Search Publications
Discovery of the most luminous quasar of the last 9 Gyr
Fan, Xiaohui; Wolf, Christian; Lai, Samuel +8 more
We report the discovery of a bright ( g = 14.5 mag (AB), K = 11.9 mag (Vega)) quasar at redshift z=0.83 — the optically brightest (unbeamed) quasar at z>0.4. SMSS J114447.77-430859.3, at a Galactic latitude of b=+18.1°, was identified by its optical colours from the SkyMapper Southern Survey (SMSS) during a search for symbiotic binary stars. Op…
Infrared Excess of a Large OB Star Sample
Jiang, Biwei; Deng, Dingshan; Wang, Yuxi +2 more
The infrared (IR) excess from OB stars is commonly considered to be a contribution from ionized stellar wind or circumstellar dust. With the newly published Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST)-OB catalog and Galactic O-Star Spectroscopic Survey data, this work steps further on understanding the IR excess of OB stars. …
Precursory Signals of Forbush Decreases Not Connected with Shock Waves
Mavromichalaki, H.; Belov, A.; Eroshenko, E. +4 more
Forbush decreases (FDs) are sharp reductions of the cosmic-ray (CR) intensity, following intense solar activity such as coronal mass ejections (CMEs) and their corresponding interplanetary shocks. In some cases, shocks create sudden storm commencements (SSCs) at the Earth's magnetosphere with significant interest for space-weather studies. Preincr…
Effects of Spectral Resolution on Simple Magnetic Field Diagnostics of the Mg II H and K Lines
Rempel, Matthias; Centeno, Rebecca; del Pino Alemán, Tanausú +1 more
We study the effects of finite spectral resolution on the magnetic field values retrieved through the weak-field approximation (WFA) from the cores of the Mg II h and k lines. The retrieval of the line-of-sight component of the magnetic field, B LOS, from synthetic spectra generated in a uniformly magnetized FAL-C atmosphere is accurate…
The GALAH Survey: improving our understanding of confirmed and candidate planetary systems with large stellar surveys
Lewis, Geraint F.; Casey, Andrew R.; Wittenmyer, Robert A. +24 more
Pioneering photometric, astrometric, and spectroscopic surveys is helping exoplanetary scientists better constrain the fundamental properties of stars within our galaxy and the planets these stars host. In this study, we use the third data release from the stellar spectroscopic GALAH Survey, coupled with astrometric data of eDR3 from the Gaia sate…
The young Galactic cluster NGC 225: binary stars' content and total mass estimate
Munari, U.; Ochner, P.; Carraro, G. +2 more
Galactic star clusters are known to harbour a significant amount of binary stars, yet their role in the dynamical evolution of the cluster as a whole is not comprehensively understood. We investigated the influence of binary stars on the total mass estimate for the case of the moderately populated Galactic star cluster NGC 225. The analysis of mul…
A search for hot subdwarf binaries in data from the Transiting Exoplanet Survey Satellite
Siwak, M.; Zola, S.; Krzesinski, J. +1 more
We present the results of a search for binary hot subdwarf stars in photometric data from the Transiting Exoplanet Survey Satellite (TESS). The sample of objects used in this work was a byproduct of another search for pulsating hot subdwarfs, which resulted in the discovery of nearly 400 non-pulsating variable candidates. The periodogram for each …
A Model-based Technique for Ad Hoc Correction of Instrumental Polarization in Solar Spectropolarimetry
Schad, Thomas A.; Tarr, Lucas A.; Jaeggli, Sarah A. +1 more
We present a new approach for correcting instrumental polarization by modeling the nondepolarizing effects of a complex series of optical elements to determine physically realizable Mueller matrices. Provided that the Mueller matrix of the optical system can be decomposed into a general elliptical diattenuator and general elliptical retarder, it i…
Gamma-Ray Orbital Modulation of the Transitioning Millisecond Pulsar Binary XSS J12270-4859
An, Hongjun
We report on gamma-ray orbital modulation of the transitioning MSP binary XSS J12270-4859 detected in the Fermi Large Area Telescope (LAT) data. We use long-term optical data taken with the XMM-Newton OM and the Swift UltraViolet Optical Telescope to inspect radio timing solutions that are limited to relatively short time intervals and find that e…
Revised Version of the New Catalogue of Suspected Variable Stars, NSV Release 2
Samus, N. N.; Kazarovets, E. V.; Durlevich, O. V.
We present NSV Release 2, an electronic version of the "New Catalogue of Suspected Variable Stars". A detailed file-by-file description of the new catalogue version is given. By its structure, we preserve the catalogue as a historical document, but the information it contains has been considerably renewed compared to its first electronic version. …