Search Publications
Hard X-ray view on intermediate polars in the Gaia era
Doroshenko, Victor; Suleimanov, Valery F.; Werner, Klaus
The hardness of the X-ray spectra of intermediate polars (IPs) is determined mainly by the white dwarf (WD) compactness (mass-radius ratio, M/R) and, thus, hard X-ray spectra can be used to constrain the WD mass. An accurate mass estimate requires the finite size of the WD magnetosphere Rm to be taken into the account. We suggested to d…
Reconciling mass estimates of ultradiffuse galaxies
Laporte, Chervin F. P.; Navarro, Julio F.; Agnello, Adriano
The virial masses of ultradiffuse galaxies (UDGs) have been estimated using the kinematics and abundance of their globular cluster populations, leading to disparate results. Some studies conclude that UDGs reside in massive dark matter haloes while van Dokkum et al., controversially, argue for the existence of UDGs with no dark matter at all. Here…
The mass-to-light ratios and the star formation histories of disc galaxies
Lelli, Federico; Schombert, James; McGaugh, Stacy
We combine new data from the main sequence (M* versus SFR) of star-forming galaxies and galaxy colours (from GALEX to Spitzer) with a flexible stellar population scheme to deduce the mass-to-light ratio (Υ*) of star-forming galaxies from the SPARC and S4G samples. We find that the main sequence for galaxies, partic…
GRB 161219B/SN 2016jca: a powerful stellar collapse
D'Avanzo, P.; Melandri, A.; Pian, E. +26 more
We report observations and analysis of the nearby gamma-ray burst GRB 161219B (redshift z = 0.1475) and the associated Type Ic supernova (SN) 2016jca. GRB 161219B had an isotropic gamma-ray energy of ∼1.6 × 1050 erg. Its afterglow is likely refreshed at an epoch preceding the first photometric points (0.6 d), which slows down the decay …
Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2
Handler, G.; Niemczura, E.; Suárez, J. C. +36 more
We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the rotational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a sample of 83 stars. Five new rapidly oscillating Ap (roAp) stars are announced. One of these pulsates with period…
ASASSN-18tb: a most unusual Type Ia supernova observed by TESS and SALT
Gromadzki, M.; Kochanek, C. S.; Stanek, K. Z. +16 more
We present photometric and spectroscopic observations of the unusual Type Ia supernova ASASSN-18tb, including a series of Southern African Large Telescope spectra obtained over the course of nearly six months and the first observations of a supernova by the Transiting Exoplanet Survey Satellite. We confirm a previous observation by Kollmeier et al…
The SkyMapper DR1.1 search for extremely metal-poor stars
Schmidt, B. P.; Da Costa, G. S.; Marino, A. F. +10 more
We present and discuss the results of a search for extremely metal-poor stars based on photometry from data release DR1.1 of the SkyMapper imaging survey of the southern sky. In particular, we outline our photometric selection procedures and describe the low-resolution (R ≈ 3000) spectroscopic follow-up observations that are used to provide estima…
The PAU Survey: early demonstration of photometric redshift performance in the COSMOS field
Carretero, J.; Castander, F. J.; Crocce, M. +23 more
The Physics of the Accelerating Universe Survey (PAUS) is an innovative photometric survey with 40 narrow-bands at the William Herschel Telescope (WHT). The narrow-bands are spaced at 100 Å intervals covering the range 4500-8500 Å and, in combination with standard broad-bands, enable excellent redshift precision. This paper describes the technique…
A high binary fraction for the most massive close-in giant planets and brown dwarf desert members
Bonavita, M.; Rice, K.; Lopez, E. +3 more
Stellar multiplicity is believed to influence planetary formation and evolution, although the precise nature and extent of this role remain ambiguous. We present a study aimed at testing the role of stellar multiplicity in the formation and/or evolution of the most massive, close-in planetary and substellar companions. Using past and new direct im…
Dust traps in the protoplanetary disc MWC 758: two vortices produced by two giant planets?
Dong, Ruobing; Baruteau, Clément; Carmona, Andrés +9 more
Resolved ALMA and VLA observations indicate the existence of two dust traps in the protoplanetary disc MWC 758. By means of two-dimensional gas+dust hydrodynamical simulations post-processed with three-dimensional dust radiative transfer calculations, we show that the spirals in scattered light, the eccentric, asymmetric ring and the crescent-shap…