Search Publications
Magnetic flux rope: What is it?
Hu, Qiang
Magnetic flux rope, a type of magnetic field structure in space plasmas, has been studied for decades through both observational and theoretical means. We provide a brief report on our recent modeling study of its magnetic field configuration based on in-situ spacecraft measurements, focusing on those made for large-scale flux ropes in the interpl…
New Hot Subdwarf Variables from Gaia eDR3
Kupfer, Thomas; Kosakowski, Alekzander; Barlow, Brad N. +1 more
We present a search for new variable hot subdwarfs from Gaia eDR3 using the Zwicky Transient Facility DR9 and the 2.1 m Otto Struve Telescope at McDonald Observatory. We report the discovery of 22 HW Vir binaries, 24 reflection effect binaries, and 14 ellipsoidally modulated systems. Candidate selection for our high-speed observations was based on…
X-ray and optical observations of two AM Her type cataclysmic variables: V388 Peg and V1189 Her
Zengi̇n Çamurdan, Dicle
We present time-resolved photometry of a polar V388 Peg and a strong candidate polar V1189 Her observed by T100 telescope at TÜBİTAK National Observatory between June-August 2014 and their X-ray observations using Swift archival data obtained in Apr 2014 (V388 Peg) and in Nov 2011 (V1189 Her). These data were supplemented by archival CRTS, ZTF, AS…
Cross-matching the General Catalogue of Variable Stars with the Gaia DR3 source catalogue
Eyer, L.; Kerschbaum, F.; Ansari, S. G.
The most recent release of the General Catalogue of Variable Stars (GCVS) (Samus et al. 2017) contains 518 different variable types, in eight different variable categories. The catalogue has now reached its 5th version available via the VizieR service and can be considered one of the primary catalogues on the subject. The Gaia Data Release 3 (DR3)…
Physical properties of the slow-rotating near-Earth asteroid (2059) Baboquivari from one apparition
Kim, Myung-Jin; Lee, Hee-Jae; Erece, Orhan +6 more
In this study, we carried out photometric, spectroscopic, and for the first time, polarimetric observations of the Amor-type near-Earth asteroid (2059) Baboquivari. Our findings represent the first reliable determination of Baboquivari's physical properties. We used data from a 1m-class telescope (T100) along with ALCDEF data for photometric analy…
Dating the Stars in the Calendrical Method Shoushili of the Yuan Dynasty
Ahn, Sang-Hyeon
Shoushili was the official calendrical method promulgated in 1280 CE by the Yuan dynasty. It contains a list of the angular spans in right ascensions for the 28 lunar lodges. They are known to have been measured by Guo Shoujing with his advanced instruments with an unprecedented precision or reading error of 5'. Such precise data are useful to det…
Constraints on star formation in Orion A from Gaia
Kounkel, Marina; Hartmann, Lee; Calvet, Nuria +4 more
We develop statistical methods within a Bayesian framework to infer the star formation history from photometric surveys of pre-main-sequence populations. Our procedures include correcting for biases due to extinction in magnitude-limited surveys, and using distributions from subsets of stars with individual extinction measurements. We also make mo…
Caracterización del sistema HD 196385 mediante imagen directa, velocidad radial y astrometría
García, L. H.; Petrucci, R.; Jofré, E. +1 more
In this paper we present a characterization of the relative orbit of HD 196385B combining data from direct imaging, radial velocity, and proper motions from the Hipparcos and Gaia missions. To perform a joint fit of the data, we used the code orvara. From the fit, we obtained ranges of possible values for the major semi-axis, the mass of the secon…
Spectroscopic follow-up of a subset of the Gaia/IPHAS catalogue of Hα-excess sources
Knigge, C.; Pala, A. F.; Monguió, M. +5 more
State-of-the-art techniques to identify Hα emission-line sources in narrow-band photometric surveys consist of searching for Hα excess with reference to nearby objects in the sky (position-based selection). However, while this approach usually yields very few spurious detections, it may fail to select intrinsically faint and/or rare Hα-excess sour…
Lack of influence of the environment in the earliest stages of massive galaxy formation
Barro, Guillermo; Pérez-González, Pablo G.; Costantin, Luca +5 more
We investigate how the environment affects the assembly history of massive galaxies. For that purpose, we make use of Survey for High-z Absorption Red and Dead Sources (SHARDS) and HST spectrophotometric data, whose depth, spectral resolution, and wavelength coverage allow to perform a detailed analysis of the stellar emission as well as obtaining…