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This work presents high spectral resolution observations of the CII line at 158 micron, one of the major cooling lines of the interstellar medium, taken with the HIFI heterodyne spectrometer on the Herschel satellite. In BCLMP 691, an HII region far north (3.3 kpc) in the disk of M 33, the CII and CO line profiles show similar velocities within $0.5 kms$, while the HI line velocities are systematically shifted towards lower rotation velocities by $sim 5kms$. Observed at the same $12$ angular resolution, the CII lines are broader than those of CO by about 50% but narrower than the HI lines. The CII line to far-infrared continuum ratio suggests a photoelectric heating efficiency of 1.1%. The data, together with published models indicate a UV field $G_0 sim 100$ in units of the solar neighborhood value, a gas density $n_H sim 1000 cc$, and a gas temperature $Tsim 200$ K. Adopting these values, we estimate the C$^+$ column density to be $N_{C^+} approx 1.3 times 10^{17} cmt$. The CII emission comes predominantly from the warm neutral region between the HII region and the cool molecular cloud behind it. From published abundances, the inferred C$^+$ column corresponds to a hydrogen column density of $N_H sim 2 times 10^{21} cmt$. The CO observations suggest that $N_H = 2 N_{H_2} sim 3.2 times 10^{21} cmt$ and 21cm measurements, also at $12$ resolution, yield $N_HI approx 1.2 times 10^{21} cmt$ within the CII velocity range. Thus, some H$_2$ not detected in CO must be present, in agreement with earlier findings based on the SPIRE 250 -- 500 $mu$m emission.
Within the framework of the HERM33ES Key Project, using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M33 to investigate the nature of the compact SPIRE emission s
Over the past few years several studies have provided estimates of the SFR (star-formation rate) or the total infrared luminosity from just one infrared band. However these relations are generally derived for entire galaxies, which are known to conta
We aim to understand the contribution of the ionized, atomic and molecular phases of the ISM to the [CII] emission from clouds near the dynamical center and the BCLMP302 HII region in the north of the nearby galaxy M33 at a spatial resolution of 50pc
We present the first 7.5x11.5 velocity-resolved map of the [CII]158um line toward the Orion molecular cloud-1 (OMC-1) taken with the Herschel/HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved maps of the
We study the far-infrared emission from the nearby spiral galaxy M33 in order to investigate the dust physical properties such as the temperature and the luminosity density across the galaxy. Taking advantage of the unique wavelength coverage (100, 1