Publications (53)
Water vapor toward starless cores: the Herschel view
P. Caselli, E. Keto, L. Pagani +63
SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7x10^-9). We investigate the chemistry of water vapor in starless cores beyo…
Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines
S. -L. Qin, P. Schilke, C. Comito +67
We have observed CH absorption lines () against the continuum source Sgr~B2(M) using the \textit{Herschel}/HIFI instrument. With the high spectral…
Magnetohydrodynamic instabilities in stellar radiative regions. I. Linear study of shear-driven instabilities
V. Durepaire, L. Petitdemange, K. Belkacem +4
This paper is the first in a series investigating magnetohydrodynamic instabilities that may contribute to angular-momentum transport and magnetic-field evolution in stellar radiat…
Herschel-HIFI detections of hydrides towards AFGL 2591 (Envelope emission versus tenuous cloud absorption)
S. Bruderer, A. O. Benz, E. F. van Dishoeck +65
The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution a…
Herschel-SPIRE FTS spectroscopy of the carbon-rich objects AFGL 2688, AFGL 618 and NGC 7027
R. Wesson, J. Cernicharo, M. J. Barlow +22
We present far-infrared and submillimetre spectra of three carbon-rich evolved objects, AFGL 2688, AFGL 618 and NGC 7027. The spectra were obtained with the SPIRE Fourier transform…
The Excitation of NH in Interstellar Molecular Clouds. I - Models
F. Daniel, J. Cernicharo, M. -L. Dubernet
We present LVG and non-local radiative transfer calculations involving the rotational and hyperfine structure of the spectrum of NH with collisional rate coefficients recen…
On the influence of collisional rate coefficients on the water vapour excitation
F. Daniel, J. R. Goicoechea, J. Cernicharo +2
Water is a key molecule in many astrophysical studies. Its high dipole moment makes this molecule to be subthermally populated under the typical conditions of most astrophysical ob…
Water in massive star-forming regions: HIFI observations of W3 IRS5
L. Chavarria, F. Herpin, T. Jacq +58
We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H17O 110-101, p-H18O 111-000, p-H2O 22 202-111, p-H2O 111-000, o-H2O 221-21…
The 35Cl/37Cl isotopic ratio in dense molecular clouds: HIFI observations of hydrogen chloride towards W3A
J. Cernicharo, J. R. Goicoechea, F. Daniel +9
We report on the detection with the HIFI instrument on board the Herschel satellite of the two hydrogen chloride isotopologues, H35Cl and H37Cl, towards the massive star-forming re…
Detection of interstellar oxidaniumyl: abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334
V. Ossenkopf, H. S. P. Müller, D. C. Lis +99
We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. The character…
The NHD hyperfine structure revealed by astrophysical observations
F. Daniel, L. H. Coudert, A. Punanova +8
The 1-1 lines of ortho and para--NHD (o/p-NHD), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in…
HIFI detection of HF in the carbon star envelope IRC +10216
M. Agundez, J. Cernicharo, L. B. F. M. Waters +5
We report the detection of emission in the J=1-0 rotational transition of hydrogen fluoride (HF), together with observations of the J=1-0 to J=3-2 rotational lines of H35Cl and H37…
Water in low-mass star-forming regions with Herschel: HIFI spectroscopy of NGC1333
L. E. Kristensen, R. Visser, E. F. van Dishoeck +64
'Water In Star-forming regions with Herschel' (WISH) is a key programme dedicated to studying the role of water and related species during the star-formation process and constraini…
Molecular abundances in the inner layers of IRC +10216
M. Agundez, J. P. Fonfria, J. Cernicharo +3
Observations towards IRC +10216 of CS, SiO, SiS, NaCl, KCl, AlCl, AlF, and NaCN have been carried out with the IRAM 30-m telescope in the 80-357.5 GHz frequency range. A large numb…
Herschel observations of the hydroxyl radical (OH) in young stellar objects
S. F. Wampfler, G. J. Herczeg, S. Bruderer +58
Water in Star-forming regions with Herschel (WISH) is a Herschel Key Program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydrox…
Herschel-PACS spectroscopy of the intermediate mass protostar NGC7129 FIRS 2
M. Fich, D. Johnstone, T. A. van Kempen +58
Aims: We present preliminary results of the first Herschel spectroscopic observations of NGC7129 FIRS2, an intermediate mass star-forming region. We attempt to interpret the observ…
Solving radiative transfer with line overlaps using Gauss Seidel algorithms
F. Daniel, J. Cernicharo
The improvement in observational facilities requires refining the modelling of the geometrical structures of astrophysical objects. Nevertheless, for complex problems such as line…
NH and NNH towards the prestellar core 16293E in L1689N
F. Daniel, A. Faure, L. Pagani +6
Understanding the processes that could lead to enrichment of molecules in N atoms is of particular interest in order to shed light on the relatively large variations observe…
Origin of the hot gas in low-mass protostars: Herschel-PACS spectroscopy of HH 46
T. A. van Kempen, L. E. Kristensen, G. J. Herczeg +62
'Water in Star-forming regions with Herschel' (WISH) is a Herschel Key Programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a f…
Collisional excitation of NH3 by atomic and molecular hydrogen
N. Bouhafs, C. Rist, F. Daniel +4
We report extensive theoretical calculations on the rotation-inversion excitation of interstellar ammonia (NH3) due to collisions with atomic and molecular hydrogen (both para- and…
Herschel observations of deuterated water towards Sgr B2(M)
Claudia Comito, Peter Schilke, Rainer Rolffs +53
Observations of HDO are an important complement for studies of water, because they give strong constraints on the formation processes -- grain surfaces versus energetic process in…
Detection of anhydrous hydrochloric acid, HCl, in IRC+10216 with the Herschel SPIRE and PACS spectrometers
J. Cernicharo, L. Decin, M. J. Barlow +31
We report on the detection of anhydrous hydrochloric acid (hydrogen chlorine, HCl) in the carbon-rich star IRC+10216 using the spectroscopic facilities onboard the Herschel satelli…
Unveiling the dust nucleation zone of IRC+10216 with ALMA
J. Cernicharo, F. Daniel, A. Castro-Carrizo +5
We report the detection in IRC+10216 of lines of HNC =3-2 pertaining to 9 excited vibrational states with energies up to 5300 K. The spectrum, observed with ALMA, also sho…
Water cooling of shocks in protostellar outflows: Herschel-PACS map of L1157
B. Nisini, M. Benedettini, C. Codella +62
In the framework of the Water in Star-forming regions with Herschel (WISH) key program, maps in water lines of several outflows from young stars are being obtained, to study the wa…
A high resolution line survey of IRC+10216 with Herschel. First results: Detection of warm silicon dicarbide SiC2
J. Cernicharo, L. B. F. M. Waters, L. Decin +24
We present the first results of a high-spectral-resolution survey of the carbon-rich evolved star IRC+10216 that was carried out with the HIFI spectrometer onboard Herschel. This s…
Warm water vapour in the sooty outflow from a luminous carbon star
L. Decin, M. Agundez, M. J. Barlow +34
In 2001, the discovery of circumstellar water vapour around the ageing carbon star IRC+10216 was announced. This detection challenged the current understanding of chemistry in old…
Stratified NH and ND emission in the prestellar core 16293E in L1689N
A. Bacmann, F. Daniel, P. Caselli +6
High degrees of deuterium fractionation are commonly found in cold prestellar cores and in the envelopes around young protostars. As it brings strong constraints to chemical models…
Detection of OH and HO towards Orion~KL
H. Gupta, P. Rimmer, J. C. Pearson +76
We report observations of the reactive molecular ions OH, HO, and HO towards Orion KL with Herschel/HIFI. All three fine-structure transitions of OH…
Silicon in the dust formation zone of IRC +10216 as observed with PACS and SPIRE on board Herschel
L. Decin, J. Cernicharo, M. J. Barlow +36
The interstellar medium is enriched primarily by matter ejected from evolved low and intermediate mass stars. The outflows from these stars create a circumstellar envelope in which…
Variations in H2O+/H2O ratios toward massive star-forming regions
F. Wyrowski, F. van der Tak, F. Herpin +63
Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2…
Collisional excitation of doubly and triply deuterated ammonia NDH and ND by H
F. Daniel, C. Rist, A. Faure +6
The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities w…
Nitrogen isotopic ratios in Barnard 1: a consistent study of the N2H+, NH3, CN, HCN and HNC isotopologues
F. Daniel, M. Gerin, E. Roueff +7
The 15N isotopologue abundance ratio measured today in different bodies of the solar system is thought to be connected to 15N-fractionation effects that would have occured in the p…
Collisional excitation of singly deuterated ammonia NHD by H
F. Daniel, A. Faure, L. Wiesenfeld +3
The availability of collisional rate coefficients with H is a pre-requisite for interpretation of observations of molecules whose energy levels are populated under non local th…
Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk
E. A. Bergin, M. R. Hogerheijde, C. Brinch +61
We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong l…
Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains
J. Cernicharo, D. Teyssier, G. Quintana-Lacaci +12
We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. T…
On the physical structure of IRC+10216. Ground-based and Herschel observations of CO and CCH
E. De Beck, R. Lombaert, M. Agúndez +17
The C-rich AGB star IRC+10216 undergoes strong mass loss, and quasi-periodic density enhancements in the circumstellar matter have been reported. CO is ubiquitous in the CSE, while…
The Water Vapor Abundance in Orion KL Outflows
J. Cernicharo, J. R. Goicoechea, F. Daniel +7
We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, towards Orion KL. Observations were perf…
Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies
Rainer Rolffs, Peter Schilke, Claudia Comito +54
To investigate the accretion and feedback processes in massive star formation, we analyze the shapes of emission lines from hot molecular cores, whose asymmetries trace infall and…
N2H+ and N2D+ in interstellar molecular clouds. II- Observations
F. Daniel, J. Cernicharo, E. Roueff +2
We present observations of the =1--0, 2--1, and 3--2 rotational transitions of NH and ND towards a sample of prototypical dark clouds. The data have been interpr…
Herschel-HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region
U. A. Yıldız, E. F. van Dishoeck, L. E. Kristensen +60
Herschel-HIFI observations of high-J lines (up to J_u=10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS…
Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sgr B2(M)
P. Schilke, C. Comito, H. S. P. Mueller +55
H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all…
Non--local radiative transfer in strongly inverted masers
F. Daniel, J. Cernicharo
Maser transitions are commonly observed in media exhibiting a large range of densities and temperatures. They can be used to obtain information on the dynamics and physical conditi…
Herschel/HIFI observation of highly excited rotational lines of HNC toward IRC +10 216
F. Daniel, M. Agúndez, J. Cernicharo +6
We report the detection in emission of various highly excited rotational transitions of HNC (J = 6-5 through J =12-11) toward the carbon-star envelope IRC +10 216 using the HIFI in…
Herschel/HIFI discovery of interstellar chloronium (HCl)
D. C. Lis, J. C. Pearson, D. A. Neufeld +102
We report the first detection of chloronium, HCl, in the interstellar medium, using the HIFI instrument aboard the \emph{Herschel} Space Observatory. The li…
Collisional excitation of water by hydrogen atoms
F. Daniel, A. Faure, P. J. Dagdigian +3
We present quantum dynamical calculations that describe the rotational excitation of HO due to collisions with H atoms. We used a recent, high accuracy potential energy surface…
Herschel observations of EXtra-Ordinary Sources: The Terahertz spectrum of Orion KL seen at high spectral resolution
N. R. Crockett, E. A. Bergin, S. Wang +60
We present the first high spectral resolution observations of Orion KL in the frequency ranges 1573.4 - 1702.8 GHz (band 6b) and 1788.4 - 1906.8 GHz (band 7b) obtained using the HI…
Herschel observations of EXtra-Ordinary Sources: the present and future of spectral surveys with Herschel/HIFI
E. A. Bergin, T. G. Phillips, C. Comito +56
We present initial results from the Herschel GT key program: Herschel observations of EXtra-Ordinary Sources (HEXOS) and outline the promise and potential of spectral surveys with…
Herschel observations of extra-ordinary sources: Detection of Hydrogen Fluoride in absorption towards Orion~KL
T. G. Phillips, E. A. Bergin, D. C. Lis +52
We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the removal of contaminating features…
HERSCHEL-HIFI spectroscopy of the intermediate mass protostar NGC7129 FIRS 2
D. Johnstone, M. Fich, C. McCoey +58
HERSCHEL-HIFI observations of water from the intermediate mass protostar NGC7129 FIRS 2 provide a powerful diagnostic of the physical conditions in this star formation environment.…
Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H2O and its isotopologues towards Orion KL
G. J. Melnick, V. Tolls, D. A. Neufeld +49
We report the detection of more than 48 velocity-resolved ground rotational state transitions of H2(16)O, H2(18)O, and H2(17)O - most for the first time - in both emission and abso…
Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C
D. C. Lis, T. G. Phillips, P. F. Goldsmith +74
We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-HO and HO in absorption towards Sagittarius~B2(M) and W31C. The…
Herschel observations of Extra-Ordinary Sources: Methanol as a probe of physical conditions in Orion KL
S. Wang, E. A. Bergin, N. R. Crockett +45
We have examined methanol emission from Orion KL with of the {\em Herschel}/HIFI instrument, and detected two methanol bands centered at 524 GHz and 1061 GHz. The 524 GHz methanol…
PACS and SPIRE Spectroscopy of the Red Supergiant VY CMa
P. Royer, L. Decin, R. Wesson +34
With a luminosity > 10^5 Lsun and a mass-loss rate of about 2.10-4 Msun/yr, the red supergiant VY CMa truly is a spectacular object. Because of its extreme evolutionary state, it c…