With appropriate spatial resolution, images of spiral galaxies in thermal infrared (~10 micron and beyond) often reveal a bright central component, distinct from the stellar bulge, superimposed on a ...disk with prominent spiral arms. ISO and Spitzer studies have shown that much of the scatter in the mid-infrared colors of spiral galaxies is related to changes in the relative importance of these two components, rather than to other modifications, such as the morphological type or star formation rate, that affect the properties of the galaxy as a whole. With the Herschel imaging capability from 70 to 500 micron, we revisit this two-component approach at longer wavelengths, to see if it still provides a working description of the brightness distribution of galaxies, and to determine its implications on the interpretation of global far-infrared properties of galaxies.
We use Herschel Space Observatory data to place observational constraints on the peak and Rayleigh-Jeans slope of dust emission observed at 70-500 microns in the nearby spiral galaxy M81. We find ...that the ratios of wave bands between 160 and 500 microns are primarily dependent on radius but that the ratio of 70 to 160 micron emission shows no clear dependence on surface brightness or radius. These results along with analyses of the spectral energy distributions imply that the 160-500 micron emission traces 15-30 K dust heated by evolved stars in the bulge and disc whereas the 70 micron emission includes dust heated by the active galactic nucleus and young stars in star forming regions.
We present Herschel-SPIRE observations at 250-500um of the giant elliptical galaxy M86 and examine the distribution of the resolved cold dust emission and its relation with other galactic tracers. ...The SPIRE images reveal three dust components: emission from the central region; a dust lane extending north-south; and a bright emission feature 10kpc to the south-east. We estimate that approximately 10^6 solar masses of dust is spatially coincident with atomic and ionized hydrogen, originating from stripped material from the nearby spiral NGC4438 due to recent tidal interactions with M86. The gas-to-dust ratio of the cold gas component ranges from ~20-80. We discuss the different heating mechanisms for the dust features.
We present infrared colours (in the 25-500 mic spectral range) and UV to radio continuum spectral energy distributions of a sample of 51 nearby galaxies observed with SPIRE on Herschel. The observed ...sample includes all morphological classes, from quiescent ellipticals to active starbursts. Active galaxies have warmer colour temperatures than normal spirals. In ellipticals hosting a radio galaxy, the far-infrared (FIR) emission is dominated bynthe synchrotron nuclear emission. The colour temperature of the cold dust is higher in quiescent E-S0a than in star-forming systems probably because of the different nature of their dust heating sources (evolved stellar populations, X-ray, fast electrons) and dust grain properties. In contrast to the colour temperature of the warm dust, the f350/f500 index sensitive to the cold dust decreases with star formation and increases with metallicity, suggesting an overabundance of cold dust or an emissivity parameter beta<2 in low metallicity, active systems.
M82 is a unique representative of a whole class of galaxies, starbursts with superwinds, in the Very Nearby Galaxy Survey with Herschel. In addition, its interaction with the M81 group has stripped a ...significant portion of its interstellar medium from its disk. SPIRE maps now afford better characterization of the far-infrared emission from cool dust outside the disk, and sketch a far more complete picture of its mass distribution and energetics than previously possible. They show emission coincident in projection with the starburst wind and in a large halo, much more extended than the PAH band emission seen with Spitzer. Some complex substructures coincide with the brightest PAH filaments, and others with tidal streams seen in atomic hydrogen. We subtract the far-infrared emission of the starburst and underlying disk from the maps, and derive spatially-resolved far-infrared colors for the wind and halo. We interpret the results in terms of dust mass, dust temperature, and global physical conditions. In particular, we examine variations in the dust physical properties as a function of distance from the center and the wind polar axis, and conclude that more than two thirds of the extraplanar dust has been removed by tidal interaction, and not entrained by the starburst wind.
Two male patients, aged 36 and 73 years respectively, gradually developed febrile pancytopenia with profound alteration of their general condition and major inflammatory repercussions. No superficial ...or deep lymph node enlargement was found initially. Patient n degree 2 had an enlarged spleen. In both cases histological examination of the bone marrow showed an extensive and apparently nonspecific myelofibrosis. The subsequent development of superficial lymphadenopathy provided a firm diagnosis of Hodgkin's disease with mixed cellularity. These two cases belong to the category of exceptional massive medullary forms of Hodgkin's disease described by Duhamel et al. in 1979.
