Molecular outflows associated with a flux-limited sample of bright far-infrared sources

Snell, R. L.; Dickman, R. L.; Huang, Y. L.

doi:10.1086/168521

Cited by 94 publications

(93 citation statements)

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“…(1) Yang et al (1990); (2) Yang et al (1991); (3) Yang et al (1995); (4) Estalella et al (1993); (5) Carpenter et al (1990); (6) Yang (1990); (7) Snell et al (1990); (8) Carpenter et al (1993); (9) Henning et al (1994); (10) Cesaroni et al (1991); (11) Strom et al (1986); (12) Mundt et al (1991); (13) Mitchell et al (1994); (14) Mundt et al (1987); (15) Hayashi et al (1994); (16) Ohashi et al (1991); (17) Ohashi et al (1996); (18) Onishi et al (1998); (19) Garnavich et al (1992); (20) Snell (1981); (21) Moriarty-Schieven et al (1995); (22) Devine et al (1999); (23) Liljeström et al (1989); (24) Reipurth & Heathcote (1990); (25) Liljeström (1991); (26) Davis et al (1997); (27) Hoddap & Ladd (1995); (28) Reipurth et al (1993); (29) Reipurth & Graham (1988); (30) Cesaroni et al (1999); (31) Zinchenko et al (1997); (32) Wilking et al (1990); (33) Harju et al (1993); (34) Tatematsu et al (1993); (35) Yun & Clemens (1994)a; (36) Moreira & Yun (1995); (37) Wang et al (1995); (38) …”

Section: Observationsmentioning

confidence: 99%

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Dense gas and the nature of the outflows

Sepúlveda

Anglada

Estalella

et al. 2011

A&A

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We present the results of the observations of the (J, K) = (1, 1) and the (J, K) = (2, 2) inversion transitions of the NH 3 molecule toward a large sample of 40 regions with molecular or optical outflows, using the 37 m radio telescope of the Haystack Observatory. We detected NH 3 emission in 27 of the observed regions, which we mapped in 25 of them. Additionally, we searched for the 6 16 −5 23 H 2 O maser line toward six regions, detecting H 2 O maser emission in two of them, HH265 and AFGL 5173. We estimate the physical parameters of the regions mapped in NH 3 and analyze for each particular region the distribution of high density gas and its relationship with the presence of young stellar objects. In particular, we identify the deflecting high-density clump of the HH270/110 jet. We were able to separate the NH 3 emission from the L1641-S3 region into two overlapping clouds, one with signs of strong perturbation, probably associated with the driving source of the CO outflow, and a second, unperturbed clump, which is probably not associated with star formation. We systematically found that the position of the best candidate for the exciting source of the molecular outflow in each region is very close to an NH 3 emission peak. From the global analysis of our data we find that in general the highest values of the line width are obtained for the regions with the highest values of mass and kinetic temperature. We also found a correlation between the nonthermal line width and the bolometric luminosity of the sources, and between the mass of the core and the bolometric luminosity. We confirm with a larger sample of regions the conclusion of Anglada et al. (1997) that the NH 3 line emission is more intense toward molecular outflow sources than toward sources with optical outflow, suggesting a possible evolutionary scheme in which young stellar objects associated with molecular outflows progressively lose their neighboring high-density gas, weakening both the NH 3 emission and the molecular outflow in the process, and making optical jets more easily detectable as the total amount of gas decreases.

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Section: Observationsmentioning

confidence: 99%

“…A.1, for the L1287 region. The NH 3 lowest contour is 0.3 K and the increment is 0.2 K. The map of the CO bipolar outflow is from Snell et al (1990).…”

Section: A3 L1287mentioning

confidence: 99%

Dense gas and the nature of the outflows

Sepúlveda

Anglada

Estalella

et al. 2011

A&A

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“…Shirley et al 2000;Johnstone et al 2001;Nutter et al 2005) or the line emission of molecules. Low frequency molecular emission traces the cold gas in the protostellar envelopes (e.g., Hogerheijde et al 1998;Jørgensen et al 2002;Maret et al 2004) or molecular outflows (e.g., Snell et al 1990;Cabrit & Bertout 1992;Bachiller & Tafalla 1999). Single-dish observations of dust using current generation bolometer arrays are able to map large areas and image the surroundings of protostars (e.g., Motte et al 1998;Shirley et al 2000;Stanke et al 2006;Nutter et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Dense and warm molecular gas in the envelopes and outflows of southern low-mass protostars

Kempen

Dishoeck

Hogerheijde

et al. 2009

A&A

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Context. Observations of dense molecular gas lie at the basis of our understanding of the density and temperature structure of protostellar envelopes and molecular outflows. The Atacama Pathfinder EXperiment (APEX) opens up the study of southern (Dec < −35 • ) protostars. Aims. We aim to characterize the properties of the protostellar envelope, molecular outflow and surrounding cloud, through observations of high excitation molecular lines within a sample of 16 southern sources presumed to be embedded YSOs, including the most luminous Class I objects in Corona Australis and Chamaeleon. Methods. Observations of submillimeter lines of CO, HCO + and their isotopologues, both single spectra and small maps (up to 80 × 80 ), were taken with the FLASH and APEX-2a instruments mounted on APEX to trace the gas around the sources. The HARP-B instrument on the JCMT was used to map IRAS 15398-3359 in these lines. HCO + mapping probes the presence of dense centrally condensed gas, a characteristic of protostellar envelopes. The rare isotopologues C 18 O and H 13 CO + are also included to determine the optical depth, column density, and source velocity. The combination of multiple CO transitions, such as 3-2, 4-3 and 7-6, allows to constrain outflow properties, in particular the temperature. Archival submillimeter continuum data are used to determine envelope masses. Results. Eleven of the sixteen sources have associated warm and/or dense (≥10 6 cm −3 ) quiescent gas characteristic of protostellar envelopes, or an associated outflow. Using the strength and degree of concentration of the HCO + 4-3 and CO 4-3 lines as a diagnostic, five sources classified as Class I based on their spectral energy distributions are found not to be embedded YSOs. The C 18 O 3-2 lines show that for none of the sources, foreground cloud layers are present. Strong molecular outflows are found around six sources, with outflow forces an order of magnitude higher than for previously studied Class I sources of similar luminosity. Conclusions. This study provides a starting point for future ALMA and Herschel surveys by identifying truly embedded southern YSOs and determining their larger scale envelope and outflow characteristics.

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“…The YSO is embedded within an ammonia core (Molinari et al 1996) and is associated with strong, variable 22 GHz maser H 2 O emission (Codella, Felli, & Natale 1996). A high-velocity CO outÑow with a roughly east-west orientation and an infrared reÑection nebula is centered on the YSO (Snell, Dickman, & Huang 1990 ;Hodapp 1994 ;Shepherd & Churchwell 1996 ;SWSC98). Beyond the area of CO emission, high surface brightness Herbig-Haro objects (HH 396/ 397) are located more than 5 pc from the YSO, making this one of the largest outÑows in the Galaxy (Devine et al 1999).…”

Section: Introductionmentioning

confidence: 99%

A 1000 AU Rotating Disk around the Massive Young Stellar Object G192.16−3.82

Shepherd

Kurtz

1999

ApJ

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We present evidence for a circumstellar disk around the luminous young stellar object G192.16[3.82. Observations of 2.6 mm, 7 mm, and 3.6 cm continuum emission and 13CO, C18O, and maser line H 2 O emission support the interpretation that a 1000 AU rotating disk exists around the central B2 star. The disk major axis is roughly perpendicular to the outÑow, and the maser velocities are consistent with Keplerian rotation. The mass of the disk plus circumstellar envelope traced by millimeter continuum emission is D15The source is embedded in a 500 molecular cloud from which a massive M _ . M _ outÑow emerges. Updated outÑow parameters yield a total Ñow mass of 95 and a mass Ñow rate of M _ 5.6 ] 10~4 yr~1. The outÑow opening angle, deÐned by a 13CO shell, is approximately 90¡. A weak, M _ one-sided, ionized jet emanates from the young stellar object system. The estimated momentum rate of the jet (D10~3 km s~1 yr~1) is about a factor of 4 too low to power the Ñow. These results are M

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Molecular outflows associated with a flux-limited sample of bright far-infrared sources

Cited by 94 publications

References 0 publications

Dense gas and the nature of the outflows

Dense gas and the nature of the outflows

Dense and warm molecular gas in the envelopes and outflows of southern low-mass protostars

A 1000 AU Rotating Disk around the Massive Young Stellar Object G192.16−3.82

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