Search Publications
The initial conditions for stellar protocluster formation. III. The Herschel counterparts of the Spitzer Dark Cloud catalogue
Peretto, N.; Ward-Thompson, D.; Fuller, G. A. +4 more
Context. Galactic plane surveys of pristine molecular clouds are key for establishing a Galactic-scale view of star formation. For this reason, an unbiased sample of infrared dark clouds in the 10° < | l | < 65°, | b | < 1° region of the Galactic plane was built using Spitzer 8 µm extinction. However, intrinsic fluctuations in the m…
Mass-loading of the solar wind at 67P/Churyumov-Gerasimenko. Observations and modelling
Holmström, M.; Behar, E.; Nilsson, H. +4 more
Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft.
Aims: Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret t…
Halo dust detection around NGC 891
Bianchi, S.; Hunt, L. K.; Schneider, R. +1 more
Context. Observations of edge-on galaxies allow us to investigate the vertical extent and properties of dust, gas and stellar distributions. NGC 891 has been studied for decades and represents one of the best studied cases of an edge-on galaxy.
Aims: We use deep Photoconductor Array Camera and Spectrometer (PACS) data together with Infrared A…
Globular cluster clustering and tidal features around ultra-compact dwarf galaxies in the halo of NGC 1399
Hilker, Michael; Voggel, Karina; Richtler, Tom
We present a novel approach to constrain the formation channels of ultra-compact dwarf galaxies (UCDs). They most probably are an inhomogeneous class of objects, composed of remnants of tidally stripped dwarf elliptical galaxies and star clusters that occupy the high mass end of the globular cluster luminosity function. We use three methods to unr…
Planck intermediate results. XXXVI. Optical identification and redshifts of Planck SZ sources with telescopes at the Canary Islands observatories
Böhringer, H.; Kneissl, R.; Dahle, H. +188 more
We present the results of approximately three years of observations of Planck Sunyaev-Zeldovich (SZ) sources with telescopes at the Canary Islands observatories as part of the general optical follow-up programme undertaken by the Planck Collaboration. In total, 78 SZ sources are discussed. Deep-imaging observations were obtained for most of these …
GeMS MCAO observations of the Galactic globular cluster NGC 2808: the absolute age
Massari, D.; Stetson, P. B.; Bono, G. +7 more
Context. Globular clusters are the oldest stellar systems in the Milky Way, and they probe the early epoch of the Galaxy formation. However, the uncertainties on their absolute age are still too large to soundly constrain how the Galactic structures have assembled.
Aims: The aim of this work is to obtain an accurate estimate of the absolute a…
Anatomy of the AGN in NGC 5548. VII. Swift study of obscuration and broadband continuum variability
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +16 more
We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spec…
Star formation efficiency along the radio jet in Centaurus A
Heywood, I.; Combes, F.; Salomé, P. +2 more
NGC 5128 (also known as Centaurus A) is the most nearby powerful AGN, widely studied at all wavelengths. Molecular gas has been found in the halo at a distance of ~ 20 kpc from the galaxy center, associated with H I shells, through CO line detection at SEST (Charmandaris et al. 2000, A&A, 356, L1). The molecular gas lies inside some IR and UV …
Spatial gradients of GCR protons in the inner heliosphere derived from Ulysses COSPIN/KET and PAMELA measurements
Gieseler, J.; Heber, B.
Context. During the transition from solar cycle 23 to 24 from 2006 to 2009, the Sun was in an unusual solar minimum with very low activity over a long period. These exceptional conditions included a very low interplanetary magnetic field (IMF) strength and a high tilt angle, which both play an important role in the modulation of galactic cosmic ra…
A physical scenario for the high and low X-ray luminosity states in the transitional pulsar PSR J1023+0038
D'Avanzo, P.; Campana, S.; Rea, N. +4 more
The binary system PSR J1023+0038 (J1023) hosts a neutron star and a low-mass companion. J1023 is the best studied transitional pulsar, alternating a faint eclipsing millisecond radio pulsar state to a brighter X-ray active state. At variance with other low-mass X-ray binaries, this active state reaches luminosities of only ~1034 erg s