Search Publications
Cone angle control of the interaction of magnetic clouds with the Earth's bow shock
Escoubet, C. P.; Kilpua, E. K. J.; Turc, L. +2 more
We study the interaction of magnetic clouds (MCs) with the near-Earth environment. Recent works suggest that the bow shock crossing may modify significantly the magnetic structure of an MC, and thus its ability to drive geomagnetic storms. This change is largely controlled by the bow shock configuration, which depends on the upstream interplanetar…
Optimal cosmic microwave background map-making in the presence of cross-correlated noise
de Bernardis, P.; Vittorio, N.; Cabella, P. +2 more
Aims: We present an extension of the ROMA map-making algorithm for the generation of optimal cosmic microwave background polarization maps. The new code allows for a possible cross-correlated noise component among the detectors of a CMB experiment. A promising application is the forthcoming LSPE balloon-borne experiment, which is devoted to t…
Nuclear discs as clocks for the assembly history of early-type galaxies: the case of NGC 4458
Morelli, L.; Maraston, C.; Corsini, E. M. +6 more
Approximately 20 per cent of early-type galaxies host small nuclear stellar discs that are tens to a few hundred parsecs in size. Such discs are expected to be easily disrupted during major galactic encounters, hence their age serve to constrain their assembly history. We use VIsible MultiObject Spectrograph integral-field spectroscopic observatio…
Molecular gas and star formation toward the IR dust bubble S 24 and its environs
Rubio, M.; Firpo, V.; Cappa, C. E. +4 more
Aims: We present a multiwavelength analysis of the infrared dust bubble S 24 and the extended IR sources G341.220-0.213 and G341.217-0.237 located in its environs. We aim to investigate the characteristics of the molecular gas and the interstellar dust linked to them and analyze the evolutionary state of the young stellar objects identified t…
X-ray Spectral and Optical Properties of a ULX in NGC 4258 (M106)
Balman, S.; Akyuz, A.; Aksaker, N. +3 more
We study the X-ray and optical properties of the ultraluminous X-ray source (ULX) X-6 in the nearby galaxy NGC 4258 (M106) based on the archival XMM-Newton, Chandra, Swift, and Hubble Space Telescope (HST) observations. The source has a peak luminosity of L X ∼ 2 × 1039 erg s-1 in the XMM-Newton observation of 2004…
XMM-Newton reveals a Seyfert-like X-ray spectrum in the z = 3.6 QSO B1422+231
Cappi, M.; Ponti, G.; Vignali, C. +5 more
Context. Matter flows from the central regions of quasi-stellar objects (QSOs) during their active phases are probably responsible for the properties of the super-massive black holes and those of the bulges of host galaxies. To understand how this mechanism works, we need to characterize the geometry and the physical state of the accreting matter …
RT Crucis: a look into the X-ray emission of a peculiar symbiotic star
Santangelo, A.; Ducci, L.; Ferrigno, C. +3 more
Symbiotic stars are a heterogeneous class of interacting binaries. Among them, RT Cru has been classified as prototype of a subclass that is characterised by hard X-ray spectra that extend past ~20 keV. We analyse ~8.6 Ms of archival INTEGRAL data collected during the period 2003-2014, ~ 140 ks of Swift/XRT data, and a Suzaku observation of 39 ks,…
Reconnection layer bounded by switch-off shocks: Dayside magnetopause crossing by THEMIS D
Phan, Tai; Eriksson, Stefan; Haaland, Stein +2 more
We discuss observations of reconnection, obtained by Time History of Events and Macroscale Interactions during Substorms (THEMIS) D during an outward bound traversal of the low-latitude dayside magnetopause. The reconnection signatures include high magnetic shear, a southward directed Alfvénic jet, bounded by slow-mode shocks near the switch-off l…
Dynamical Estimate of Post-main-sequence Stellar Masses in 47 Tucanae
Heyl, Jeremy; Richer, Harvey; Kalirai, Jason +2 more
We use the effects of mass segregation on the radial distribution of different stellar populations in the core of 47 Tucanae to find estimates for the masses of stars at different post-main-sequence evolutionary stages. We take samples of main-sequence (MS) stars from the core of 47 Tucanae, at different magnitudes (I.e., different masses), and us…
Analysis of the dust jet imaged by Rosetta VIRTIS-M in the coma of comet 67P/Churyumov-Gerasimenko on 2015 April 12
Bieler, A.; Capaccioni, F.; Combi, M. R. +10 more
This work is a part of a more global effort aimed at understanding and interpreting in situ and remote sensing data acquired by instruments on board Rosetta. This study aims at deriving the dust mass source rate and the location of the dust jet source observed by Rosetta VIRTIS-M on 2015 April 12. The analysis is performed by means of the coupled …