Search Publications
Carbon dredge-up required to explain the Gaia white dwarf colour-magnitude bifurcation
Blouin, Simon; Tremblay, Pier-Emmanuel; Bédard, Antoine
The Gaia colour-magnitude diagram reveals a striking separation between hydrogen-atmosphere white dwarfs and their helium-atmosphere counterparts throughout a significant portion of the white dwarf cooling track. However, pure-helium atmospheres have Gaia magnitudes that are too close to the pure-hydrogen case to explain this bifurcation. To repro…
The demographics of obscured AGN from X-ray spectroscopy guided by multiwavelength information
Aird, James; Lapi, Andrea; Carrera, Francisco J. +10 more
A complete census of active galactic nuclei (AGNs) is a prerequisite for understanding the growth of supermassive black holes across cosmic time. A significant challenge towards this goal is the whereabouts of heavily obscured AGN that remain uncertain. This paper sets new constraints on the demographics of this population by developing a methodol…
The mystery in Gaia DR3 triples: occurrence rates, orientations, and eccentricities of wide tertiaries around close binaries
Hwang, Hsiang-Chih
The formation of close binaries has been an open question for decades. A large fraction of close binaries are in triple systems, suggesting that their formation may be associated with the Kozai-Lidov mechanism. However, this picture remains under debate because the configurations of many observed triples are unlikely to trigger the Kozai-Lidov mec…
Precise physical conditions for the warm gas outflows in the nearby active galaxy IC 5063
Morganti, Raffaella; Oosterloo, Tom; Holden, Luke R. +1 more
Active galactic nucleus (AGN)-driven outflows are now routinely used in models of galaxy evolution as a feedback mechanism; however, many of their properties remain highly uncertain. Perhaps the greatest source of uncertainty is the electron density of the outflowing gas, which directly affects derived kinetic powers and mass outflow rates. Here w…
The complex organic molecular content in the L1517B starless core
Martín-Pintado, J.; Caselli, P.; Spezzano, S. +5 more
Recent observations of the pre-stellar core L1544 and the younger starless core L1498 have revealed that complex organic molecules (COMs) are enhanced in the gas phase towards their outer and intermediate-density shells. Our goal is to determine the level of chemical complexity towards the starless core L1517B, which seems younger than L1498, and …
Multiscale stellar associations across the star formation hierarchy in PHANGS-HST nearby galaxies: methodology and properties
Kruijssen, J. M. Diederik; Leroy, Adam K.; Rosolowsky, Erik +19 more
We develop a method to identify and determine the physical properties of stellar associations using Hubble Space Telescope (HST) NUV-U-B-V-I imaging of nearby galaxies from the Physics at High Angular Resolution in Nearby GalaxieS with the Hubble Space Telescope (PHANGS-HST) survey. We apply a watershed algorithm to density maps constructed from p…
Stochastic gravitational wave background constraints from Gaia DR3 astrometry
García-Bellido, Juan; Kuroyanagi, Sachiko; Braglia, Matteo +2 more
Astrometric surveys can be used to constrain the stochastic gravitational wave background (SGWB) at very low frequencies. We use proper motion data provided by Gaia DR3 to fit a generic dipole+quadrupole field. We analyse several quasar-based data sets and discuss their purity and idoneity to set constraints on gravitational waves. For the cleanes…
Substructure, supernovae, and a time-resolved star formation history for Upper Scorpius
Chanamé, Julio; Briceño-Morales, Geovanny
The improved astrometry precision of Gaia-eDR3 allows us to perform a detailed study of the Upper Scorpius OB association and revisit its spatial, kinematic, and age substructure. We achieve this by combining clustering techniques and complementing with age estimations based on Gaia photometry. Our census retrieves 3661 candidate members for Upper…
The extreme super-eddington NLS1 RX J0134.2-4258 - II. A weak-line Seyfert linking to the weak-line quasar
Done, Chris; Ward, Martin; Jin, Chichuan +3 more
RX J0134.2-4258 is one of the most super-Eddington narrow-line Seyfert 1 (NLS1) galaxies, on which we conducted a monitoring campaign from radio to X-rays. In this paper, we present a detailed analysis of its optical/UV spectra and broad-band spectral energy distribution. Our study shows that the preferred black hole mass of RX J0134.2-4258 is M
An environmental analysis of the fast transient AT2018cow and implications for its progenitor and late-time brightness
Sun, Ning-Chen; Shao, Yali; Maund, Justyn R. +1 more
The nature of the newly discovered fast blue optical transients (FBOTs) is still puzzling astronomers. In this paper, we carry out a comprehensive analysis of the molecular gas, ionized gas, and stellar populations in the environment of the nearby FBOT AT2018cow based on ALMA, VLT/MUSE, and HST/WFC3 observations. A prominent molecular concentratio…