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We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24 mu m-selected galaxies with S-24 (mu m) > 0: 30 mJy and I 10(11) L-circle dot galaxies at 0.6

As part of a large study to investigate the nature of the longer wavelength continuum emission of radio-loud AGNs, we present new mid- to far-infrared (MFIR) and high-frequency radio observations for a complete sample of 2 Jy powerful southern radio galaxies at intermediate redshifts (0.05

We present predictions for the evolution of the galaxy luminosity function, number counts and redshift distributions in the IR based on the Lambda-CDM cosmological model. We use the combined GALFORM semi-analytical galaxy formation model and GRASIL spectrophotometric code to compute galaxy SEDs including the reprocessing of radiation by dust. The model, which is the same as that in Baugh et al (2005), assumes two different IMFs: a normal solar neighbourhood IMF for quiescent star formation in disks, and a very top-heavy IMF in starbursts triggered by galaxy mergers. We have shown previously that the top-heavy IMF seems to be necessary to explain the number counts of faint sub-mm galaxies. We compare the model with observational data from the SPITZER Space Telescope, with the model parameters fixed at values chosen before SPITZER data became available. We find that the model matches the observed evolution in the IR remarkably well over the whole range of wavelengths probed by SPITZER. In particular, the SPITZER data show that there is strong evolution in the mid-IR galaxy luminosity function over the redshift range z ~ 0-2, and this is reproduced by our model without requiring any adjustment of parameters. On the other hand, a model with a normal IMF in starbursts predicts far too little evolution in the mid-IR luminosity function, and is therefore excluded., LaTeX, 26 pages, 19 figures. Accepted for publication in MNRAS. Minor changes from original version in response to referee's report

The quantity of dust in a spiral disk can be estimated using the dust's typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. The two measurements reflect, respectively, the average and apparent optical depth of a disk section. Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ISM geometry, relative contributions of different stellar populations, and dust emissivity are all free parameters in galaxy spectral energy distribution ( SED) models; they are also sometimes degenerate, depending on wavelength coverage. Our aim is to constrain the typical ISM geometry. The apparent optical depth measurement comes from the number of distant galaxies seen in Hubble Space Telescope (HST) images through the foreground disk, calibrated with the synthetic field method (SFM). We discuss what can be learned from the SFM measurement alone regarding ISM geometry. We measure the IR flux in images from the Spitzer Infrared Nearby Galaxy Survey in the same section of the disk that was covered by HST. A physical model of the dust is fit to the SED to estimate the dust surface density, mean temperature, and brightness in these disk sections. The surface density is subsequently converted into the average optical depth estimate. The two measurements generally agree, and the SED model finds mostly cold dust ( T

The uncertainty surrounding the nature of the heating mechanism for the dust that emits at mid- to far-IR ( MFIR) wavelengths in active galaxies limits our understanding of the links between active galactic nuclei ( AGNs) and galaxy evolution, as well as our ability to interpret the prodigious infrared and submillimeter emission of some of the most distant galaxies in the universe. Here we report deep Spitzer observations of a complete sample of powerful, intermediate-redshift (0.05

The uncertainty surrounding the nature of the heating mechanism for the dust that emits at mid- to far-IR ( MFIR) wavelengths in active galaxies limits our understanding of the links between active galactic nuclei ( AGNs) and galaxy evolution, as well as our ability to interpret the prodigious infrared and submillimeter emission of some of the most distant galaxies in the universe. Here we report deep Spitzer observations of a complete sample of powerful, intermediate-redshift (0.05

The uncertainty surrounding the nature of the heating mechanism for the dust that emits at mid- to far-IR (MFIR) wavelengths in active galaxies limits our understanding of the links between active galactic nuclei (AGN) and galaxy evolution, as well as our ability to interpret the prodigious infrared and sub-mm emission of some of the most distant galaxies in the Universe. Here we report deep Spitzer observations of a complete sample of powerful, intermediate redshift (0.05 < z < 0.7) radio galaxies and quasars. We show that AGN power, as traced by [OIII]5007 emission, is strongly correlated with both the mid-IR (24 micron) and the far-IR (70 micron) luminosities, however, with increased scatter in the 70 micron correlation. A major cause of this increased scatter is a group of objects that falls above the main correlation and displays evidence for prodigious recent star formation activity at optical wavelengths, along with relatively cool MFIR colours. These results provide evidence that illumination by the AGN is the primary heating mechanism for the dust emitting at both 24 and 70 microns, with starbursts dominating the heating of the cool dust in only 20 -- 30% of objects. This implies that powerful AGN are not always accompanied by the type of luminous starbursts that are characteristic of the peak of activity in major gas-rich mergers.

We present spatially resolved observations of IRAS sources from the Japanese infrared astronomy satellite AKARI All-Sky Survey during the performance verification phase of the mission. We extracted reliable point sources matched with the IRAS point source catalogue. By comparing IRAS and AKARI fluxes, we found that the flux measurements of some IRAS sources could have been over or underestimated, and affected by the local background, rather than the global background. We also found possible candidates for new AKARI sources and confirmed that AKARI observations resolved IRAS sources into multiple sources. All-Sky Survey observations are expected to verify the accuracies of IRAS flux measurements and to find new extragalactic point sources.

We present spatially resolved observations of IRAS sources from the Japanese infrared astronomy satellite AKARI All-Sky Survey during the performance verification phase of the mission. We extracted reliable point sources matched with the IRAS point source catalogue. By comparing IRAS and AKARI fluxes, we found that the flux measurements of some IRAS sources could have been over or underestimated, and affected by the local background, rather than the global background. We also found possible candidates for new AKARI sources and confirmed that AKARI observations resolved IRAS sources into multiple sources. All-Sky Survey observations are expected to verify the accuracies of IRAS flux measurements and to find new extragalactic point sources.

Aims. In order to show the importance of high spatial resolution observations of extra-galactic sources when compared to observations obtained with larger apertures such as ISO, we present N-band spectra (8-13 mu m) of some locations in three starburst galaxies. In particular, we show the two galactic nuclei of the spiral galaxy NGC 3256, the compact IR supernebula in the dwarf galaxy II Zw40 and the two brightest IR knots in the central starburst of the WR galaxy He 2-10.Methods. The spectra were obtained with TIMMI2 on the ESO 3.6 m telescope. An inventory of the spectra in terms of atomic fine-structure lines and molecular bands is presented.Results. We show the value of these high spatial resolution data in constraining properties such as the extinction in the mid-IR, metallicity or stellar content (age, IMF, etc.). We have constrained the stellar content of the IR compact knot in II Zw40 by using the mid-IR fine-structure lines and setting restrictions on the nebular geometry. We have constructed a new mid-/far-IR diagnostic diagram based on the 11.2 mu m PAH and continuum, accessible to ground-based observations. We find that extra-galactic nuclei and star clusters observed at high spatial resolution ( as is the case of the TIMMI2 observations) are closer in PAH/far-IR to compact H-II regions, while galaxies observed by large apertures such as ISO are closer to exposed PDRs such as Orion. This is likely due to the aperture difference. We find a dependence between the presence of PAHs and the hardness of the radiation field as measured by the [S-IV]/[Ne-II] ratio that may be explained by the PAH-dust competition for FUV photons or the relative contribution of the different phases of the interstellar medium.

We discuss the panchromatic properties of 99 088 galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 1 'main' spectroscopic sample ( a flux-limited sample for 1360 deg(2)). These galaxies are positionally matched to sources detected by ROSAT, Galaxy Evolution Explorer (GALEX), two-Micron All-Sky Survey (2MASS), Infrared Astronomical Satellite ( IRAS), Green Bank GB6 survey ( GB6), Faint Images of the Radio Sky at Twenty-centimetres ( FIRST), NRAO VLA Sky Survey (NVSS) and Westerbork Northern Sky Survey (WENSS). The matching fraction varies from

We present deep K-s 83 mu Jy ( the similar to 80% completeness limit of the Spitzer/GTO 24 mu m catalog); 36% of our galaxies have spectroscopic redshifts ( mostly at z 10(12) L-circle dot) at redshifts z less than or similar to 2-3. Massive star-forming galaxies at redshifts 2 less than or similar to z less than or similar to 3 are characterized by very high star formation rates (SFR > 500 M-circle dot yr(-1)), and some of them are able to construct a mass of approximate to 10(10) - 10(11) M-circle dot in a single burst lifetime ( similar to 0.01 - 0.1 Gyr). At lower redshifts z less than or similar to 2, massive star-forming galaxies are also present but appear to be building their stars on long timescales, either quiescently or in multiple modest burstlike episodes. At redshifts z similar to 1 2, the ability of the burstlike mode to produce entire galaxies in a single event is limited to some lower ( M less than or similar to 7; 10(10) M-circle dot) mass systems, and it is basically negligible at z less than or similar to 1. Our results support a scenario in which star formation activity is differential with assembled stellar mass and redshift, and where the relative importance of the burstlike mode proceeds in a downsizing way from high to low redshifts.

In this paper we analyze the evolution of actively star forming galaxies in the mid-infrared (MIR). This spectral region, characterized by continuum emission by hot dust and by the presence of strong emission features generally ascribed to polycyclic aromatic hydrocarbon (PAH) molecules, is the most strongly affected by the heating processes associated with star formation and/or active galactic nuclei (AGN). Following the detailed observational characterization of galaxies in the MIR by ISO, we have updated the modelling of this spectral region in our spectro-photometric model GRASIL (Silva et al. 1998). In the diffuse component we have updated the treatment of PAHs according to the model by Li & Draine (2001). As for the dense phase of the ISM associated with the star forming regions, the molecular clouds, we strongly decrease the abundance of PAHs as compared to that in the cirrus, basing on the observational evidences of the lack or weakness of PAH bands close to the newly formed stars, possibly due to the destruction of the molecules in strong UV fields. The robustness of the model is checked by fitting near infrared to radio broad band spectra and the corresponding detailed MIR spectra of a large sample of galaxies (Lu et al. 2003), at once. With this model, we have analyzed the larger sample of actively star forming galaxies by Dale et al. (2000). We show that the observed trends of galaxies in the ISO-IRAS-Radio color-color plots can be interpreted in terms of different evolutionary phases of star formation activity, and the consequent different dominance in the spectral energy distribution (SED) of the diffuse or dense phase of the ISM., Accepted for publication in MNRAS

We present results from Chandra observations of 14 ultraluminous infrared galaxies [ULIRGs; log(L(IR)/L.) >= 12] with redshifts between 0.04 and 0.16. The goals of the observations were to investigate any correlation between infrared color or luminosity and the properties of the X-ray emission and to attempt to determine whether these objects are powered by starbursts or active galactic nuclei (AGNs). The sample contains approximately the same number of high- and low-luminosity objects and "warm'' and "cool'' ULIRGs. All 14 galaxies were detected by Chandra. Our analysis shows that the X-ray emission of the two Seyfert 1 galaxies in our sample is dominated by an AGN. The remaining 12 sources are too faint for conventional spectral fitting to be applicable. Hardness ratios were used to estimate the spectral properties of these faint sources. The photon indices, Gamma-values, for our sample plus the Chandra-observed 2003 sample from Ptak et al. peak in the range 1.0-1.5, consistent with expectations for X-ray binaries in a starburst, an absorbed AGN, or hot bremsstrahlung from a starburst or AGN. The values of Gamma for the objects in our sample classified as Seyferts (type 1 or 2) are larger than 2, while those classified as H II regions or LINERs tend to be less than 2. The hard X-ray to far-infrared ratios for the 12 weak sources are similar to those of starbursts, but we cannot rule out the possibility of absorbed, possibly Compton-thick, AGNs in some of these objects. Two of these faint sources were found to have X-ray counterparts to their double optical and infrared nuclei.

We report the spectroscopic detection of silicate emission at 10 and 18 microns in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for Active Galactic Nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detected silicate emission features range from 0.12 to 1.25 times the continuum at 10 microns and from 0.20 to 0.79 times the continuum at 18 microns. The silicate grain temperatures inferred from the ratio of 18-to-10 micron silicate features under the assumption of optically thin emission range from 140 to 220K., Comment: 4 pages, including 2 tables and 3 figures. Accepted by ApJL

We present the first near-infrared (K'-band) homogeneous observations of a complete sub-sample of the 3CR radio catalogue comprising all High Excitation Galaxies (HEGs) at z, Comment: Accepted for publication in A&A; high resolution version can be downloaded at http://www.astro.yale.edu/danilom/

We present the 90 micron luminosity function of the Final Analysis of the European Large Area ISO Survey (ELAIS), extending the sample size of our previous analysis (paper IV) by about a factor of 4. Our sample extends to z=1.1, around 50 times the comoving volume of paper IV, and 10^{7.7} < h^{-2}L/Lsun < 10^{12.5}. From our optical spectroscopy campaigns of the northern ELAIS 90 mircon survey (7.4 deg^2 in total, to S(90um)>70mJy), we obtained redshifts for 61% of the sample (151 redshifts) to B, Comment: MNRAS accepted. 7 pages, 5 figures. Uses BoxedEPS (included)

Infrared (IR) emission features at 3.3, 6.2, 7.7, 8.6, and 11.3 mum are generally attributed to IR fluorescence from ( mainly) far-ultraviolet (FUV) pumped large polycyclic aromatic hydrocarbon (PAH) molecules. As such, these features trace the FUV stellar flux and are thus a measure of star formation. We examined the IR spectral characteristics of Galactic massive star-forming regions and of normal and starburst galaxies, as well as active galactic nuclei (AGNs) and ultraluminous infrared galaxies (ULIRGs). The goal of this study is to analyze whether PAH features are a good qualitative and/or quantitative tracer of star formation, and hence to evaluate the application of PAH emission as a diagnostic tool in order to identify the dominant processes contributing to the infrared emission from Seyfert galaxies and ULIRGs. We develop a new mid-infrared (MIR)/far-infrared ( FIR) diagnostic diagram based on our Galactic sample and compare it to the diagnostic tools of Genzel and coworkers and Laurent and coworkers, with these diagnostic tools also applied to our Galactic sample. This MIR/FIR diagnostic is derived from the FIR normalized 6.2 mum PAH flux and the FIR normalized 6.2 mum continuum flux. Within this diagram, the Galactic sources form a sequence spanning a range of 3 orders of magnitude in these ratios, ranging from embedded compact H II regions to exposed photodissociation regions (PDRs) and the ( diffuse) interstellar medium ( ISM). However, the variation in the 6.2 mum PAH feature - to - continuum ratio is relative small. Comparison of our extragalactic sample with our Galactic sources revealed an excellent resemblance of normal and starburst galaxies to exposed PDRs. While Seyfert 2 galaxies coincide with the starburst trend, Seyfert 1 galaxies are displaced by at least a factor of 10 in 6.2 mum continuum flux, in accordance with general orientation-dependent unification schemes for AGNs. ULIRGs show a diverse spectral appearance. Some show a typical AGN hot dust continuum. More, however, either are starburst-like or show signs of strong dust obscuration in the nucleus. One characteristic of the ULIRGs also seems to be the presence of more prominent FIR emission than either starburst galaxies or AGNs. We discuss the observed variation in the Galactic sample in view of the evolutionary state and the PAH/dust abundance and discuss the use of PAHs as quantitative tracers of star formation activity. Based on these investigations, we find that PAHs may be better suited as a tracer of B stars, which dominate the Galactic stellar energy budget, than as a tracer of massive star formation (O stars).

Infrared (IR) emission features at 3.3, 6.2, 7.7, 8.6, and 11.3 mum are generally attributed to IR fluorescence from ( mainly) far-ultraviolet (FUV) pumped large polycyclic aromatic hydrocarbon (PAH) molecules. As such, these features trace the FUV stellar flux and are thus a measure of star formation. We examined the IR spectral characteristics of Galactic massive star-forming regions and of normal and starburst galaxies, as well as active galactic nuclei (AGNs) and ultraluminous infrared galaxies (ULIRGs). The goal of this study is to analyze whether PAH features are a good qualitative and/or quantitative tracer of star formation, and hence to evaluate the application of PAH emission as a diagnostic tool in order to identify the dominant processes contributing to the infrared emission from Seyfert galaxies and ULIRGs. We develop a new mid-infrared (MIR)/far-infrared ( FIR) diagnostic diagram based on our Galactic sample and compare it to the diagnostic tools of Genzel and coworkers and Laurent and coworkers, with these diagnostic tools also applied to our Galactic sample. This MIR/FIR diagnostic is derived from the FIR normalized 6.2 mum PAH flux and the FIR normalized 6.2 mum continuum flux. Within this diagram, the Galactic sources form a sequence spanning a range of 3 orders of magnitude in these ratios, ranging from embedded compact H II regions to exposed photodissociation regions (PDRs) and the ( diffuse) interstellar medium ( ISM). However, the variation in the 6.2 mum PAH feature - to - continuum ratio is relative small. Comparison of our extragalactic sample with our Galactic sources revealed an excellent resemblance of normal and starburst galaxies to exposed PDRs. While Seyfert 2 galaxies coincide with the starburst trend, Seyfert 1 galaxies are displaced by at least a factor of 10 in 6.2 mum continuum flux, in accordance with general orientation-dependent unification schemes for AGNs. ULIRGs show a diverse spectral appearance. Some show a typical AGN hot dust continuum. More, however, either are starburst-like or show signs of strong dust obscuration in the nucleus. One characteristic of the ULIRGs also seems to be the presence of more prominent FIR emission than either starburst galaxies or AGNs. We discuss the observed variation in the Galactic sample in view of the evolutionary state and the PAH/dust abundance and discuss the use of PAHs as quantitative tracers of star formation activity. Based on these investigations, we find that PAHs may be better suited as a tracer of B stars, which dominate the Galactic stellar energy budget, than as a tracer of massive star formation (O stars).

We report the detection of strong absorption and weak emission features in the 4-27 μm Spitzer Infrared Spectrograph (IRS) spectrum of the distant ultraluminous infrared galaxy IRAS F00183-7111 (z = 0.327). The absorption features of CO2 and CO gas, water ice, hydrocarbons, and silicates are indicative of a strongly obscured (A9.6 ≥ 5.4; AV ≥ 90) and complex line of sight through both the hot diffuse interstellar medium and shielded cold molecular clouds toward the nuclear power source. From the profile of the 4.67 μm CO fundamental vibration mode, we deduce that the absorbing gas is dense (n ~ 106 cm-3) and warm (720 K) and has a CO column density of ~1019.5 cm-2, equivalent to NH ~ 1023.5 cm-2. The high temperature and density, as well as the small inferred size (

We present a multiwavelength catalog (15 mum, R-band, K-band, and 1.4 GHz flux) plus spectroscopic identifications for 406 15 mum sources detected in the European Large Area ISO Survey (ELAIS) region S1, over the flux density range 0.5

We present a multi-wavelength catalog (15 um, R, K-band, 1.4 GHz flux) plus spectroscopic identifications for 406 15 um sources detected in the ELAIS region S1, over the flux density range 0.5, Comment: Scheduled on AJ, Vol. 127/6, 2004 June. Table 2 (+ 15um sources coordinates) at http://www.fis.uniroma3.it/~ELAIS_S/lafrancabab.tab2.dat . Table 3 at http://www.fis.uniroma3.it/~ELAIS_S/lafrancabab.tab3.dat . Other related data and papers at http://www.fis.uniroma3.it/~ELAIS_S/ . Few luminosities in Table 2 corrected

Deep far-infrared (FIR) imaging data obtained with ISOPHOT at 90 mum, 150 mum, and 200 mum detected the thermal emission from cold dust in the northern shell region of NGC5128 (Centaurus A), where previously neutral hydrogen and molecular gas has been found. A somewhat extended FIR emission region is present in both the 150 mum and 200 mum map, while only an upper flux limit could be derived from the 90 mum data. The FIR spectral energy distribution can be reconciled with a modified blackbody spectrum with very cold dust color temperatures and emissivity indices in the range 13K beta > 1, respectively, where the data favor the low temperature end. A representative value for the associated dust mass is M(Dust) approximate to 7 x 10(4) M(.), which together with the HI gas mass gives a gas-to-dust ratio of approximate to300, close the average values of normal inactive spiral galaxies. This value, in conjunction with the atomic to molecular gas mass ratio typical for a spiral galaxy, indicates that the interstellar medium (ISM) from the inner part of a captured disk galaxy is likely the origin of the outlying gas and dust. These observations are in agreement with recent theoretical considerations that in galaxy interactions leading to stellar shell structures the less dissipative clumpy component of the ISM from the captured galaxy can lead to gaseous shells. Alternatively, the outlying gas and dust could be a rotating ring structure resulting from an interaction or even late infall of tidal material of a merger in the distant past. With all three components ( atomic gas, molecular gas, dust) of the ISM present in the northern shell region, local star formation may account for the chains of young blue stars surrounding the region to the east and north. The dust cloud may also be involved in the disruption of the large scale radio jet before entering the brighter region of the northern radio lobe.

We present Infrared Space Observatory mid- and far-infrared spectroscopy of the merging galaxy NGC 6240, an object presenting many aspects of importance for the role of star formation and AGN activity in [ultra]luminous infrared galaxies. The mid-infrared spectrum shows starburst indicators in the form of low excitation fine-structure line emission and aromatic `PAH' features. A strong high excitation [OIV] line is observed which most likely originates in the Narrow Line Region of an optically obscured AGN. NGC 6240 shows extremely powerful emission in the pure rotational lines of molecular hydrogen. We argue that this emission is mainly due to shocks in its turbulent central gas component and its starburst superwind. The total shock cooling in infrared emission lines accounts for ~0.6% of the bolometric luminosity, mainly through rotational H_2 emission and the [OI] 63micron line. We analyse several ways of estimating the luminosities of the starburst and the AGN in NGC 6240 and suggest that the contributions to its bolometric luminosity are most likely in the range 50-75% starburst and 25-50% AGN., 5 figures. Accepted for publication in A&A

The 2002 status of unification models for extragalactic radio sources is examined, with particular emphasis on the dust properties of these objects., Comment: 9 pages, no figures, in Proceedings Radio Galaxy Workshop, Leiden, 11-15 November 2002

Two-dimensional radiative transfer is employed to obtain the broad-band infrared spectrum of active galaxies. In the models we vary the geometry and size of the obscuring medium, the surface density, the opacity and the grain size distribution. Resulting spectral energy distributions are constructed for different orientations of the toroid. Colour-colour comparisons with observational data are consistent with previous observations that the emission longward of 60 micron is produced by star-formation and unrelated to the presence of an obscuring torus. We also find that the toroid cannot be flat, but is rather conical or flaring. The density is most likely constant with radius, and the size is relatively large with an inner radius around 10 pc. A direct comparison with radio galaxy Cygnus A yields a best fit for a conical disk with constant surface density, and a size from 10 to 30 pc assuming the far-infrared emission is due to star-formation in the host galaxy., 20 pages including 15 figures, accepted for publication by A&A

The composition of ice grains provides an important tool for the study of the molecular environment of star forming regions. Using ISAAC at the VLT to obtain spectra around 4.65 microns we have detected for the first time `XCN' and CO ice in an extragalactic environment: the nuclear region of the nearby dusty starburst/AGN galaxy NGC4945. The profile of the solid CO band reveals the importance of thermal processing of the ice while the prominence of the XCN band attests to the importance of energetic processing of the ice by FUV radiation and/or energetic particles. In analogy to the processing of ices by embedded protostars in our Galaxy, we attribute the processing of the ices in the center of NGC4945 to ongoing massive star formation. Our M-band spectrum also shows strong HI Pfund-beta and H2 0-0 S(9) line emission and gas phase CO absorption lines. The HI, H2, PAH, gas phase CO and the ices seem to be embedded in a rotating molecular disk which is undergoing vigorous star formation. Recently, strong OCN- absorption has been detected in the spectrum of the Galactic center star GC:IRS19. The most likely environment for the OCN- absorption is the strongly UV-exposed GC molecular ring. The presence of processed ice in the center of NGC4945 and our Galactic center leads us to believe that processed ice may be a common characteristic of dense molecular material in star forming galactic nuclei., 9 pages, 8 figures. Accepted for publication in A&A. Also available at this http://www.astro.rug.nl/~spoon/publications.html

IAU Symposium, 304, ISSN:0074-1809, ISSN:1743-9213, Multiwavelength AGN surveys and studies : proceedings of the 304th Symposium of the International Astronomical Union held in Yerevan, Armenia October 7-11, 2013, ISBN:978-1-107-04524-8

In order to study the nature of the far-infrared emission observed in radio-loud active galaxies, we have obtained 1.2 mill observations with the IRAM 30 m telescope for a sample of eight radio-loud active galaxies. In all objects we find that the 1.2 mm emission is dominated by non-thermal emission. An extrapolation of the non-thermal radio spectrum indicates that the contribution of synchrotron emission to the far-infrared is less than 10% in quasars. and negligible ill the radio galaxies. The quasars in the sample show signs of relativistic beaming at millimeter wavelengths, and the quasar 3C 334 shows evidence for strong variability.

We present high-angular-resolution, far-infrared images of the Small Magellanic Cloud (SMC). The images were reconstructed from data obtained with the Infrared Astronomical Satellite (IRAS), using the Pyramid Maximum Entropy algorithm. The angular resolutions of the images are 1 arcmin at 12, 25 and 60 mu m, and 1.7 arcmin at 100 mu m, which provides an excellent complement to the recent neutral hydrogen (H I) survey from the Australia Telescope Compact Array, which has a resolution of 1.6 arcmin. We use the 60- and 100-mu m data, together with a standard dust model, to derive a temperature map and a dust column density distribution. Dust temperatures range from 23 to 45 K, which is, on average, warmer than for the Galaxy, although there is a deficit of warm, very small dust grains in the SMC. The total amount of cool dust in the SMC is 1.8(-0.2)(+1.3) x 10(4) M.. There is a significant variation of the observed dust-to-gas ratio across the SMC. This may be caused by corresponding variations in metallicity, but this explanation is not supported by the limited available data in the literature. Alternatively, there may be a large amount of molecular hydrogen (H(2)) in the SMC, similar to 8 x 10(8) M., and/or a large amount (similar to 10(6) M.) of cold dust (less than or equal to 15 K) not seen by IRAS or COBE/DIRBE. The average dust-to-atomic gas ratio is, by mass, 8.2 x 10(-5), which is a factor of similar to 30 below the Galactic value. The spatial power spectrum of the dust column density image can be approximated by P(d)(k) proportional to k(-3.1), which shows that, as with the H I power spectrum, there is no preferred scale size for dust clouds. A spatial coherence analysis shows that, over a wide range of spatial scales (greater than or similar to 50 pc), H I and dust are well correlated (> 60 per cent).