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Bright Points: Multithermal Analysis as a Test of Steady Heating Models
Golub, L.; Schmelz, J. T.; Pathak, S. +4 more
X-ray bright points are small, million-degree features in the solar atmosphere composed of short coronal loops. They are magnetically driven structures associated with photospheric magnetic bipoles. Their relatively small size and simple structure suggest they are ideal candidates for comparisons with coronal heating models. In this paper, we pres…
Model of outgrowths in the spiral galaxies NGC 4921 and NGC 7049 and the origin of spiral arms
Carlqvist, Per
NGC 4921 and 7049 are two spiral galaxies presenting narrow, distinct dust features. A detailed study of the morphology of those features has been carried out using Hubble Space Telescope archival images. NGC 4921 shows a few but well-defined dust arms midway to its centre while NGC 7049 displays many more dusty features, mainly collected within a…
Mapping the complex kinematics of LL objects in the Orion nebula
O'Dell, C. R.; García-Díaz, Ma. T.; Henney, William J. +1 more
LL Orionis-type objects (LL objects) are hyperbolic bowshocks visible around young stars in the outer Orion nebula, many of which are also associated with curved, highly collimated jets. The bowshocks are clearly due to the supersonic interaction between an outflow from the young star and an environmental flow from the core of the nebula, but the …
Empirical determination of the temperature stratification in the photosphere of the quiet Sun
Faurobert, M.; Ricort, G.; Aime, C.
Context. Detailed realistic 3D simulations of the photosphere of the Sun are now available, but 1D models of the average quiet-Sun photosphere are still widely used, in particular for spectro-polarimetric inversions.
Aims: Here we present an empirical determination of the average radiation temperature variations as a function of the geometric…
A multi-wavelength study of the gravitational lens COSMOS J095930+023427
Paolillo, Maurizio; Cao, Shuo; Zhu, Zong-Hong +1 more
We present a multi-wavelength study of the gravitational lens COSMOS J095930+023427 (z1 = 0.892), together with the associated galaxy group along the line of sight located at z ~ 0.7, and the lensed background galaxy. The source redshift is currently unknown, but estimated to be at zs ~ 2. This analysis is based on publicly a…
Contrasting behaviour from two Be/ X-ray binary pulsars: insights into differing neutron star accretion modes
Hill, A. B.; Coe, M. J.; Bird, A. J. +4 more
In this paper we present the identification of two periodic X-ray signals coming from the direction of the Small Magellanic Cloud (SMC). On detection with the Rossi X-ray Timing Explorer (RXTE), the 175.4 s and 85.4 s pulsations were considered to originate from new Be/ X-ray binary (BeXRB) pulsars with unknown locations. Using rapid follow-up INT…
Physical properties of outflows. Comparing CO- and H2O-based parameters in Class 0 sources
Liseau, R.; Melnick, G.; Bjerkeli, P. +4 more
Context. The observed physical properties of outflows from low-mass sources put constraints on possible ejection mechanisms. Historically, these quantities have been derived from CO using ground-based observations. It is, therefore, important to investigate whether parameters such as momentum rate (thrust) and mechanical luminosity (power) are the…
Extragalactic point source detection in Wilkinson Microwave Anisotropy Probe 7-year data at 61 and 94 GHz
de Zotti, G.; González-Nuevo, J.; Herranz, D. +4 more
The detection of point sources in cosmic microwave background maps is usually based on a single-frequency approach, whereby maps at each frequency are filtered separately and the spectral information on the sources is derived combining the results at the different frequencies. In contrast, in the case of multifrequency detection methods, source de…
XMM-Newton Observations of Luminous Sources in Nearby Galaxies NGC 4395, NGC 4736, and NGC 4258
Balman, S.; Akyuz, A.; Sonbas, E. +3 more
We present the results of a study of non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources have been detected within the D 25 regions of the target galaxies.…
Giant events in the 23rd solar cycle: Common and specific features
Struminsky, A. B.
Giant X-ray events (>X17) in the 23rd solar cycle (October 28 and November 4, 2003, and September 7, 2005) are considered, which were almost completely observed in hard X rays (>150 keV) from the INTEGRAL satellite and partly from the RHESSI satellite. These events are compared with two events completely observed from the RHESSI satellite (X…