Search Publications
The chemical composition of TS 01, the most oxygen-deficient planetary nebula. AGB nucleosynthesis in a metal-poor binary star
Rauch, T.; Morisset, C.; Simón-Díaz, S. +10 more
The planetary nebula TS 01 (also called PN G 135.9+55.9 or SBS 1150+599A) with its record-holding low oxygen abundance and its double degenerate close binary core (period 3.9 h) is an exceptional object located in the Galactic halo. We have secured observational data in a complete wavelength range to pin down the abundances of half a dozen element…
The EUV spectrum of the Sun: long-term variations in the SOHO CDS NIS spectral responsivities
Andretta, V.; Del Zanna, G.; Thompson, W. T. +2 more
We present SOHO Coronal Diagnostic Spectrometer (CDS) normal incidence, extreme-ultraviolet spectra of the Sun taken from the beginning of the mission in 1996 until now. We use various methods to study the performance of the instrument during such a long time span. Assuming that the basal chromospheric-transition region emission in the quiet parts…
The Herschel view of GAS in Protoplanetary Systems (GASPS). First comparisons with a large grid of models
Pinte, C.; Ménard, F.; Duchêne, G. +49 more
The Herschel GASPS key program is a survey of the gas phase of protoplanetary discs, targeting 240 objects which cover a large range of ages, spectral types, and disc properties. To interpret this large quantity of data and initiate self-consistent analyses of the gas and dust properties of protoplanetary discs, we have combined the capabilities o…
Herschel/HIFI observations of high-J CO transitions in the protoplanetary nebula CRL 618
Waters, L. B. F. M.; Menten, K. M.; Olofsson, H. +25 more
Aims: We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas components in the protoplanetary nebula CRL 618. These components are particularly important for understanding the evolution of the nebula.
Methods: We performed Herschel/HIFI observations of several CO lines in the far-i…
Herschel observations of EXtra-Ordinary Sources (HEXOS): detecting spiral arm clouds by CH absorption lines
Menten, K. M.; Falgarone, E.; Martin, P. G. +67 more
We have observed CH absorption lines (J = 3/2, N = 1 ≤ftarrow J = 1/2, N = 1) against the continuum source Sgr B2(M) using the Herschel/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line widths are detected and identified. The narrower …
Water production in comet 81P/Wild 2 as determined by Herschel/HIFI
Blommaert, J. A. D. L.; Küppers, M.; Thomas, N. +42 more
The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we present HIFI observations of the fundamental 110-101 (557 GHz) ortho and 111-00 (1113 GHz) para rota…
Cold fronts and multi-temperature structures in the core of Abell 2052
Simionescu, A.; Kaastra, J. S.; de Plaa, J. +3 more
Context. The physics of the coolest phases in the hot intra-cluster medium (ICM) of clusters of galaxies is yet to be fully unveiled. X-ray cavities blown by the central active galactic nucleus (AGN) contain enough energy to heat the surrounding gas and stop cooling, but locally blobs or filaments of gas appear to be able to cool to low temperatur…
X-ray and multiwavelength view of NGC 4278. A LINER-Seyfert connection?
Grosso, N.; Porquet, D.; Reeves, J. N. +3 more
Context. The emission mechanism responsible for the bulk of energy from radio to X-rays in low ionization emission line regions (LINERs) and low luminosity active galactic nuclei (LLAGN) has been long debated. Based on UV to X-ray and radio to UV flux ratios, some argue that LINERs/LLAGN are a scaled-down version of their more luminous predecessor…
Apparent high metallicity in 3-4 keV galaxy clusters: the inverse iron-bias in action in the case of the merging cluster Abell 2028
Gastaldello, F.; Ghizzardi, S.; Tozzi, P. +6 more
Context. Recent work based on a global measurement of the ICM properties finds evidence for an increase in the iron abundance in galaxy clusters with temperatures around 2-4 keV up to a value about 3 times higher than is typical of very hot clusters ZFe ≃ 0.25 Z_⊙.
Aims: We have started a study of the metal distribution in nearby X…
Characterization of horizontal flows around solar pores from high-resolution time series of images
Martínez Pillet, V.; Vargas Domínguez, S.; Bonet, J. A. +1 more
Context. Though there is increasing evidence linking the moat flow and the Evershed flow along the penumbral filaments, there is not a clear consensus regarding the existence of a moat flow around umbral cores and pores, and the debate is still open. Solar pores appear to be a suitable scenario to test the moat-penumbra relation as they correspond…