2016A&A...587A..47T


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.06CEST09:48:05

2016A&A...587A..47T - Astronomy and Astrophysics, volume 587A, 47-47 (2016/3-1)

Two-level hierarchical fragmentation in the northern filament of the Orion Molecular Cloud 1.

TEIXEIRA P.S., TAKAHASHI S., ZAPATA L.A. and HO P.T.P.

Abstract (from CDS):

The filamentary structure of molecular clouds may set important constraints on the mass distribution of stars forming within them. It is therefore important to understand which physical mechanism dominates filamentary cloud fragmentation and core formation. Orion A is the nearest giant molecular cloud, and its so-called ∫-shaped filament is a very active star-forming region that is a good target for such a study. We have recently reported on the collapse and fragmentation properties of the northernmost part of this structure, located ∼2.4 pc north of Orion KL - Orion Molecular Cloud (OMC) 3. As part of our project to study the ∫-shaped filament, we analyze the fragmentation properties of the northern OMC1 filament (located ≲0.3pc north of Orion KL). This filament is a dense structure previously identified by JCMT/SCUBA submillimeter continuum and VLA NH3 observations and was shown to have fragmented into clumps. Our aim is to search for cores and young protostars embedded within OMC1n and to study how the filament is fragmenting to form them. We observed OMC1North (hereafter OMC1n) with the Submillimeter Array (SMA) at 1.3mm and report on our analysis of the continuum data. We discovered 24 new compact sources, ranging in mass from 0.1 to 2.3, in size from 400 to 1300au, and in density from 2.6x107 to 2.8x106cm–3. The masses of these sources are similar to those of the SMA protostars in OMC3, but their typical sizes and densities are lower by a factor of ten. Only 8% of the new sources have infrared counterparts, but there are five associated CO molecular outflows. These sources are thus likely in the Class 0 evolutionary phase but it cannot be excluded that some of the sources might still be pre-stellar cores. The spatial analysis of the protostars shows that they are divided into small groups that coincide with previously identified JCMT/SCUBA 850 µm and VLA NH3 clumps, which are separated by a quasi-equidistant length of ≃30' (0.06pc). This separation is dominated by the Jeans length and therefore indicates that the main physical process in the filament evolution was thermal fragmentation. Within the protostellar groups, the typical separation is ≃6" (∼2500au), which is a factor 2-3 smaller than the Jeans length of the parental clumps within which the protostars are embedded. These results point to a hierarchical (two-level) thermal fragmentation process of the OMC1n filament.

Abstract Copyright:

Journal keyword(s): techniques: interferometric - stars: formation - ISM: clouds - ISM: structure - stars: protostars - submillimeter: ISM

VizieR on-line data: <Available at CDS (J/A+A/587/A47): list.dat map.fits>

Nomenclature: Fig. 2, Tables 3-4: [TTZ2016] SMA-NN (Nos 1-24).

Simbad objects: 48

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Number of rows : 48

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 LDN 1495 DNe 04 18.1 +27 37           ~ 293 1
2 Barnard 213 DNe 04 20 51 +27 16.3           ~ 155 0
3 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3496 0
4 QSO J0530+13 QSO 05 30 56.41672 +13 31 55.1495     20.0 19.35   ~ 880 1
5 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 1985 1
6 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 1016 2
7 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2005 1
8 [TTZ2016] SMA-2 mm 05 35 14.35 -05 18 50.8           ~ 1 0
9 NAME OMC 1N PoC 05 35 14.5 -05 22 07           ~ 16 1
10 [TTZ2016] SMA-1 mm 05 35 14.59 -05 18 46.1           ~ 1 0
11 [TTZ2016] SMA-18 mm 05 35 14.59 -05 18 46.1           ~ 2 0
12 [TTZ2016] SMA-24 mm 05 35 14.91 -05 21 12.3           ~ 1 0
13 [TTZ2016] SMA-16 mm 05 35 14.98 -05 20 40.8           ~ 1 0
14 [TTZ2016] SMA-23 mm 05 35 15.31 -05 21 05.9           ~ 1 0
15 [TTZ2016] SMA-15 mm 05 35 15.69 -05 20 39.4           ~ 1 0
16 [TTZ2016] SMA-14 mm 05 35 15.95 -05 20 14.4           ~ 1 0
17 [TTZ2016] SMA-13 mm 05 35 16.01 -05 20 05.4           ~ 1 0
18 [TTZ2016] SMA-12 mm 05 35 16.06 -05 19 59.0           ~ 1 0
19 [TTZ2016] SMA-11 mm 05 35 16.17 -05 19 55.3           ~ 1 0
20 [TTZ2016] SMA-9 mm 05 35 16.39 -05 19 32.9           ~ 1 0
21 [TTZ2016] SMA-22 mm 05 35 16.45 -05 21 07.1           ~ 1 0
22 [TTZ2016] SMA-10 mm 05 35 16.50 -05 19 36.7           ~ 1 0
23 [TTZ2016] SMA-21 mm 05 35 16.67 -05 21 00.6           ~ 1 0
24 [TTZ2016] SMA-8 mm 05 35 16.67 -05 19 32.3           ~ 1 0
25 [TTZ2016] SMA-19 mm 05 35 16.72 -05 20 44.2           ~ 1 0
26 [TTZ2016] SMA-7 mm 05 35 16.87 -05 19 26.1           ~ 1 0
27 [TTZ2016] SMA-17 mm 05 35 17.07 -05 20 38.7           ~ 1 0
28 [TTZ2016] SMA-6 mm 05 35 17.29 -05 19 19.1           ~ 1 0
29 [TTZ2016] SMA-3 mm 05 35 17.85 -05 18 48.9           ~ 1 0
30 NAME Ori Complex Cld 05 35.3 -05 23           ~ 334 0
31 [TTZ2016] SMA-5 mm 05 35 18.00 -05 19 11.7           ~ 1 0
32 [TTZ2016] SMA-4 mm 05 35 18.25 -05 19 08.4           ~ 1 0
33 [TTZ2016] SMA-20 mm 05 35 18.35 -05 20 48.5           ~ 1 0
34 OMC 3 MoC 05 35 20.0 -05 01 00           ~ 220 1
35 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 718 0
36 OMC 5 MoC 05 35.4 -05 55           ~ 17 0
37 OMC 2 MoC 05 35 27 -05 10.1           ~ 384 1
38 OMC 4 MoC 05 36 06 -05 35.7           ~ 48 0
39 NAME Ori A MoC 05 38 -07.1           ~ 2678 0
40 QSO B0539-057 QSO 05 41 38.08338 -05 41 49.4284     20.4 20.70   ~ 210 2
41 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1167 0
42 NAME ORI MOL CLOUD MoC 05 56 -01.8           ~ 851 1
43 QSO B0605-0834 QSO 06 07 59.69923743 -08 34 49.9781718     18.5 17.70   ~ 395 1
44 NGC 2264 OpC 06 40 58 +09 53.7     3.9     ~ 1592 1
45 NAME Mon OB1 D PoC 06 41 09.9 +09 34 34           ~ 52 1
46 3C 273 BLL 12 29 06.6996828061 +02 03 08.598846466   13.05 14.830 14.11   ~ 5324 1
47 [CCE98b] 011.11-0.12 Cld 18 10.5 -19 23           ~ 85 1
48 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2510 2

    Equat.    Gal    SGal    Ecl

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2020.08.06-09:48:05

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