Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues First data release for the inner Milky Way:+68 degrees \textgreater= l \textgreater=-70 degrees

S. Molinari (1) , E. Schisano (2) , D. Elia (2) , M. Pestalozzi , A. Traficante , S. Pezzuto (3) , B. M. Swinyard , A. Noriega-Crespo (4, 5) , J. Bally , T. J. T. Moore , R. Plume (6) , Annie Zavagno (7) , A. M. Di Giorgio , S. J. Liu , G. L. Pilbratt (8) , J. C. Mottram , D. Russeil (7) , L. Piazzo , M. Veneziani (9) , M. Benedettini (2) , L. Calzoletti , F. Faustini , P. Natoli , F. Piacentini , M. Merello , A. Palmese , R. del Grande , D. Polychroni , K. L. J. Ryg , G. Polenta (10) , M. J. Barlow , J. -P. Bernard (11) , P. G. Martin , L. Testi (12) , B. Ali (13) , P. André (14) , M. T. Beltran , N. Billot (15) , S. Carey , R. Cesaroni (12) , M. Compiègne (16) , D. Eden , Y. Fukui (17) , P. Garcia-Lario (18, 19) , M. G. Hoare , M. Huang , G. Joncas , T. L. Lim (20) , . D. Lord , S. Martinavarro-Armengol , F. Motte (14) , R. Paladini (5) , D. Paradis (11) , N. Peretto (14, 21) , T. Robitaille , P. Schilke (22) , N. Schneider (23, 24) , B. Schulz , B. Sibthorpe (25) , F. Strafella , M. A. Thompson (26) , G. Umana , D. Ward-Thompson (27) , F. Wyrowski (28)

1 OAR - INAF - Osservatorio Astronomico di Roma
2 IAPS - Istituto di Astrofisica e Planetologia Spaziali - INAF
3 Faculty of Informatics [Lugano]
4 STSci - Space Telescope Science Institute
5 IPAC - Infrared Processing and Analysis Center
6 Department of Physics and Astronomy [Calgary]
7 LAM - Laboratoire d'Astrophysique de Marseille
8 ESTEC - European Space Research and Technology Centre
9 APC (UMR_7164) - AstroParticule et Cosmologie
10 IAP - Institut d'Astrophysique de Paris
11 IRAP - Institut de recherche en astrophysique et planétologie
12 OAA - INAF - Osservatorio Astrofisico di Arcetri
13 ENSA - École Nationale Supérieure d’Agronomie [Alger]
14 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
15 IRAM - Instituto de RadioAstronomía Milimétrica
16 LOA - Laboratoire d’Optique Atmosphérique - UMR 8518
17 Department of Astrophysics [Nagoya]
18 ESA - Espagne - ISO Data Centre
19 ESA Espagne - Herschel Science Centre
20 RAL - STFC Rutherford Appleton Laboratory
21 DAP - Département d'Astrophysique (ex SAP)
22 Physikalisches Institut [Köln]
23 University Hospital of Cologne [Cologne]
24 FORMATION STELLAIRE 2016
25 SRON - SRON Netherlands Institute for Space Research
26 AUTRES
27 Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston]
28 MPIFR - Max-Planck-Institut für Radioastronomie

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 mu m, encompassing the peak of the spectral energy distribution of cold dust for 8 less than or similar to T less than or similar to 50 K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68 degrees greater than or similar to l greater than or similar to -70 degrees in a vertical bar b vertical bar \textless= 1 degrees 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 degrees x 2 degrees “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 1 sigma-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.

Domaines: Astrophysique [astro-ph]

S. Molinari, E. Schisano, D. Elia, M. Pestalozzi, A. Traficante, et al.. Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues First data release for the inner Milky Way:+68 degrees \textgreater= l \textgreater=-70 degrees. Astronomy and Astrophysics - A&A, 2016, 591, ⟨10.1051/0004-6361/201526380⟩. ⟨hal-01440127⟩