As a GT Key Program we propose to perform full HIFI and PACS line surveys of 5 sources in the giant molecular clouds Orion and Sagittarius B2. These extraordinary star-forming regions contain the best studied examples of physical and chemical processes prevalent in the interstellar medium, includinggravitational compression, thermal and turbulent pressure support, photodissociation, gas and grain chemistry in dense and diffuse quiescent gas, and shocks. With high excitation, rich chemistry, and large molecular column theygive the highest chance for new detections in a sensitive search for new molecules. Line surveys of sources (Orion KL, Orion S, Orion Bar, Sgr B2 N+M) defined by these phenomena form the backbone of this proposed program. Herschel offers unprecedented sensitivity and relative calibration accuracy,as well as continuous spectral coverage across the gaps imposed by theatmosphere, opening up a largely unexplored wavelength regime to high resolution spectroscopy. These data will take line surveys to a new level and we will use them to comprehensively characterize the physics (density,thermal balance, kinematics, radiation field) and chemistry (chemical assay,ionization, deuterium fractionation, water ortho/para ratio) of star-forming molecular gas in a manner not previously possible. The opening of this spectral range is also an opportunity to detect the bending transitions of carbon chains and polycyclic aromatic hydrocarbons, along with the rotational transitions of complex organics. Given that these sources have the richest emission spectra seen for star-forming regions in the Galaxy, we anticipate that the proposed observations will define the sub-millimeter/far infrared region of the spectrum and that these data will form a lasting Herschel legacy.
Publication
The physical and chemical structure of Sagittarius B2. I. Three-dimensional thermal dust and free-free continuum modeling on 100 au to 45 pc scales | Schmiedeke A. et al. | Astronomy & Astrophysics Volume 588 id.A143 30 pp. | 588 | 10.1051\\/0004-6361\\/201527311 | 2016A&A...588A.143S | http://adsabs.harvard.edu/abs/2016A%26A...588A.143S
Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M) | Schilke P. et al. | Astronomy and Astrophysics Volume 521 id.L11 7 pp. | 521 | 10.1051\\/0004-6361\\/201015087 | 2010A&A...521L..11S | http://adsabs.harvard.edu/abs/2010A%26A...521L..11S
Herschel observations of deuterated water towards Sgr B2(M) | Comito C. et al. | Astronomy and Astrophysics Volume 521 id.L38 5 pp. | 521 | 10.1051\\/0004-6361\\/201015121 | 2010A&A...521L..38C | http://adsabs.harvard.edu/abs/2010A%26A...521L..38C
Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies | Rolffs R. et al. | Astronomy and Astrophysics Volume 521 id.L46 5 pp. | 521 | 10.1051\\/0004-6361\\/201015106 | 2010A&A...521L..46R | http://adsabs.harvard.edu/abs/2010A%26A...521L..46R
Herschel observations of extraordinary sources: full Herschel/HIFI molecular line survey of Sagittarius B2(M) | Moller T. et al. | Astronomy and Astrophysics | null | null | 2021A&A...651A...9M |
Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C | Lis D. C. et al. | Astronomy and Astrophysics Volume 521 id.L26 5 pp. | 521 | 10.1051\\/0004-6361\\/201015072 | 2010A&A...521L..26L | http://adsabs.harvard.edu/abs/2010A%26A...521L..26L
Interstellar bromine abundance is consistent with cometary ices from Rosetta | Ligterink N. F. W. et al. | Astronomy & Astrophysics Volume 614 id.A112 8 pp. | 614 | 10.1051\\/0004-6361\\/201732325 | 2018A&A...614A.112L | http://adsabs.harvard.edu/abs/2018A%26A...614A.112L
The Laboratory Millimeter and Submillimeter Rotational Spectrum of Lactaldehyde and an Astronomical Search in Sgr B2(N), Orion-KL, and NGC 6334I | Alonso Elena R. et al. | The Astrophysical Journal | null | null | 2019ApJ...883...18A |
The Central 300 pc of the Galaxy Probed by Infrared Spectra of HSUB_OPEN3SUB_CLOSE SUP_OPEN+SUP_CLOSE and CO. III. Locations of Sgr B2 and Star Iota | Oka Takeshi et al. | The Astrophysical Journal | null | null | 2022ApJ...927...97O |
Herschel observations of EXtra-Ordinary Sources (HEXOS): detecting spiral arm clouds by CH absorption lines | Qin S.-L. et al. | Astronomy and Astrophysics Volume 521 id.L14 5 pp. | 521 | 10.1051\\/0004-6361\\/201015107 | 2010A&A...521L..14Q | http://adsabs.harvard.edu/abs/2010A%26A...521L..14Q
Instrument
HIFI_HifiFS_freq
Temporal Coverage
2010-03-01T01:52:07Z/2010-03-05T05:36:28Z
Version
SPG v14.1.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth cornerstone mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
European Space Agency, bergin et al., 2010, 'HEXOS: Herschel Observations of Extra-Ordinary Sources: The Orion and Sgr B2 Star-Forming Regions', SPG v14.1.0, European Space Agency, https://doi.org/10.5270/esa-gk94vvn
