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Exploring the properties of the obscured hyperluminous quasar COS-87259 at z = 6.853
Farrah, Duncan; Efstathiou, Andreas; Varnava, Charalambia
In this paper we explore the properties of the
Cluster membership analysis with supervised learning and N-body simulations
Berczik, P.; Pang, X.; Bissekenov, A. +3 more
Context. Membership analysis is an important tool for studying star clusters. There are various approaches to membership determination, including supervised and unsupervised machine-learning (ML) methods. Aims. We perform membership analysis using the supervised ML approach. Methods. We trained and tested our ML models on two sets of star cluster …
Fierce Feedback in an Obscured, Sub-Eddington State of the Seyfert 1.2 Markarian 817
Brandt, W. N.; Zoghbi, Abderahmen; Miller, Jon M. +7 more
Mrk 817 is a bright and variable Seyfert 1.2 active galactic nucleus (AGN). X-ray monitoring of Mrk 817 with the Neil Gehrels Swift Observatory in 2022 revealed that the source flux had declined to a lower level than recorded at any prior point in the then 19 yr mission. We present an analysis of deep XMM-Newton and NuSTAR observations obtained in…
Hierarchical Bayesian inference of globular cluster properties
Speagle, Joshua S.; Webb, Jeremy J.; Eadie, Gwendolyn M. +1 more
We present a hierarchical Bayesian inference approach to estimating the structural properties and the phase-space centre of a globular cluster (GC) given the spatial and kinematic information of its stars based on lowered isothermal cluster models. As a first step towards more realistic modelling of GCs, we built a differentiable, accurate emulato…
TOI-1199 b and TOI-1273 b: Two new transiting hot Saturns detected and characterized with SOPHIE and TESS
Deleuil, M.; Moutou, C.; Narita, N. +41 more
We report the characterization of two planet candidates detected by the Transiting Exoplanet Survey Satellite (TESS), TOI-1199 b and TOI-1273 b, with periods of 3.7 and 4.6 days, respectively. Follow-up observations for both targets, which include several ground-based light curves, confirmed the transit events. High-precision radial velocities fro…
Characterizing B stars from Kepler/K2 Campaign 11. Optical analysis and seismic diagnostics
Eidam, Jéssica M.; Andrade, Laerte; Emilio, Marcelo +5 more
Aims: In this study, we analyze 122 B-type star candidates observed during Campaign 11 of the Kepler/K2 mission to investigate their variability and pulsation characteristics. A subset of 45 B star candidates was observed during the Kepler/K2 mission's Campaign 11 between September and December 2016. Our analyses aim to gain a deeper understa…
Evidence for Dust Depletion in a Misaligned Protoplanetary Disk with JWST
Zhu, Z.; Reynolds, M.; Calvet, N. +12 more
Here we report the detection of dust depletion in a misaligned inner disk around UX Tau A using JWST MIRI spectra. Mid-infrared (MIR) continuum "seesaw" variability was detected in this disk by Spitzer and attributed to variable shadows cast on the outer disk by the inner disk. The JWST MIRI spectrum of UX Tau A also shows seesaw variability but w…
Discovery of an extended horizontal branch in the Large Magellanic Cloud globular cluster NGC 1835
Vesperini, Enrico; Cadelano, Mario; Pallanca, Cristina +6 more
We present a high-angular-resolution multi-wavelength study of the massive globular cluster NGC 1835 in the Large Magellanic Cloud. Thanks to a combination of optical and near-ultraviolet images acquired with the WFC3 on board the HST, we performed a detailed inspection of the stellar population in this stellar system, adopting a `UV-guided search…
Constraints on the z ∼ 5 Star-forming Galaxy Luminosity Function From Hubble Space Telescope Imaging of an Unbiased and Complete Sample of Long Gamma-Ray Burst Host Galaxies
Strader, Jay; Perley, Daniel A.; Chornock, Ryan +4 more
We present rest-frame UV Hubble Space Telescope imaging of the largest and most complete sample of 23 long-duration gamma-ray burst (GRB) host galaxies between redshifts 4 and 6. Of these 23, we present new WFC3/F110W imaging for 19 of the hosts, which we combine with archival WFC3/F110W and WFC3/F140W imaging for the remaining four. We use the ph…
Cosmic-Ray Transport in the Presence of a Fisk-type Heliospheric Magnetic Field: Investigating the Influence of Drift
Engelbrecht, N. E.; Steyn, P. J.; Troskie, J. S.
Drifts due to the gradients in, and curvatures of, the heliospheric magnetic field (HMF) play a significant role in the transport of galactic cosmic rays (GCRs) in the heliosphere. Although this has been well studied for the Parker HMF, the influence of Fisk-type fields, with their unique geometry, has hitherto received less attention. Here, drift…