Search Publications
Monoceros OB4: a new association in Gaia DR2
Alves, J.; Teixeira, P. S.; Scholz, A. +2 more
We use Gaia DR2 data to survey the classic Monoceros OB1 region and look for the existence of a dispersed young population, co-moving with the cloud complex. An analysis of the distribution of proper motions reveals a 20-30 Myr association of young stars, about 300-400 pc away from the far side of the Mon OB1 complex, along the same general line o…
The search for ultraviolet luminous objects in GALEX data
Zhao, Gang; Malkov, Oleg Yu; Karpov, Sergey V.
Selection of extreme objects in data from large-scale sky surveys is a powerful tool for the detection of new classes of astrophysical objects or rare stages of their evolution. The cross-matching of catalogues and analysis of the colour indices of their objects is the usual approach to this problem, which has already provided a lot of interesting…
Preservation and variation of ion-to-electron temperature ratio in the plasma sheet in geo-magnetotail
Chen, ChuXin
Primary Velocity and Orbital Phase Effects on Planetary Detectability from Small Epoch Number Data Sets
Benneke, Björn; Blake, Geoffrey A.; Pelletier, Stefan +2 more
Cross-correlation analyses of high-resolution spectroscopic data have recently shown great success in directly detecting planetary signals and enabling the characterization of their atmospheres. One such technique aims to observe a system at multiple epochs and combine the measured planetary radial velocities from each epoch into a measurement of …
Probing ultradiffuse galaxies out to the virial radius of the Coma cluster with XMM-Newton
Walker, S. A.; Mirakhor, M. S.
We probe the formation scenarios and the active galactic nucleus (AGN) occupation fraction of ultradiffuse galaxies (UDGs) in the nearby Coma cluster by utilizing XMM-Newton observations of 779 out of 854 UDG candidates identified by the Subaru survey. Their origin is probed by measuring the dark matter halo mass of the stacked sample of UDGs and …
Orbital Parameters and Binary Properties of 37 FGK Stars in the Cores of Open Clusters NGC 2516 and NGC 2422
Mateo, Mario; Bailey, John I., III; Roederer, Ian U. +4 more
We present orbits for 24 binaries in the field of open cluster NGC 2516 (~150 Myr) and 13 binaries in the field of open cluster NGC 2422 (~130 Myr) using results from a multiyear radial-velocity (RV) survey of the cluster cores. Six of these systems are double-lined spectroscopic binaries. We fit these RV variable systems with orvara, a MCMC-based…
Observations of AR Sco with Chandra and AstroSat soft X-ray telescope
Singh, K. P.; Buckley, D. A. H.; Rana, V. +6 more
We present our AstroSat soft X-ray observations of a compact binary system, AR Sco, and analysis of its X-ray observations with Chandra that were taken only about a week before the AstroSat observations. An analysis of the soft X-ray (0.3–2.0 keV) data limits the modulation of the spin, orbital, or beat periods to less than 0.03 counts s
Changes in the Period of SU Sct, a Population II Cepheid
Berdnikov, L. N.; Pastukhova, E. N.
The reduction of all the available photometry for the Cepheid SU Sct has allowed its $O-C$ diagram spanning a time interval of 60 years to be constructed. Six abrupt changes in the period have been detected. The pulsation stability test proposed by Lombard and Koen (1993) has confirmed that the changes in the period are real. The absolute magnitud…
High-Resolution Spectroscopy of the B[e] Star MWC 645
Miroshnichenko, A. S.; Manset, N.; Zharikov, S. V. +4 more
Optical high-resolution spectroscopic observations of the emission-line star MWC645 are presented. The spectrum exhibits strong variable double-peaked Balmer emission lines as well as low-excitation emission lines of FeII, [FeII], and [OI] which are signatures of the B[e] phenomenon, while lines of helium have not been found. In addition to the em…
The star catalogue of Wilhelm IV, Landgraf von Hessen-Kassel. Accuracy of the catalogue and of the measurements
Verbunt, Frank; Schrimpf, Andreas
We analyse a manuscript star catalogue by Wilhem IV, Landgraf von Hessen-Kassel from 1586. From measurements of altitudes and of angles between stars, given in the catalogue, we find that the measurement accuracy averages 26″ for eight fundamental stars, compared to 49″ of the measurements by Brahe. The computation in converting altitudes to decli…