Search Publications
Exploring the relationship between X-ray binaries and compact star clusters (I): NGC 4490 and NGC 4214
Akyuz, A.; Aksaker, N.; Allak, S. +3 more
We conducted a study to investigate the relationship between X-ray binaries (XRBs) and compact star clusters in the nearby star-forming galaxies NGC 4490 and NGC 4214. By analysing archival data from Chandra, we identified a total of 32 XRBs with X-ray luminosities Lx > 1036 erg s-1 in both galaxies. Utilizing d…
X-ray flux and spectral variability of the blazar OJ 287 with Suzaku
Gupta, Alok C.; Wiita, Paul J.; Xu, Haiguang +4 more
We present analyses of Suzaku XIS light curves and spectra of the BL Lac object OJ 287 with observations positioned primarily around proposed recurrent optical outbursts. The first two observations were performed in 2007 April 10-13 (epoch 1) and 2007 November 7-9 (epoch 2) that, respectively, correspond to a low and a high optical state and which…
HD 28185 revisited: an outer planet, instead of a brown dwarf, on a Saturn-like orbit
Vanderburg, Andrew; Wittenmyer, Robert A.; Huang, Chelsea X. +3 more
As exoplanet surveys reach ever-higher sensitivities and durations, planets analogous to the Solar system giant planets are increasingly within reach. HD 28185 is a Sun-like star known to host a
Evidence of dark contents in the centre of NGC 6517
Xie, Yi; Zhang, Liyun; Lian, Yujie +3 more
Millisecond pulsars can serve as effective probes to investigate the presence of intermediate-mass black holes (IMBHs) within Galactic globular clusters (GCs). Based on the standard structure models for GCs, we conduct simulations to analyse the distributions of pulsar accelerations within the central region of NGC 6517. By comparing the measured …
Deciphering the evolution of thermodynamic properties and their connection to the global kinematics of high-speed coronal mass ejections using FRIS model
Wang, Yuming; Nieves-Chinchilla, Teresa; Mishra, Wageesh +3 more
Most earlier studies have been limited to estimating the kinematic evolution of coronal mass ejections (CMEs), and only limited efforts have been made to investigate their thermodynamic evolution. We focus on the interplay of the thermal properties of CMEs with their observed global kinematics. We implement the Flux rope Internal State model to es…
Charging effects on Rosetta dust measurements
Deca, Jan; Horányi, Mihály
Dust particles released from comet 67P/Churyumov-Gerasimenko collect electrostatic charges. Their motion is influenced by the electric fields induced by the flow of the solar wind and by the charging of the Rosetta spacecraft itself. Dust grains with sufficiently low tensile strength might even be destroyed en route from the nucleus to Rosetta. A …
Time evolution of X-ray bright points observed with NuSTAR
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present analysis on two X-ray bright points observed over several hours during the recent solar minimum (2020 February 21 and 2020 September 12-13) with the Nuclear Spectroscopic Telescope Array (NuSTAR), a sensitive hard X-ray imaging spectrometer. This is so far the most detailed study of bright points in hard X-rays, emission which can be us…
A statistical approach to polarimetric and photometric investigation of the intermediate-age open cluster NGC 1912
Biswas, Samrat; Medhi, Biman J.; Deb, Sushmita +3 more
This paper presents a comprehensive multiwavelength investigation of the intermediate-age open cluster NGC 1912. We identified 401 member stars for NGC 1912 using K-nearest neighbour and Gaussian Mixture Model machine learning techniques. The fundamental parameters determined for the cluster are metallicity (z) = 0.0141 $\pm$ 0.0006, log(age) = 8.…
On stellar migration from Andromeda to the Milky Way
Schwarz, Dominik J.; Fairbairn, Malcolm; Gülzow, Lukas
Recent Gaia observations suggest that some hypervelocity stars (HVSs) might originate from outside the Galaxy. We ask whether these HVSs could come from as far as Andromeda. Therefore, we simulate HVSs originating in Andromeda with initial conditions based on attributes of high-velocity stars measured in the Milky Way and a simple model for the gr…
Long-term orbital evolution of dimorphos boulders and implications on the origin of meteorites
Carbognani, A.; Fenucci, M.
By using recent observations of the Dydimos-Dimorphos system from the Hubble Space Telescope, 37 boulders with a size of 4 to 7 m ejected from the system during the impact with the DART spacecraft were identified. In this work, we studied the orbital evolution of a swarm of boulders with a similar size to that of the detected ones. By using recent…