Distribution of Cold Dust in Orion A and B

Mookerjea, B.; Ghosh, S. K.; Rengarajan, T. N.; Tandon, S. N.; Verma, R. P.

doi:10.1086/301554

Cited by 29 publications

(38 citation statements)

References 22 publications

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“…This makes identification of discrete sources and photometry in the mid-infrared difficult. The physical appearance of the region in the mid-infrared differs quite significantly from the structures seen in low resolution IRAS and far-infrared data (Mookerjea et al 2000), the moderate resolution 1.3 mm data (Launhardt et al 1996) and the sub-mm SCUBA data presented here. In the far-infrared wavelengths the Table 3 and the open squares denote the location of the free-free emission sources VLA 1-3 (Reipurth et al 2004). emission is from the HD 37903 and the bright sources directly to the south of it.…”

Section: Large Scale Overview Of the Ngc2023contrasting

confidence: 54%

Young stars and protostellar cores near NGC 2023

Mookerjea

Sandell

Jarrett

et al. 2009

A&A

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Context. We investigate the young (proto)stellar population in NGC 2023 and the L 1630 molecular cloud bordering the h ii region IC 434, using Spitzer IRAC and MIPS archive data, JCMT SCUBA imaging and spectroscopy as well as targeted BIMA observations of one of the Class 0 protostars, NGC 2023 MM 1. Aims. We study the distribution of gas, dust and young stars in this region to see where stars are forming, whether the expansion of the h ii region has triggered star formation, and whether dense cold cores have already formed stars. Methods.We have performed photometry of all IRAC and MIPS images, and used color-color diagrams to identify and classify all young stars seen within a 22 × 26 field along the boundary between IC 434 and L 1630. For some stars, which have sufficient optical, IR, and/or sub-millimeter data we have also used the online SED fitting tool for a large 2D archive of axisymmetric radiative transfer models to perform more detailed modeling of the observed SEDs. We identify 5 sub-millimeter cores in our 850 and 450 μm SCUBA images, two of which have embedded class 0 or I protostars. Observations with BIMA are used to refine the position and characteristics of the Class 0 source NGC 2023 MM 1. These observations show that it is embedded in a very cold cloud core, which is strongly enhanced in NH 2 D. Results. We find that HD 37903 is the most massive member of a cluster with 20-30 PMS stars. We also find smaller groups of PMS stars formed from the Horsehead nebula and another elephant trunk structure to the north of the Horsehead. Star formation is also occurring in the dark lane seen in IRAC images and in the sub-millimeter continuum. We refine the spectral classification of HD 37903 to B2 Ve. We find that the star has a clear IR excess, and therefore it is a young Herbig Be star.Conclusions. Our study shows that the expansion of the IC 434 h ii region has triggered star formation in some of the dense elephant trunk structures and compressed gas inside the L 1630 molecular cloud. This pre-shock region is seen as a sub-millimeter ridge in which stars have already formed. The cluster associated with NGC 2023 is very young, and has a large fraction of Class I sources.

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Section: Large Scale Overview Of the Ngc2023contrasting

confidence: 54%

Young stars and protostellar cores near NGC 2023

Mookerjea

Sandell

Jarrett

et al. 2009

A&A

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“…Early 2.2 m observations of a large part of the molecular cloud made by Lada et al (1991b) identified four embedded star clusters, and subsequent wide-field imaging of the stellar component is available via the Two Micron All Sky Survey (2MASS) images (Carpenter 2000). The distribution of relatively warm dust was mapped by the Infrared Astronomical Satellite (IRAS ), although for our purposes with limited angular resolution, and in far-infrared emission at 138 and 205 m ( Mookerjea et al 2000). The molecular component has been surveyed by a number of authors, e.g., Miesh & Bally (1994) in the 13 CO J ¼ 1-0 transition and by Kramer et al (1996) with lower angular resolution in the 13 CO and 12 CO J ¼ 2-1 and 3-2 transitions.…”

Section: Introductionmentioning

confidence: 99%

Large Area Mapping at 850 μm. IV. Analysis of the Clump Distribution in the Orion B South Molecular Cloud

Johnstone

Matthews

Mitchell

2006

ApJ

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We present results from a survey of a 1300 arcmin 2 region of the Orion B South molecular cloud, including NGC 2024, NGC 2023, and the Horsehead Nebula ( B33), obtained using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). Submillimeter continuum observations at 450 and 850 m are discussed. Using an automated algorithm, 57 discrete emission features (''clumps'') are identified in the 850 m map. The physical conditions within these clumps are investigated under the assumption that the objects are in quasi-hydrostatic equilibrium. The best-fit dust temperature for the clumps is found to be T d ¼ 18 AE 4 K, with the exception of those associated with the few known far-infrared sources residing in NGC 2024. The latter internally heated sources are found to be much warmer. In the region surrounding NGC 2023, the clump dust temperatures agree with clump gas temperatures determined from molecular line excitation measurements of the CO molecule. The bounding pressure on the clumps lies in the range log (k À1 P cm 3 K À1 ) ¼ 6:1 AE 0:3. The cumulative mass distribution is steep at the high-mass end, as is the stellar initial mass function. The distribution flattens significantly at lower masses, with a turnover around 3-10 M .

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“…From a comparison of the two temperature maps of figure 4, two differences are found: (1) the dust temperature T(60/100) derived from the two IRAS bands is, on an average, 10 Kelvin higher than T LG and (2) the T(60/100) map (figure 4b) shows the same spurious-pattern as seen in the IRAS 100 µm map. Mookerjea et al (2000) presented a dust temperature map derived from their 138 and 205 µm intensities around Orion KL neighborhood and northern ridge. However, because their temperature map covers too small an area, a comparison with the present work is not meaningful.…”

Section: Dust Temperature and Optical Depthmentioning

confidence: 99%

“…Previous investigations successfully revealed the dust distribution of this region, but covered only a part of the ISF-OMC-1 and its vicinity, OMC-2, and OMC-3. Mookerjea et al (2000) mapped this region at 138 and 205 µm with a spatial resolution of 1.…”

Section: Introductionmentioning

confidence: 99%

Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex

Arimura

Shibai

Teshima

et al. 2004

Publications of the Astronomical Society of Japan

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We present the results of a wide-area mapping of the far-infrared continuum emission toward the Orion complex by using a Japanese balloon-borne telescope. The 155-µm continuum emission was detected over a region of 1.5 deg 2 around the KL nebula with 3 ′ resolution similar to that of the IRAS 100-µm map. Assuming a singletemperature model of the thermal equilibrium dust, maps of the temperature and the optical depth were derived from the 155 µm intensity and the IRAS 100 µm intensity. 1The derived dust temperature is 5 -15 K lower and the derived dust optical thickness were derived from the 155-µm intensity and the IRAS 100-µm intensity. The derived dust temperature is 5 -15 K lower and the derived dust optical depth is 5 -300 times larger than those derived from the IRAS 60 and 100-µm intensities due to the significant contribution of the statistically heated very small grains to the IRAS 60-µm intensity. The optical-thickness distribution shows a filamentary dust ridge that has a 1.• 5 extent in the north -south direction and well resembles the Integral-Shaped Filament (ISF) molecular gas distribution. The gas-to-dust ratio derived from the CO molecular gas distribution along the ISF is in the range 30 -200, which may be interpreted as being an effect of CO depletion due to the photodissociation and/or the freezing on dust grains.

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Distribution of Cold Dust in Orion A and B

Cited by 29 publications

References 22 publications

Young stars and protostellar cores near NGC 2023

Young stars and protostellar cores near NGC 2023

Large Area Mapping at 850 μm. IV. Analysis of the Clump Distribution in the Orion B South Molecular Cloud

Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex

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