Search Publications
A new parameterization of the reionisation history
Aghanim, N.; Douspis, M.; Ilić, S. +1 more
Motivated by the current constraints on the epoch of reionisation from recent cosmic microwave background observations, ionising background measurements of star-forming galaxies, and low redshifts line-of-sight probes, we propose a new data-motivated parameterisation of the history of the average ionisation fraction. This parameterisation describe…
Can we trace very cold dust from its emission alone?
Juvela, M.; Pagani, L.; Pelkonen, V. -M. +2 more
Context. Dust is a good tracer of cold dark clouds but its column density is difficult to quantify.
Aims: We want to check whether the far-infrared and submillimeter high-resolution data from Herschel PACS and SPIRE and cameras combined with ground-based telescope bolometers allow us to retrieve the whole dust content of cold dark clouds.
Searching for coherent pulsations in ultraluminous X-ray sources
Santangelo, A.; Ducci, L.; Doroshenko, V.
Luminosities of ultraluminous X-ray sources (ULXs) are uncomfortably large when compared to the Eddington limit for isotropic accretion onto stellar-mass object. Most often either supercritical accretion onto stellar mass black holes or accretion onto intermediate mass black holes is invoked the high luminosities of ULXs. However, the recent disco…
Velocity resolved [C ii], [C i], and CO observations of the N159 star-forming region in the Large Magellanic Cloud: a complex velocity structure and variation of the column densities
Wiesemeyer, Helmut; Güsten, Rolf; Okada, Yoko +4 more
Context. The [C ii] 158 µm fine structure line is one of the dominant cooling lines in star-forming active regions. Together with models of photon-dominated regions, the data is used to constrain the physical properties of the emitting regions, such as the density and the radiation field strength. According to the modeling, the [C ii] 158 &m…
The XMM deep survey in the CDF-S. IX. An X-ray outflow in a luminous obscured quasar at z ≈ 1.6
Bauer, F. E.; Brandt, W. N.; Fiore, F. +13 more
In active galactic nuclei (AGN)-galaxy co-evolution models, AGN winds and outflows are often invoked to explain why super-massive black holes and galaxies stop growing efficiently at a certain phase of their lives. They are commonly referred to as the leading actors of feedback processes. Evidence of ultra-fast (v ≳ 0.05c) outflows in the innermos…
The spectral energy distribution of the redshift 7.1 quasar ULAS J1120+0641
Hewett, P. C.; Banerji, M.; Warren, S. J. +7 more
We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7.084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength spectral energy distribution (SED), with the goals of mea…
Study of the X-ray activity of Sagittarius A* during the 2011 XMM-Newton campaign
Grosso, Nicolas; Mossoux, Enmanuelle; Porquet, Delphine +1 more
Context. At the dynamical center of the Milky Way, there is the closest supermassive black hole: Sgr A*. Its non-flaring luminosity is several orders of magnitude lower than the Eddington luminosity, but flares can be observed in the infrared and X-rays. This flaring activity can help us to understand radiation mechanisms from Sgr A*.
Aims: O…
New constraints on the CH4 vertical profile in Uranus and Neptune from Herschel observations
Hartogh, P.; Lellouch, E.; Feuchtgruber, H. +6 more
Dedicated line observations of CH4 rotational lines performed with Herschel/PACS and HIFI in 2009-2011 provide new inferences of the mean methane profile in the upper tropospheres and stratospheres of Uranus and Neptune. At Uranus, CH4 is found to be near saturation, with a ~9 × 10-4 tropopause/lower stratosphere m…
Pan-STARRS1 variability of XMM-COSMOS AGN. I. Impact on photometric redshifts
Salvato, M.; Chambers, K. C.; Flewelling, H. +12 more
Aims: Upcoming large area sky surveys like Euclid and eROSITA, which are dedicated to studying the role of dark energy in the expansion history of the Universe and the three-dimensional mass distribution of matter, crucially depend on accurate photometric redshifts. The identification of variable sources, such as active galactic nuclei (AGNs)…
From forced collapse to H ii region expansion in Mon R2: Envelope density structure and age determination with Herschel⋆
Bernard, J. -P.; Hill, T.; White, G. J. +32 more
Context. The surroundings of H ii regions can have a profound influence on their development, morphology, and evolution. This paper explores the effect of the environment on H ii regions in the MonR2 molecular cloud.
Aims: We aim to investigate the density structure of envelopes surrounding H ii regions and to determine their collapse and ion…