Search Publications
Many new variable stars discovered in the core of the globular cluster NGC 6715 (M 54) with EMCCD observations
Surdej, J.; Snodgrass, C.; Horne, K. +39 more
Context. We show the benefits of using electron-multiplying CCDs and the shift-and-add technique as a tool to minimise the effects of atmospheric turbulence, such as blending between stars in crowded fields, and to avoid saturated stars in the fields observed. We intend to complete, or improve on, the census of the variable star population in glob…
Method for improving line flux and redshift measurements with narrowband filters
Milvang-Jensen, B.; Fynbo, J. P. U.; Nilsson, K. K. +5 more
Context. High redshift star-forming galaxies are discovered routinely because of a flux excess in narrowband filters caused by an emission line. In most cases, the width of such filters is broader than typical line widths, and the throughput of the filters varies substantially within the bandpass. This leads to substantial uncertainties in redshif…
Combining strong lensing and dynamics in galaxy clusters: integrating MAMPOSSt within LENSTOOL. I. Application on SL2S J02140-0535
Gastaldello, F.; Jullo, E.; Biviano, A. +12 more
Context. The mass distribution in galaxy clusters and groups is an important cosmological probe. It has become clear in recent years that mass profiles are best recovered when combining complementary probes of the gravitational potential. Strong lensing (SL) is very accurate in the inner regions, but other probes are required to constrain the mass…
Solar irradiance observations with PREMOS filter radiometers on the PICARD mission: In-flight performance and data release
Egorova, T.; Schmutz, W.; Rozanov, E. +22 more
Context. The PREcision Monitoring Sensor (PREMOS) is a solar radiometer on board the French PICARD mission that was launched in June 2010 and decommissioned in April 2014.
Aims: The PREMOS radiometer obtains solar irradiance measurements in specific spectral windows in the UV, visible, and near-infrared. In this paper, the PREMOS data and cal…
Wave propagation in a solar quiet region and the influence of the magnetic canopy
Tziotziou, K.; Tsiropoula, G.; Kontogiannis, I.
Aims: We seek indications or evidence of transmission/conversion of magnetoacoustic waves at the magnetic canopy, as a result of its impact on the properties of the wave field of the photosphere and chromosphere.
Methods: We use cross-wavelet analysis to measure phase differences between intensity and Doppler signal oscillations in the H…
Formation of a solar Hα filament from orphan penumbrae
Solanki, S. K.; Lagg, A.; van Noort, M. +1 more
Aims: The formation and evolution of an Hα filament in active region (AR) 10953 is described.
Methods: Observations from the Solar Optical Telescope (SOT) aboard the Hinode satellite starting from UT 18:09 on 27th April 2007 until UT 06:08 on 1st May 2007 were analysed. 20 scans of the 6302 Å Fe I line pair recorded by SOT/SP were invert…
Searching for narrow absorption and emission lines in XMM-Newton spectra of gamma-ray bursts
D'Avanzo, P.; Campana, S.; Tagliaferri, G. +7 more
We present the results of a spectroscopic search for narrow emission and absorption features in the X-ray spectra of long gamma-ray burst (GRB) afterglows. Using XMM-Newton data, both EPIC and RGS spectra, of six bright (fluence > 10-7 erg cm-2) and relatively nearby (z = 0.54-1.41) GRBs, we performed a blind search for em…
XMM-Newton study of the Draco dwarf spheroidal galaxy
Sasaki, Manami; Saeedi, Sara; Ducci, Lorenzo
Aims: We present the results of the analysis of five XMM-Newton observations of the Draco dwarf spheroidal galaxy (dSph). The aim of the work is the study of the X-ray population in the field of the Draco dSph.
Methods: We classified the sources on the basis of spectral analysis, hardness ratios, X-ray-to-optical flux ratio, X-ray variab…
X-ray deficiency on strongly accreting T Tauri stars. Comparing Orion with Taurus
Bouy, H.; Manara, C. F.; Merín, B. +3 more
Context. Depending on whether a T Tauri star accretes material from its circumstellar disk or not, different X-ray emission properties can be found. The accretion shocks produce cool heating of the plasma, contributing to the soft X-ray emission from the star.
Aims: Using X-ray data from the Chandra Orion Ultra-deep Project and accretion rate…
Two giant outbursts of V0332+53 observed with INTEGRAL
Kretschmar, Peter; Pottschmidt, Katja; Wilms, Jörn +7 more
Context. In July 2015, the high-mass X-ray binary V0332+53 underwent a giant outburst, a decade after the previous one. V0332+53 hosts a strongly magnetized neutron star. During the 2004-2005 outburst, an anti-correlation between the centroid energy of its fundamental cyclotron resonance scattering features (CRSFs) and the X-ray luminosity was obs…