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Context. Using the ISOPHOT Serendipity Survey (ISOSS) at 170 μm, a sample of galactic starforming regions has been established that exhibits very cold dust temperatures (<$ 20$K) and high masses (>100 $M_\odot$).

Context.Due to the short timescales involved and observational difficulties, our knowledge of the earliest phases of massive star formation remains incomplete.

Aims.To further increase the scientific utilization of the strip scanning measurements of the ISOPHOT Serendipity Survey (ISOSS), the slew data has been assembled to a sky atlas with ≈15% sky coverage in the hitherto unobserved far-infrared wavelength band around 170 μm.

Aims.A complex study of visual and infrared properties of ISM and an examination of cloud morphology was carried out using USNO, 2MASS, DIRBE, IRAS, and ISO data of an extended region in Cepheus to explore the conditions of cloud and star formation.

The LGG 138 galaxy group members NGC 2292 and NGC 2293 were imaged with ISOPHOT in the far-infrared (FIR) at ${\rm 60\,\mu m}$, ${\rm 100\,\mu m}$, and ${\rm 200\,\mu m}$. While no FIR emission is seen at ${\rm 60\,\mu m}$, and only very low level emission is present at ${\rm 100\,\mu m}$, compact FIR emission from both NGC 2292 and NGC 2293 galaxy centres and extended emission likely associated with tidally removed dust and the HI ring surrounding NGC 2292 / 2293 is strongly detected at ${\rm 200\,\mu m}$. Additionally, a compact FIR source associated with the neighbouring galaxy NGC 2295 is strongly detected at ${\rm 200\,\mu m}$. Remarkably, none of these three galaxies have been detected individually in 21 cm HI emission. The steeply rising far-infrared spectral energy distribution of the apparently interacting NGC 2292 / 2293 pair towards longer wavelengths indicates the thermal emission of very cold dust with a temperature of 13 K, much lower than typical values of interacting systems or even quiescent spiral galaxies. The FIR data of this galaxy group clearly shows for the first time that there could be FIR dust emission not accompanied by HI, that dust even in an interacting system can have a very low dust temperature, and furthermore that gravitational interaction can give rise to an extended diffuse dust distribution.

We present the complete set of ISOPHOT observations of 3CR radio galaxies and quasars, which are contained in the ISO Data Archive, providing 75 mid- and far-infrared spectral energy distributions (SEDs) between 5 and 200 μm. For 28 sources they are supplemented with MAMBO 1.2 mm observations and for 15 sources with new submillimetre data from the SCUBA archive. The sample includes flat and steep spectrum quasars, broad and narrow line radio galaxies, as well as Fanaroff-Riley FR 1 and FR 2 types. The SED shapes exhibit a diversity in the infrared (IR), ranging from a smooth dominating synchrotron component in flat spectrum sources to a thermal dust bump around 60-100 μm in steep spectrum sources. The detection rate of a thermal bump in more than 50% of the cases suggests that dust emission may be a general phenomenon in these sources. We check the orientation-dependent unified scheme, in which the powerful FR 2 narrow line galaxies are quasars viewed at high inclination, so that their nuclei are hidden behind a dust torus intercepting the optical-ultraviolet AGN radiation and reemitting it in the infrared. We find that (1) both the quasars and the galaxies show a high mid- to far-infrared luminosity ratio typical for powerful AGNs and (2) – when matched in 178 MHz luminosity – both show the same ratio of isotropic far-infrared to isotropic 178 MHz lobe power. Therefore, from our large sample investigated here we find strong evidence for the orientation-dependent unification of the powerful FR 2 galaxies with the quasars. The distribution of the dust-to-lobe luminosity ratio shows a dispersion which we suggest to be most likely due to the additional influence of evolution and environment superposed on the orientation-dependent unification. We discuss our data also in the frame of the receding torus model. At the high 178 MHz luminosities of our sources above 10$^{\rm 26.5}$W/Hz we do not find any support for this model in its original formulation and therefore we propose a refinement: The scale height of the torus might not be independent of luminosity, rather it may increase at high luminosities due to the impact of supernovae from starbursts accompanying the AGN phenomena.

The ISOPHOT Serendipity Sky Survey strip-scanning measurements covering ≈$15\%$of the far-infrared (FIR) sky at ${\rm 170\,\mu m}$were searched for compact sources associated with optically identified galaxies. Compact Serendipity Survey sources with a high signal-to-noise ratio in at least two ISOPHOT C200 detector pixels were selected that have a positional association with a galaxy identification in the NED and/or Simbad databases and a galaxy counterpart visible on the Digitized Sky Survey plates. A catalog with ${\rm 170\,\mu m}$fluxes for more than 1900 galaxies has been established, 200 of which were measured several times. The faintest ${\rm 170\,\mu m}$fluxes reach values just below 0.5 Jy, while the brightest, already somewhat extended galaxies have fluxes up to ≈600 Jy. For the vast majority of listed galaxies, the ${\rm 170\,\mu m}$fluxes were measured for the first time. While most of the galaxies are spirals, about 70 of the sources are classified as ellipticals or lenticulars. This is the only currently available large-scale galaxy catalog containing a sufficient number of sources with ${\rm 170\,\mu m}$fluxes to allow further statistical studies of various FIR properties.

We present a multi-wavelength study of the star forming region ISOSS J 20298+3559, which was identified by a cross-correlation of cold compact sources from the 170 μm ISOPHOT Serendipity Survey (ISOSS) database coinciding with objects detected by the MSX, 2MASS and IRAS infrared surveys. ISOSS J 20298+3559 is associated with a massive dark cloud complex (M~ 760 $M_{\odot}$) and located in the Cygnus X giant molecular cloud. We derive a distance of 1800 pc on the basis of optical extinction data. The low average dust temperature (T~ 16 K) and large mass (M~ 120 $M_{\odot}$) of the dense inner part of the cloud, which has not been dispersed, indicates a recent begin of star formation. The youth of the region is supported by the early evolutionary stage of several pre- and protostellar objects discovered across the region: I) two candidate Class 0 objects with masses of 8 and 3.5 $M_{\odot}$, II) a gravitationally bound, cold (T~ 12 K) and dense (n(H2) ~ 2 $\times$105cm-3) cloud core with a mass of 50 $M_{\odot}$and III) a Herbig B2 star with a mass of 6.5 $M_{\odot}$and a bolometric luminosity of 2200 $L_{\odot}$, showing evidence for ongoing accretion and a stellar age of less than 40 000 years. The dereddened SED of the Herbig star is well reproduced by an accretion disc + star model. The externally-heated cold cloud core is a good candidate for a massive pre-protostellar object. The star formation efficiency in the central cloud region is about 14%.

We present a multi-wavelength study of the unusual galaxy ISOSS J 15079+7247. With a bolometric luminosity of $L_{\rm FIR} \sim 2 \times 10^{12}~{L_{\odot}}$ this object is one of the most luminous galaxies detected by the 170 ${\rm \mu m}$ ISOPHOT Serendipity Survey (ISOSS). We have obtained 1.2 mm continuum and CO (1–0) line observations, optical spectra and deep $R$-band images of the system. The CO emission originates from a giant elliptical galaxy at redshift $z=0.2136$, yielding a molecular gas mass of $2.9 \times 10^{10}~{M_{\odot}}$. The high gas mass favors the picture that the dust emission is associated with the elliptical galaxy. The nature of the ultraluminous IR emission can be explained by an opaque, hidden starburst in the center of the elliptical. The huge dust mass of $5 \times 10^{8}~{M_{\odot}}$ corresponds to a visual extinction of $A_{\rm V} \sim 1000~{\rm mag}$. This is consistent with the non-detection of any optical signatures of a strong starburst in ISOSS J 15079+7247 and the strength of non-thermal radio continuum emission.

Mining the ISO data archive we provide the complete ISO view of PG quasars containing 64 infrared spectral energy distributions between 5 and 200 $\mu$m. About half of the sample was supplemented by MAMBO and SCUBA (sub-)millimetre data. Since the PG quasars were selected optically, the high infrared detection rate of more than 80% suggests that every quasar possesses luminous to hyperluminous dust emission with dust masses comparable to Seyferts and ultraluminous IR galaxies (ULIRGs). The gas-to-dust mass ratio (of those sources where CO measurements are available in the literature) is consistent with the galactic value providing further evidence for the thermal nature of the IR emission of radio quiet quasars. The SEDs represent templates of unprecedented detail and sensitivity. The power–law like near- to mid-IR SEDs ($F_{\nu} \propto \nu^{\rm \alpha}$) are smooth up to far-infrared wavelengths, favouring dust heating by the central AGN, and we conclude that, in particular for our hyperluminous quasars at $z=1$, starbursts play only a minor role for powering the dust emission, even in the FIR. The IR spectral slopes $\alpha$ $_{\rm 1-10~ \mu m}$ range from –0.9 to –2.2 with a mean of $\rm -1.3\,\pm\,0.3$. They neither correlate with the optical spectral slope $\alpha$ $_{\rm 0.3-1~ \mu m}$, nor with the IR luminosity, nor with the FIR/MIR luminosity ratio, nor with inclination-dependent extinction effects in the picture of a dusty torus. We suggest that the diversity of the SEDs reflects largely the evolution of the dust distribution, and we propose a classification of the SED shapes as well as an evolutionary scheme in which this variety can be understood. During the evolution the surrounding dust redistributes, settling more and more into a torus/disk like configuration, while the SEDs show an initial FIR bump, then an increasing MIR emission and a steeper near- to mid-infrared slope, both of which finally also decrease. Strikingly, based on the sensitive ISO data now we do not only see the coarse IR differences between ULIRGs and quasars, but also the details and a possible evolution of the dust distribution and emission even among the optically selected PG sample. Regarding cosmic evolution, our hyperluminous quasars in the ”local” universe at $z=1$ do not show the hyperluminous ($L_{\rm FIR}$  $\ga$ 10$^{\rm 13}$  $L_{\odot}$) starburst activity inferred for $z=4$ quasars detected in several (sub-)millimetre surveys. In view of several caveats this difference should be established further, but it already suggests that in the early dense universe stronger merger events led to more powerful starbursts accompanying the quasar phenomenon, while at later cosmic epochs any coeval starbursts obviously do not reach that high power and are outshone by the AGN.

MESS (Mass-loss of Evolved StarS) is a guaranteed time key program that uses the PACS and SPIRE instruments on board the Herschel space observatory to observe a representative sample of evolved stars, that include asymptotic giant branch (AGB) and post-AGB stars, planetary nebulae and red supergiants, as well as luminous blue variables, Wolf-Rayet stars and supernova remnants. In total, of order 150 objects are observed in imaging and about 50 objects inspectroscopy.

We summarize the first results from the Gould Belt Survey, obtained toward the Aquila rift and Polaris Flare regions during the science demonstration phase of Herschel. Our 70–500 μm images taken in parallel mode with the SPIRE and PACS cameras reveal a wealth of filamentary structure, as well as numerous dense cores embedded in the filaments. Between ~350 and 500 prestellar cores and ~45–60 Class 0 protostars can be identified in the Aquila field, while ~300 unbound starless cores and no protostars are observed in the Polaris field. The prestellar core mass function (CMF) derived for the Aquila region bears a strong resemblance to the stellar initial mass function (IMF), already confirming the close connection between the CMF and the IMF with much better statistics than earlier studies. Comparing and contrasting our Herschelresults in Aquila and Polaris, we propose an observationally-driven scenario for core formation according to which complex networks of long, thin filaments form first within molecular clouds, and then the densest filaments fragment into a number of prestellar cores via gravitational instability.

We present Herschelfar-infrared (FIR) observations of two sub-mm bright quasars at high redshift: SDSS J1148+5251 (z= 6.42) and BR 1202–0725 (z= 4.69) obtained with the PACS instrument. Both objects are detected in the PACS photometric bands. The Herschelmeasurements provide additional data points that constrain the FIR spectral energy distributions (SEDs) of both sources, and they emphasise a broad range of dust temperatures in these objects. For λrest≲ 20 μm, the two SEDs are very similar to the average SEDs of quasars at low redshift. In the FIR, however, both quasars show excess emission compared to low-zQSO templates, most likely from cold dust powered by vigorous star formation in the QSO host galaxies. For SDSS J1148+5251 we detect another object at 160 μm with a distance of ~10´´ from the QSO. Although no physical connection between the quasar and this object can be shown with the available data, it could potentially confuse low-resolution measurements, thus resulting in an overestimate of the FIR luminosity of the z= 6.42 quasar.

Aims. FIR imaging of interacting galaxies allows locating even hidden sites of star formation and measuring of the relative strength of nuclear and extra-nuclear star formation. We want to resolve the star-forming sites in the nearby system of the Antennae.Methods. Thanks to the unprecedented sharpness and depth of the PACS camera onboard ESA's HerschelSpace Observatory, it is possible for the first time to achieve a complete assessment of individual star-forming knots in the FIR with scan maps at 70, 100, and 160 μm. We used clump extraction photometry and SED diagnostics to derive the properties related to star-forming activity.Results. The PACS 70, 100, and 160 μm maps trace the knotty structure of the most recent star formation along an arc between the two nuclei in the overlap area. The resolution of the starburst knots and additional multi-wavelength data allow their individual star formation history and state to be analysed. In particular, the brightest knot in the mid-infrared (K1), east of the southern nucleus, exhibits the highest activity by far in terms of dust heating and star formation rate, efficiency, and density. With only 2 kpc in diameter, this area has a 10–1000 μm luminosity, which is as high as that of our Milky Way. It shows the highest deficiency in radio emission in the radio-to-FIR luminosity ratio and a lack of X-ray emission, classifying it as a very young complex. The brightest 100 and 160 μm emission region (K2), which is close to the collision front and consists of 3 knots, also shows a high star formation density and efficiency and lack of X-ray emission in its most obscured part, but an excess in the radio-to-FIR luminosity ratio. This suggests a young stage, too, but different conditions in its interstellar medium. Our results provide important checkpoints for numerical simulations of interacting galaxies when modelling the star formation and stellar feedback.

Context. We present the first results from the project Galactic cold cores, where the cold interstellar clouds detected by the Plancksatellite are studied with Herschelphotometric observations. The final Planckcatalogue is expected to contain several thousand sources. The Herschelobservations during the science demonstration phase provided the first glimpse into the nature of these sources.Aims. The main goal of the project is to derive the physical properties of the cold core population revealed by Planck. We examine three fields and confirm the Planckdetections with Herscheldata, which we also use to establish the evolutionary stage of the identified cores.Methods. We study the morphology and spectral energy distribution of the sources using the combined wavelength coverage of Planckand Herschel. The dust colour temperatures and emissivity indices are determined. The masses of the cores are determined with distance estimates which are taken from the literature and are confirmed by kinematic and extinction information. Results. The observations reveal extended regions of cold dust with dust colour temperatures down to Tdust~ 11 K. The fields represent different evolutionary stages ranging from a quiescent, cold filament in Musca to regions of active star formation in Cepheus. Conclusions. The Herschelobservations confirm that the all-sky survey of Planckis capable of making a large number of new cold core detections. Our results suggest that many of the sources may already have left the pre-stellar phase or are at least closely associated with active star formation. High-resolution Herschelobservations are needed to establish the true nature of the Planckdetections.

NGC 1097 is a nearby SBb galaxy with a Seyfert nucleus and a bright starburst ring. We study the physical properties of the interstellar medium (ISM) in the ring using spatially resolved far-infrared spectral maps of the circumnuclear starburst ring of NGC 1097, obtained with the PACS spectrometer on board the HerschelSpace Observatory. In particular, we map the important ISM cooling and diagnostic emission lines of [OI] 63 μm, [OIII] 88 μm, [NII] 122 μm, [CII] 158 μm and [NII] 205 μm. We observe that in the [OI] 63 μm, [OIII] 88 μm, and [NII] 122 μm line maps, the emission is enhanced in clumps along the NE part of the ring. We observe evidence of rapid rotation in the circumnuclear ring, with a rotation velocity of ~220 km s-1(inclination uncorrected) measured in all lines. The [OI] 63 μm/[CII] 158 μm ratio varies smoothly throughout the central region, and is enhanced on the northeastern part of the ring, which may indicate a stronger radiation field. This enhancement coincides with peaks in the [OI] 63 μm and [OIII] 88 μm maps. Variations of the [NII] 122 μm/[NII] 205 μm ratio correspond to a range in the ionized gas density between 150 and 400 cm-3.

Using the 3.5-m HerschelSpace Observatory, imaging photometry of Cas A has been obtained in six bands between 70 and 500 μm with the PACS and SPIRE instruments, with angular resolutions ranging from 6 to 37”. In the outer regions of the remnant the 70-μm PACS image resembles the 24-μm image Spitzerimage, with the emission attributed to the same warm dust component, located in the reverse shock region. At longer wavelengths, the three SPIRE bands are increasingly dominated by emission from cold interstellar dust knots and filaments, particularly across the central, western and southern parts of the remnant. Nonthermal emission from the northern part of the remnant becomes prominent at 500 μm. We have estimated and subtracted the contributions from the nonthermal, warm dust and cold interstellar dust components. We confirm and resolve for the first time a cool (~35 K) dust component, emitting at 70-160 μm, that is located interior to the reverse shock region, with an estimated mass of 0.075 $M_\odot$.

We present Herschelobservations of the isolated, low-mass star-forming Bok globule CB244. It contains two cold sources, a low-mass Class 0 protostar and a starless core, which is likely to be prestellar in nature, separated by 90" (~18 000 AU). The Herscheldata sample the peak of the Planckspectrum for these sources, and are therefore ideal for dust-temperature and column density modeling. With these data and a near-IR extinction map, the MIPS 70 μm mosaic, the SCUBA 850 μm map, and the IRAM 1.3 mm map, we model the dust-temperature and column density of CB 244 and present the first measured dust-temperature map of an entire star-forming molecular cloud. We find that the column-averaged dust-temperature near the protostar is ~17.7 K, while for the starless core it is ~10.6 K, and that the effect of external heating causes the cloud dust-temperature to rise to ~17 K where the hydrogen column density drops below 1021cm-2. The total hydrogen mass of CB 244 (assuming a distance of 200 pc) is 15 ± 5 $M_{\odot}$. The mass of the protostellar core is 1.6 ± 0.1 $M_{\odot}$and the mass of the starless core is 5 ± 2 $M_{\odot}$, indicating that ~45% of the mass in the globule is participating in the star-formation process.