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The Putative Old, Nearby Cluster Lodén 1 Does Not Exist
Wright, Jason T.; Curtis, Jason L.; Han, Eunkyu
Astronomers have access to precious few nearby, middle-aged benchmark star clusters. Within 500 pc, there are only NGC 752 and Ruprecht 147 (R147) at 1.5 and 3 Gyr, respectively. The Database for Galactic Open Clusters (WEBDA) also lists Lodén 1 as a 2 Gyr cluster at a distance of 360 pc. If this is true, Lodén 1 could become a useful benchmark cl…
The Star Cluster Mass-Galactocentric Radius Relation: Implications for Cluster Formation
Fan, Zhou; de Grijs, Richard; Cameron, Ewan +1 more
Whether or not the initial star cluster mass function is established through a universal, galactocentric-distance-independent stochastic process, on the scales of individual galaxies, remains an unsolved problem. This debate has recently gained new impetus through the publication of a study that concluded that the maximum cluster mass in a given p…
Rosetta mission operations for landing
Accomazzo, Andrea; Lodiot, Sylvain; Companys, Vicente
The International Rosetta Mission of the European Space Agency (ESA) was launched on 2nd March 2004 on its 10 year journey to comet Churyumov-Gerasimenko and has reached it early August 2014. The main mission objectives were to perform close observations of the comet nucleus throughout its orbit around the Sun and deliver the lander Philae to its …
Constraining the escape fraction of ionizing photons from H II regions within NGC 300: A concept paper
Bastian, N.; Niederhofer, F.; Hilker, M. +1 more
Using broadband photometry from the Hubble Space Telescope in combination with Very Large Telescope narrowband Hα observations of the nearby spiral galaxy NGC 300, we explore a method for estimating the escape fractions of hydrogen-ionizing photons from H II regions within this galaxy. Our goal in this concept study is to evaluate the spectral typ…
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 …