Search Publications
Evidence of scattering effects influenced by plasma flows in C VI 1548 Å, 1550 Å spectral lines emitted from the Sun
Vial, J. -C.; Gontikakis, C.
Aims: We search for, and study, individual spectral profiles where the complex shape of the C iv 1548 Å line is different from the shape of the simultaneously recorded C iv 1550 Å line. Such an asymmetry is not expected for line emission resulting from collisional excitation. Therefore we propose an explanation of these observations through t…
Probing the photoionised outflow in the NLS1 Arakelian 564: An XMM-Newton view
Khanna, Shourya; Kaastra, Jelle. S.; Mehdipour, Missagh
We present a detailed analysis of XMM-Newton X-ray observations of the narrow-line Seyfert-1 (NLS1) galaxy Ark 564, taken between 2000 and 2011. High-resolution X-ray spectroscopy was carried out on the resultant high signal-to-noise stacked spectrum. We find three separate photoionised warm absorbers, which outflow at velocities unusually lower t…
A low-luminosity type-1 QSO sample . IV. Molecular gas contents and conditions of star formation in three nearby Seyfert galaxies
Eckart, Andreas; Moser, Lydia; Krips, Melanie +8 more
We present a pilot study of ~3'' resolution observations of low CO transitions with the Submillimeter Array in three nearby Seyfert galaxies, which are part of the low-luminosity quasi-stellar object (LLQSOs) sample consisting of 99 nearby (z = 0.06) type-1 active galactic nuclei (AGN) taken from the Hamburg/ESO quasi-stellar object (QSO) survey. …
Detailed study of SNR G306.3-0.9 using XMM-Newton and Chandra observations
Miceli, M.; Combi, J. A.; García, F. +3 more
Aims: We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant (SNR) G306.3-0.9 in detail to obtain constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant.
Methods: We used combined data from XMM-Newton and Chandra o…
The far-infrared emission of the radio-loud quasar 3C 318
Peletier, R. F.; Barthel, P. D.; Podigachoski, P. +1 more
3C 318, a radio-loud quasar at z = 1.574, is a subgalactic-sized radio source, and a good test-bed for the interplay between black hole and galaxy growth in the high-z Universe. Based on its IRAS, ISO, and SCUBA detections, it has long been considered as one of the most intrinsically luminous (LIR > 1013 L⊙) inf…
The peculiar optical-UV X-ray spectra of the X-ray weak quasar PG 0043+039
Talavera, A.; Schartel, N.; Rodríguez-Pascual, P. M. +4 more
Context. The object PG 0043+039 has been identified as a broad absorption line (BAL) quasar based on its UV spectra. However, this optical luminous quasar has not been detected before in deep X-ray observations, making it the most extreme X-ray weak quasar known today.
Aims: This study aims to detect PG 0043+039 in a deep X-ray exposure. The …
Microwave observations of a large-scale coronal wave with the Nobeyama radioheliograph
Mann, G.; Shibasaki, K.; Warmuth, A. +1 more
Context. Large-scale globally propagating waves in the solar corona have been studied extensively, mainly using extreme ultraviolet (EUV) observations. In a few events, corresponding wave signatures have been detected in microwave radioheliograms provided by the Nobeyama radioheliograph (NoRH). Several aspects of these observations seem to contrad…
Characterizing elusive, faint dusty star-forming galaxies: a lensed, optically undetected ALMA galaxy at z 3.3
Berta, S.; Daddi, E.; Elbaz, D. +19 more
We present the serendipitous ALMA detection of a faint submillimeter galaxy (SMG) lensed by a foreground z 1 galaxy. By optimizing the source detection to deblend the system, we accurately build the full spectral energy distribution of the distant galaxy from the I814 band to radio wavelengths. It is extremely red, with a I-K colour larger than 2.…
Exploring high-z galaxies with the E-ELT
Gullieuszik, M.; Falomo, R.; Greggio, L. +2 more
We present simulated observations of galaxies at z = 2 and z = 3 to probe the capabilities of next-generation telescopes (E-ELT and JWST) to measure the structural and photometrical properties of high-redshift galaxies. We carry out an extensive set of simulations of high-redshift galaxies adopting the specifications of the E-ELT first light instr…
Radiation-driven winds of hot luminous stars. XVIII. The unreliability of stellar and wind parameter determinations from optical vs. UV spectral analysis of selected central stars of planetary nebulae and the possibility of some CSPNs as single-star supernova Ia progenitors
Pauldrach, A. W. A.; Kaschinski, C. B.; Hoffmann, T. L.
Context. The uncertainty in the degree to which radiation-driven winds of hot stars might be affected by small inhomogeneities in the density leads to a corresponding uncertainty in the determination of the atmospheric mass loss rates from the strength of optical recombination lines and - since the mass loss rate is not a free parameter but a func…