Search Publications
Spirality: A Novel Way to Measure Spiral Arm Pitch Angle
Davis, Benjamin L.; Boe, Benjamin; Kennefick, Daniel +7 more
We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 min per galaxy, assuming 8 GB of working memory. We tested the code using 117 synthetic spiral images with known pitches, varying both the spiral pro…
Cosmological Model Tests with JWST
Lovyagin, Nikita; Raikov, Alexander; Yershov, Vladimir +1 more
The James Webb Space Telescope (JWST), which has recently become operational, is capable of detecting objects at record-breaking redshifts, z≳15. This is a crucial advance for observational cosmology, as at these redshifts the differences between alternative cosmological models manifest themselves in the most obvious way. In recent years, some obs…
The Interstellar Medium of Dwarf Galaxies
Hunt, Leslie K.; Izotov, Yuri I.; Henkel, Christian
Dwarf galaxies are by far the most numerous galaxies in the Universe, showing properties that are quite different from those of their larger and more luminous cousins. This review focuses on the physical and chemical properties of the interstellar medium of those dwarfs that are known to host significant amounts of gas and dust. The neutral and io…
Blazars at Very High Energies: Emission Modelling
Zech, Andreas; Sol, Hélène
Blazars are very broadband cosmic sources with spectra spanning over twenty orders of magnitude in frequency, down to the 100 MHz regime in the radio range, up to VHE at several tens of TeV. The modelling of their spectral energy distribution at high energies currently considers two main classes of models, leptonic and lepto-hadronic, which both s…
Fundamental Properties of Late-Type Stars in Eclipsing Binaries
Ribas, Ignasi; Giménez, Álvaro; Morales, Juan Carlos +1 more
Evidence from the analysis of eclipsing binary systems revealed that late-type stars are larger and cooler than predicted by models, and that this is probably caused by stellar magnetic activity. In this work, we revisit this problem taking into account the advancements in the last decade. We provide and updated a list of 32 eclipsing binary or mu…
A Preliminary Investigation of CSPN in the HASH Database
Parker, Quentin A.; Ritter, Andreas; Xiang, Zou
We present some preliminary findings on the population of planetary nebula where central stars (CSPN) have been independently identified in the HASH catalogue. Many new discoveries and candidates have been found (416 at the time of this writing), adding significantly to the previously known sample of about 600. We also present results from a compa…
Further Studies of the Association of Planetary Nebula BMP J16135406 with Galactic Open Cluster NGC 6067
Parker, Quentin A.; Sabin, Laurence; Zijlstra, Albert A. +3 more
Planetary Nebulae (PNe) that are physical members of Galactic open clusters are powerful probes that allow precise determination of their distance and crucially their initial mass on the main sequence. Here, we revisit the physical association of the PN BMP J1613–5406 with the open cluster NGC 6067 and present our preliminary results based on our …
The Accreting White Dwarfs in Cataclysmic Variables
Sion, Edward M.; Godon, Patrick
Accreting white dwarfs (WDs) in cataclysmic variables (CVs) provide crucial insights about the accretion of mass and angular momentum in all types of binaries, including accreting NSs and BHs. Accreting WDs are the critical component in the single degenerate pathway to SNe Ia, along with the double degenerate merger pathway, they are the standard …
Understanding High-Energy (UV and X-ray) Emission from AGB Stars—Episodic Accretion in Binary Systems
Sanz-Forcada, Jorge; Sahai, Raghvendra; Ortiz, Roberto +2 more
X-ray surveys of UV-emitting AGB stars show that ∼40% of objects with FUV emission and GALEX FUV/NUV flux ratio Rfuv/nuv ∼> 0.2 (fuvAGB stars) have variable X-ray emission characterized by very high temperatures (Tx∼35–160 MK) and luminosities (Lx∼0.002–0.2 L⊙), indicating the presence of accretion associated with a close binary companion. Howe…
Plasma Diagnostics in the Era of Integral Field Spectroscopy
Ueta, Toshiya
To understand the physical conditions of various gaseous systems, plasma diagnostics must be performed properly. To that end, it is equally important to have extinction correction performed properly, even before performing plasma diagnostics. This means that the physical conditions of the target sources—the very quantities to be derived via plasma…