Search Publications
Explaining changing-look AGN with state transition triggered by rapid mass accretion rate drop
Done, Chris; Noda, Hirofumi
We model the broad-band (optical/UV and X-ray) continuum spectrum of the `changing-look' active galactic nucleus (AGN) Mrk 1018, as it fades from Seyfert 1 to 1.9 in ∼ 8 years. The brightest spectrum, with Eddington ratio L/LEdd ∼ 0.08 has a typical type 1 AGN continuum, with a strong `soft X-ray excess' spanning between the UV and soft…
A physical model of the broad-band continuum of AGN and its implications for the UV/X relation and optical variability
Done, Chris; Kubota, Aya
We develop a new spectral model for the broad-band spectral energy distribution (SED) of active galactic nuclei (AGN). This includes an outer standard disc, an inner warm Comptonizing region to produce the soft X-ray excess and a hot corona. We tie these together energetically by assuming Novikov-Thorne emissivity, and use this to define a size sc…
Confirming chemical clocks: asteroseismic age dissection of the Milky Way disc(s)
Serenelli, A. M.; Johnson, J. A.; Lund, M. N. +22 more
Investigations of the origin and evolution of the Milky Way disc have long relied on chemical and kinematic identifications of its components to reconstruct our Galactic past. Difficulties in determining precise stellar ages have restricted most studies to small samples, normally confined to the solar neighbourhood. Here, we break this impasse wit…
A detached stellar-mass black hole candidate in the globular cluster NGC 3201
Brinchmann, Jarle; Weilbacher, Peter M.; Kamann, Sebastian +7 more
As part of our massive spectroscopic survey of 25 Galactic globular clusters with MUSE, we performed multiple epoch observations of NGC 3201 with the aim of constraining the binary fraction. In this cluster, we found one curious star at the main-sequence turn-off with radial velocity variations of the order of 100 km s- 1, indicating th…
The [C II] emission as a molecular gas mass tracer in galaxies at low and high redshifts
Daddi, E.; Elbaz, D.; Dickinson, M. +19 more
We present ALMA Band 9 observations of the [C II]158 µm emission for a sample of 10 main-sequence galaxies at redshift z ∼ 2, with typical stellar masses (log M⋆/M⊙ ∼ 10.0-10.9) and star formation rates (∼35-115 M⊙ yr-1). Given the strong and well-understood evolution of the interstellar medium fro…
GAMA/G10-COSMOS/3D-HST: the 0 < z < 5 cosmic star formation history, stellar-mass, and dust-mass densities
Wilkins, Stephen M.; Holwerda, Benne; Conselice, Christopher J. +30 more
We use the energy-balance code MAGPHYS to determine stellar and dust masses, and dust corrected star formation rates for over 200 000 GAMA galaxies, 170 000 G10-COSMOS galaxies, and 200 000 3D-HST galaxies. Our values agree well with previously reported measurements and constitute a representative and homogeneous data set spanning a broad range in…
A stellar census in globular clusters with MUSE: The contribution of rotation to cluster dynamics studied with 200 000 stars
Dreizler, S.; Roth, M. M.; Kamann, S. +10 more
This is the first of a series of papers presenting the results from our survey of 25 Galactic globular clusters with the MUSE integral-field spectrograph. In combination with our dedicated algorithm for source deblending, MUSE provides unique multiplex capabilities in crowded stellar fields and allows us to acquire samples of up to 20 000 stars wi…
StarHorse: a Bayesian tool for determining stellar masses, ages, distances, and extinctions for field stars
da Costa, L. N.; Maia, M. A. G.; Anders, F. +12 more
Understanding the formation and evolution of our Galaxy requires accurate distances, ages, and chemistry for large populations of field stars. Here, we present several updates to our spectrophotometric distance code, which can now also be used to estimate ages, masses, and extinctions for individual stars. Given a set of measured spectrophotometri…
LISA verification binaries with updated distances from Gaia Data Release 2
Rossi, E. M.; Groot, P. J.; Marsh, T. R. +6 more
Ultracompact binaries with orbital periods less than a few hours will dominate the gravitational wave signal in the mHz regime. Until recently, 10 systems were expected to have a predicted gravitational wave signal strong enough to be detectable by the Laser Interferometer Space Antenna (LISA), the so-called `verification binaries'. System paramet…
The Hubble Space Telescope UV legacy survey of galactic globular clusters - XVI. The helium abundance of multiple populations
Anderson, J.; Milone, A. P.; Cordoni, G. +16 more
Recent work, based on data from the Hubble Space Telescope (HST ) UV Legacy Survey of Galactic Globular Clusters (GCs), has revealed that all the analysed clusters host two groups of first- (1G) and second-generation (2G) stars. In most GCs, both 1G and 2G stars host substellar populations with different chemical composition. We compare multiwavel…