Search Publications
Revealing the intrinsic X-ray reverberation lags in IRAS 13224-3809 through the Granger causality test
Chainakun, P.; Young, A. J.; Nakhonthong, N. +1 more
The Granger causality is an econometric test for determining whether one time series is useful for forecasting another one with a certain Granger lag. Here, the light curves in the 0.3-1 keV (reflection dominated, soft) and 1.2-5 keV (continuum dominated, hard) bands of active galactic nuclei are produced, and the Granger lags are estimated and co…
Time-dependent boundary conditions for data-driven coronal global and spherical wedge-shaped models
Feng, Xueshang; Jiang, Chaowei; Xiang, Changqing +1 more
The development of an efficient and accurate method for boundary condition treatments is of fundamental importance to data-driven magnetohydrodynamic (MHD) modelling of the global solar corona and solar active region. Particularly, in a 3D spherical wedge-shaped volume, suitable to the numerical study of solar active region, the transverse terms c…
High-energy gamma-ray emission powered by a young protostar: the case of S255 NIRS 3
Su, Yang; de Oña Wilhelmi, Emma; López-Coto, Rubén
Evidence of efficient acceleration of cosmic rays in massive young stellar objects has been recently reported. Among these massive protostars, S255 NIRS 3, for which extreme flaring events associated with radio jets have been detected, is one of the best objects to test this hypothesis. We search for gamma-ray emission associated with this object …
ALMA and Keck analysis of Fomalhaut field sources: JWST's Great Dust Cloud is a background object
Kalas, Paul; Fitzgerald, Michael P.; Kennedy, Grant M. +1 more
At 7.7 pc, the A-type star Fomalhaut hosts a bright debris disc with multiple radial components. The disc is eccentric and misaligned, strongly suggesting that it is sculpted by interaction with one or more planets. Compact sources are now being detected with JWST, suggesting that new planet detections may be imminent. However, to confirm such sou…
Alignment and rotational disruption of dust grains in the Galactic Centre revealed by polarized dust emission
Hoang, Thiem; Akshaya, M. S.
We study the alignment and rotational disruption of dust grains at the centre of our Galaxy using polarized thermal dust emission observed by SOFIA/HAWC+ and JCMT/SCUPOL at 53, 216, and 850 µm. We analysed the relationship between the observed polarization degree with total emission intensity, dust temperature, gas column density, and polarization…
Varstrometry selected radio-loud candidates of dual and off-nucleus quasars at sub-kpc scales
Wang, Jun-Xian; Gu, Min-Feng; Wang, Hao-Chen +1 more
Dual super massive black holes (SMBHs) at sub-kpc to kpc scales, the product of galaxy mergers, are progenitors of eventually coalescing binary SMBHs. If both or one of the dual SMBHs are accreting, they may appear as dual AGNs or off-nucleus AGNs. Studying such systems is essential to learn the dynamical evolution of binary SMBHs as well as the p…
Constraints on galaxy formation from the cosmic-far-infrared-background - optical-imaging cross-correlation using Herschel and UNIONS
McConnachie, Alan W.; Cuillandre, Jean-Charles; Gwyn, Stephen +11 more
Using Herschel-SPIRE imaging and the Canada-France Imaging Survey (CFIS) Low Surface Brightness data products from the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS), we present a cross-correlation between the cosmic far-infrared background and cosmic optical background fluctuations. The cross-spectrum is measured for two cases: all ga…
Revealing the Milky Way's most recent major merger with a Gaia EDR3 catalogue of machine-learned line-of-sight velocities
Lisanti, Mariangela; Dropulic, Adriana; Ostdiek, Bryan +1 more
Machine learning can play a powerful role in inferring missing line-of-sight velocities from astrometry in surveys such as Gaia. In this paper, we apply a neural network to Gaia Early Data Release 3 (EDR3) and obtain line-of-sight velocities and associated uncertainties for ~92 million stars. The network, which takes as input a star's parallax, an…
Detecting low-mass perturbers in cluster lenses using curved arc bases
Dvorkin, Cora; Birrer, Simon; Natarajan, Priyamvada +1 more
Strong gravitationally lensed arcs produced by galaxy clusters have been observationally detected for several decades now. These strong lensing constraints provided high-fidelity mass models for cluster lenses that include substructure down to $10^{9{-}10}\, \mathrm{M}_\odot$. Optimizing lens models, where the cluster mass distribution is modelled…
A systematic survey of millimetre-wavelength flaring variability of young stellar objects in the Orion Nebula Cluster
Menten, K. M.; Güdel, M.; Hacar, A. +3 more
High-energy processes are ubiquitous even in the earliest stages of protostellar evolution. Motivated by the results of our systematic search for intense centimetre radio flares in Young Stellar Objects (YSOs) and by rare findings of strong millimetre-wavelength variability, we have conducted a systematic search for such variability in the Orion N…