Search Publications
SPIDERS: selection of spectroscopic targets using AGN candidates detected in all-sky X-ray surveys
Georgakakis, A.; Salvato, M.; Buchner, J. +19 more
SPIDERS (SPectroscopic IDentification of eROSITA Sources) is a Sloan Digital Sky Survey IV (SDSS-IV) survey running in parallel to the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) cosmology project. SPIDERS will obtain optical spectroscopy for large numbers of X-ray-selected active galactic nuclei (AGN) and galaxy cluster members detec…
Constraining neutrino mass and extra relativistic degrees of freedom in dynamical dark energy models using Planck 2015 data in combination with low-redshift cosmological probes: basic extensions to ΛCDM cosmology
Zhang, Jing-Fei; Zhang, Xin; Li, Yun-He +1 more
We investigate how the properties of dark energy affect the cosmological measurements of neutrino mass and extra relativistic degrees of freedom. We limit ourselves to the most basic extensions of Λ cold dark matter (CDM) model, I.e. the wCDM model with one additional parameter w, and the w0waCDM model with two additional par…
UVI colour gradients of 0.4 < z < 1.4 star-forming main-sequence galaxies in CANDELS: dust extinction and star formation profiles
Kocevski, Dale D.; Koekemoer, Anton M.; Pacifici, Camilla +10 more
This paper uses radial colour profiles to infer the distributions of dust, gas and star formation in z = 0.4-1.4 star-forming main-sequence galaxies. We start with the standard UVJ-based method to estimate dust extinction and specific star formation rate (sSFR). By replacing J with I band, a new calibration method suitable for use with ACS+WFC3 da…
MUSE deep-fields: the Ly α luminosity function in the Hubble Deep Field-South at 2.91 < z < 6.64
Bacon, Roland; Blaizot, Jérémy; Garel, Thibault +14 more
We present the first estimate of the Ly α luminosity function using blind spectroscopy from the Multi Unit Spectroscopic Explorer, MUSE, in the Hubble Deep Field-South. Using automatic source-detection software, we assemble a homogeneously detected sample of 59 Ly α emitters covering a flux range of -18.0 < log10 (F) < -16.3 (erg …
Discovery of a variable lead-rich hot subdwarf: UVO 0825+15
Reed, M. D.; Jeffery, C. S.; Woolf, V. M. +8 more
UVO 0825+15 is a hot bright helium-rich subdwarf which lies in K2 Field 5 and in a sample of intermediate helium-rich subdwarfs observed the Subaru High Dispersion Spectrograph. The K2 light curve shows low-amplitude variations, whilst the Subaru spectrum shows Pb IV absorption lines, indicative of a very high lead overabundance. UVO 0825+15 also …
HICOSMO: cosmology with a complete sample of galaxy clusters - II. Cosmological results
Reiprich, T. H.; Schellenberger, G.
The X-ray bright, hot gas in the potential well of a galaxy cluster enables systematic X-ray studies of samples of galaxy clusters to constrain cosmological parameters. HIFLUGCS consists of the 64 X-ray brightest galaxy clusters in the Universe, building up a local sample. Here, we utilize this sample to determine, for the first time, individual h…
The structural and size evolution of star-forming galaxies over the last 11 Gyr
Sobral, David; Buitrago, Fernando; Afonso, José +1 more
We present new results on the evolution of rest-frame blue/UV sizes and Sérsic indices of Hα-selected star-forming galaxies over the last 11 Gyr. We investigate how the perceived evolution can be affected by a range of biases and systematics such as cosmological dimming and resolution effects. We use GALFIT and an artificial redshifting technique,…
The cosmic assembly of stellar haloes in massive early-type Galaxies
Pérez-González, Pablo G.; Curtis-Lake, Emma; Trujillo, Ignacio +5 more
Using the exquisite depth of the Hubble Ultra Deep Field (HUDF12 programme) data set, we explore the ongoing assembly of the outermost regions of the most massive galaxies (Mstellar ≥ 5× 1010 M⊙) at z ≤ 1. The outskirts of massive objects, particularly early-type Galaxies (ETGs), are expected to suffer a dramatic t…
An improved age-activity relationship for cool stars older than a gigayear
Poppenhaeger, K.; Silva Aguirre, V.; Wolk, S. J. +2 more
Stars with convective envelopes display magnetic activity, which decreases over time due to the magnetic braking of the star. This age dependence of magnetic activity is well studied for younger stars, but the nature of this dependence for older stars is not well understood. This is mainly because absolute stellar ages for older stars are hard to …
Extragalactic background light: a measurement at 400 nm using dark cloud shadow - II. Spectroscopic separation of the dark cloud's light, and results★
Leinert, Ch.; Väisänen, P.; Lehtinen, K. +2 more
In a project aimed at measuring the optical extragalactic background light (EBL), we are using the shadow of a dark cloud. We have performed, with the ESO VLT/FORS, spectrophotometry of the surface brightness towards the high-galactic-latitude dark cloud Lynds 1642. A spectrum representing the difference between the opaque core of the cloud and se…