Search Publications
Galaxy interactions are the dominant trigger for local type 2 quasars
Ramos Almeida, C.; Tadhunter, C.; Pierce, J. C. S. +8 more
The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 …
Metal Mixing in the r-process Enhanced Ultrafaint Dwarf Galaxy Reticulum II
Klessen, Ralf S.; Johnson, Christian I.; Mateo, Mario +9 more
The ultrafaint dwarf galaxy Reticulum II was enriched by a single rare and prolific r-process event. The r-process content of Reticulum II thus provides a unique opportunity to study metal mixing in a relic first galaxy. Using multi-object high-resolution spectroscopy with VLT/GIRAFFE and Magellan/M2FS, we identify 32 clear spectroscopic member st…
Small Region, Big Impact: Highly Anisotropic Lyman-continuum Escape from a Compact Starburst Region with Extreme Physical Properties
Mahler, Guillaume; Chisholm, John; Rigby, Jane R. +13 more
Extreme, young stellar populations are considered to be the primary contributor to cosmic reionization. How the Lyman continuum (LyC) escapes these galaxies remains highly elusive, and it is challenging to observe this process in actual LyC emitters without resolving the relevant physical scales. We investigate the Sunburst Arc, a strongly lensed …
Defining the Middle Corona
Giordano, Silvio; Andretta, Vincenzo; Reeves, Katharine K. +39 more
The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the reg…
Phantom dark energy as a natural selection of evolutionary processes a ^ la genetic algorithm and cosmological tensions
Gangopadhyay, Mayukh R.; Sami, M.; Sharma, Mohit K.
We study the late-time cosmological tensions using the low-redshift background and redshift-space distortion data by employing a machine learning (ML) technique. By comparing the generated observables with the standard cosmological scenario, our findings indicate support for the phantom nature of dark energy, which ultimately leads to a reduction …
15 000 ellipsoidal binary candidates in TESS: Orbital periods, binary fraction, and tertiary companions
Maoz, Dan; Rix, Hans-Walter; Green, Matthew J. +5 more
We present a homogeneously selected sample of 15 779 candidate binary systems with main sequence primary stars and orbital periods shorter than 5 d. The targets were selected from TESS full-frame image light curves on the basis of their tidally induced ellipsoidal modulation. Spectroscopic follow-up suggests a sample purity of 83 ± 13 per cent. In…
Reducing the Uncertainty on the Hubble Constant up to 35% with an Improved Statistical Analysis: Different Best-fit Likelihoods for Type Ia Supernovae, Baryon Acoustic Oscillations, Quasars, and Gamma-Ray Bursts
Iwasaki, Kazunari; Bargiacchi, Giada; Zhang, Bing +5 more
Cosmological models and their parameters are widely debated, especially about whether the current discrepancy between the values of the Hubble constant, H 0, obtained by Type Ia supernovae (SNe Ia) and the Planck data from the cosmic microwave background radiation could be alleviated when alternative cosmological models are considered. …
Outflows from the youngest stars are mostly molecular
Östlin, G.; Güdel, M.; Ray, T. P. +20 more
The formation of stars and planets is accompanied not only by the build-up of matter, namely accretion, but also by its expulsion in the form of highly supersonic jets that can stretch for several parsecs1,2. As accretion and jet activity are correlated and because young stars acquire most of their mass rapidly early on, the most powerf…
Reflections on nebulae around young stars. A systematic search for late-stage infall of material onto Class II disks
Ginski, C.; Testi, L.; Williams, J. P. +10 more
Context. While it is generally assumed that Class II sources evolve largely in isolation from their environment, many still lie close to molecular clouds and may continue to interact with them. This may result in late accretion of material onto the disk that can significantly influence disk processes and planet formation.
Aims: In order to sy…
Morphology-density relation, quenching, and mergers in CARLA clusters and protoclusters at 1.4 < z < 2.8
Noirot, Gaël; Gonzalez, Anthony H.; Stern, Daniel +11 more
At redshifts of z ≲ 1.3, early-type galaxies (ETGs) and passive galaxies are mainly found in dense environments, such as galaxy clusters. However, it remains unclear whether these well-known morphology-density and passive-density relations have already been established at higher redshifts. To address this question, we performed an in-depth study o…