Excitation and kinematics in H2 bow shocks: near-infrared observations of HH 99 and VLA 1623A (HH 313)

Davis, C. J.; Smith, Michael D.; Eislöffel, J.; Davies, John K.

doi:10.1046/j.1365-8711.1999.02772.x

Cited by 38 publications

(63 citation statements)

References 43 publications

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“…Partially responsible for the large spread might be the fact that the actual extinction curve is different from the one used here. Extinction values for extended regions of the ρ Oph cloud and as high as those derived here have been reported also by others (e.g., Davis et al 1999;Whittet et al 2008). Especially remarkable, and in line with our own findings, is the result of Davis et al (1999) for HH 313A, who found at 0 · 6 resolution variations of the K-band extinction by 3 mag (ΔA V = 30 mag) over only 6 , i.e., the size of one CAM pixel.…”

Section: T N(hsupporting

confidence: 91%

“…Comparing to the data of Table 3, a beam filling below the 10% percent level would be indicated, which would correspond to linear source sizes of the order of 20 . This is not unreasonable, as small scale structure is observed in ro-vibrationally excited H 2 emission (Dent et al 1995;Davis et al 1999;Caratti o Garatti et al 2006), and also in [S II] lines from HH 313 (Wilking et al 1997;Gómez et al 2003;Phelps & Barsony 2004). …”

Section: Compact High-density Gas and Standard O-abundancementioning

confidence: 95%

“…1) signal the presence of shocks with strong temperature gradients on relatively small spatial scales (Davis et al 1999;Eislöffel et al 2000). The extent of these localized regions is comparable to (or smaller than) the size of the 6 CAM-CVF pixel, i.e.…”

Section: B1 the Single-temperature Approximationmentioning

confidence: 99%

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Oxygen in dense interstellar gas

Liseau

Justtanont

2009

A&A

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Context. Oxygen is the third most abundant element in the universe, but its chemistry in the interstellar medium is still not understood well. Aims. To critically examine the entire oxygen budget, we initially attempt to estimate the abundance of atomic oxygen, O, in the only region where molecular oxygen, O 2 , has been detected to date. Methods. We analysed ISOCAM-CVF spectral image data toward ρ Oph A to derive the temperatures and column densities of H 2 at the locations of ISO-LWS observations of two [O I] 3 P J lines. The intensity ratios of the (J = 1-2) 63 μm to (J = 0-1) 145 μm lines largely exceed ten, attesting to these lines being optically thin. This is confirmed by radiative transfer calculations, making these lines suitable for abundance determinations. For that purpose, we calculated line strengths and compared them to the LWS observations. Results. Excess [O I] emission is observed to be associated with the molecular outflow from VLA 1623. For this region, we determine the physical parameters, T and N(H 2 ), from the CAM observations, and the gas density, n(H 2 ), is determined from the flux ratio of Conclusions. As option (1) disregards valid [O i] 145 μm data, we do not find it very compelling; instead, we favour option (3), as lower abundances are expected as a result of chemical cloud evolution, but we are not able to dismiss option (2) entirely. Observations at higher angular resolution than offered by the LWS are required to decide between these possibilities.

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Section: T N(hsupporting

confidence: 91%

Section: Compact High-density Gas and Standard O-abundancementioning

confidence: 95%

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Oxygen in dense interstellar gas

Liseau

Justtanont

2009

A&A

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“…In contrast, near-infrared (H 2 2.12 µm) imaging observations have detected and explored shock-excited knots and jets located in highly obscured areas (Davis & Eisloeffel 1995;Dent et al 1995;Davis et al 1999;Grosso et al 2001). These searches have been confined to small regions, typically 5 × 5 .…”

Section: Introductionmentioning

confidence: 99%

An unbiased search for the signatures of protostars in the ρ Ophiuchi A molecular cloud

Khanzadyan¹,

Gredel²,

Smith³

et al. 2004

A&A

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Abstract. We present an unbiased search for molecular hydrogen emission in the L1688 cloud within the ρ Ophiuchi molecular cloud complex. Our near-infrared survey covers a connected region of extent 35 × 35 . We detect several new H 2 flows but the total number of detected outflows is low and is consistent with the paucity of Class 0 and Class 1 sources in the molecular cloud. From the spatial distribution, their collimation and the individual shapes of the bow shocks, we suggest possible candidates for the outflow sources. Most of the candidate driving sources are deeply embedded in dense cores of the molecular cloud. A very young outflow arises from the newly discovered Class 0 source MMS 126. Two major outflows in the NE-SW direction arise from the YLW 15 and YLW 16 Class I sources. Three additional outflows, which both extend over several arcminutes, arise from the Class I sources YLW 31 and YLW 52. Flow directions are generally NE-SW, perpendicular to the elongation directions of the cloud filaments. The apparent extents of molecular flows are related to either the widths of cloud filaments or to the separation between filaments. The estimated jet power needed to continuously drive and excite the detected portions of the shocked H 2 outflows lies in the range 0.02−0.2 L . Given the critical dependence on the environment, however, the total sizes and powers of the outflows may be considerably larger.

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“…3 from B are detected (Bb1 and Br1 knots). We note that, assuming an inclination angle with respect to the line of sight of 75 • as for the A outflow (Davis et al 1999), the maximum projected velocities of 14 km s −1 (with respect to the ambient systemic velocity of 3.6 km s …”

Section: Resultsmentioning

confidence: 99%

Disentangling the jet emission from protostellar systems

Santangelo

Murillo

Nisini

et al. 2015

A&A

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Context. High-resolution studies of class 0 protostars represent the key to constraining protostar formation models. VLA16234−2417 represents the prototype of class 0 protostars, and it has been recently identified as a triple non-coeval system. Aims. We aim at deriving the physical properties of the jets in VLA16234−2417 using tracers of shocked gas. Methods. ALMA Cycle 0 Early Science observations of CO(2−1) in the extended configuration are presented in comparison with previous SMA CO(3−2) and Herschel-PACS [Oi] 63 μm observations. Gas morphology and kinematics were analysed to constrain the physical structure and origin of the protostellar outflows. Results. We reveal a collimated jet component associated with the [Oi] 63 μm emission at about 8 (∼960 AU) from source B. This newly detected jet component is inversely oriented with respect to the large-scale outflow driven by source A, and it is aligned with compact and fast jet emission very close to source B (about 0. 3) rather than with the direction perpendicular to the A disk. We also detect a cavity-like structure at low projected velocities, which surrounds the [Oi] 63 μm emission and is possibly associated with the outflow driven by source A. Finally, no compact outflow emission is associated with source W. Conclusions. Our high-resolution ALMA observations seem to suggest there is a fast and collimated jet component associated with source B. This scenario would confirm that source B is younger than A, that it is in a very early stage of evolution, and that it drives a faster, more collimated, and more compact jet with respect to the large-scale slower outflow driven by A. However, a different scenario of a precessing jet driven by A cannot be firmly excluded from the present observations.

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Excitation and kinematics in H2 bow shocks: near-infrared observations of HH 99 and VLA 1623A (HH 313)

Cited by 38 publications

References 43 publications

Oxygen in dense interstellar gas

Oxygen in dense interstellar gas

An unbiased search for the signatures of protostars in the ρ Ophiuchi A molecular cloud

Disentangling the jet emission from protostellar systems

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