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Author Griffin, M. J.; Abergel, A.; Abreu, A.; Ade, P. A. R.; André, P.; Augueres, J.-L.; Babbedge, T.; Bae, Y.; Baillie, T.; Baluteau, J.-P.; Barlow, M. J.; Bendo, G.; Benielli, D.; Bock, J. J.; Bonhomme, P.; Brisbin, D.; Brockley-Blatt, C.; Caldwell, M.; Cara, C.; Castro-Rodriguez, N.; Cerulli, R.; Chanial, P.; Chen, S.; Clark, E.; Clements, D. L.; Clerc, L.; Coker, J.; Communal, D.; Conversi, L.; Cox, P.; Crumb, D.; Cunningham, C.; Daly, F.; Davis, G. R.; de Antoni, P.; Delderfield, J.; Devin, N.; di Giorgio, A.; Didschuns, I.; Dohlen, K.; Donati, M.; Dowell, A.; Dowell, C. D.; Duband, L.; Dumaye, L.; Emery, R. J.; Ferlet, M.; Ferrand, D.; Fontignie, J.; Fox, M.; Franceschini, A.; Frerking, M.; Fulton, T.; Garcia, J.; Gastaud, R.; Gear, W. K.; Glenn, J.; Goizel, A.; Griffin, D. K.; Grundy, T.; Guest, S.; Guillemet, L.; Hargrave, P. C.; Harwit, M.; Hastings, P.; Hatziminaoglou, E.; Herman, M.; Hinde, B.; Hristov, V.; Huang, M.; Imhof, P.; Isaak, K. J.; Israelsson, U.; Ivison, R. J.; Jennings, D.; Kiernan, B.; King, K. J.; Lange, A. E.; Latter, W.; Laurent, G.; Laurent, P.; Leeks, S. J.; Lellouch, E.; Levenson, L.; Li, B.; Li, J.; Lilienthal, J.; Lim, T.; Liu, S. J.; Lu, N.; Madden, S.; Mainetti, G.; Marliani, P.; McKay, D.; Mercier, K.; Molinari, S.; Morris, H.; Moseley, H.; Mulder, J.; Mur, M.; Naylor, D. A.; Nguyen, H.; O'Halloran, B.; Oliver, S.; Olofsson, G.; Olofsson, H.-G.; Orfei, R.; Page, M. J.; Pain, I.; Panuzzo, P.; Papageorgiou, A.; Parks, G.; Parr-Burman, P.; Pearce, A.; Pearson, C.; Pérez-Fournon, I.; Pinsard, F.; Pisano, G.; Podosek, J.; Pohlen, M.; Polehampton, E. T.; Pouliquen, D.; Rigopoulou, D.; Rizzo, D.; Roseboom, I. G.; Roussel, H.; Rowan-Robinson, M.; Rownd, B.; Saraceno, P.; Sauvage, M.; Savage, R.; Savini, G.; Sawyer, E.; Scharmberg, C.; Schmitt, D.; Schneider, N.; Schulz, B.; Schwartz, A.; Shafer, R.; Shupe, D. L.; Sibthorpe, B.; Sidher, S.; Smith, A.; Smith, A. J.; Smith, D.; Spencer, L.; Stobie, B.; Sudiwala, R.; Sukhatme, K.; Surace, C.; Stevens, J. A.; Swinyard, B. M.; Trichas, M.; Tourette, T.; Triou, H.; Tseng, S.; Tucker, C.; Turner, A.; Vaccari, M.; Valtchanov, I.; Vigroux, L.; Virique, E.; Voellmer, G.; Walker, H.; Ward, R.; Waskett, T.; Weilert, M.; Wesson, R.; White, G. J.; Whitehouse, N.; Wilson, C. D.; Winter, B.; Woodcraft, A. L.; Wright, G. S.; Xu, C. K.; Zavagno, A.; Zemcov, M.; Zhang, L.; Zonca, E. openurl 
  Title The Herschel-SPIRE instrument and its in-flight performance Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal A&A  
  Volume 518 Issue Pages 7  
  Keywords (down) SPIRE  
  Abstract The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory`s submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 μm (447-1550 GHz). The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 0.3 K. The photometer has a field of view of 4Â´× 8´, observed simultaneously in the three spectral bands. Its main operating mode is scan-mapping, whereby the field of view is scanned across the sky to achieve full spatial sampling and to cover large areas if desired. The spectrometer has an approximately circular field of view with a diameter of 2.6´. The spectral resolution can be adjusted between 1.2 and 25 GHz by changing the stroke length of the FTS scan mirror. Its main operating mode involves a fixed telescope pointing with multiple scans of the FTS mirror to acquire spectral data. For extended source measurements, multiple position offsets are implemented by means of an internal beam steering mirror to achieve the desired spatial sampling and by rastering of the telescope pointing to map areas larger than the field of view. The SPIRE instrument consists of a cold focal plane unit located inside the Herschel cryostat and warm electronics units, located on the spacecraft Service Module, for instrument control and data handling. Science data are transmitted to Earth with no on-board data compression, and processed by automatic pipelines to produce calibrated science products. The in-flight performance of the instrument matches or exceeds predictions based on pre-launch testing and modelling: the photometer sensitivity is comparable to or slightly better than estimated pre-launch, and the spectrometer sensitivity is also better by a factor of 1.5-2.  
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  Call Number RPLAB @ gujma @ Serial 695  
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Author Poglitsch, A.; Waelkens, C.; Geis, N.; Feuchtgruber, H.; Vandenbussche, B.; Rodriguez, L.; Krause, O.; Renotte, E.; van Hoof, C.; Saraceno, P.; Cepa, J.; Kerschbaum, F.; Agnèse, P.; Ali, B.; Altieri, B.; Andreani, P.; Augueres, J.-L.; Balog, Z.; Barl, L.; Bauer, O. H.; Belbachir, N.; Benedettini, M.; Billot, N.; Boulade, O.; Bischof, H.; Blommaert, J.; Callut, E.; Cara, C.; Cerulli, R.; Cesarsky, D.; Contursi, A.; Creten, Y.; De Meester, W.; Doublier, V.; Doumayrou, E.; Duband, L.; Exter, K.; Genzel, R.; Gillis, J.-M.; Grözinger, U.; Henning, T.; Herreros, J.; Huygen, R.; Inguscio, M.; Jakob, G.; Jamar, C.; Jean, C.; de Jong, J.; Katterloher, R.; Kiss, C.; Klaas, U.; Lemke, D.; Lutz, D.; Madden, S.; Marquet, B.; Martignac, J.; Mazy, A.; Merken, P.; Montfort, F.; Morbidelli, L.; Müller, T.; Nielbock, M.; Okumura, K.; Orfei, R.; Ottensamer, R.; Pezzuto, S.; Popesso, P.; Putzeys, J.; Regibo, S.; Reveret, V.; Royer, P.; Sauvage, M.; Schreiber, J.; Stegmaier, J.; Schmitt, D.; Schubert, J.; Sturm, E.; Thiel, M.; Tofani, G.; Vavrek, R.; Wetzstein, M.; Wieprecht, E.; Wiezorrek, E. openurl 
  Title The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal A&A  
  Volume 518 Issue Pages 12  
  Keywords (down) PACS  
  Abstract The Photodetector Array Camera and Spectrometer (PACS) is one of the three science instruments on ESA's far infrared and submillimetre observatory. It employs two Ge:Ga photoconductor arrays (stressed and unstressed) with 16×25 pixels, each, and two filled silicon bolometer arrays with 16×32 and 32×64 pixels, respectively, to perform integral-field spectroscopy and imaging photometry in the 60-210 μm wavelength regime. In photometry mode, it simultaneously images two bands, 60-85 μm or 85-125 μm and 125-210 μm, over a field of view of ~1.75'× 3.5', with close to Nyquist beam sampling in each band. In spectroscopy mode, it images a field of 47” × 47”, resolved into 5×5 pixels, with an instantaneous spectral coverage of ~1500 km s-1 and a spectral resolution of ~175 km s-1. We summarise the design of the instrument, describe observing modes, calibration, and data analysis methods, and present our current assessment of the in-orbit performance of the instrument based on the performance verification tests. PACS is fully operational, and the achieved performance is close to or better than the pre-launch predictions.  
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  Call Number RPLAB @ gujma @ Serial 694  
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Author Soifer, B. T.; Pipher, J. L. url  doi
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  Title Instrumentation for infrared astronomy Type Journal Article
  Year 1978 Publication Annual Rev. Astron. Astrophys. Abbreviated Journal  
  Volume 16 Issue 1 Pages 335-369  
  Keywords (down) infrared applications  
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  ISSN 0066-4146 ISBN Medium  
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  Notes Approved no  
  Call Number Serial 492  
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Author Pütz, P.; Honingh, C. E.; Jacobs, K.; Justen, M.; Schultz, M.; Stutzki, J. openurl 
  Title Terahertz hot electron bolometer waveguide mixers for GREAT Type Journal Article
  Year 2012 Publication Astron. Astrophys. Abbreviated Journal A&A  
  Volume 542 Issue Pages L2  
  Keywords (down) HEB mixer, applications  
  Abstract Context. Supplementing the publications based on the first-light observations with the German REceiver for Astronomy at Terahertz frequencies (GREAT) on SOFIA, we present background information on the underlying heterodyne detector technology. This Letter complements the GREAT instrument Letter and focuses on the mixers itself.

Aims. We describe the superconducting hot electron bolometer (HEB) detectors that are used as frequency mixers in the L1 (1400 GHz), L2 (1900 GHz), and M (2500 GHz) channels of GREAT. Measured performance of the detectors is presented and background information on their operation in GREAT is given.

Methods. Our mixer units are waveguide-based and couple to free-space radiation via a feedhorn antenna. The HEB mixers are designed, fabricated, characterized, and flight-qualified in-house. We are able to use the full intermediate frequency bandwidth of the mixers using silicon-germanium multi-octave cryogenic low-noise amplifiers with very low input return loss.

Results. Superconducting HEB mixers have proven to be practical and sensitive detectors for high-resolution THz frequency spectroscopy on SOFIA. We show that our niobium-titanium-nitride (NbTiN) material HEBs on silicon nitride (SiN) membrane substrates have an intermediate frequency (IF) noise roll-off frequency above 2.8 GHz, which does not limit the current receiver IF bandwidth. Our mixer technology development efforts culminate in the first successful operation of a waveguide-based HEB mixer at 2.5 THz and deployment for radioastronomy. A significant contribution to the success of GREAT is made by technological development, thorough characterization and performance optimization of the mixer and its IF interface for receiver operation on SOFIA. In particular, the development of an optimized mixer IF interface contributes to the low passband ripple and excellent stability, which GREAT demonstrated during its initial successful astronomical observation runs.		  
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  Call Number Serial 907  
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Author Chavarr'ıa, L.; Herpin, F.; Jacq, T.; Braine, J.; Bontemps, S.; Baudry, A.; Marseille, M.; van der Tak, F.; Pietropaoli, B.; Wyrowski, F.; Shipman, R.; Frieswijk, W.; van Dishoeck, E. F.; Cernicharo, J.; Bachiller, R.; Benedettini, M.; Benz, A. O.; Bergin, E.; Bjerkeli, P.; Blake, G. A.; Bruderer, S.; Caselli, P.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J. R.; de Graauw, T.; Hartogh, P.; Helmich, F.; Herczeg, G. J.; Hogerheijde, M. R.; Johnstone, D.; Jørgensen, J. K.; Kristensen, L. E.; Larsson, B.; Lis, D.; Liseau, R.; McCoey, C.; Melnick, G.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-Garc'ıa, J.; Saraceno, P.; Stutzki, J.; Szczerba, R.; Tafalla, M.; Tielens, A.; van Kempen, T. A.; Visser, R.; Wampfler, S. F.; Willem, J.; Yıldız, U. A. doi  openurl
  Title Water in massive star-forming regions: HIFI observations of W3 IRS5 Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L37 (1 to 5)  
  Keywords (down) HEB mixer applications, HIFI, Herschel, stars: formation, stars: massive, ISM: molecules, ISM: abundances, dust, extinction, radio lines: ISM  
  Abstract We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H217O 110-101, p-H218O 111-000, p-H2O 202-111, p-H2O 111-000, o-H2O 221-212, and o-H2O 212-101 lines, covering a frequency range from 552 up to 1669 GHz, have been detected at high spectral resolution with HIFI. The water lines in W3 IRS5 show well-defined high-velocity wings that indicate a clear contribution by outflows. Moreover, the systematically blue-shifted absorption in the H2O lines suggests expansion, presumably driven by the outflow. No infall signatures are detected. The p-H2O 111-000 and o-H2O 212-101 lines show absorption from the cold material (T ~ 10 K) in which the high-mass protostellar envelope is embedded. One-dimensional radiative transfer models are used to estimate water abundances and to further study the kinematics of the region. We show that the emission in the rare isotopologues comes directly from the inner parts of the envelope (T â‰<b3> 100 K) where water ices in the dust mantles evaporate and the gas-phase abundance increases. The resulting jump in the water abundance (with a constant inner abundance of 10-4) is needed to reproduce the o-H217O 110-101 and p-H218O 111-000 spectra in our models. We estimate water abundances of 10-8 to 10-9 in the outer parts of the envelope (T â‰<b2> 100 K). The possibility of two protostellar objects contributing to the emission is discussed.  
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  Notes Approved no  
  Call Number Chav13HEBapplHIFIb Serial 1086  
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Author Justtanont, K.; Decin, L.; Schöier, F. L.; Maercker, M.; Olofsson, H.; Bujarrabal, V.; Marston, A. P.; Teyssier, D.; Alcolea, J.; Cernicharo, J.; Dominik, C.; de Koter, A.; Melnick, G.; Menten, K.; Neufeld, D.; Planesas, P.; Schmidt, M.; Szczerba, R.; Waters, R.; de Graauw, Th.; Whyborn, N.; Finn, T.; Helmich, F.; Siebertz, O.; Schmülling, F.; Ossenkopf, V.; Lai, R. doi  openurl
  Title A HIFI preview of warm molecular gas around χ Cygni: first detection of H2O emission toward an S-type AGB star Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L6  
  Keywords (down) HEB mixer applications, HIFI, Herschel, stars: AGB and post-AGB / circumstellar matter / stars: kinematics and dynamics / stars: individual: χ Cyg / stars: late-type / stars: mass-loss  
  Abstract Aims. A set of new, sensitive, and spectrally resolved, sub-millimeter line observations are used to probe the warm circumstellar gas around the S-type AGB star χ Cyg. The observed lines involve high rotational quantum numbers, which, combined with previously obtained lower-frequency data, make it possible to study in detail the chemical and physical properties of, essentially, the entire circumstellar envelope of χ Cyg.

Methods. The data were obtained using the HIFI instrument aboard Herschel, whose high spectral resolution provides valuable information about the line profiles. Detailed, non-LTE, radiative transfer modelling, including dust radiative transfer coupled with a dynamical model, has been performed to derive the temperature, density, and velocity structure of the circumstellar envelope.

Results. We report the first detection of circumstellar H2O rotational emission lines in an S-star. Using the high-J CO lines to derive the parameters for the circumstellar envelope, we modelled both the ortho- and para-H2O lines. Our modelling results are consistent with the velocity structure expected for a dust-driven wind. The derived total H2O abundance (relative to H2) is (1.1±0.2) × 10-5, much lower than that in O-rich stars. The derived ortho-to-para ratio of 2.1±0.6 is close to the high-temperature equilibrium limit, consistent with H2O being formed in the photosphere.		  
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  Call Number Serial 1096  
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Author Hartogh, P.; Jarchow, C.; Lellouch, E.; de Val-Borro, M.; Rengel, M.; Moreno, R.; Medvedev, A. S.; Sagawa, H.; Swinyard, B. M.; Cavalié, T.; Lis, D. C.; BłÄ™cka, M. I.; Banaszkiewicz, M.; Bockelée-Morvan, D.; Crovisier, J.; Encrenaz, T.; Küppers, M.; Lara, L.-M.; Szutowicz, S.; Vandenbussche, B.; Bensch, F.; Bergin, E. A.; Billebaud, F.; Biver, N.; Blake, G. A.; Blommaert, J. A. D. L.; Cernicharo, J.; Decin, L.; Encrenaz, P.; Feuchtgruber, H.; Fulton, T.; de Graauw, T.; Jehin, E.; Kidger, M.; Lorente, R.; Naylor, D. A.; Portyankina, G.; Sánchez-Portal, M.; Schieder, R.; Sidher, S.; Thomas, N.; Verdugo, E.; Waelkens, C.; Whyborn, N.; Teyssier, D.; Helmich, F.; Roelfsema, P.; Stutzki, J.; LeDuc, H. G.; Stern, J. A. doi  openurl
  Title Herschel/HIFI observations of Mars: First detection of O2 at submillimetre wavelengths and upper limits on HCl and H2O2 Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L49  
  Keywords (down) HEB mixer applications, HIFI, Herschel, planets and satellites: atmospheres / radiative transfer / submillimeter: general / molecular processes  
  Abstract We report on an initial analysis of Herschel/HIFI observations of hydrogen chloride (HCl), hydrogen peroxide (H2O2), and molecular oxygen (O2) in the Martian atmosphere performed on 13 and 16 April 2010 (Ls ~ 77°). We derived a constant volume mixing ratio of 1400 ± 120 ppm for O2 and determined upper limits of 200 ppt for HCl and 2 ppb for H2O2. Radiative transfer model calculations indicate that the vertical profile of O2 may not be constant. Photochemical models determine the lowest values of H2O2 to be around Ls ~ 75° but overestimate the volume mixing ratio compared to our measurements.  
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  Notes Approved no  
  Call Number Serial 1093  
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Author Pineda, J. L.; Velusamy, T.; Langer, W. D.; Goldsmith, P. F.; Li, D.; Yorke, H. W. doi  openurl
  Title A sample of [C II] clouds tracing dense clouds in weak FUV fields observed by Herschel Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L19  
  Keywords (down) HEB mixer applications, HIFI, Herschel, ISM: structure / photon-dominated region / ISM: supernova remnants / evolution  
  Abstract The [C ii] fine-structure line at 158 μm is an excellent tracer of the warm diffuse gas in the ISM and the interfaces between molecular clouds and their surrounding atomic and ionized envelopes. Here we present the initial results from Galactic observations of terahertz C+ (GOT C+), a Herschel key project devoted to studying the [C ii] emission in the Galactic plane using the HIFI instrument. We used the [C ii] emission, together with observations of CO, as a probe to understand the effects of newly formed stars on their interstellar environment and characterize the physical and chemical state of the star-forming gas. We collected data along 16 lines-of-sight passing near star-forming regions in the inner Galaxy near longitudes 330° and 20°. We identified fifty-eight [C ii] components that are associated with high-column density molecular clouds as traced by 13CO emission. We combined [C ii], 12CO, and 13CO observations to derive the physical conditions of the [C ii]-emitting regions in our sample of high-column density clouds based on comparing results from a grid of photon dominated region (PDR) models. From this unbiased sample, our results suggest that most of the [C ii] emission originates in clouds with H2 volume densities between 103.5 and 105.5 cm-3 and weak FUV strength (χ0 = 1–10). We find two regions where our analysis suggest high densities >105 cm-3 and strong FUV fields (χ0 = 104–106), likely associated with massive star formation. We suggest that [C ii] emission in conjunction with CO isotopes is a good tool for differentiating regions of massive star formation (high densities/strong FUV fields) and regions that are distant from massive stars (lower densities/weaker FUV fields) along the line-of-sight.  
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  Call Number Serial 1101  
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Author Velusamy, T.; Langer, W. D.; Pineda, J. L.; Goldsmith, P. F.; Li, D.; Yorke, H. W. doi  openurl
  Title [CII] observations of H2 molecular layers in transition clouds Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L18  
  Keywords (down) HEB mixer applications, HIFI, Herschel, ISM: structure / ISM: molecules / ISM: atoms / submillimeter: ISM  
  Abstract We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 μm (1.9 THz) towards Galactic longitudes near 340° (5 LOSs) & 20° (11 LOSs) as part of the HIFI tests and GOT C+ survey. Out of the total 146 [CII] velocity components detected by profile fitting we identify 53 as diffuse molecular clouds with associated 12CO emission but without 13CO emission and characterized by AV < 5 mag. We estimate the fraction of the [CII] emission in the diffuse HI layer in each cloud and then determine the [CII] emitted from the molecular layers in the cloud. We show that the excess [CII] intensities detected in a few clouds is indicative of a thick H2 layer around the CO core. The wide range of clouds in our sample with thin to thick H2 layers suggests that these are at various evolutionary states characterized by the formation of H2 and CO layers from HI and C+, respectively. In about 30% of the clouds the H2 column densities (“dark gas”) traced by the [CII] is 50% or more than that traced by 12CO emission. On the average ~25% of the total H2 in these clouds is in an H2 layer which is not traced by CO. We use the HI, [CII], and 12CO intensities in each cloud along with simple chemical models to obtain constraints on the FUV fields and cosmic ray ionization rates.  
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  Call Number Serial 1102  
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Author Joblin, C.; Pilleri, P.; Montillaud, J.; Fuente, A.; Gerin, M.; Berné, O.; Ossenkopf, V.; Le Bourlot, J.; Teyssier, D.; Goicoechea, J. R.; Le Petit, F.; Röllig, M.; Akyilmaz, M.; Benz, A. O.; Boulanger, F.; Bruderer, S.; Dedes, C.; France, K.; Güsten, R.; Harris, A.; Klein, T.; Kramer, C.; Lord, S. D.; Martin, P. G.; Martin-Pintado, J.; Mookerjea, B.; Okada, Y.; Phillips, T. G.; Rizzo, J. R.; Simon, R.; Stutzki, J.; van der Tak, F.; Yorke, H. W.; Steinmetz, E.; Jarchow, C.; Hartogh, P.; Honingh, C. E.; Siebertz, O.; Caux, E.; Colin, B. doi  openurl
  Title Gas morphology and energetics at the surface of PDRs: New insights with Herschel observations of NGC 7023 Type Journal Article
  Year 2010 Publication Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L25  
  Keywords (down) HEB mixer applications, HIFI, Herschel, ISM: structure / ISM: kinematics and dynamics / ISM: molecules / submillimeter: ISM  
  Abstract Context. We investigate the physics and chemistry of the gas and dust in dense photon-dominated regions (PDRs), along with their dependence on the illuminating UV field.

Aims. Using Herschel/HIFI observations, we study the gas energetics in NGC 7023 in relation to the morphology of this nebula. NGC 7023 is the prototype of a PDR illuminated by a B2V star and is one of the key targets of Herschel.

Methods. Our approach consists in determining the energetics of the region by combining the information carried by the mid-IR spectrum (extinction by classical grains, emission from very small dust particles) with that of the main gas coolant lines. In this letter, we discuss more specifically the intensity and line profile of the 158 μm (1901 GHz) [C ii] line measured by HIFI and provide information on the emitting gas.

Results. We show that both the [C ii] emission and the mid-IR emission from polycyclic aromatic hydrocarbons (PAHs) arise from the regions located in the transition zone between atomic and molecular gas. Using the Meudon PDR code and a simple transfer model, we find good agreement between the calculated and observed [C ii] intensities.

Conclusions. HIFI observations of NGC 7023 provide the opportunity to constrain the energetics at the surface of PDRs. Future work will include analysis of the main coolant line [O i] and use of a new PDR model that includes PAH-related species.		  
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  Notes Approved no  
  Call Number Serial 1095  
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