Search Publications
Study of structural parameters and systemic proper motion of Sextans dwarf spheroidal galaxy with Subaru Hyper Suprime-Cam data
Komiyama, Yutaka; Takada, Masahiro; Hayashi, Kohei +4 more
We use the Subaru Hyper Suprime-Cam (HSC) data to study structural parameters and systemic proper motion of the Sextans dwarf spheroidal galaxy at the heliocentric distance of 86 kpc, which is one of the most important targets for studies of dark matter nature and galaxy formation physics. Thanks to the superb image quality and wide area coverage,…
Tidal debris from Omega Centauri discovered with unsupervised machine learning
Lind, Karin; Kushniruk, Iryna; Youakim, Kris
The gravitational interactions between the Milky Way and in-falling satellites offer a wealth of information about the formation and evolution of our Galaxy. In this paper, we explore the high-dimensionality of the GALAH DR3 plus Gaia eDR3 data set to identify new tidally stripped candidate stars of the nearby star cluster Omega Centauri ($\omega …
A search for missing radio sources at z ≳ 4 using Lyman dropouts
Norris, Ray P.; Hopkins, Andrew M.; Shabala, Stanislav S. +5 more
Using the Lyman Dropout technique, we identify 148 candidate radio sources at z ≳ 4-7 from the 887.5 MHz Australian Square Kilometre Array Pathfinder (ASKAP) observations of the GAMA23 field. About 112 radio sources are currently known beyond redshift z ~ 4. However, simulations predict that hundreds of thousands of radio sources exist in that red…
Predicting light curves of RR Lyrae variables using artificial neural network based interpolation of a grid of pulsation models
Marconi, Marcella; Das, Susmita; Kanbur, Shashi M. +4 more
We present a new technique to generate the light curves of RRab stars in different photometric bands (I and V bands) using artificial neural networks (ANN). A pre-computed grid of models was used to train the ANN, and the architecture was tuned using the I-band light curves. The best-performing network was adopted to make the final interpolators i…
CHEOPS's hunt for exocomets: photometric observations of 5 Vul
Lecavelier Des Etangs, Alain; Zieba, Sebastian; Rebollido, Isabel +3 more
The presence of minor bodies in exoplanetary systems is in most cases inferred through infrared excesses, with the exception of exocomets. Even if over 35 yr have passed since the first detection of exocomets around β Pic, only ~25 systems are known to show evidence of evaporating bodies, and most of them have only been observed in spectroscopy. W…
Morpho-kinematic and photoionization models of the multipolar structures in planetary nebula NGC 6572
Parthasarathy, Mudumba; Das, Ramkrishna; Kar, Subhajit +1 more
We have studied planetary nebula (PN) NGC 6572 through 3D morpho-kinematic and photoionization modelling. The 3D morphology is reconstructed from the Hubble Space Telescope images in different narrow-band filters and position-velocity spectra. The PN has a multipolar morphology consisting of highly collimated outflows. The nebular image shows sign…
Diving into the magnetosphere of the Of?p star HD 108
Neiner, Coralie; Nazé, Yaël; Rauw, Gregor +1 more
We analyse optical and X-ray spectroscopy of the Of?p star HD 108, known for its strong dipolar magnetic field and its optical line profile variability with a time-scale of 54 ± 3 yrs, interpreted as the stellar rotation period. Optical emission lines have now recovered from their minimum emission state reached in 2007-2008. The variations of the …
The 3D kinematics of stellar substructures in the periphery of the Large Magellanic Cloud
Erkal, Denis; Belokurov, Vasily; Aguado, David S. +4 more
We report the 3D kinematics of 27 Mira-like stars in the northern, eastern, and southern periphery of the Large Magellanic Cloud (LMC), based on Gaia proper motions and a dedicated spectroscopic follow-up. Low-resolution spectra were obtained for more than 40 Mira-like candidates, selected to trace known substructures in the LMC periphery. Radial …
Multiwavelength study of radio galaxy Pictor A: detection of western hotspot in far-UV and possible origin of high energy emissions
Stalin, C. S.; Sreekumar, P.; Bhattacharya, Debbijoy +2 more
A comprehensive study of the nucleus and western hotspot of Pictor A is carried out using AstroSat observations, 13 yr of Fermi, and archival Swift observations along with other published data. We report the first detection of the western hotspot of Pictor A in the far-UV band using observations from AstroSat-UVIT. The broad-band SED of the wester…
A deep dive into the Type II globular cluster NGC 1851
Milone, A. P.; Cordoni, G.; Marino, A. F. +13 more
About one-fifth of the Galactic globular clusters (GCs), dubbed Type II GCs, host distinct stellar populations with different heavy elements abundances. NGC 1851 is one of the most studied Type II GCs, surrounded by several controversies regarding the spatial distribution of its populations and the presence of star-to-star [Fe/H], C+N+O, and age d…