Search Publications
A revisited study of Cepheids in open clusters in the Gaia era
Grebel, Eva K.; Medina, Gustavo E.; Lemasle, Bertrand
In this paper, we revisit the problem of identifying bona fide cluster Cepheids by performing an all-sky search for Cepheids associated with open clusters and making use of state-of-the-art catalogued information for both Cepheids and clusters, based on the unparalleled astrometric precision of the second and early third data releases of the Gaia …
AGN and star formation across cosmic time
Page, M. J.; Symeonidis, M.
We investigate the balance of power between stars and AGN across cosmic history, based on the comparison between the infrared (IR) galaxy luminosity function (LF) and the IR AGN LF. The former corresponds to emission from dust heated by stars and AGN, whereas the latter includes emission from AGN-heated dust only. We find that at all redshifts (at…
On the mechanism of polarized metre-wave stellar emission
Vedantham, H. K.
Two coherent radio emission mechanisms operate in stellar coronae: plasma emission and cyclotron emission. They directly probe the electron density and magnetic field strength respectively. Most stellar radio detections have been made at cm-wavelengths where it is often not possible to uniquely identify the emission mechanism, hindering the utilit…
Dynamical modelling of the twisted galaxy PGC 046832
Brinchmann, Jarle; Krajnović, Davor; Emsellem, Eric +2 more
We analyse VLT/MUSE observations of PGC 046832, the brightest cluster galaxy of Abell 3556. The velocity structure of this galaxy is startling and shows two reversals in sign along the minor axis, and one along the major axis. We use triaxial Schwarzschild models to infer the intrinsic shape, central black hole mass, and orbit distribution of this…
Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - XI. CHIRON investigation of long-period binaries
Smith, A. M. S.; Anderson, D. R.; Hellier, C. +8 more
We present the results of a spectroscopic campaign on eclipsing binaries with long orbital period (P = 20-75 d) carried out with the CHIRON spectrograph. Physical and orbital solutions for seven systems were derived from the V band, and I band ASAS, WASP, and TESS photometry, while radial velocities were calculated from high-quality optical spectr…
The rare X-ray flaring activity of the ultraluminous X-ray source NGC 4559 X7
Salvaterra, R.; Wolter, A.; Pintore, Fabio +9 more
Ultraluminous X-ray sources are considered amongst the most extremely accreting objects in the local Universe. The recent discoveries of pulsating neutron stars in ULXs strengthened the scenario of highly super-Eddington accretion mechanisms on stellar mass compact objects. In this work, we present the first long-term light curve of the source NGC…
Ultracool dwarfs in deep extragalactic surveys using the virtual observatory: ALHAMBRA and COSMOS
Béjar, V. J. S.; Martín, E. L.; Huélamo, N. +8 more
Ultracool dwarfs (UCDs) encompass a wide variety of compact stellar-like objects with spectra classified as late-M, L, T, and Y. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology …
Hierarchically modelling Kepler dwarfs and subgiants to improve inference of stellar properties with asteroseismology
Chaplin, William J.; Davies, Guy R.; Huber, Daniel +9 more
With recent advances in modelling stars using high-precision asteroseismology, the systematic effects associated with our assumptions of stellar helium abundance (Y) and the mixing-length theory parameter (αMLT) are becoming more important. We apply a new method to improve the inference of stellar parameters for a sample of Kepler dwarf…
New measurements of the cyclotron line energy in Cen X-3
Paul, Biswajit; Pradhan, Pragati; Tomar, Gunjan
We report results from the analysis of data from two observations of the accreting binary X-ray pulsar Cen X-3 carried out with the broad-band X-ray observatories Suzaku and NuSTAR. The pulse profile is dominated by a broad single peak and show some energy dependence with two additional weak pulse peaks at energies below 15 and 25 keV, respectivel…
High-sensitivity radio study of the non-thermal stellar bow shock EB27
del Palacio, Santiago; Benaglia, Paula; Hales, Christopher +1 more
We present a deep radio-polarimetric observation of the stellar bow shock EB27 associated with the massive star BD+43○3654. This is the only stellar bow shock confirmed to have non-thermal radio emission. We used the Jansky Very Large Array in S band (2-4 GHz) to test whether this synchrotron emission is polarized. The unprecedented sen…