2001ApJS..136..703L


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.28CET23:56:54

2001ApJS..136..703L - Astrophys. J., Suppl. Ser., 136, 703-734 (2001/October-0)

A survey for infall motions toward starless cores. II. CS (2-1) and N2H+ (1-0) mapping observations.

LEE C.W., MYERS P.C. and TAFALLA M.

Abstract (from CDS):

We present the results of an extensive mapping survey of ``starless'' cores in the optically thick line of CS (2-1) and the optically thin lines of N2H+ (1-0) and C18O (1-0). The purpose of this survey was to search for signatures of extended inward motions. A total of 53 targets were observed in the three lines with the FCRAO 14 m telescope. Thirty-three regions were mapped in both CS and N2H+, and thirty seven well-defined N2H+ cores have been identified. The N2H+ emission is generally compact enough to find a peak, while the CS and C18O emissions are more diffuse. For each core, we have derived the normalized velocity difference (δVCS) between the thick CS and thin N2H+ peak velocities. We define 10 ``strong'' and nine ``probable'' infall candidates, based on δVCS analysis and on the spectral shapes of CS lines. From our analysis of the blue-skewed CS spectra and the δVCS parameter, we find typical infall radii of 0.06-0.14 pc. Also, using a simple two-layer radiative transfer model to fit the profiles, we derive one-dimensional infall speeds, the values of half of which lie in the range of 0.05-0.09 km.s–1. These values are similar to those found in L1544 by Tafalla et al., and this result confirms that infall speeds in starless cores are generally faster than expected from ambipolar diffusion in a strongly subcritical core. In addition, the observed infall regions are too extended to be consistent with the ``inside-out'' collapse model applied to a very low mass star. In the largest cores, the spatial extent of the CS spectra with infall asymmetry is larger than the extent of the N2H+ core by a factor of 2-3. All these results suggest that extended inward motions are a common feature in starless cores, and that they could represent a necessary stage in the condensation of a star-forming dense core.

Abstract Copyright:

Journal keyword(s): ISM: Globules - ISM: Kinematics and Dynamics - Stars: Formation

Nomenclature: Tables 1-4: [LM99] LNNNNA, [LM99] LNNNNA-N, [LM99] LNNNN-A, [LM99] LNNNN-W, [LM99] LNNNNAN, [LM99] BNNNA, [LM99] BNNN-N, [LM99] CB NNN, [LM99] CB NNN-N, [LM99] DC LLLl+BB, [LM99] DC LLLl+BB-N, [LM99] DC LLLl+BBb, [LM99] DC LLLl+BBb-N, [LM99] VNN, [LM99] VNN-N, [LM99] Ch NN, [LM99] VNN, [LM99] Ch NN-N, [LM99] Mu NN, [LM99] TMC NA, [LM99] TMC N-N, N=53+37+37+19.

Simbad objects: 75

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Number of rows : 75

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 1333 DNe 02 26 04 +75 28.5           ~ 50 0
2 LDN 1355 DNe 02 52.7 +69 02           ~ 15 0
3 NAME [BM89] L1498 PoC 04 10 51.4 +25 09 58           ~ 187 0
4 LDN 1498 DNe 04 11.0 +24 58           ~ 243 0
5 NAME [BM89] L1495 PoC 04 14 08.2 +28 09 31           ~ 170 0
6 [LM99] L1495B cor 04 18 05.1 +28 22 22           ~ 3 0
7 LDN 1495 DNe 04 18.1 +27 37           ~ 280 1
8 NAME L1495N-A cor 04 18 31.8 +28 27 31           ~ 11 0
9 LDN 1495A DNe 04 18.6 +28 25           ~ 9 0
10 NAME L1495A-S cor 04 18 41.8 +28 23 50           ~ 10 0
11 NAME [BM89] L1521B cor 04 24 12.7 +26 36 53           ~ 60 0
12 NAME [BM89] L1400 DNe 04 24 56.1 +55 01 52           ~ 16 0
13 LDN 1400 DNe 04 25.0 +54 57           ~ 20 0
14 LDN 1521F DNe 04 28 39.3 +26 51 43           ~ 177 1
15 NAME [BM89] L1521E DNe 04 29 21.0 +26 14 19           ~ 83 1
16 LDN 1400FD DNe 04 29 51.4 +54 12 19           ~ 1 0
17 NAME [BM89] L1400A DNe 04 30 40.1 +54 52 36           ~ 13 0
18 Bad 16 Y*O 04 30 50.280 +23 00 08.85   18.08   14.95   F1 132 0
19 LDN 1445 DNe 04 32.1 +46 36           ~ 15 0
20 NAME Kutner's Cloud MoC 04 32 44.6 +24 23 13           ~ 209 0
21 NAME [BM89] TMC-2 PoC 04 32 44.7 +24 25 13           ~ 186 0
22 [OMK96] 32 PoC 04 39.5 +25 51           ~ 3 0
23 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1334 0
24 [OMK96] 34 PoC 04 41.8 +25 42           ~ 3 0
25 LDN 1507A DNe 04 42 38.3 +29 43 45           ~ 18 0
26 LDN 1507 MoC 04 43 32 +29 40.0           ~ 32 0
27 LDN 1517C PoC 04 54 47.4 +30 34 48           ~ 20 0
28 LDN 1517A PoC 04 55 06.3 +30 33 40           ~ 25 0
29 NAME [BM89] L1517B cor 04 55 18.8 +30 38 04           ~ 128 0
30 LDN 1512 MoC 05 04 09.7 +32 43 09           ~ 159 0
31 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 661 0
32 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 434 1
33 LDN 1552 DNe 05 17.7 +26 03           ~ 21 0
34 LDN 1622 DNe 05 54 28 +01 48.2           ~ 89 0
35 [LM99] L1622A2 cor 05 54 38.8 +01 53 44           ~ 7 0
36 [LM99] L1622A1 cor 05 54 53.1 +01 57 23           ~ 6 0
37 LDN 134A DNe 15 53 36.4 -04 35 26           ~ 48 0
38 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 675 1
39 NAME Ophiuchus D MoC 16 28 29.2 -24 18 25           ~ 102 0
40 LDN 1696B cor 16 28 59.3 -24 20 43           ~ 19 0
41 LDN 1709A DNe 16 30 50.7 -23 41 03           ~ 24 0
42 LDN 1709C DNe 16 33 53.3 -23 38 32           ~ 12 0
43 LDN 1689B DNe 16 34 42.1 -24 36 11           ~ 131 0
44 LDN 204C DNe 16 47 38.4 -12 08 04           ~ 10 0
45 LDN 204B DNe 16 47 47.1 -11 55 16           ~ 9 0
46 LDN 191 DNe 16 47.8 -12 45           ~ 13 0
47 LDN 204F cor 16 47 48.4 -11 56 06           ~ 6 0
48 LDN 158 DNe 16 47 50 -14 05.3           ~ 32 0
49 NAME LDN 234E C PoC 16 48 01.8 -10 46 20           ~ 3 0
50 NAME LDN 234E N PoC 16 48 02.0 -10 47 08           ~ 3 0
51 LDN 234E DNe 16 48 04.5 -10 56 58           ~ 25 0
52 NAME [LM99] L234E-S cor 16 48 08.6 -10 57 25           ~ 13 0
53 LDN 63 DNe 16 50 15.5 -18 06 06           ~ 74 0
54 LDN 492 DNe 18 15 51 -03 44.4           ~ 43 0
55 [LM99] L429-1 cor 18 17 11.6 -08 13 30           ~ 10 0
56 [LM99] L429-2 cor 18 17 16.3 -08 17 52           ~ 6 0
57 LDN 663 DNe 19 36 55 +07 34.4           ~ 544 0
58 [LM99] L694-2 cor 19 41 04.6 +10 57 02           ~ 58 0
59 LDN 1148 DNe 20 40 31.6 +67 21 45           ~ 59 0
60 LDN 1147 DNe 20 40 32 +67 20.7           ~ 29 0
61 LDN 1148B DNe 20 41 03.2 +67 22 47           ~ 3 0
62 LDN 1148A DNe 20 41 10.9 +67 20 35           ~ 1 0
63 LDN 1155C DNe 20 43 18.1 +67 50 36           ~ 30 0
64 [LM99] L1155C-2 cor 20 43 22.1 +67 50 31           ~ 8 0
65 [LM99] L1155C1 cor 20 43 29.9 +67 52 42           ~ 9 0
66 NAME [BM89] L1082C DNe 20 51 27.4 +60 19 00           ~ 32 0
67 [LM99] L981-1 cor 21 00 13.2 +50 20 06           ~ 10 0
68 LDN 1063 DNe 21 07.9 +56 18           ~ 11 0
69 LDN 1103 DNe 21 41.7 +56 44           ~ 22 0
70 LDN 1235 DNe 22 14 55 +73 25.0           ~ 25 0
71 LDN 1235B cor 22 16 00.2 +73 22 30           ~ 3 0
72 LDN 1197 DNe 22 37 20 +58 56.1           ~ 29 0
73 LDN 1234 DNe 23 17 43 +62 26.1           ~ 11 0
74 LDN 1262 MoC 23 25 47 +74 17.6           ~ 130 0
75 LDN 1253 DNe 23 56 32 +58 31.7           ~ 52 0

    Equat.    Gal    SGal    Ecl

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2020.01.28-23:56:55

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