation between the mass of Compact Massive Objects and their host galaxies
Capuzzo-Dolcetta, R.; Tosta e Melo, I.
Supermassive black holes and/or very dense stellar clusters are found in the central regions of galaxies. Nuclear star clusters (NSCs) are present mainly in faint galaxies, while supermassive black holes are common in galaxies with masses ≥1010 M⊙. In the intermediate galactic mass range, both types of compact massive objects…
X-ray study of bow shocks in runaway stars
De Becker, M.; Romero, G. E.; del Valle, M. V. +2 more
Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bo…
Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability
Lähteenmäki, A.; Giroletti, M.; Villata, M. +59 more
In 2015 July 29-September 1, the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 h. During one of these epochs, simultaneous observations by the Swift satellite were requested to compare the results of the X-ray and optical-UV instruments. Optical, near-infrared and radio monitoring was carried out …
Investigating short-time-scale variations in cometary ions around comet 67P
Karlsson, Tomas; Simon Wedlund, Cyril; Nilsson, Hans +10 more
The highly varying plasma environment around comet 67P/Churyumov-Gerasimenko inspired an upgrade of the ion mass spectrometer (Rosetta Plasma Consortium Ion Composition Analyzer) with new operation modes, to enable high time resolution measurements of cometary ions. Two modes were implemented, one having a 4 s time resolution in the energy range 0…
Migration and kinematics in growing disc galaxies with thin and thick discs
Binney, James; Schönrich, Ralph; Aumer, Michael
We analyse disc heating and radial migration in N-body models of growing disc galaxies with thick and thin discs. Similar to thin-disc-only models, galaxies with appropriate non-axisymmetric structures reproduce observational constraints on radial disc heating in and migration to the Solar Neighbourhood (Snhd). The presence of thick discs can supp…
Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power
Page, M. J.; Hardcastle, M. J.; Elvis, M. +6 more
Several studies support the existence of a link between the active galactic nucleus (AGN) and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and l…
OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - II. Environmental influence on integrated star formation properties and AGN activity
Chies-Santos, Ana L.; Wolf, Christian; Aragón-Salamanca, Alfonso +6 more
We present a study of the star formation and AGN activity for galaxies in CP 15051 the Abell 901/2 multicluster system at z ∼ 0.167 as part of the OSIRIS Mapping of Emission-line Galaxies in A901/2 (OMEGA) survey. Using Tuneable Filter data obtained with the OSIRIS instrument at the Gran Telescopio Canarias, we produce spectra covering the Hα and …
Potential cooling of an accretion-heated neutron star crust in the low-mass X-ray binary 1RXS J180408.9-342058
Altamirano, D.; Degenaar, N.; Wijnands, R. +11 more
We have monitored the transient neutron star low-mass X-ray binary 1RXS J180408.9-342058 in quiescence after its ∼4.5 month outburst in 2015. The source has been observed using Swift and XMM-Newton. Its X-ray spectra were dominated by a thermal component. The thermal evolution showed a gradual X-ray luminosity decay from ∼18 × 1032 to ∼…
Suzaku spectroscopy of the neutron star transient 4U 1608-52 during its outburst decay.
Armas Padilla, M.; Muñoz-Darias, T.; Hori, T. +2 more
We test the proposed three-component spectral model for neutron star low-mass X-ray binaries using broad-band X-ray data. We have analysed four X-ray spectra (0.8-30 keV) obtained with Suzaku during the 2010 outburst of 4U 1608-52, which have allowed us to perform a comprehensive spectral study covering all the classical spectral states. We use a …
A systematic search for near-infrared counterparts of nearby ultraluminous X-ray sources (II)
Harrison, F. A.; Roberts, T. P.; Torres, M. A. P. +5 more
We present the results of our continued systematic search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within 10 Mpc. We observed 42 ULXs in 24 nearby galaxies and detected NIR candidate counterparts to 15 ULXs. Fourteen of these ULXs appear to have a single candidate counterpart in our images and the remain…