Search Publications
A new method to detect globular clusters with the S-PLUS survey
Cortesi, Arianna; Chies-Santos, Ana L.; Forbes, Duncan A. +17 more
In this paper, we describe a new method to select globular cluster (GC) candidates, including galaxy subtraction with unsharp masking, template fitting techniques, and the inclusion of Gaia's proper motions. We report the use of the 12-band photometric system used by S-PLUS to determine radial velocities and stellar populations of GCs around nearb…
On the use of field RR Lyrae as galactic probes - VI. Mixed mode RR Lyrae variables in Fornax and in nearby dwarf galaxies
Di Criscienzo, M.; Marinoni, S.; Marrese, P. M. +11 more
We investigate the properties of the mixed-mode (RRd) RR Lyrae (RRL) variables in the Fornax dwarf spheroidal (dSph) galaxy by using B- and V-band time series collected over 24 yr. We compare the properties of the RRds in Fornax with those in the Magellanic Clouds and in nearby dSphs, with special focus on Sculptor. We found that the ratio of RRds…
Spectral-timing of AGN ionized outflows with Athena
Costantini, E.; Uttley, P.; Juráňová, A.
Spectral-timing techniques have proven valuable in studying the interplay between the X-ray corona and the accretion disc in variable active galactic nuclei (AGNs). Under certain conditions, photoionized outflows emerging from central AGN regions also play a role in the observable spectral-timing properties of the nuclear components. The variable …
Helium line emissivities for nebular astrophysics
Del Zanna, G.; Storey, P. J.
We present the results of several collisional-radiative models describing optically thin emissivities of the main lines in neutral helium formed by recombination, for a grid of electron temperatures and densities, typical of H II regions and planetary nebulae. Accurate emissivities are required for example to measure the helium abundance in nebula…
Transit timings variations in the three-planet system: TOI-270
Gorjian, Varoujan; Mikal-Evans, Thomas; Triaud, Amaury H. M. J. +69 more
We present ground- and space-based photometric observations of TOI-270 (L231-32), a system of three transiting planets consisting of one super-Earth and two sub-Neptunes discovered by TESS around a bright (K-mag = 8.25) M3V dwarf. The planets orbit near low-order mean-motion resonances (5:3 and 2:1) and are thus expected to exhibit large transit t…
Period-change rates in Large Magellanic Cloud Cepheids revisited
Catelan, M.; Orquera-Rojas, C.; Torres, P. +10 more
The period-change rate (PCR) of pulsating variable stars is a useful probe of changes in their interior structure, and thus of their evolutionary stages. So far, the PCRs of classical Cepheids in the Large Magellanic Cloud (LMC) have been explored in a limited sample of the total population of these variables. Here, we use a template-based method …
The VMC survey - XLVII. Turbulence-controlled hierarchical star formation in the Large Magellanic Cloud
Sun, Ning-Chen; de Grijs, Richard; Marconi, Marcella +9 more
We perform a statistical clustering analysis of upper main-sequence stars in the Large Magellanic Cloud (LMC) using data from the Visible and Infrared Survey Telescope for Astronomy survey of the Magellanic Clouds. We map over 2500 young stellar structures at 15 significance levels across ~120 square degrees centred on the LMC. The structures have…
Forecasting cosmic acceleration measurements using the Lyman-α forest
Liske, Jochen; Gonzalez, Anthony; Dong, Chenxing +5 more
We present results from end-to-end simulations of observations designed to constrain the rate of change in the expansion history of the Universe using the redshift drift of the Lyman-α forest absorption lines along the lines of sight towards bright quasars. For our simulations, we take Lyman-α forest lines extracted from Keck/HIRES spectra of brig…
The centre-to-limb variation of non-thermal velocities using IRIS Si IV
Del Zanna, Giulio; Rao, Yamini K.; Mason, Helen E.
We study the non-thermal velocities in the quiet Sun using various high spatial, temporal, and spectral resolution observations from the Interface Region Imaging Spectrograph (IRIS). We focus our analysis on the transition region using the optically thin line (Si IV 1393.7 Å), and select line profiles that are nearly Gaussian. We find evidence of …
Spatially resolved gas flows around the Milky Way
Fox, Andrew J.; Bordoloi, Rongmon; Clark, Sean
We present spatially resolved measurements of cool gas flowing into and out of the Milky Way (MW), using archival ultraviolet spectra of background quasars from the Hubble Space Telescope/Cosmic Origins Spectrograph. We co-add spectra of different background sources at close projected angular separation on the sky. This novel stacking technique dr…