Search Publications
Dwarf spheroidals in the M 81 group - Metallicity distribution functions and population gradients
Grebel, E. K.; Koch, A.; Lianou, S.
Aims: We study the dwarf spheroidal galaxies in the nearby M 81 group in order to construct their photometric metallicity distributions and to investigate the potential presence of population gradients. We select all the dwarf spheroidals with available Hubble Space Telescope / Advanced Camera for Surveys archival observations, nine in total.…
First detection of ND in the solar-mass protostar IRAS16293-2422
Falgarone, E.; Maret, S.; Henning, T. +64 more
Context. In the past decade, much progress has been made in characterising the processes leading to the enhanced deuterium fractionation observed in the ISM and in particular in the cold, dense parts of star forming regions such as protostellar envelopes. Very high molecular D/H ratios have been found for saturated molecules and ions. However, lit…
[CII] observations of H2 molecular layers in transition clouds
Li, D.; Goldsmith, P. F.; Langer, W. D. +3 more
We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 µm (1.9 THz) towards Galactic longitudes near 340° (5 LOSs) & 20° (11 LOSs) as part of the HIFI tests and GOT C+ survey. Out of the total 146 [CII] velocity components detected by profile fitting we identify 53 as diffuse molecular clouds…
On the influence of non-thermal pressure on the mass determination of galaxy clusters
Laganá, T. F.; de Souza, R. S.; Keller, G. R.
Aims: Given that in most cases just thermal pressure is taken into account in the hydrostatic equilibrium equation to estimate galaxy cluster mass, the main purpose of this paper is to consider the contribution of all three non-thermal components to total mass measurements. The non-thermal pressure is composed by cosmic rays, turbulence and m…
Puzzling asteroid 21 Lutetia: our knowledge prior to the Rosetta fly-by
Barucci, M. A.; Fornasier, S.; Fulchignoni, M. +5 more
Aims: A wide observational campaign was carried out in 2004-2009 that aimed to complete the ground-based investigation of Lutetia prior to the Rosetta fly-by in July 2010.
Methods: We obtained BVRI photometric and V-band polarimetric measurements over a wide range of phase angles, and visible and infrared spectra in the 0.4-2.4 µm …
Herschel photometric observations of the low metallicity dwarf galaxy NGC 1705
Elbaz, D.; Bock, J. J.; Clements, D. L. +56 more
We present Herschel SPIRE and PACS photometeric observations of the low metallicity (Z ~ 0.35 Z⊙) nearby dwarf galaxy, NGC 1705, in six wavelength bands as part of the Dwarf Galaxy Survey guaranteed time Herschel key program. We confirm the presence of two dominant circumnuclear IR-bright regions surrounding the central super star clust…
The energy spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters
Zezas, A.; Trümper, J. E.; Kylafis, N. D. +1 more
Context. Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) exhibit characteristic X-ray luminosities (both soft and hard) of around 1035 erg s-1 and characteristic power-law, hard X-ray spectra extending to about 200 keV. Two AXPs also exhibit pulsed radio emission.
Aims: Assuming that AXPs and SGRs accr…
GMRT observations of the Ophiuchus galaxy cluster
Paltani, S.; Eckert, D.; Govoni, F. +4 more
Aims: Observations with the Very Large Array telescope at 1477 MHz revealed the presence of a radio mini-halo surrounding the faint central point-like radio source in the Ophiuchus cluster of galaxies. In this work we present a study of the radio emission from this cluster of galaxies at lower radio frequencies.
Methods: We observed the …
Herschel PACS and SPIRE imaging of CW Leonis
Ivison, R. J.; Blommaert, J. A. D. L.; Olofsson, G. +25 more
Herschel PACS and SPIRE images have been obtained over a 30' × 30' area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of 22' diameter, which is cospatial with the termination shock due to interaction with the interstellar medium (ISM) as defined by Sahai & Chronopoulos from ultravio…
Polarimetric observations of comet 67P/Churyumov-Gerasimenko during its 2008-2009 apparition
Lasue, J.; Sen, A. K.; Gupta, R. +2 more
Context. Remote observations of the light scattered by comet 67P/Churyumov-Gerasimenko dust coma are of major importance for determining the physical properties of the particles and prepare the rendezvous with the ESA/Rosetta spacecraft in 2014.
Aims: Light scattering and especially linear polarization observations allow comparison between di…