Search Publications
Chemical evolution models: the role of type Ia supernovae in the α-elements over iron relative abundances and their variations in time and space
Galbany, L.; Monteiro, H.; Mollá, M. +6 more
The role of type Ia supernovae (SN Ia), mainly the delay time distributions (DTDs) determined by the binary systems, and the yields of elements created by different explosion mechanisms, are studied by using the MULCHEM chemical evolution model applied to our Galaxy. We explored 15 DTDs and 12 tables of elemental yields produced by different SN Ia…
Accretion properties of a low-mass active galactic nucleus: UGC 6728
Safi-Harb, Samar; Naik, Sachindra; Chatterjee, Arka +4 more
We present a comprehensive analysis of approximately 15 years (2006-2021) of X-ray observations of UGC 6728, a low-mass bare AGN, for the first time. Our study encompasses both spectral and temporal aspects of this source. The spectral properties of this source are studied using various phenomenological and physical models. We conclude that (a) th…
The interaction of a large-scale nuclear wind with the high-velocity H II region G0.17+0.15
Yusef-Zadeh, F.; Wardle, M.; Rudnick, L. +4 more
We investigate the nature of a Galactic Centre source, G0.17+0.15, lying along the northern extension of the radio arc near l ~ 0.2°. G0.17+0.15 is an H II region located towards the eastern edge of the radio bubble, embedded within the highly polarized Galactic Centre eastern lobe where a number of radio filaments appear to cross through the H II…
Relative alignments between magnetic fields, velocity gradients, and dust emission gradients in NGC 1333
Pattle, Kate; Karoly, Janik; Bastien, Pierre +24 more
Magnetic fields play an important role in shaping and regulating star formation in molecular clouds. Here, we present one of the first studies examining the relative orientations between magnetic (B) fields and the dust emission, gas column density, and velocity centroid gradients on the 0.02 pc (core) scales, using the BISTRO and VLA+GBT observat…
Abundant sub-micron grains revealed in newly discovered extreme debris discs
Henning, Thomas; Moór, Attila; Pawellek, Nicole +7 more
Extreme debris discs (EDDs) are bright and warm circumstellar dusty structures around main sequence stars. They may represent the outcome of giant collisions occuring in the terrestrial region between large planetesimals or planetary bodies, and thus provide a rare opportunity to peer into the aftermaths of these events. Here, we report on results…
Typing supernova remnant G352.7-0.1 using XMM-Newton X-ray observations
Vink, Jacco; Zhou, Ping; Mao, Junjie +4 more
G352.7-0.1 is a mixed-morphology (MM) supernova remnant (SNR) with multiple radio arcs and has a disputed supernova origin. We conducted a spatially resolved spectroscopic study of the remnant with XMM-Newton X-ray data to investigate its explosion mechanism and explain its morphology. The global X-ray spectra of the SNR can be adequately reproduc…
Ensemble X-ray variability of optically selected QSOs: dependence on black hole mass and Eddington ratio
Georgakakis, A.; Salvato, M.; Buchner, J. +7 more
Although flux variability is one of the defining properties of accretion flows on to supermassive black holes, its dependence on physical parameters such as the mass of the compact object and the Eddington ratio remains under discussion. In this paper, we address this issue using the structure function statistic to measure the variability at X-ray…
Quantifying interstellar extinction at high Galactic latitudes
Gilmore, Gerry; Mandel, Kaisey S.; O'Callaghan, Matthew
A detailed map of the distribution of dust at high Galactic latitudes is essential for future cosmic microwave background polarization experiments because the dust, while diffuse, remains a significant foreground in these regions. We develop a Bayesian model to identify a region of the Hertzsprung-Russell (HR) diagram suited to constrain the singl…
Atmospheric characterization and tighter constraints on the orbital misalignment of WASP-94 A b with HARPS
Ehrenreich, D.; Wheatley, P. J.; Nealon, R. +10 more
We present high spectral resolution observations of the hot Jupiter WASP-94 A b using the HARPS instrument on ESO's 3.6-m telescope in La Silla, Chile. We probed for Na absorption in its atmosphere as well as constrained the previously reported misaligned retrograde orbit using the Rossiter-McLaughlin effect. Additionally, we undertook a combined …
Fundamental effective temperature measurements for eclipsing binary stars - V. The circumbinary planet system EBLM J0608-59
Maxted, P. F. L.; Martin, D. V.; Triaud, A. H. M. J. +3 more
EBLM J0608$-$59/TOI-1338/BEBOP-1 is a 12$^{\rm th}$-magnitude, F9 V star in an eclipsing binary with a much fainter M dwarf companion on a wide, eccentric orbit (P = 14.6 d). The binary is orbited by two circumbinary planets: one transiting on a 95-d orbit and one non-transiting on a 215-d orbit. We have used high-precision photometry from the TES…