NANTEN Observations of the Pipe Nebula; A Filamentary Massive Dark Cloud with Very Low Star-Formation Activity

Onishi, Toshikazu; Kawamura, Akiko; Abe, Rihei; Yamaguchi, Nobuyuki; Saito, Hiro; Moriguchi, Y.; Mizuno, Akira; Ogawa, Hideo; Fukui, Y.

doi:10.1093/pasj/51.6.871

Cited by 83 publications

(134 citation statements)

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“…The raw data were calibrated using the MIR package for IDL that was developed for reduction of SMA data based on the Owens Valley Radio Observatory MMA package (Scoville et al Figure 1 shows the AzTEC/ASTE 1.1 mm FRUIT image obtained toward the north end of the Pipe Nebula. The image shows two dusty clumps which correspond to Core 1 (i.e., B59) and Core 2 detected in a previous low spatial resolution C 18 O(1-0) map (Onishi et al 1999). The clump associated with Core 2 has a filamentary structure ∼0.6 pc long.…”

Section: Sma Data Reductionmentioning

confidence: 72%

“…The crosses, circles, and boxes show the positions of Class-I, flat, and Class-II YSOs, respectively (Forbrich et al 2009). The white circles in panel (a) show the locations and the extents of Core 1 and Core 2 identified by Onishi et al (1999). (A color version of this figure is available in the online journal.)…”

Section: Sma Data Reductionmentioning

confidence: 99%

“…Onishi et al (1999) carried out mapping observations toward the Pipe Nebula in the CO(1-0) and C 18 O(1-0) lines, and detected 14 C 18 O dense cores. A CO(1-0) outflow was detected only for B59, suggesting that B59 is the only active star-forming region in the Pipe Nebula (Onishi et al 1999). Spitzer observations have revealed 20 low-mass young stellar objects (YSOs) and suggest that the star formation efficiency of the cluster is ∼20% (Brooke et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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The Rotating Outflow, Envelope, and Disk of the Class-0/I Protostar [Bhb2007]#11 in the Pipe Nebula

Hara

Shimajiri

Tsukagoshi

et al. 2013

ApJ

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We present the results of observations toward a low-mass Class-0/I protostar [BHB2007]#11 (B59#11) in the nearby (d = 130 pc) star-forming region Barnard 59 (B59), in the Pipe Nebula. We utilize the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope (∼22 resolution), focusing on the CO(3-2), HCO + , H 13 CO + (4-3), and 1.1 mm dust-continuum emission transitions. We also show Submillimeter Array (SMA) data with ∼5 resolution in 12 CO, 13 CO, C 18 O(2-1), and 1.3 mm dust-continuum emission. From ASTE CO(3-2) observations, we found that B59#11 is blowing a collimated outflow whose axis lies almost on the plane of the sky. The outflow traces well a cavity-like structure seen in the 1.1 mm dust-continuum emission. The results of SMA 13 CO and C 18 O(2-1) observations have revealed that a compact and elongated structure of dense gas is associated with B59#11; the structure is oriented perpendicular to the outflow axis. There is a compact dust condensation with a size of 350 × 180 AU seen in the SMA 1.3 mm continuum map, and the direction of its major axis is almost the same as that of the dense gas elongation. The distributions of 13 CO and C 18 O emission also show velocity gradients along their major axes, which are thought to arise from the envelope/disk rotation. From detailed analysis of the SMA data, we infer that B59#11 is surrounded by a Keplerian disk with a radius of less than 350 AU. In addition, the SMA CO(2-1) image shows a velocity gradient in the outflow in the same direction as that of the dense gas rotation. We suggest that this velocity gradient indicates rotation in the outflow.

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Section: Sma Data Reductionmentioning

confidence: 72%

Section: Sma Data Reductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Rotating Outflow, Envelope, and Disk of the Class-0/I Protostar [Bhb2007]#11 in the Pipe Nebula

Hara

Shimajiri

Tsukagoshi

et al. 2013

ApJ

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“…We therefore use the HNC 1−0 and 13 CO 2−1 as optically thick tracers for the "infall" signature in Cha III. 13 CO 2−1 likely traces the outer core material (e.g., Onishi et al 1999;Arce et al 2011) and any "infall" signature found with this transition may only correspond to large-scale contraction motions. On the other hand, C 18 O and C 17 O 2−1 were found to correlate very well with the dust extinction between 6 and 15 mag in Cha I (Belloche et al 2011a).…”

Section: Contraction Motionsmentioning

confidence: 96%

Star formation in Chamaeleon I and III: a molecular line study of the starless core population

Tsitali

Беллоче

Garrod

et al. 2015

A&A

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Context. The Chamaeleon dark molecular clouds are excellent nearby targets for low-mass star formation studies. Even though they belong to the same cloud complex, Cha I and II are actively forming stars while Cha III shows no sign of ongoing star formation. Aims. We aim to determine the driving factors that have led to the very different levels of star formation activity in Cha I and III and examine the dynamical state and possible evolution of the starless cores within them. Methods. Observations were performed in various molecular transitions with the APEX and Mopra telescopes. We examine the kinematics of the starless cores in the clouds through a virial analysis, a search for contraction motions, and velocity gradients. The chemical differences in the two clouds are explored through their fractional molecular abundances, derived from a non-LTE analysis, and comparison to predictions of chemical models.Results. Five cores are gravitationally bound in Cha I and one in Cha III. The so-called infall signature indicating contraction motions is seen toward 8-17 cores in Cha I and 2-5 cores in Cha III, which leads to a range of 13-28% of the cores in Cha I and 10-25% of the cores in Cha III that are contracting and may become prestellar. There is no significant difference in the turbulence level in the two clouds. Future dynamical interactions between the cores will not be dynamically significant in either Cha I or III, but the subregion Cha I North may experience collisions between cores within ∼0.7 Myr. Turbulence dissipation in the cores of both clouds is seen in the high-density tracers N 2 H + 1-0 and HC 3 N 10-9 which have lower non-thermal velocity dispersions compared to C 17 O 2-1, C 18 O 2-1, and C 34 S 2-1. Evidence of depletion in the Cha I core interiors is seen in the abundance distributions of the latter three molecules. The median fractional abundance of C 18 O is lower in Cha III than Cha I by a factor of ∼2. The median abundances of most molecules (except methanol) in the Cha III cores lie at the lower end of the values found in the Cha I cores. A difference in chemistry is thus seen. Chemical models suitable for the Cha I and III cores are used to constrain the effectiveness of the HC 3 N to N 2 H + abundance ratio as an evolutionary indicator. Both contraction and static chemical models indicate that this ratio is a good evolutionary indicator in the prestellar phase for both gravitationally bound and unbound cores. In the framework of these models, we find that the cores in Cha III and the southern part of Cha I are in a similar evolutionary stage and are less chemically evolved than the central region of Cha I. Conclusions. The measured HC 3 N/N 2 H + abundance ratio and the evidence for contraction motions seen towards the Cha III starless cores suggest that Cha III is younger than Cha I Centre and that some of its cores may form stars in the future if contraction does not cease. The cores in Cha I South may on the other hand be transient structures.

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“…typically a few times 10 22 cm −2 : c.f. Onishi et al 1999;Tachihara et al 2000); therefore, we can assume that GMCs have rather pancake shape than perfect spherical structure, which suggests that the GMCs' surface area is roughly proportional to their mass. In addition, the amount of HI cloud accumulated onto pre-existing GMCs through the multiple episodes of compression is presumably proportional to the GMC's surface area.…”

Section: Self-growth Termmentioning

confidence: 99%

Evolutionary Description of Giant Molecular Cloud Mass Functions on Galactic Disks

Kobayashi

Inutsuka

Kobayashi

et al. 2017

ApJ

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Recent radio observations show that the giant molecular cloud (GMC) mass functions noticeably vary across galactic disks. High-resolution magnetohydrodynamics simulations show that multiple episodes of compression are required for creating a molecular cloud in the magnetized interstellar medium. In this article, we formulate the evolution equation for the GMC mass function to reproduce the observed profiles, for which multiple compression are driven by the network of expanding shells due to HII regions and supernova remnants. We introduce the cloud-cloud collision (CCC) terms in the evolution equation in contrast to the previous work (Inutsuka et al. 2015). The computed time evolution suggests that the GMC mass function slope is governed by the ratio of GMC formation timescale to its dispersal timescale, and that the CCC effect is limited only in the massive-end of the mass function. In addition, we identify a gas resurrection channel that allows the gas dispersed by massive stars to regenerate GMC populations or to accrete onto the pre-existing GMCs. Our results show that almost all of the dispersed gas contribute to the mass growth of pre-existing GMCs in arm regions whereas less than 60% in inter-arm regions. Our results also predict that GMC mass functions have a single power-law exponent in the mass range < 10 5.5 M (where M represents the solar mass), which is well characterized by GMC self-growth and dispersal timescales. Measurement of the GMC mass function slope provides a powerful method to constrain those GMC timescales and the gas resurrecting factor in various environment across galactic disks.

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NANTEN Observations of the Pipe Nebula; A Filamentary Massive Dark Cloud with Very Low Star-Formation Activity

Cited by 83 publications

References 0 publications

The Rotating Outflow, Envelope, and Disk of the Class-0/I Protostar [Bhb2007]#11 in the Pipe Nebula

The Rotating Outflow, Envelope, and Disk of the Class-0/I Protostar [Bhb2007]#11 in the Pipe Nebula

Star formation in Chamaeleon I and III: a molecular line study of the starless core population

Evolutionary Description of Giant Molecular Cloud Mass Functions on Galactic Disks

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