Search Publications
Long-term evolution of cyclotron line energy in an eclipsing pulsar 4U 1538-522
Tobrej, Mohammed; Rai, Binay; Ghising, Manoj +2 more
We present the timing and spectral analysis of the high-mass X-ray binary source 4U 1538-522 using Nuclear Spectroscopic Telescope Array (NuSTAR) observations. One of the observations partially covers the X-ray eclipse of the source along with eclipse ingress. The source is found to spin down at the rate of 0.163 ± 0.002 s yr-1 between …
TIARA TESS 1: estimating exoplanet yields from Years 1 and 3 SPOC light curves
Bayliss, Daniel; Gill, Samuel; Hawthorn, Faith +1 more
We present a study of the detection efficiency for the TESS mission, focusing on the yield of longer period transiting exoplanets (P > 25 d). We created the Transit Investigation and Recoverability Application (TIARA) pipeline to use real TESS data with injected transits to create sensitivity maps which we combine with occurrence rates derived …
On the identification of the first two young asteroid families in g-type non-linear secular resonances
Carruba, V.; Aljbaae, S.; Domingos, R. C. +10 more
Linear secular resonances happen when there is a commensurability between the precession frequency of the pericenter, g, or longitude of the node, s, of an asteroid and a planet. Non-linear resonances are higher order combinations of these frequencies. Here, we studied the three most diffusive g-type non-linear secular resonances using Artificial …
Multiple power-law tails in the density and column-density distribution in contracting star-forming clumps
Klessen, Ralf S.; Veltchev, Todor V.; Donkov, Sava +3 more
We present a numerical study of the evolution of power-law tails (PLTs) in the (column-)density distributions (N-PDF, ρ-PDF) in contracting star-forming clumps in primordial gas, without and with some initial rotational and/or turbulent support. In all considered runs multiple PLTs emerge shortly after the formation of the first protostar. The fir…
Simba-C: the evolution of the thermal and chemical properties in the intragroup medium
Hough, Renier T.; Shao, Zhiwei; Cui, Weiguang +5 more
The newly updated GIZMO and Simba based simulation, Simba-C, with its new stellar feedback, chemical enrichment, and recalibrated AGN feedback, allows for a detailed study of the intragroup medium X-ray properties. We discuss the impact of various physical mechanisms, e.g. stellar and AGN feedback, and chemical enrichment, on the composition and t…
The impact of stellar metallicity on rotation and activity evolution in the Kepler field using gyro-kinematic ages
Amard, Louis; See, Victor; Lu, Yuxi (Lucy) +1 more
In recent years, there has been a push to understand how chemical composition affects the magnetic activity levels of main sequence low-mass stars. Results indicate that more metal-rich stars are more magnetically active for a given stellar mass and rotation period. This metallicity dependence has implications for how the rotation periods and acti…
The radius distribution of M dwarf-hosted planets and its evolution
Gaidos, Eric; Kraus, Adam L.; Rowe, Jason F. +1 more
M dwarf stars are the most promising hosts for detection and characterization of small and potentially habitable planets, and provide leverage relative to solar-type stars to test models of planet formation and evolution. Using Gaia astrometry, adaptive optics imaging, and calibrated gyrochronologic relations to estimate stellar properties and fil…
Atmospheric parameters and chemical abundances within 100 pc: a sample of G, K, and M main-sequence stars
Stassun, Keivan G.; Kounkel, Marina; Lane, Richard R. +9 more
To date, we have access to enormous inventories of stellar spectra that allow the extraction of atmospheric parameters and chemical abundances essential in stellar studies. However, characterizing such a large amount of data is complex and requires a good understanding of the studied object to ensure reliable and homogeneous results. In this study…
Study of star formation in dual nuclei galaxies using UVIT observations
Kharb, P.; Das, M.; Rahna, P. T. +3 more
We have used the Ultraviolet Imaging Telescope (UVIT) aboard AstroSat to study star formation in a sample of nine dual nuclei galaxies with separations ⪅ 11 kpc, which is an expected outcome of galaxy mergers. To minimize the contribution of active galactic nuclei (AGN) emission, we have used mid-IR colour cut-offs and masked the AGN-dominated nuc…
Photospheric signatures of CME onset
Fletcher, L.; Romano, P.; MacTaggart, D. +2 more
Coronal mass ejections (CMEs) are solar eruptions that involve large-scale changes to the magnetic topology of an active region. There exists a range of models for CME onset which are based on twisted or sheared magnetic field above a polarity inversion line (PIL). We present observational evidence that topological changes at PILs, in the photosph…