Dust Filaments and Star Formation in OMC-2 and OMC-3

Chini, R.; Reipurth, Bo; Ward-Thompson, Derek; Bally, John; Nyman, L. Å.; Sievers, A.; Billawala, Youssef

doi:10.1086/310436

Cited by 197 publications

(476 citation statements)

References 16 publications

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“…In either case, the H Ñow from MMS 9 Ðts all of the criteria for class 0 YSOs listed in Barsony (1995) : it has a short dynamic timescale ; it is not observable at 2 km ; it has a bolometric to submillimeter luminosity ratio of L bol /L submm \ 145 (Chini et al 1997) ; its SED is Ðtted by a blackbody temperature of 20 K (Chini et al 1997) ; and it has an associated outÑow.…”

Section: T He Class 0 Status Of Mmsmentioning

confidence: 95%

“…Many of these clumps are located in regions that have not been surveyed for outÑows or for YSOs. For instance, panels f and g show bright high-velocity CO emission from the Ðlament to the north and northwest of the northernmost known submillimeter cores found in OMC-3 by Chini et al (1997).…”

Section: Observationsmentioning

confidence: 99%

“…C-shocks are expected to be important in regions of high density and low ionization fraction (conditions found deep inside molecular clouds), where magnetic precursors can gently heat the gas, eliminating J-shocks (Draine 1980 ;Draine, Roberge, & Dalgarno 1983). Such conditions would be expected to be more common in colder cloud regions, such as OMC-3, which, based on the number of millimeter cores, is far less evolved and cooler than OMC-2 (Chini et al 1997).…”

Section: C-shocks Versus J-shocksmentioning

confidence: 99%

“…This region contains one of the most active sites of star formation known as evidenced by the number of young stars in the region (Johnson et al 1990 ;Jones et al 1994), the nearly 30 warm dust cores that could contain protostars in early stages of collapse (Chini et al 1997 ;Lis et al 1998 ;Johnstone & Bally 1999), the 11 compact radio sources associated with a number of the cores (Reipurth, & Chini 1999), Rodr•guez, the CO outÑows mapped at low resolution (Fischer et al 1985 ;Castets & Langer 1995 ;Aso et al 2000), and the dozen or more outÑows (Yu, Bally, & Devine 1997, H 2 hereafter YBD97). YBD97 tabulated 80 knots of emis-H 2 sion in this region.…”

Section: Introductionmentioning

confidence: 99%

“…All subsequent contours increase in increments of 6 K km s~1, except for dÈf where they increase by 15 K km s~1. The small crosses represent millimeter and FIR cores found by Chini et al (1997) and Mezger et al (1990). with YSOs in OMC-2/3 are located. We also present new 12CO J \ 2 ] 1 maps of molecular outÑows in this region, a 12CO J \ 3 ] 2 map centered on a Ñow north of OMC-2, and high-resolution spectroscopy of the v \ 1È0 S(1) H 2 line of a select number of knots.…”

Section: Introductionmentioning

confidence: 99%

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A Multiwavelength Study of Outflows in OMC-2/3

Billawala

Smith

et al. 2000

The Astronomical Journal

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We present new v \ 1È0 S(1) 12CO J \ 2 ] 1, and 12CO J \ 3 ] 2 observations of the star-H 2 , forming clouds OMC-2 and OMC-3, one of the densest known groupings of outÑows from low-mass young stellar objects (YSOs) in the sky. High-velocity 12CO J \ 2 ] 1 gas in this region suggests that previously discoveredÑows are driving and entraining molecular outÑows. However, the large H 2 number of sources and Ñows within the narrow molecular Ðlament means it is difficult to make a Ðrm association of molecular outÑow gas with Ñows, except for in the case of the bipolar east-west H H 2 Ñow. A number of Herbig-Haro (HH) objects, including ones far to the west and east of the main ridge, are identiÐed with knots. High-resolution spectroscopy in the v \ 1È0 S(1) line of 10 knots shows H 2 H 2 line proÐles consistent with dual forward and reverse shocks. C-shock modeling suggest that asymmetries seen in suspected bow shocks could be evidence of varying magnetic Ðeld orientations throughout the cloud. One of the bow shocks in the H Ñow, YBD-5, can be successfully modeled by a 100 km s~1 C-shock propagating into a magnetized, 106 cm~3 medium, although the observations and limitations within the computer code itself do not entirely rule out J-shocks. Mass spectra of the H Ñow are broken power laws, which might be evidence for a jet that has two entrainment mechanisms for accelerating ambient molecular gas into the outÑow. The luminosity in this Ñow is many times smaller than H 2 the CO mechanical luminosity, but this fact cannot rule out the possibility that a narrow highly collimated jet drives the molecular outÑow, owing to uncertainties in extinction, outÑow dynamic times, cooling contributions from other lines, and the wind model used. OutÑows from OMC-2/3 are likely to contribute to the turbulent pumping of gas within the molecular ridge north of the Orion Nebula. Highvelocity gas clumps north of the sources investigated here may represent evidence of additional undiscovered outÑows from young stars.

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Section: T He Class 0 Status Of Mmsmentioning

confidence: 95%

Section: Observationsmentioning

confidence: 99%