Search Publications
Spatially-resolved dust properties of the GRB 980425 host galaxy
Berta, S.; Le Floc'h, E.; Covino, S. +30 more
Gamma-ray bursts (GRBs) have been proposed as a tool for studying star formation in the Universe, so it is crucial to investigate whether their host galaxies and immediate environments are in any way special compared with other star-forming galaxies. Here we present spatially resolved maps of dust emission of the host galaxyof the closest known GR…
On the Detection of Molecules in the Atmosphere of HD 189733b Using HST NICMOS Transmission Spectroscopy
Line, Michael R.; Swain, Mark R.; Deroo, Pieter
The Hubble Space Telescope/NICMOS transmission spectrum measurements of HD 189733b that suggest the detection of methane (CH4) in an exoplanet atmosphere have been a source of significant controversy. With what is probably the best analyzed exoplanet spectroscopy data set to date, different teams, using different methods, have claimed e…
A hyperspectral view of Cassiopeia A
Drissen, Laurent; Alarie, Alexandre; Bilodeau, Antoine
We used the imaging Fourier transform spectrometer Spectromètre Imageur de l'Observatoire du Mont-Mégantic (SpIOMM) to obtain hyperspectral cubes of the young supernova remnant Cassiopeia A (Cas A). The cubes contain over 5000 spatially resolved spectra covering the spectral range 6480-7050 Å. We first investigate the slow-moving N-rich quasi-stat…
Turbulent magnetic field fluctuations in Saturn's magnetosphere
Saur, J.; Alexandrova, O.; von Papen, M.
We analyze the statistical properties of magnetic field fluctuations measured by the Cassini spacecraft inside Saturn's magnetosphere. We introduce Saturn's magnetosphere as a new laboratory for plasma turbulence, where background magnetic field is strong (1 nT<B0≤75 nT), fluctuations are weak (<δB/B> = 0.07), and the ion plasm…
The X-Ray Luminosity Functions of Field Low-mass X-Ray Binaries in Early-type Galaxies: Evidence for a Stellar Age Dependence
Lehmer, B. D.; Hornschemeier, A. E.; Yukita, M. +11 more
We present direct constraints on how the formation of low-mass X-ray binary (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The lumi…
A Tale of Two Feedbacks: Star Formation in the Host Galaxies of Radio AGNs
Kim, Seong Jin; Ohyama, Youichi; Pearson, Chris +19 more
Several lines of argument support the existence of a link between activity at the nuclei of galaxies, in the form of an accreting supermassive black hole, and star formation activity in these galaxies. Radio jets have long been argued to be an ideal mechanism that allows active galactic nuclei (AGNs) to interact with their host galaxies and affect…
Planck CMB anomalies: astrophysical and cosmological secondary effects and the curse of masking
Starck, J. -L.; Sureau, F.; Bobin, J. +2 more
Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is f…
The extinction law inside the 30 Doradus nebula
Panagia, Nino; De Marchi, Guido
We have studied the interstellar extinction in a field of ∼3 arcmin × 3 arcmin at the core of the 30 Doradus nebula, including the central R 136 cluster, in the Large Magellanic Cloud. Observations at optical and near-infrared wavelengths, obtained with the WFC 3 camera on board the Hubble Space Telescope, show that the stars belonging to the red …
Water and methanol in low-mass protostellar outflows: gas-phase synthesis, ice sputtering and destruction
van Dishoeck, E. F.; Kristensen, L. E.; Mottram, J. C. +2 more
Water in outflows from protostars originates either as a result of gas-phase synthesis from atomic oxygen at T ≳ 200 K, or from sputtered ice mantles containing water ice. We aim to quantify the contribution of the two mechanisms that lead to water in outflows, by comparing observations of gas-phase water to methanol (a grain surface product) towa…
Probing nuclear rates with Planck and BICEP2
Di Valentino, Eleonora; Melchiorri, Alessandro; Lesgourgues, Julien +4 more
Big-bang nucleosynthesis (BBN) relates key cosmological parameters to the primordial abundance of light elements. In this paper, we point out that the recent observations of cosmic microwave background anisotropies by the Planck satellite and by the BICEP2 experiment constrain these parameters with such a high level of accuracy that the primordial…