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Constraining spinning primordial black holes with global 21-cm signal
Natwariya, Pravin Kumar; Nayak, Alekha C.; Srivastava, Tripurari
We study the upper projected bounds on the dark matter fraction in the form of the primordial black holes (PBHs) with a non-zero spin by using the absorption feature in the global 21-cm signal at redshift z ≈ 17. The mass and spin are fundamental properties of a black hole, and they can substantially affect the evaporation rate of the black hole. …
New strong lensing modelling of SDSS J2222+2745 enhanced with VLT/MUSE spectroscopy
Brammer, G.; Grillo, C.; Tozzi, P. +8 more
Context. SDSS J2222+2745, at z = 0.489, is one of the few currently known lens clusters with multiple images (six) of a background (z = 2.801) quasar with measured time delays between two image pairs (with a sub-percent relative error for the longer time delay). Systems of this kind can be exploited as alternative cosmological probes through high-…
AGN accretion and black hole growth across compact and extended galaxy evolution phases
Kocevski, Dale D.; Aird, James; Coil, Alison L.
The extent of black hole growth during different galaxy evolution phases and the connection between galaxy compactness and active galactic nucleus (AGN) activity remain poorly understood. We use Hubble Space Telescope imaging of the CANDELS fields to identify star-forming and quiescent galaxies at z = 0.5-3 in both compact and extended phases and …
Invited Review: Short-term Variability with the Observations from the Helioseismic and Magnetic Imager (HMI) Onboard the Solar Dynamics Observatory (SDO): Insights into Flare Magnetism
Kazachenko, Maria D.; Welsch, Brian T.; Albelo-Corchado, Marcel F. +1 more
Continuous vector magnetic-field measurements by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) allow us to study magnetic-field properties of many flares. Here, we review new observational aspects of flare magnetism described using SDO data, including statistical properties of magnetic-reconnection fluxes …
J1721+8842: a gravitationally lensed binary quasar with a proximate damped Lyman-α absorber
Courbin, F.; Sluse, D.; Lemon, C. +5 more
High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line of sight. However, only three sub-10-kpc binaries have been confirmed above z = 1. Gravitational lensing would provide a way to easily resolve such binaries, study them…
Binary Formation in the Orion Nebula Cluster: Exploring the Substellar Limit
Reiter, Megan; Meyer, Michael R.; De Furio, Matthew +3 more
We present results constraining the multiplicity of the very low mass stars and substellar objects in the Orion Nebula Cluster (ONC). Our sample covers primary masses 0.012-0.1 M ⊙ using archival Hubble Space Telescope data obtained with the Advanced Camera for Surveys using multiple filters. Studying the binary populations of clusters …
V606 Cen: A Newly Formed Massive Contact Binary in a Hierarchical Triple System
Zhang, J.; Qian, S. -B.; Liao, W. -P. +3 more
V606 Centauri (V606 Cen) is an early B-type close binary with an orbital period of 1.4950935 days, and its complete light curves are very difficult to observe on the ground. By analyzing the continuous light curve obtained by TESS, we found that it is a marginal contact binary with a very low fill-out factor of about 2%. The O - C diagram of V606 …
The effect of hierarchical structure of the surface dust layer on the modelling of comet gas production
Blum, J.; Hartogh, P.; Bentley, M. S. +3 more
A hierarchical model of microstructure of cometary dust seems to accurately capture the morphological complexity of these particles as observed by the Rosetta mission to the 67P/Churyumov-Gerasimenko. The main aim of this work is to investigate how uncertainties in the knowledge of the microstructure of the surface layer affect our estimates of ga…
Recent progress with observations and models to characterize the magnetic fields from star-forming cores to protostellar disks
Hennebelle, Patrick; Maury, Anaëlle; Girart, Josep Miquel
In this review article, we aim at providing a global outlook on the progresses made in the recent years to characterize the role of magnetic fields during the embedded phases of the star formation process. Thanks to the development of observational capabilities and the parallel progress in numerical models, capturing most of the important physics …
The HST Large Program on ω Centauri. V. Exploring the Ultracool Dwarf Population with Stellar Atmosphere and Evolutionary Modeling
Anderson, Jay; Salaris, Maurizio; Burgasser, Adam J. +5 more
Brown dwarfs can serve as both clocks and chemical tracers of the evolutionary history of the Milky Way due to their continuous cooling and high sensitivity of spectra to composition. We focus on brown dwarfs in globular clusters that host some of the oldest coeval populations in the galaxy. Currently, no brown dwarfs in globular clusters have bee…