High spatial resolution isotopic CO and CS observations of M17 SW - The clumpy structure of the molecular cloud core

Stutzki, J.; Guêsten, R.

doi:10.1086/168859

Cited by 428 publications

(397 citation statements)

References 0 publications

Supporting

Mentioning

374

Contrasting

Order By: Relevance

“…The different values of β B satisfying these conditions are consistently lower than ∼−2, and have a weighted average and formal error of β = −2.3 ± 0.2 (see Rodón 2009, for a more detailed description of this method). We see then that our results for the CMF slope are steeper than the ∼−1.6 found for the clump mass functions (e.g., Stutzki & Guesten 1990;Kramer et al 1998), which were obtained from CO emission maps for structures of sizes on the order of ∼0.1 pc. Going to at least a one order of magnitude higher spatial resolution, we found that the slope of the mass function is consistently steeper, indicating that there has been further fragmentation on smaller spatial scales.…”

Section: The Differential Core Mass Functioncontrasting

confidence: 73%

Fragmentation in the massive star-forming region IRAS 19410+2336

Rodón

Beuther

Schilke

2012

A&A

View full text Add to dashboard Cite

Context. The core mass functions (CMFs) of low-mass star-forming regions are found to resemble the shape of the initial mass function (IMF). A similar result is observed for the dust clumps in high-mass star-forming regions, although on spatial scales of clusters that do not resolve the substructure that is found in these massive clumps. The region IRAS 19410+2336 is one exception, having been observed on spatial scales on the order of ∼2500 AU, which are sufficient to resolve the clump substructure into individual cores. Aims. We investigate the protostellar content of IRAS 19410+2336 at high spatial resolution at 1.4 mm, determining the temperature structure of the region and deriving its CMF. Methods. The massive star-forming region IRAS 19410+2336 was mapped with the PdBI (BCD configurations) at 1.4 mm and 3 mm in the continuum and several transitions of formaldehyde (H 2 CO) and methyl cyanide (CH 3 CN). The H 2 CO transitions were also observed with the IRAM 30 m Telescope. Results. We detect 26 continuum sources at 1.4 mm with a spatial resolution as low as ∼2200 AU, several of them with counterparts at near-and mid-infrared wavelengths, distributed in two (proto)clusters. With the PdBI CH 3 CN and PdBI/IRAM 30 m H 2 CO emission, we derive the temperature structure of the region, ranging from 35 K to 90 K. Using these temperatures, we calculate the core masses of the detected sources, ranging from ∼0.7 M to ∼8 M . These masses are strongly affected by the spatial filtering of the interferometer, which removes a common envelope with ∼90% of the single-dish flux. Considering only the detected dense cores and accounting for binning effects as well as cumulative distributions, we derive a CMF, with a power-law index β = −2.3 ± 0.2. We resolve the Jeans length of the (proto)clusters by one order of magnitude, and only find a small velocity dispersion between the different subsources. Conclusions. Since we cannot unambiguously differentiate between protostellar and prestellar cores, the derived CMF is not prestellar. Furthermore, because of the large fraction of missing flux, we cannot establish a firm link between the CMF and the IMF. This implies that future high-mass CMF studies will need to complement the interferometer continuum data with the short spacing information, a task suitable for ALMA. We note that the method of extracting temperatures using H 2 CO lines becomes less applicable when reaching the dense core scales of the interferometric observations because most of the H 2 CO appears to originate in the envelope structure.

show abstract

Section: The Differential Core Mass Functioncontrasting

confidence: 73%

Fragmentation in the massive star-forming region IRAS 19410+2336

Rodón

Beuther

Schilke

2012

A&A

View full text Add to dashboard Cite

show abstract

“…We ran a decomposition of the CO data cube into individual structures, using the task Gaussclumps (developed initially by Stutzki & Guesten 1990) in GILDAS/Mapping. The algorithm searches iteratively for 3D Gaussians in the data cube until it reaches a specified threshold value.…”

Section: Giant Molecular Associations (Gmas) In Ngc 1614mentioning

confidence: 99%

The NGC 1614 interacting galaxy

König

Aalto

Müller

et al. 2013

A&A

View full text Add to dashboard Cite

Minor mergers frequently occur between giant and gas-rich low-mass galaxies and can provide significant amounts of interstellar matter to refuel star formation and power active galactic nuclei (AGN) in the giant systems. Major starbursts and/or AGN result when fresh gas is transported and compressed in the central regions of the giant galaxy. This is the situation in the starburst minor merger NGC 1614, whose molecular medium we explore at half-arcsecond angular resolution through our observations of 12 CO (2−1) emission using the Submillimeter Array (SMA). We compare our 12 CO (2−1) maps with optical and Paα, Hubble Space Telescope and high angular resolution radio continuum images to study the relationships between dense molecular gas and the NGC 1614 starburst region. The most intense 12 CO emission occurs in a partial ring with ∼230 pc radius around the center of NGC 1614, with an extension to the northwest into the dust lane that contains diffuse molecular gas. We resolve ten giant molecular associations (GMAs) in the ring, which has an integrated molecular mass of ∼8 × 10 8 M . Our interferometric observations filter out a large part of the 12 CO (1−0) emission mapped at shorter spacings, indicating that most of the molecular gas is diffuse and that GMAs only exist near and within the circumnuclear ring. The molecular ring is uneven with most of the mass on the western side, which also contains GMAs extending into a pronounced tidal dust lane. The spatial and kinematic patterns in our data suggest that the northwest extension of the ring is a cosmic umbilical cord that is feeding molecular gas associated with the dust lane and tidal debris into the nuclear ring, which contains the bulk of the starburst activity. The astrophysical process for producing a ring structure for the final resting place of accreted gas in NGC 1614 is not fully understood, but the presence of numerous GMAs suggests an orbit-crowding or resonance phenomenon. There is some evidence that star formation is progressing radially outward within the ring, indicating that a self-triggering mechanism may also affect star formation processes. The net result of this merger therefore very likely increases the central concentration of stellar mass in the NGC 1614 remnant giant system.

show abstract

“…Gaussclumps (Stutzki & Güsten 1990;Kramer et al 1998) and Clumpfind (Williams et al 1994) are two of the most popular numerical codes used to extract sources from large-scale Fig. 3.…”

Section: Source Extraction With Gaussclumpsmentioning

confidence: 99%

The end of star formation in Chamaeleon I?

Беллоче

Schüller

Parise

et al. 2011

A&A

144

View full text Add to dashboard Cite

Context. Chamaeleon I is the most active region in terms of star formation in the Chamaeleon molecular cloud complex. Although it is one of the nearest low-mass star forming regions, its population of prestellar and protostellar cores is not known and a controversy exists concerning its history of star formation. Aims. Our goal is to search for prestellar and protostellar cores and characterize the earliest stages of star formation in this cloud. Methods. We used the bolometer array LABOCA at the APEX telescope to map the cloud in dust continuum emission at 870 μm with a high sensitivity. This deep, unbiased survey was performed based on an extinction map derived from 2MASS data. The 870 μm map is compared with the extinction map and C 18 O observations, and decomposed with a multiresolution algorithm. The extracted sources are analysed by carefully taking into account the spatial filtering inherent in the data reduction process. A search for associations with young stellar objects is performed using Spitzer data and the SIMBAD database. Results. Most of the detected 870 μm emission is distributed in five filaments. We identify 59 starless cores, one candidate first hydrostatic core, and 21 sources associated with more evolved young stellar objects. The estimated 90% completeness limit of our survey is 0.22 M for the starless cores. The latter are only found above a visual extinction threshold of 5 mag. They are less dense than those detected in other nearby molecular clouds by a factor of a few on average, maybe because of the better sensitivity of our survey. The core mass distribution is consistent with the IMF at the high-mass end but is overpopulated at the low-mass end. In addition, at most 17% of the cores have a mass larger than the critical Bonnor-Ebert mass. Both results suggest that a large fraction of the starless cores may not be prestellar in nature. Based on the census of prestellar cores, Class 0 protostars, and more evolved young stellar objects, we conclude that the star formation rate has decreased with time in this cloud. Conclusions. The low fraction of candidate prestellar cores among the population of starless cores, the small number of Class 0 protostars, the high global star formation efficiency, the decrease of the star formation rate with time, and the low mass per unit length of the detected filaments all suggest that we may be witnessing the end of the star formation process in Chamaeleon I.

show abstract

High spatial resolution isotopic CO and CS observations of M17 SW - The clumpy structure of the molecular cloud core

Cited by 428 publications

References 0 publications

Fragmentation in the massive star-forming region IRAS 19410+2336

Fragmentation in the massive star-forming region IRAS 19410+2336

The NGC 1614 interacting galaxy

The end of star formation in Chamaeleon I?

Contact Info

Product

Resources

About