The CHESS spectral survey of star forming regions: Peering into the protostellar shock L1157-B1

Codella, C.; Leflóch, B.; Ceccarelli, C.; Cernicharo, J.; Caux, E.; Lorenzani, A.; Viti, S.; Hily-Blant, Pierre; Parise, B.; Maret, S.; Nisini, B.; Caselli, P.; Cabrit, S.; Pagani, L.; Benedettini, M.; Boogert, A. C. A.; Gueth, F.; Melnick, Gary J.; Neufeld, David A.; Pacheco, S.; Salez, M.; Schuster, K.; Bacmann, A.; Baudry, A.; Bell, T. A.; Bergin, Edwin A.; Blake, Geoffrey A.; Bottinelli, S.; Castets, A.; Comito, C.; Coutens, A.; Crimier, N.; Dominik, C.; Demyk, K.; Encrenaz, P.; Falgarone, É.; Fuente, A.; Gérin, M.; Goldsmith, Paul F.; Helmich, Frank; Hennebelle, P.; Henning, Th.; Herbst, Eric; Jacq, T.; Kahane, C.; Kama, M.; Klotz, A.; Langer, W. D.; Lis, D. C.; Lord, S. D.; Pearson, J. C.; Phillips, T. G.; Saraceno, P.; Schilke, P.; Tielens, Xander; Tak, F. F. S. van der; Wiel, M. H. D. van der; Vastel, C.; Wakelam, Valentine; Walters, A.; Wyrowski, F.; Yorke, H. W.; Borys, C.; Delorme, Y.; Krämer, C.; Larsson, Bengt; Mehdi, Imran; Ossenkopf, V.; Stützki, J.

doi:10.1051/0004-6361/201014582

Cited by 99 publications

(61 citation statements)

References 22 publications

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“…Of course, the relevance of this observation of W33 A to conditions in L1157 B1 is open to question. As we shall see in Section 3, the intensity of the 572 GHz line of ortho-NH 3 -observed in L1157 B1 by means of Herschel/HIFI (Codella et al 2010) -suggests that the initial abundance of NH 3 ice is much less than the observations of W33 A would imply; a similar conclusion is reached in the case of CH 3 OH.…”

Section: Chemistrymentioning

confidence: 59%

“…2. Also shown in this figure are the intensity of the J = 5 → 4 transition, observed with the Herschel/HIFI instrument (Codella et al 2010), and the intensities of the J = 3 → 2 and J = 6 → 5 lines, reported by Lefloch et al (2010), which were derived from Caltech Submillimeter Observatory (CSO) observations and smoothed to the 39 arcsec diameter of the HIFI band 1b beam. The line intensities predicted by the CJ-type model are also plotted.…”

Section: Co Emissionmentioning

confidence: 99%

“…Recently, it was a priority target of the key programmes CHESS and WISH, following the commissioning of the Herschel satellite. These initial observations (Ceccarelli et al 2010;Codella et al 2010;Lefloch et al 2010;Nisini et al 2010a) showed that the blue (B1) component has a rich submillimetre and far-infrared emission-line spectrum, containing transitions of CO, CH 3 OH, H 2 O, NH 3 and other molecular species. Rovibrational transitions of H 2 from this same source had been observed previously, from the ground (Caratti o Garatti et al 2006), and pure rotational transitions of H 2 have been observed by means of the Infrared Space Observatory (ISO) satellite (Cabrit et al 1999) and the Spitzer Space Telescope (Nisini et al 2010b).…”

Section: Introductionmentioning

confidence: 99%

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Time-dependent modelling of the molecular line emission from shock waves in outflow sources

Flower

Forêts

2012

Monthly Notices of the Royal Astronomical Society

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We have developed further the technique of time‐dependent modelling of magnetohydrodynamic shock waves, with a view to interpreting the molecular line emission from outflow sources. The extensively observed source L1157 B1 was chosen as an exemplar of the application of this technique. The dynamical age of the shock wave model was varied in the range 500 ≤t≤ 5000 yr, with the best fit to the observed line intensities being obtained for t= 1000 yr; this is of the same order as the dynamical age derived by Gueth, Guilloteau & Bachiller from their observations of L1157 B1. The emission line spectra of H2, CO, SiO, ortho‐ and para‐H2O, ortho‐ and para‐NH3, and A‐ and E‐type CH3OH were calculated in parallel with the dynamical and chemical parameters of the model, using the ‘large velocity gradient’ (LVG) approximation to the line transfer problem. We compared the predictions of the models with the observed intensities of emission lines of H2, CO, SiO, ortho‐H2O, ortho‐NH3 and CH3OH, which include recent Herschel satellite measurements. In the case of SiO, we show (in Appendix A) that extrapolations of the collisional rate coefficients beyond the range of kinetic temperature for which they were originally calculated lead to spurious rotational line intensities and profiles. The computed emission‐line spectra of SiO, NH3 and CH3OH are shown to depend on the assumed initial composition of the grain mantles, from whence they are released, by sputtering in the shock wave, into the gas phase. The dependence of the model predictions on the adopted form of the grain‐size distribution is investigated in Appendix B; the corresponding integral line intensities are given in tabular form, for a range of C‐type shock speeds, in the online Supporting Information.

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Section: Chemistrymentioning

confidence: 59%

Section: Co Emissionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time-dependent modelling of the molecular line emission from shock waves in outflow sources

Flower

Forêts

2012

Monthly Notices of the Royal Astronomical Society

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“…In addition to the Spitzer data, the recent millimeter and submillimeter spectral line observations of outflows and jets from ground (e.g., Tafalla et al 2010;Santiago-García et al 2009) and from Herschel (e.g., Codella et al 2010;Lefloch et al 2010) will offer new clues to the nature of the EHV gas and its relation to the lowvelocity outflow shells. Though a few selected outflows have been well studied in H 2 emission using all H 2 pure rotational lines from S(0) to S(7) with IRS (e.g., Neufeld et al 2006;Nisini et al 2010), the IRAC images available in the Spitzer archives have the potential to study the H 2 emission in a large sample of outflow sources.…”

Section: Discussionmentioning

confidence: 99%

JETS AND WIDE-ANGLE OUTFLOWS IN CEPHEUS E: NEW EVIDENCE FROMSPITZER

Velusamy

Langer

Kumar

et al. 2011

ApJ

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Outflows and jets are believed to play a crucial role in determining the mass of the central protostar and its planetforming disk by virtue of their ability to transport energy, mass, and momentum of the surrounding material, and thus terminate the infall stage in star and disk formation. In some protostellar objects both wide-angle outflows and collimated jets are seen, while in others only one is observed. Spitzer provides unprecedented sensitivity in the infrared to study both the jet and outflow features. Here, we use HiRes deconvolution to improve the visualization of spatial morphology by enhancing resolution (to subarcsecond levels in the Infrared Array Camera (IRAC) bands) and removing the contaminating sidelobes from bright sources. We apply this approach to study the jet and outflow features in Cep E, a young, energetic Class 0 protostar. In the reprocessed images we detect (1) wide-angle outflow seen in scattered light, (2) morphological details on at least 29 jet-driven bow shocks and jet heads or knots, (3) three compact features in 24 μm continuum image as atomic/ionic line emission coincident with the jet heads, and (4) a flattened ∼35 size protostellar envelope seen against the interstellar background polycyclic aromatic hydrocarbon emission as an absorption band across the protostar at 8 μm. By separating the protostellar photospheric scattered emission in the wide-angle cavity from the jet emission we show that we can study directly the scattered light spectrum. We present the H 2 emission line spectra, as observed in all IRAC bands, for 29 knots in the jets and bow shocks and use them in the IRAC color-color space as a diagnostic of the thermal gas in the shocks driven by the jets. The data presented here will enable detailed modeling of the individual shocks retracing the history of the episodic jet activity and the associated accretion on to the protostar. The Spitzer data analysis presented here shows the richness of its archive as a resource to study the jet/outflow features in H 2 and scattered light in a large homogeneous sample.

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“…[1][2][3][4][5][6][7][8][9][10][11] The range of relevant temperatures is very broad, from 5 K up to 2500 K, and the role of scattering partner (quencher) is played by the interstellar background gasses, mostly He and H 2 , but also by H 2 O in cometary comas. Usually, calculations of inelastic cross sections 12 are carried out using quantum scattering codes such as MOLSCAT.…”

Section: Introductionmentioning

confidence: 99%

Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames

Семенов

Babikov

2013

The Journal of Chemical Physics

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We formulated the mixed quantum/classical theory for rotationally and vibrationally inelastic scattering process in the diatomic molecule + atom system. Two versions of theory are presented, first in the space-fixed and second in the body-fixed reference frame. First version is easy to derive and the resultant equations of motion are transparent, but the state-to-state transition matrix is complexvalued and dense. Such calculations may be computationally demanding for heavier molecules and/or higher temperatures, when the number of accessible channels becomes large. In contrast, the second version of theory requires some tedious derivations and the final equations of motion are rather complicated (not particularly intuitive). However, the state-to-state transitions are driven by realvalued sparse matrixes of much smaller size. Thus, this formulation is the method of choice from the computational point of view, while the space-fixed formulation can serve as a test of the bodyfixed equations of motion, and the code. Rigorous numerical tests were carried out for a model system to ensure that all equations, matrixes, and computer codes in both formulations are correct.

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The CHESS spectral survey of star forming regions: Peering into the protostellar shock L1157-B1

Cited by 99 publications

References 22 publications

Time-dependent modelling of the molecular line emission from shock waves in outflow sources

Time-dependent modelling of the molecular line emission from shock waves in outflow sources

JETS AND WIDE-ANGLE OUTFLOWS IN CEPHEUS E: NEW EVIDENCE FROMSPITZER

Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames

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