Search Publications
Probing the existence of very massive first stars
Salvadori, S.; Bonifacio, P.; Caffau, E. +4 more
We present a novel approach aimed at identifying the key chemical elements to search for the (missing) descendants of very massive first stars exploding as pair instability supernovae (PISN). Our simple and general method consists in a parametric study accounting for the unknowns related to early cosmic star formation and metal-enrichment. Our app…
Reference Star Differential Imaging of Close-in Companions and Circumstellar Disks with the NIRC2 Vortex Coronagraph at the W. M. Keck Observatory
Matthews, Keith; Serabyn, Eugene; Absil, Olivier +11 more
Reference star differential imaging (RDI) is a powerful strategy for high-contrast imaging. Using example observations taken with the vortex coronagraph mode of Keck/NIRC2 in L‧ band, we demonstrate that RDI provides improved sensitivity to point sources at small angular separations compared to angular differential imaging (ADI). Applying RDI to i…
Revisiting long-standing puzzles of the Milky Way: the Sun and its vicinity as typical outer disk chemical evolution
Haywood, M.; Lehnert, M. D.; Di Matteo, P. +2 more
We present a scenario of the chemical enrichment of the solar neighborhood that solves the G-dwarf problem by taking into account constraints on a larger scale. We argue that the Milky Way disk within 10 kpc has been enriched to solar metallicity by a massive stellar population: the thick disk, which itself formed from a massive turbulent gaseous …
Independent confirmation of a methane spike on Mars and a source region east of Gale Crater
Cardesín-Moinelo, Alejandro; Marín-Yaseli de la Parra, Julia; Aoki, Shohei +11 more
Reports of methane detection in the Martian atmosphere have been intensely debated. The presence of methane could enhance habitability and may even be a signature of life. However, no detection has been confirmed with independent measurements. Here, we report a firm detection of 15.5 ± 2.5 ppb by volume of methane in the Martian atmosphere above G…
The tidal disruption event AT2017eqx: spectroscopic evolution from hydrogen rich to poor suggests an atmosphere and outflow
Berger, E.; Challis, P.; Foley, R. J. +24 more
We present and analyse a new tidal disruption event (TDE), AT2017eqx at redshift z = 0.1089, discovered by Pan-STARRS and ATLAS. The position of the transient is consistent with the nucleus of its host galaxy; the spectrum shows a persistent blackbody temperature T ≳ 20 000 K with broad H I and He II emission; and it peaks at a blackbody luminosit…
Galaxy populations in the most distant SPT-SZ clusters. I. Environmental quenching in massive clusters at 1.4 ≲ z ≲ 1.7
Bayliss, M. B.; Sharon, K.; Schrabback, T. +25 more
We present the first results from a galaxy population study in the highest redshift galaxy clusters identified in the 2500 deg2 South Pole Telescope Sunyaev Zel'dovich effect (SPT-SZ) survey, which is sensitive to M500 ≳ 3 × 1014 M⊙ clusters from z ∼ 0.2 out to the highest redshifts where such massive st…
Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere
Wang, Yuming; Liu, Jiajia; Erdélyi, Robert +2 more
The multi-million degree temperature increase from the middle to the upper solar atmosphere is one of the most fascinating puzzles in plasma-astrophysics. Although magnetic waves might transport enough energy from the photosphere to heat up the local chromosphere and corona, observationally validating their ubiquity has proved challenging. Here, w…
New light on the Gaia DR2 parallax zero-point: influence of the asteroseismic approach, in and beyond the Kepler field
Khan, S.; Cantat-Gaudin, T.; Chaplin, W. J. +15 more
The importance of studying the Gaia DR2 parallax zero-point by external means was underlined by the articles that accompanied the release, and initiated by several works making use of Cepheids, eclipsing binaries, and asteroseismology. Despite a very efficient elimination of basic-angle variations, a small fluctuation remains and shows up as a sma…
X-ray emission of z > 2.5 active galactic nuclei can be obscured by their host galaxies
Feltre, A.; Massardi, M.; Vignali, C. +6 more
We present a multiwavelength study of seven active galactic nuclei (AGN) at spectroscopic redshift >2.5 in the 7 Ms Chandra Deep Field South that were selected for their good far-infrared (FIR) and submillimeter (submm) detections. Our aim is to investigate the possibility that the obscuration observed in the X-rays can be produced by the inter…
MOBSTER - II. Identification of rotationally variable A stars observed with TESS in sectors 1-4
Wade, G. A.; Neiner, C.; Paunzen, E. +7 more
Recently, high-precision optical 2-min cadence light curves obtained with TESS for targets located in the mission's defined first four sectors have been released. The majority of these high-cadence and high-precision measurements currently span {∼ }28 d, thereby allowing periodic variability occurring on time-scales {≲ }14 d to potentially be dete…