Search Publications
Early- and late-stage mergers among main sequence and starburst galaxies at 0.2 ≤ z ≤ 2
Daddi, E.; Elbaz, D.; Le Floc'h, E. +12 more
We investigate the fraction of close pairs and morphologically identified mergers on and above the star-forming main sequence (MS) at 0.2 ≤ z ≤2.0. The novelty of our work lies in the use of a non-parametric morphological classification performed on resolved stellar mass maps, reducing the contamination by non-interacting, high-redshift clumpy gal…
A volume-limited survey of mCP stars within 100 pc - I. Fundamental parameters and chemical abundances
Wade, G. A.; Neiner, C.; Sikora, J. +1 more
We present the first results of a volume-limited survey of main-sequence (MS) magnetic chemically peculiar (mCP) stars. The sample consists of all identified intermediate-mass MS stars (mCP and non-mCP) within a heliocentric distance of 100 pc as determined using Hipparcos parallaxes. The two populations are compared in order to determine the uniq…
Radial velocity confirmation of K2-100b: a young, highly irradiated, and low-density transiting hot Neptune
Tamura, M.; Aigrain, S.; Pagano, I. +37 more
We present a detailed analysis of HARPS-N radial velocity observations of K2-100, a young and active star in the Praesepe cluster, which hosts a transiting planet with a period of 1.7 d. We model the activity-induced radial velocity variations of the host star with a multidimensional Gaussian Process framework and detect a planetary signal of 10.6…
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…