Search Publications
The missing radial velocities of Gaia: Blind predictions for DR3
Widmark, Axel; Naik, Aneesh P.
While Gaia has observed the phase space coordinates of over a billion stars in the Galaxy, in the overwhelming majority of cases it has only obtained five of the six coordinates, the missing dimension being the radial (line-of-sight) velocity. Using a realistic mock data set, we show that Bayesian neural networks are highly capable of 'learning' t…
Counterparts of candidate dusty starbursts at z > 6
Yan, Haojing; Ling, Chenxiaoji; Ma, Zhiyuan
We present an analysis of the optical-to-near-infrared (IR) counterparts of a sample of candidate dusty starbursts at z > 6. These objects were pre-selected based on the rising trend of their far-IR-to-sub-millimeter spectral energy distributions and the fact that they are radio-weak. Their precise positions are available through millimeter and…
A search for period changes of eight short-period Type II Cepheids
Whitelock, Patricia A.; Kniazev, Alexei Y.; Yacob, Alemiye M. +2 more
In this study, we investigate the period changes of eight short-period Type II Cepheids of the BL Her subtype, i.e. with periods in the 1-4 d range. The O - C diagrams for these stars are constructed using all suitable observational data from ground and space surveys. This spans a time interval of over one century and includes digitized photograph…
Identification of new hot subdwarf binary systems by means of Virtual Observatory tools
Álvarez, M. A.; Dafonte, C.; Manteiga, M. +7 more
The estimation of the binary fraction of hot subdwarfs is key to shed light on the different evolution scenarios proposed to explain the loss of the hydrogen envelope during the red giant branch phase. In this paper, we analyse the spectral energy distribution of the hot subdwarfs included in a recent and comprehensive catalogue with the aim of id…
Machine learning for galactic archaeology: a chemistry-based neural network method for identification of accreted disc stars
Grand, Robert J. J.; Gómez, Facundo A.; Marinacci, Federico +4 more
We develop a method ('Galactic Archaeology Neural Network', GANN) based on neural network models (NNMs) to identify accreted stars in galactic discs by only their chemical fingerprint and age, using a suite of simulated galaxies from the Auriga Project. We train the network on the target galaxy's own local environment defined by the stellar halo a…
20 Orbits of binaries based on soar speckle observations
Docobo, José A.; Campo, Pedro P.; Mendez, Rene A. +3 more
New observational data obtained during the 2018, 2019, and 2020 speckle runs with the 4.1-m Southern Astrophysical Research (SOAR) telescope located at Cerro Pachón (Chile) allowed us to recalculate the orbits of the visual binaries: WDS 00277-1625 (YR 1 Aa,Ab), WDS 00462-2214 (RST4155), WDS 03124-4425 (JC 8), WDS 07427-3510 (HDS 1091), WDS 10093+…
A compact symmetric ejection from the low mass AGN in the LINER galaxy NGC 4293
Yang, Xiaolong; Wang, Ruiling; Guo, Quan
We conducted a Very Long Baseline Array (VLBA) observation of the low mass active galactic nucleus (AGN) in galaxy NGC 4293 (z = 0.003). The object is associated with a low-ionization nuclear emission-line region (LINER). Its black hole mass is estimated as ~105 or ${\sim}10^7 \, \mathrm{M}_\odot$. The VLBA 1.5 GHz image shows an invers…
A cosmological distance measure using radio-loud quasars
Huang, L.; Chang, Z. X.
We use the X-ray luminosity relation of radio-loud quasars (RLQs) to measure these luminosity distances as well as estimate cosmological parameters. We adopt four parametric models of X-ray luminosity to test luminosity correlation for RLQs and radio-intermediate quasars (RIQs) and give these cosmological distances. By Bayesian information criteri…
TIC 257060897b: An inflated, low-density, hot-Jupiter transiting a rapidly evolving subgiant star
Montalto, M.; Piotto, G.; Nascimbeni, V. +7 more
We report the discovery of a new transiting exoplanet orbiting the star TIC 257060897 and detected using TESS full frame images. We acquired HARPS-N time-series spectroscopic data, and ground-based photometric follow-up observations from which we confirm the planetary nature of the transiting body. For the host star we determined: Teff …
Near-infrared spectroscopy of extreme BAL QSOs from the QUBRICS bright quasar survey
Grazian, Andrea; Selvelli, Pierluigi; Boutsia, Konstantina +8 more
We report on the spectral confirmation of 18 quasi-stellar object (QSO) candidates from the QUasars as BRIght beacons for Cosmology in the Southern hemisphere (QUBRICS) survey, previously observed in the optical band, for which we acquired new spectroscopic data in the near-infrared band with the Folded-port InfraRed Echellette (FIRE) spectrograph…