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Journal ArticleDOI

The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory

01 Jul 2010-Astronomy and Astrophysics (EDP Sciences)-Vol. 518, Iss: 4, pp 1-12
TL;DR: The Photodetector Array Camera and Spectrometer (PACS) as discussed by the authors is one of the three science instruments on ESA's far infrared and sub-mil- limetre observatory.
Abstract: The Photodetector Array Camera and Spectrometer (PACS) is one of the three science instruments on ESA's far infrared and submil- limetre 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 photom- etry in the 60−210 μm wavelength regime. In photometry mode, it simultaneously images two bands, 60−85 μ mo r 85−125 μ ma nd 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 afi eld 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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Citations
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Journal ArticleDOI
TL;DR: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and sub-millimetre spectral range 55 671 m.
Abstract: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and submillimetre spectral range 55 671 m. Herschel carries a 3.5 metre diameter passively cooled Cassegrain telescope, which is the largest of its kind and utilises a novel silicon carbide technology. The science payload comprises three instruments: two direct detection cameras/medium resolution spectrometers, PACS and SPIRE, and a very high-resolution heterodyne spectrometer, HIFI, whose focal plane units are housed inside a superfluid helium cryostat. Herschel is an observatory facility operated in partnership among ESA, the instrument consortia, and NASA. The mission lifetime is determined by the cryostat hold time. Nominally approximately 20,000 hours will be available for astronomy, 32% is guaranteed time and the remainder is open to the worldwide general astronomical community through a standard competitive proposal procedure.

3,359 citations


Cites background from "The Photodetector Array Camera and ..."

  • ...The Photodetector Array Camera and Spectrometer (PACS, Poglitsch et al. 2010), PI: A. Poglitsch, Max-Planck-Institut für extraterrestrische Physik (MPE), Garching....

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Journal ArticleDOI
TL;DR: In this paper, the authors review progress over the past decade in observations of large-scale star formation, with a focus on the interface between extragalactic and Galactic studies.
Abstract: We review progress over the past decade in observations of large-scale star formation, with a focus on the interface between extragalactic and Galactic studies. Methods of measuring gas contents and star-formation rates are discussed, and updated prescriptions for calculating star-formation rates are provided. We review relations between star formation and gas on scales ranging from entire galaxies to individual molecular clouds.

2,525 citations


Cites background from "The Photodetector Array Camera and ..."

  • ...Herschel surveys will be providing higher resolution [25′′ at 350 µm (Griffin et al. 2010) and 6′′ at 70 µm (Poglitsch et al. 2010)] images of the nearby clouds (André et al. 2010), the Galactic Plane (Molinari et al. 2010), and many other galaxies (e.g., Skibba et al. 2011; Wuyts et al. 2011)....

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Journal ArticleDOI
Matthew Joseph Griffin, Alain Abergel1, A. Abreu, Peter A. R. Ade2  +186 moreInstitutions (27)
TL;DR: The Spectral and Photometric Imaging REceiver (SPIRE) is the Herschel Space Observatory's sub-millimetre camera and spectrometer as discussed by the authors, which is used for image and spectroscopic data acquisition.
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 mu m, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 mu m (447-1550 GHz) The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 03 K The photometer has a field of view of 4' x 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 26' The spectral resolution can be adjusted between 12 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 15-2

2,425 citations


Cites methods from "The Photodetector Array Camera and ..."

  • ...The relative merits of feedhorn-coupled detectors, as used by SPIRE, and filled array detectors, which are used byHerschel-PACS (Poglitsch et al. 2010) and some ground-based instruments such as SCUBA-2 (Audley et al. 2007) and SHARC-II (Dowell et al. 2003), are discussed in detail in Griffin et al.…...

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  • ...The same3He cooler design (Duband et al. 2008) is used in SPIRE and in the PACS instrument (Poglitsch et al. 2010)....

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Journal ArticleDOI
TL;DR: In this paper, the first results from the Gould Belt survey, obtained toward the Aquila Rift and Polaris Flare regions during the'science demonstration phase' of Herschel, were summarized.
Abstract: 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 micron 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 ~ 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 Herschel results 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.

1,542 citations


Cites background from "The Photodetector Array Camera and ..."

  • ...…first highlights from the Gould Belt Survey, one of the largest key projects with Herschel (cf. André & Saraceno 2005), based on extensive farinfrared and submillimeter mapping of nearby molecular clouds with both the SPIRE (Griffin et al. 2010) and PACS (Poglitsch et al. 2010) bolometer cameras....

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Journal ArticleDOI
TL;DR: In this article, the authors investigate the evolution of the star-forming galaxy (SFG) main sequence (MS) in stellar mass and star formation rate (SFR) out to z ~ 6.4 Gyr.
Abstract: Using a compilation of 25 studies from the literature, we investigate the evolution of the star-forming galaxy (SFG) main sequence (MS) in stellar mass and star formation rate (SFR) out to z ~ 6. After converting all observations to a common set of calibrations, we find a remarkable consensus among MS observations (~0.1 dex 1σ interpublication scatter). By fitting for time evolution of the MS in bins of constant mass, we deconvolve the observed scatter about the MS within each observed redshift bin. After accounting for observed scatter between different SFR indicators, we find the width of the MS distribution is ~0.2 dex and remains constant over cosmic time. Our best fits indicate the slope of the MS is likely time-dependent, with our best-fit log SFR(M_*, t) = (0.84 ± 0.02 – 0.026 ± 0.003 × t)log M_* – (6.51 ± 0.24 – 0.11 ± 0.03 × t), where t is the age of the universe in Gyr. We use our fits to create empirical evolutionary tracks in order to constrain MS galaxy star formation histories (SFHs), finding that (1) the most accurate representations of MS SFHs are given by delayed-τ models, (2) the decline in fractional stellar mass growth for a "typical" MS galaxy today is approximately linear for most of its lifetime, and (3) scatter about the MS can be generated by galaxies evolving along identical evolutionary tracks assuming an initial 1σ spread in formation times of ~1.4 Gyr.

1,336 citations


Cites methods from "The Photodetector Array Camera and ..."

  • ...The UV sample consists of sBzK galaxies taken from D07 (GOODS-S) and McCracken et al. (2010) (COSMOS), while the flux-limited IR sample was observed with Herschel ’s Photodetector Array Camera & Spectrometer (PACS; Poglitsch et al. 2010)....

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References
More filters
Journal ArticleDOI
TL;DR: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and sub-millimetre spectral range 55 671 m.
Abstract: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and submillimetre spectral range 55 671 m. Herschel carries a 3.5 metre diameter passively cooled Cassegrain telescope, which is the largest of its kind and utilises a novel silicon carbide technology. The science payload comprises three instruments: two direct detection cameras/medium resolution spectrometers, PACS and SPIRE, and a very high-resolution heterodyne spectrometer, HIFI, whose focal plane units are housed inside a superfluid helium cryostat. Herschel is an observatory facility operated in partnership among ESA, the instrument consortia, and NASA. The mission lifetime is determined by the cryostat hold time. Nominally approximately 20,000 hours will be available for astronomy, 32% is guaranteed time and the remainder is open to the worldwide general astronomical community through a standard competitive proposal procedure.

3,359 citations

Journal ArticleDOI
TL;DR: In this article, a variable-pixel linear reconstruction (VPLR) method was proposed for linear reconstruction of an image from under-sampled, dithered data, which preserves photometry and resolution, weight input images according to the statistical significance of each pixel, and removes the effects of geometric distortion both on image shape and photometry.
Abstract: We have developed a method for the linear reconstruction of an image from undersampled, dithered data. The algorithm, known as Variable-Pixel Linear Reconstruction, or informally as “Drizzle”, preserves photometry and resolution, can weight input images according to the statistical significance of each pixel, and removes the effects of geometric distortion both on image shape and photometry. This paper presents the method and its implementation. The photometric and astrometric accuracy and image fidelity of the algorithm as well as the noise characteristics of output images are discussed. In addition, we describe the use of drizzling to combine dithered images in the presence of cosmic rays.

875 citations

Posted Content
10 Aug 1998
TL;DR: The photometric and astrometric accuracy and image fidelity of the algorithm as well as the noise characteristics of output images are discussed and the use of drizzling to combine dithered images in the presence of cosmic rays is described.

585 citations

01 Feb 2003

196 citations


"The Photodetector Array Camera and ..." refers methods in this paper

  • ...Details of the design of both arrays are given in Kraft et al. 2000, Kraft et al. 2001, Poglitsch et al. 2003....

    [...]

Journal ArticleDOI
TL;DR: The Photodetector Array Camera and Spectrometer (PACS) as discussed by the authors is one of the three science instruments on ESA's far infrared and submillimetre observatory.
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 16x25 pixels, each, and two filled silicon bolometer arrays with 16x32 and 32x64 pixels, respectively, to perform integral-field spectroscopy and imaging photometry in the 60-210\mu\ m wavelength regime. In photometry mode, it simultaneously images two bands, 60-85\mu\ m or 85-125\mu\m and 125-210\mu\ m, over a field of view of ~1.75'x3.5', with close to Nyquist beam sampling in each band. In spectroscopy mode, it images a field of 47"x47", resolved into 5x5 pixels, with an instantaneous spectral coverage of ~1500km/s and a spectral resolution of ~175km/s. 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.

127 citations

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