Search Publications
Obscuration-dependent Evolution of Active Galactic Nuclei
Nandra, Kirpal; Aird, James; Liu, Zhu +9 more
We aim to constrain the evolution of active galactic nuclei (AGNs) as a function of obscuration using an X-ray-selected sample of ~2000 AGNs from a multi-tiered survey including the CDFS, AEGIS-XD, COSMOS, and XMM-XXL fields. The spectra of individual X-ray sources are analyzed using a Bayesian methodology with a physically realistic model to infe…
Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang
Wuyts, S.; Förster Schreiber, N. M.; Genzel, R. +14 more
Most present-day galaxies with stellar masses ≥1011 solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which time scales, and how this “quenching” relate…
Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun
Accolla, Mario; Altobelli, Nicolas; Bertaux, Jean-Loup +78 more
Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astro…
67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio
Wurz, P.; Bochsler, P.; Altwegg, K. +29 more
The provenance of water and organic compounds on Earth and other terrestrial planets has been discussed for a long time without reaching a consensus. One of the best means to distinguish between different scenarios is by determining the deuterium-to-hydrogen (D/H) ratios in the reservoirs for comets and Earth’s oceans. Here, we report the direct i…
Stellar Masses from the CANDELS Survey: The GOODS-South and UDS Fields
Wuyts, S.; Lee, S. -K.; Cooper, M. C. +35 more
We present the public release of the stellar mass catalogs for the GOODS-S and UDS fields obtained using some of the deepest near-IR images available, achieved as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey project. We combine the effort from 10 different teams, who computed the stellar masses using the same photomet…
The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta
Langevin, Y.; Bellucci, G.; Jaumann, R. +75 more
The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared…
Lyα Emission from Green Peas: The Role of Circumgalactic Gas Density, Covering, and Kinematics
Martin, Crystal L.; Scarlata, Claudia; Henry, Alaina +1 more
We report Hubble Space Telescope/Cosmic Origins Spectrograph observations of the Lyα emission and interstellar absorption lines in a sample of 10 star-forming galaxies at z ∼ 0.2. Selected on the basis of high equivalent width optical emission lines, the sample, dubbed "Green Peas," make some of the best analogs for young galaxies in an early univ…
Abundant molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko
Wurz, P.; Bochsler, P.; Altwegg, K. +30 more
The composition of the neutral gas comas of most comets is dominated by H2O, CO and CO2, typically comprising as much as 95 per cent of the total gas density. In addition, cometary comas have been found to contain a rich array of other molecules, including sulfuric compounds and complex hydrocarbons. Molecular oxygen (O2…
Lymanα Emission from a Luminous z = 8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization
Labbé, Ivo; Stark, Daniel P.; Ellis, Richard S. +6 more
We report the discovery of Lyman-alpha emission (Lyα) in the bright galaxy EGSY-2008532660 (hereafter EGSY8p7) using the Multi-Object Spectrometer For Infra-Red Exploration spectrograph at the Keck Observatory. First reported by Roberts-Borsani et al., this galaxy was selected for spectroscopic observations because of its photometric redshift ({z}…
The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3
Vignali, C.; Lusso, E.; Prochaska, J. X. +4 more
The ionizing continuum from active galactic nuclei is fundamental for interpreting their broad emission lines and understanding their impact on the surrounding gas. Furthermore, it provides hints on how matter accretes on to supermassive black holes. Using Hubble Space Telescope's Wide Field Camera 3, we have constructed the first stacked ultravio…