Search Publications
Exploring the high-density reflection model for the soft excess in RBS 1124
Stern, D.; Fabian, A. C.; Hardcastle, M. J. +13 more
'Bare' active galactic nuclei (AGN) are a subclass of Type 1 AGN that show little or no intrinsic absorption. They offer an unobscured view of the central regions of the AGN and therefore serve as ideal targets to study the relativistic reflection features originating from the innermost regions of the accretion disc. We present a detailed broad-ba…
Searching for globular clusters in the inner halo of the Circinus galaxy
Minniti, D.; Gómez, M.; Obasi, C. +3 more
In this study, we search for globular clusters (GCs) in the inner halo of the Circinus galaxy using a combination of observational data. Our data set includes observations from the VISTA Variables in the Vía Láctea Extended Survey (VVVX), optical data from Gaia Release 3 (DR3), and observations from the Dark Energy Camera (DECam). These multiple d…
The radio to GeV picture of PSR B1259-63 during the 2021 periastron passage
van Soelen, B.; Chernyakova, M.; Malyshev, D. +3 more
PSR B1259-63 is a gamma-ray binary system with a radio pulsar orbiting an O9.5Ve star, LS 2883, with a period of ${\sim} 3.4$ yr. Close to the periastron the system is detected at all wavelengths, from radio to the TeV energies. The emission in this time period is believed to originate from the interaction of LS 2883 and pulsar's outflows. The obs…
Observational bias and young massive cluster characterization - II. Can Gaia accurately observe young clusters and associations?
Naylor, Tim; Buckner, Anne S. M.; Rieder, Steven +2 more
Observations of clusters suffer from issues such as completeness, projection effects, resolving individual stars, and extinction. As such, how accurate measurements and conclusions are likely to be? Here, we take cluster simulations (Westerlund2- and Orion-type), synthetically observe them to obtain luminosities, accounting for extinction, and the…
A new mass and radius determination of the ultra-short period planet K2-106b and the fluffy planet K2-106c
Fridlund, M.; Guenther, E. W.; Gandolfi, D. +5 more
Ultra-short period planets (USPs) have orbital periods of less than 1 d. Since their masses and radii can be determined to a higher precision than long-period planets, they are the preferred targets to determine the density of planets which constrains their composition. The K2-106 system is particularly interesting because it contains two planets …
Velocity gradient and stellar polarization: magnetic field tomography towards the L1688 cloud
Hu, Yue; Schmaltz, Tyler; Lazarian, Alex
Magnetic fields are a defining yet enigmatic aspect of the interstellar medium, with their three-dimensional (3D) mapping posing a substantial challenge. In this study, we harness the innovative velocity gradient technique (VGT), underpinned by magnetohydrodynamic turbulence theories, to map the magnetic field structure by applying it to the atomi…
Swift/UVOT discovery of Swift J221951-484240: a UV luminous ambiguous nuclear transient
Troja, E.; Cenko, S. B.; Sakamoto, T. +57 more
We report the discovery of Swift J221951-484240 (hereafter: J221951), a luminous slow-evolving blue transient that was detected by the Neil Gehrels Swift Observatory Ultraviolet/Optical Telescope (Swift/UVOT) during the follow-up of gravitational wave alert S190930t, to which it is unrelated. Swift/UVOT photometry shows the UV spectral energy dist…
A dusty protocluster surrounding the binary galaxy HerBS-70 at z = 2.3
Berta, S.; Ivison, R. J.; Omont, A. +38 more
We report on deep SCUBA-2 observations at 850 $\mu$m and NOrthern Extended Millimetre Array (NOEMA) spectroscopic measurements at 2 mm of the environment surrounding the luminous, massive (M* ≈ 2 × 1011 M⊙) Herschel-selected source HerBS-70. This source was revealed by previous NOEMA observations to be a binary sys…
The structural properties of nearby dwarf galaxies in low-density environments - size, surface brightness, and colour gradients
Kaviraj, S.; Watkins, A. E.; Lazar, I. +3 more
We use a complete sample of 211 nearby (
Chemical abundances and ionizing mechanisms in the star-forming double-ring of AM 0644-741 using MUSE data
Oskinova, L. M.; Sander, A. A. C.; Charlot, S. +6 more
We present the analysis of archival Very Large Telescope Multi-Unit Spectroscopic Explorer observations of 179 H II regions in the star-forming double-ring collisional galaxy AM 0644-741 at 98.6 Mpc. We determined ionic abundances of He, N, O, and Fe using the direct method for the brightest H II region (ID 39); we report $\log \rm {(\frac{N}{O})}…