Search Publications
X-ray view of a merging supermassive black hole binary candidate SDSS J1430+2303: Results from the first ∼200 days of observations
Zheng, Zhen-Ya; Shu, Xinwen; Pan, Zhen +7 more
Context. Recently we discovered an unprecedented supermassive black hole binary (SMBHB) candidate in the nearby Seyfert galaxy SDSS J1430+2303, which is predicted to merge within three years. X-ray spectroscopy may bring unique kinematic evidence for the last inspiraling stage, when the binary is too close to allow each of them to hold an individu…
Sampling molecular gas in the Helix planetary nebula: Variation in HNC/HCN with UV flux
Kastner, J. H.; Alcolea, J.; Santander-García, M. +4 more
Context. Observations of molecular clouds, prestellar cores, and protoplanetary disks have established that the HNC/HCN ratio may be a potent diagnostic of molecular gas physical conditions. The processes that govern the relative abundances of these molecules nevertheless remain poorly understood.
Aims: We seek to exploit the wide range of UV…
Gaia EDR3 comparative study of protoplanetary disk fractions in young stellar clusters
Mendigutía, I.; Huélamo, N.; Solano, E. +4 more
Context. The lifetime of protoplanetary disks around young stars limits the timescale of planet formation. A disk dissipation timescale ≤10 Myr was inferred from surveys that count the relative number of stars with disks - the disk fraction - in young stellar clusters with different ages. However, most previous surveys focused on the compact regio…
Confirmation and characterisation of three giant planets detected by TESS from the FIES/NOT and Tull/McDonald spectrographs
Bieryla, Allyson; Quinn, Samuel N.; Cochran, William D. +37 more
We report the confirmation and characterisation of TOI-1820 b, TOI-2025 b, and TOI-2158 b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around 4.9 d,…
AutoSourceID-Light. Fast optical source localization via U-Net and Laplacian of Gaussian
Groot, P. J.; Jóhannesson, G.; Vreeswijk, P. +9 more
Aims: With the ever-increasing survey speed of optical wide-field telescopes and the importance of discovering transients when they are still young, rapid and reliable source localization is paramount. We present AutoSourceID-Light (ASID-L), an innovative framework that uses computer vision techniques that can naturally deal with large amount…
Star-forming and gas-rich brightest cluster galaxies at z ∼ 0.4 in the Kilo-Degree Survey
Castignani, G.; Moscardini, L.; Radovich, M. +9 more
Brightest cluster galaxies (BCGs) are typically massive ellipticals at the centers of clusters. They are believed to experience strong environmental processing, and their mass assembly and star formation history are still debated. We have selected three star-forming BCGs in the equatorial field of the Kilo-Degree Survey (KiDS). They are KiDS 0920 …
Galactic and stellar perturbations of long-period comet motion. Practical considerations
Dybczyński, Piotr A.; Breiter, Sławomir
Context. Thanks to our expanding knowledge of the Galactic and stellar neighborhood of the Solar System, modern long-period comet motion studies must take into account both stellar perturbations and the overall Galactic potential.
Aims: Our aim is to propose algorithms and methods that aid in performing numerical integrations of equations of …
The detection of magnetic chemically peculiar stars using Gaia BP/RP spectra
Paunzen, E.; Prišegen, M.
Context. The magnetic chemically peculiar (mCP) stars of the upper main sequence are perfectly suited to studying the effects of rotation, diffusion, mass-loss, accretion, and pulsation in the presence of an organized stellar magnetic field. Therefore, many important models can only be tested with this star group.
Aims: In this case study we …
The Gaia-ESO survey: A spectroscopic study of the young open cluster NGC 3293
Gilmore, G.; Gosset, E.; Herrero, A. +24 more
We present a spectroscopic analysis of the GIRAFFE and UVES data collected by the Gaia-ESO survey for the young open cluster NGC 3293. Archive spectra from the same instruments obtained in the framework of the `VLT-FLAMES survey of massive stars' are also analysed. Atmospheric parameters, non-local thermodynamic equilibrium (LTE) chemical abundanc…
An X-ray fading, UV brightening QSO at z ≈ 6
Bauer, F. E.; Brandt, W. N.; Vignali, C. +13 more
Explaining the existence of super massive black holes (SMBHs) with MBH ≳ 108 M⊙ at z ≳ 6 is a persistent challenge to modern astrophysics. Multiwavelength observations of z ≳ 6 quasi-stellar objects (QSOs) reveal that, on average, their accretion physics is similar to that of their counterparts at lower redshift. H…