Search Publications
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
MUSE observations of the lensing cluster Abell 1689
Bina, D.; Pelló, R.; Richard, J. +14 more
Context. This paper presents the results obtained with the Multi Unit Spectroscopic Explorer (MUSE) for the core of the lensing cluster Abell 1689, as part of MUSE's commissioning at the ESO Very Large Telescope.
Aims: Integral-field observations with MUSE provide a unique view of the central 1 × 1 arcmin2 region at intermediate sp…
The Bullet cluster at its best: weighing stars, gas, and dark matter
Kneib, J. -P.; Jullo, E.; Richard, J. +4 more
Aims: We present a new strong lensing mass reconstruction of the Bullet cluster (1E 0657-56) at z = 0.296, based on WFC3 and ACS HST imaging and VLT/FORS2 spectroscopy. The strong lensing constraints underwent substantial revision compared to previously published analysis, there are now 14 (six new and eight previously known) multiply-imaged …
The mass of the black hole in RE J1034+396
Hryniewicz, K.; Życki, P. T.; Czerny, B. +7 more
Context. The black hole mass measurement in active galaxies is a challenge, particularly in sources where the reverberation method cannot be applied.
Aims: We aim to determine the black hole mass in a very special object, RE J1034+396, one of the two active galactic nuclei (AGN) with quasi-periodic oscillations detected in X-rays, and a singl…
A closer look at a coronal loop rooted in a sunspot umbra
Peter, H.; Chitta, L. P.; Young, P. R.
Context. Extreme UV (EUV) and X-ray loops in the solar corona connect regions of enhanced magnetic activity, but they are not usually rooted in the dark umbrae of sunspots because the strong magnetic field found there suppresses convection. This means that the Poynting flux of magnetic energy into the upper atmosphere is not significant within the…
Theoretical modelling of the AGN iron line vs. continuum time-lags in the lamp-post geometry
Papadakis, I. E.; Emmanoulopoulos, D.; Dovčiak, M. +4 more
Context. Theoretical modelling of time-lags between variations in the Fe Kα emission and the X-ray continuum might shed light on the physics and geometry of the X-ray emitting region in active galaxies (AGN) and X-ray binaries. We here present the results from a systematic analysis of time-lags between variations in two energy bands (5-7 vs. 2-4 k…
Controversial age spreads from the main sequence turn-off and red clump in intermediate-age clusters in the LMC
Cabrera-Ziri, I.; Bastian, N.; Kozhurina-Platais, V. +5 more
Most star clusters at an intermediate age (1-2 Gyr) in the Large and Small Magellanic Clouds show a puzzling feature in their color-magnitude diagrams (CMD) that is not in agreement with a simple stellar population. The main sequence turn-off of these clusters is much broader than expected from photometric uncertainties. One interpretation of this…
The atmosphere of comet 67P/Churyumov-Gerasimenko diagnosed by charge-exchanged solar wind alpha particles
Kallio, E.; Gunell, H.; Behar, E. +6 more
Context. The ESA/Rosetta mission has been orbiting comet 67P/Churyumov-Gerasimenko since August 2014, measuring its dayside plasma environment. The ion spectrometer onboard Rosetta has detected two ion populations, one energetic with a solar wind origin (H+, He2+, He+), the other at lower energies with a cometary o…