The pointing system of the Herschel space observatory

Sánchez‐Portal, M.; Marston, A. P.; Altiéri, B.; Aussel, H.; Feuchtgruber, H.; Klaas, U.; Linz, H.; Lutz, D.; Merın, Bruno; Müller, Thomas; Nielbock, M.; Oort, M.J.A.; Pilbratt, G. L.; Schmidt, M.; Stephenson, Craig; Tuttlebee, M.

doi:10.1007/s10686-014-9396-z

Cited by 39 publications

(28 citation statements)

References 10 publications

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“…Total drifts over the 12.75 hr observing intervals were~ 2 and~ 1 for the observations starting 2011 August 31 and 2011 September 01, respectively. This is consistent with pointing uncertainties given by Sánchez-Portal et al (2014).…”

Section: Observations and Reductionsupporting

confidence: 92%

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL

Stone

Marrone

Dowell

et al. 2016

ApJ

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Variable emission from SgrA * , the luminous counterpart to the super-massive black hole at the center of our Galaxy, arises from the innermost portions of the accretion flow. Better characterization of the variability is important for constraining models of the low-luminosity accretion mode powering SgrA * , and could further our ability to use variable emission as a probe of the strong gravitational potential in the vicinity of the´ M 4 10 6 black hole. We use the Herschel Spectral and Photometric Imaging Receiver (SPIRE) to monitor SgrA * at wavelengths that are difficult or impossible to observe from the ground. We find highly significant variations at 0.25, 0.35, and 0.5 mm, with temporal structure that is highly correlated across these wavelengths. While the variations correspond to <1% changes in the total intensity in the Herschel beam containing SgrA * , comparison to independent, simultaneous observations at 0.85 mm strongly supports the reality of the variations. The lowest point in the light curves, ∼0.5 Jy below the time-averaged flux density, places a lower bound on the emission of SgrA * at 0.25 mm, the first such constraint on the THz portion of the spectral energy distribution. The variability on few hour timescales in the SPIRE light curves is similar to that seen in historical 1.3 mm data, where the longest time series is available, but the distribution of variations in the sub-mm do not show a tail of large-amplitude variations seen at 1.3 mm. Simultaneous X-ray photometry from XMM-Newton shows no significant variation within our observing period, which may explain the lack of very large submillimeter variations in our data if X-ray and submillimeter flares are correlated.

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Section: Observations and Reductionsupporting

confidence: 92%

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL

Stone

Marrone

Dowell

et al. 2016

ApJ

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“…This effect was corrected for by lowering the operational temperature of the tracking telescopes. In general, the astrometric accuracy up to OD 320 was better than 2 arcsec, but outliers at more than 8 arcsec were observed (for a detailed report on the Herschel astrometric accuracy see Sánchez-Portal et al 2014).…”

Section: Astrometric Correctionsmentioning

confidence: 99%

Hi-GAL, theHerschelinfrared Galactic Plane Survey: photometric maps and compact source catalogues

Molinari

Schisano

Elia

et al. 2016

A&A

238

272

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Aims. We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500 µm, encompassing the peak of the spectral energy distribution of cold dust for 8 < ∼ T < ∼ 50 K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68 • > ∼ > ∼ −70 • in a |b| ≤ 1 • latitude strip. Methods. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2 • × 2 • "tile" that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Results. Hi-GAL DR1 images are cirrus noise limited and reach the 1σ-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60 s −1 scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 123210, 308509, 280685, 160972, and 85460 compact sources in the five bands.

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“…We retrieved the data from the previous bulk processing with the HIPE 12.1 software version, currently contained in the HSA. We included the newly developed data reduction step calcAttitude: a correction of the frames pointing product based on the Herschel gyroscope housekeeping (Sánchez-Portal et al 2014). This often improves the absolute pointing accuracy and mitigates the pointing jitter effect on individual frames.…”

Section: Herschel/pacsmentioning

confidence: 99%

Hierarchical fragmentation and collapse signatures in a high-mass starless region

Beuther

Henning

Linz

et al. 2015

A&A

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Aims. We study the fragmentation and collapse properties of the dense gas during the onset of high-mass star formation. Methods. We observed the massive (∼800 M ) starless gas clump IRDC 18310-4 with the Plateau de Bure Interferometer (PdBI) at subarcsecond resolution in the 1.07 mm continuum and N 2 H + (3-2) line emission. Results. Zooming from a single-dish low-resolution map to previous 3 mm PdBI data, and now the new 1.07 mm continuum observations, the substructures hierarchically fragment on the increasingly smaller spatial scales. While the fragment separations may still be roughly consistent with pure thermal Jeans fragmentation, the derived core masses are almost two orders of magnitude larger than the typical Jeans mass at the given densities and temperatures. However, the data can be reconciled with models using non-homogeneous initial density structures, turbulence, and/or magnetic fields. While most subcores remain (far-)infrared dark even at 70 μm, we identify weak 70 μm emission toward one core with a comparably low luminosity of ∼16 L , supporting the notion of the general youth of the region. The spectral line data always exhibit multiple spectral components toward each core with comparably small line widths for the individual components (in the 0.3 to 1.0 km s −1 regime). Based on single-dish C 18 O(2-1) data we estimate a low virial-to-gas-mass ratio ≤0.25. We propose that the likely origin of these spectral properties may be the global collapse of the original gas clump that results in multiple spectral components along each line of sight. Even within this dynamic picture the individual collapsing gas cores appear to have very low levels of internal turbulence.

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The pointing system of the Herschel space observatory

Cited by 39 publications

References 10 publications

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL

Hi-GAL, theHerschelinfrared Galactic Plane Survey: photometric maps and compact source catalogues

Hierarchical fragmentation and collapse signatures in a high-mass starless region

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The pointing system of the Herschel space observatory

Cited by 39 publications

References 10 publications

FAR INFRARED VARIABILITY OF SAGITTARIUS A*: 25.5 hr OF MONITORING WITH HERSCHEL*

FAR INFRARED VARIABILITY OF SAGITTARIUS A*: 25.5 hr OF MONITORING WITH HERSCHEL*

Hi-GAL, theHerschelinfrared Galactic Plane Survey: photometric maps and compact source catalogues

Hierarchical fragmentation and collapse signatures in a high-mass starless region

Contact Info

Product

Resources

About

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL

FAR INFRARED VARIABILITY OF SAGITTARIUS A: 25.5 hr OF MONITORING WITH HERSCHEL