Search Publications
Comparison of the active galactic nuclei Baldwin effect with the modified Baldwin effect of the ultraviolet-optical emission lines in a single sample
Shang, Zhaohui; Brotherton, Michael S.; Wang, Yongjiang +1 more
The inverse relationship between equivalent width (EW) of broad emission lines and the underlying continuum luminosity, known as the Baldwin effect (BE), is an important and well-studied correlation in active galactic nuclei (AGNs). However, the EW is also considered to be anticorrelated with the Eddington ratio, referred to as the modified Baldwi…
The evolutionary state of the chemically peculiar members of the open cluster NGC 2516
Hubrig, S.; Schöller, M.; Piskunov, A. E. +1 more
We aim at establishing safe membership and evolutionary status of 11 chemically peculiar (CP) stars that are residing in the domain of the open cluster NGC 2516 and are frequently referred to as cluster members. We queried the Gaia EDR3 catalogue in an area with a radius of 1° and selected 37 508 stars brighter than G = 19 mag. The cluster members…
XMM-Newton detection of soft time lags in the TDE candidate AT 2018fyk
Zhang, Wenda
In this letter, we report a tentative detection of soft time lags (i.e. variability of softer photons lags behind the variability of harder photons) in one XMM-Newton observation of the tidal disruption event (TDE) candidate AT 2018fyk while the source was in the hard spectral state. The lags are detected at $6.51\times 10^{-5}~\rm Hz$. The amplit…
Collision of two stellar associations in the nearby Gum Nebula
White, Russel J.; Yep, Alexandra C.
Based on Gaia DR2 data and new CHIRON radial velocities, we have discovered that two nearby stellar associations UPK 535 (318.08 ± 0.29 pc, $25^{+15}_{-10}$ Myr, 174 stars) and Yep 3 (339.54 ± 0.25 pc, $45^{+55}_{-20}$ Myr, 297 stars) in the Gum Nebula have recently collided. We project stars' current positions, motions, and measurement uncertaint…
H I in and behind the Hubble Frontier Field clusters: a deep MeerKAT pilot search out to z ∼ 0.5
Obreschkow, Danail; Heywood, Ian; Deane, Roger +2 more
The Hubble Frontier Fields (HFF) are a selection of well-studied galaxy clusters used to probe dense environments and distant gravitationally lensed galaxies. We explore the 21cm neutral hydrogen (H I) content of galaxies in three of the HFF clusters, Abell 2744 (z = 0.308), Abell S1063 (z = 0.346), and Abell 370 (z = 0.375), to investigate the ev…
Two years of optical and NIR observations of the superluminous supernova UID 30901 discovered by the UltraVISTA SN survey
Milvang-Jensen, B.; Fynbo, J. P. U.; Anderson, J. P. +6 more
We present deep optical and near-infrared photometry of UID 30901, a superluminous supernova (SLSN) discovered during the UltraVISTA survey. The observations were obtained with VIRCAM (YJHKs) mounted on the VISTA telescope, DECam (griz) on the Blanco telescope, and SUBARU Hyper Suprime-Cam (HSC; grizy). These multiband observations comp…
Estimating accurate reddening values of LAMOST M dwarfs
Chen, B. -Q.; Yuan, H. -B.; Sun, W. -X. +3 more
M dwarfs are the dominating type of stars in the solar neighbourhood. They serve as excellent tracers for the study of the distribution and properties of the nearby interstellar dust. In this work, we aim to obtain high accuracy reddening values of M dwarf stars from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) Data Relea…
Approach of the Hyades star cluster to the Solar system
Vereshchagin, S. V.; Sizova, M. D.; Emel'yanenko, V. V.
We present the results of calculations of the motion of the Hyades open cluster in the gravitational field of the Galaxy in the recent past. Our calculations show that the recent close passage of Hyades by the Solar system could cause a noticeable shift of the perihelion distances q of comets. The shift is negligible from q = 3 au to 2.6 au for th…
Survey for distant solar twins (SDST) - II. Design, observations, and data
Kos, Janez; Martell, Sarah L.; Murphy, Michael T. +5 more
Studies of solar twins have key impacts on the astronomical community, but only ~100-200 nearby solar twins (<1 kpc) have been reliably identified over the last few decades. The aim of our survey (SDST) is to identify ~150-200 distant solar twins and analogues (up to ≲4 kpc) closer to the Galactic Centre. We took advantage of the precise Gaia a…
Scattering and sublimation: a multiscale view of µm-sized dust in the inclined disc of HD 145718
Monnier, John D.; Schaefer, Gail H.; Lanthermann, Cyprien +16 more
We present multi-instrument observations of the disc around the Herbig Ae star, HD 145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orientation, the vertical and radial extent of the near-infrared (NIR) scattering surface, and the properties of the dust in the disc surface and sublimation rim. The disc appe…