Search Publications
Hemispheric analysis of the magnetic flux in regular and irregular solar active regions
Zhukova, A.
Studying the hemispheric distribution of active regions (ARs) with different magnetic morphologies may clarify the features of the dynamo process that is hidden under the photospheric level. The magnetic flux data for 3047 ARs from the CrAO catalogue (https://sun.crao.ru/databases/catalog-mmc-ars), between May 1996 and December 2021 (cycles 23 and…
Unveiling the complex circumgalactic medium: a comparative study of merging and non-interacting galaxy groups
Kacprzak, Glenn G.; Barone, Tania M.; Fisher, Deanne B. +5 more
While most galaxies live in group environments where they undergo an accelerated evolution, the characteristics of their circumgalactic medium (CGM) remain uncertain. We present an analysis of the CGM of two galaxy groups in different stages of interaction: (G1) a close pair of galaxies (z = 0.043) separated by 87 kpc that do not show signs of int…
The oldest stars with low neutron-capture element abundances and origins in ancient dwarf galaxies
Frebel, Anna; Andales, Hillary Diane; Santos Figueiredo, Ananda +2 more
We present a detailed chemical abundance and kinematic analysis of six extremely metal-poor (-4.2 ≤ [Fe/H] ≤-2.9) halo stars with very low neutron-capture abundances ([Sr/H] and [Ba/H]) based on high-resolution Magellan/MIKE spectra. Three of our stars have [Sr/Ba] and [Sr/H] ratios that resemble those of metal-poor stars in ultra-faint dwarf gala…
Massive compact quiescent galaxies in the M⋆ versus σe plane: insights from stellar population properties
Clerici, K. Slodkowski; Schnorr-Müller, A.; Trevisan, M. +1 more
We investigated the stellar population properties of a sample of 1858 massive compact galaxies (MCGs) extracted from the Sloan Digital Sky Survey (SDSS). Motivated by previous results showing that older compact galaxies tend to have larger velocity dispersion at fixed stellar mass, we used the distance to the σe versus Re and…
Identifying and fitting eclipse maps of exoplanets with cross-validation
Kreidberg, Laura; Parmentier, Vivien; Hammond, Mark +10 more
Eclipse mapping uses the shape of the eclipse of an exoplanet to measure its two-dimensional structure. Light curves are mostly composed of longitudinal information, with the latitudinal information only contained in the brief ingress and egress of the eclipse. This imbalance can lead to a spuriously confident map, where the longitudinal structure…
Is quasar variability regulated by the close environment of accretion?
Wang, Jun-Xian; Kang, Wen-Yong; Wu, Liang +1 more
Ultraviolet (UV)/optical variability in quasars is a well-observed phenomenon, yet its primeval origins remain unclear. This study investigates whether the accretion disc turbulence, which is responsible for UV/optical variability, is influenced by the close environment of the accretion by analysing the correlation between variability and infrared…
Search for interacting galaxy clusters from SDSS DR-17 employing optimized friends-of-friends algorithm and multimessenger tracers
Paul, Surajit; Oak, Tejas
In the theoretical framework of hierarchical structure formation, galaxy clusters evolve through continuous accretion and mergers of substructures. Cosmological simulations have revealed the best picture of the universe as a 3D filamentary network of dark-matter distribution called the cosmic web. Galaxy clusters are found to form at the nodes of …
Exploring faint white dwarfs and the luminosity function with Subaru HSC and SDSS in Stripe 82
Takada, Masahiro; Kashiyama, Kazumi; Yasuda, Naoki +4 more
We present 5080 white dwarf (WD) candidates selected from stars matching between the multiband imaging data sets of the Subaru Hyper Suprime-Cam (HSC) Survey and the Sloan Digital Sky Survey in the Stripe82 region covering about 165 deg
Upper limits of HO2 in the atmosphere of Mars from the ExoMars Trace Gas Orbiter
Montmessin, Franck; Belyaev, Denis A.; Fedorova, Anna A. +10 more
Odd-hydrogen (HO$_\mathrm{x}$) species have a crucial role in regulating the chemistry of the atmosphere of Mars and are important to understand some of the most fundamental aspects regarding its atmospheric composition such as the long-term stability of CO$_2$. Despite the key role of these species for our understanding of the Martian photochemis…
The density of the Milky Way's corona at z ≈ 1.6 through ram pressure stripping of the Draco dSph galaxy
Marinacci, Federico; Brown, Anthony G. A.; Helmi, Amina +4 more
Satellite galaxies within the Milky Way's (MW's) virial radius Rvir are typically devoid of cold gas due to ram pressure stripping by the MW's corona. The density of this corona is poorly constrained today and essentially unconstrained in the past, but can be estimated using ram pressure stripping. In this paper, we probe the MW's coron…