Search Publications
COSMOS brightest group galaxies: III. Evolution of stellar ages
Finoguenov, A.; Ilbert, O.; Magdis, G. E. +15 more
The unique characteristics of the brightest group galaxies (BGGs) serve as a link in the evolutionary continuum between galaxies such as the Milky Way and the more massive brightest cluster galaxies found in dense clusters. This research investigates the evolution of the stellar properties of BGGs over cosmic time (z = 0.08 ‑ 1.30), extending the …
Multipoint observations of compressional Pc5-6 pulsations in the dawn side magnetosphere: A case study
Sibeck, D. G.; Korotova, G. I.
We present a case study of compressional Pc5-6 pulsations observed by THEMIS-D and -E in the dawn sector of the magnetosphere following 1100 UT on January 22, 2010. The pulsations were observed during a moderate substorm triggered by the IMF discontinuity and an accompanying change in the solar wind dynamic pressure at 1045 UT. The event can be co…
Testing the flux tube expansion factor - solar wind speed relation with Solar Orbiter data
Maksimovic, M.; Louarn, P.; Démoulin, P. +5 more
Context. The properties of the solar wind measured in situ in the heliosphere are largely controlled by energy deposition in the solar corona, which is in turn closely related to the properties of the coronal magnetic field. Previous studies have shown that long-duration and large-scale magnetic structures show an inverse relation between the sola…
Radial Metallicity Gradients for the Chemically Selected Galactic Thin Disc Main-Sequence Stars
Seabroke, G. M.; Bilir, S.; Ak, T. +3 more
We present the radial metallicity gradients within the Galactic thin disc population through main-sequence stars selected on the chemical plane using GALAH DR3 accompanied with Gaia DR3 astrometric data. The [Fe/H], [α/Fe] and [Mg/H] radial gradients are estimated for guiding radius as -0.074±0.006, +0.004±0.002, -0.074±0.006 dex kpc -1…
Discovery of Two Different Full Disk Evolutionary Patterns of M-type T Tauri Stars with LAMOST DR8
Zhao, Yongheng; Duan, Fuqing; Li, Guang-Wei +2 more
The full disk, full of gas and dust, determines the upper limit of planet masses, and its lifetime is critical for planet formation, especially for giant planets. In this work, we studied the evolutionary timescales of the full disks of T Tauri stars (TTSs) and their relations to accretion. Combined with Gaia EDR3, Two Micron All Sky Survey, and W…
PeVatron candidate SNR G106.3+2.7 in a low-density cavity: a multiwavelength test
Liu, Ruo-Yu; Chen, Yang; Ge, Chong +1 more
In this paper, we constrain the density of the interstellar medium (ISM) around the hadronic PeVatron candidate, supernova remnant (SNR) G106.3+2.7, based on X-ray and γ-ray observations. The purpose of this investigation is to understand the influence of the gaseous environment on this SNR as a proton PeVatron candidate. By modelling the self-reg…
Telescope control software and proto-model siderostat for the SDSS-V Local Volume Mapper
Kollmeier, Juna A.; Drory, Niv; Froning, Cynthia S. +19 more
The fifth Sloan Digital Sky Survey Local Volume Mapper (LVM) is a wide-field integral field unit survey that uses an array of four 160 mm fixed telescopes with siderostats to minimize the number of moving parts. An individual telescope observes the science or calibration field independently and is synchronized with the science exposure. We develop…
VLBI astrometry of radio stars to link radio and optical celestial reference frames: observing strategies
Sun, Yan; Zhang, Bo; Chen, Wen +12 more
The Gaia celestial reference frame (Gaia-CRF) will benefit from a close assessment with independent methods, such as Very Long Baseline Interferometry (VLBI) measurements of radio stars at bright magnitudes. However, obtaining full astrometric parameters for each radio star through VLBI measurements demands a significant amount of observation time…
Photometric Completeness Modelled with Neural Networks
Speagle, Joshua S.; Harris, William E.
In almost any study involving optical/near-infrared photometry, understanding the completeness of detection and recovery is an essential part of the work. The recovery fraction is, in general, a function of several variables including magnitude, color, background sky noise, and crowding. We explore how completeness can be modeled, with the use of …
NuSTAR and Swift observations of two supergiant fast X-ray transients: AX J1841.0-0536 and SAX J1818.6-1703
Romano, P.; Ferrigno, C.; Bozzo, E.
Supergiant fast X-ray transients are wind-fed binaries hosting neutron star accretors, which display a peculiar variability in the X-ray domain. Different models have been proposed to explain this variability and the strength of the compact object magnetic field is generally considered a key parameter to discriminate among possible scenarios. We p…