A 2-MICRON Map of the Ophiuchus Dark-Cloud Region

Grasdalen, G. L.; Strom, K. M.; Strom, Steve

doi:10.1086/181287

Cited by 96 publications

(70 citation statements)

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“…By comparison, the 12 CO spectra (André et al 1990) associated with the molecular flow have velocity widths on the order of ∆V = ∼8 km s −1 and are likely blends of several velocity components. Also coinciding with our position is the bright infrared source GSS 30 (Graasdalen et al 1973). …”

Section: G5supporting

confidence: 88%

Zeeman line splitting measurements sampling dense gas in dark cloud and star-forming cores

Uchida

Fiebig

Güsten

2001

A&A

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Abstract. We present measurements of Zeeman splitting in SO JN = 12 − 11 line emission/absorption arising from dense thermal gas (>10 6 cm −3 ) associated with ten compact H II and star-forming regions. No line-of-sight magnetic field, above an average 1σ limit of 0.57 mG, is detected toward any of these sources. The W3(OH) region, found in a previous study to have a line-of-sight field of 3 mG in its dense gas, is thus unique in this respect. The implication of this study is that the magnetic fields in dense clouds are supercritical in the sense that they are not capable of supporting their host clouds against gravitational collapse. The relatively low average field limit is consistent with those theories predicting the quick onset of and short timescales for ambipolar diffusion. Also presented are (1) Zeeman splitting measurements of the CCS JN = 10 − 01 line probing the 10 4−5 cm −3 gas towards three positions in the Taurus star forming region, giving a 1σ average upper limit of 66 µG, and (2) measurements of Zeeman splitting in the OH 2 Π 3/2 J = 7/2 F = 3 + − 3 − hyperfine line toward the compact H II regions DR-21 and G10.62.

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Section: G5supporting

confidence: 88%

Zeeman line splitting measurements sampling dense gas in dark cloud and star-forming cores

Uchida

Fiebig

Güsten

2001

A&A

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“…However, we found that MHO 2151 is not associated with blue-shifted or red-shifted lobe of AS outflow, so it seems impossible that MHO 2151 is driven by LFAM 3. Greene & Young (1992b), GSS is from Grasdalen et al (1973), LFAM is from Leous et al (1991), YLW is from Young et al (1986b), BBRCG is from Barsony et al (1989), WLY is from Wilking et al (1989), WSB is from Wilking et al (1987), WL is from Wilking & Lada (1983), and EM*SR is from Struve & Rudkjøbing (1949).…”

Section: Discussionmentioning

confidence: 99%

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

Zhang

Brandner

Wang

et al. 2013

A&A

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Context. Proper motion measurements provide unique and powerful means to identify the driving sources of mass outflows, which are of particular importance in regions with complex star formation activity and deeply embedded protostars. They also provide the necessary kinematic information to study the dynamics of mass outflows, the interaction between outflows and the ambient medium, and the evolution of outflows with the age of the driving sources. Aims. We aim to take a census of molecular hydrogen emission line objects (MHOs) in the ρ Ophiuchi molecular cloud and to make the first systematic proper motion measurements of these objects in this region. The driving sources are identified based on the measured proper motions, and the outflow properties are characterized. The relationship between outflow properties and the evolutionary stages of the driving sources are also investigated. Methods. Deep H 2 near-infrared imaging is performed to search for molecular hydrogen emission line objects. Multi-epoch data are used to derive the proper motions of the features of these objects, and the lengths and opening angles of the molecular hydrogen outflows. Results. Our imaging covers an area of ∼0.11 deg 2 toward the L1688 core in the ρ Ophiuchi molecular cloud. In total, six new MHOs are discovered, 32 previously known MHOs are detected, and the proper motions for 86 features of the MHOs are measured. The proper motions lie in the range of 14 to 247 mas/yr, corresponding to transversal velocities of 8 to 140 km s −1 with a median velocity of about 35 km s −1 . Based on morphology and proper motion measurements, 27 MHOs are ascribed to 21 driving sources. The molecular hydrogen outflows have a median length of ∼0.04 pc and random orientations. We find no obvious correlation between H 2 jet length, jet opening angle, and the evolutionary stage of the driving sources as defined by their spectral indices. We find that the fraction of protostars (23%) that drive molecular hydrogen outflows is similar to the one for Class II sources (15%). For most molecular hydrogen outflows, no obvious velocity variation along the outflow has been found. Conclusions. In Ophiuchus the frequency of occurrence of molecular hydrogen outflows has no strong dependency on the evolutionary stage of the driving source during the evolution from the protostellar stage to the classical T Tauri stage.

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“…Barsony et al (1997), HBC is from Herbig & Bell (1988), and WSB is from . Barsony et al (1997), Elias 2 is from Elias (1978), GSS is from Grasdalen et al (1973), [GY92] is from Greene & Young (1992), and [SKS95] is from Strom et al (1995). Barsony et al (1997), [GY92] is from Greene & Young (1992), GSS is from Grasdalen et al (1973), and [SKS95] is from Strom et al (1995).…”

Section: Discussionmentioning

confidence: 99%

Jets and Herbig-Haro Objects in the Ophiuchi Embedded Cluster

et al. 2003

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We present results from a near-infrared 2.12 lm survey covering a large portion of the Ophiuchi cloud (three regions of $20 0 Â 20 0 each, on average) in an effort to improve the detection of embedded molecular hydrogen emission objects in the cloud. We complement these observations with deep optical [S ii] images of six areas of 10 0 Â 10 0 each. We recovered all previously known optical jets/Herbig-Haro (HH) objects as well as H 2 outflows in the region and report the detection of four new HH objects and 13 near-infrared knots. We provide coordinates and describe the morphology of these knots, several of which are identified as belonging to the same flow on the basis of morphological and proximity arguments. We discuss likely exciting sources. A unique association of the driving star is not always possible, as several young stars lie in close proximity to these knots.

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A 2-MICRON Map of the Ophiuchus Dark-Cloud Region

Cited by 96 publications

References 0 publications

Zeeman line splitting measurements sampling dense gas in dark cloud and star-forming cores

Zeeman line splitting measurements sampling dense gas in dark cloud and star-forming cores

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

Jets and Herbig-Haro Objects in the Ophiuchi Embedded Cluster

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