2010ApJ...725..466C


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.20CEST12:22:04

2010ApJ...725..466C - Astrophys. J., 725, 466-479 (2010/December-2)

Magnetic fields in interstellar clouds from Zeeman observations: inference of total field strengths by Bayesian analysis.

CRUTCHER R.M., WANDELT B., HEILES C., FALGARONE E. and TROLAND T.H.

Abstract (from CDS):

The only direct measurements of interstellar magnetic field strengths depend on the Zeeman effect, which samples the line-of-sight component Bz of the magnetic vector. In this paper, we use a Bayesian approach to analyze the observed probability density function (PDF) of Bz from Zeeman surveys of H I, OH, and CN spectral lines in order to infer a density-dependent stochastic model of the total field strength B in diffuse and molecular clouds. We find that at n < 300/cm3 (in the diffuse interstellar medium sampled by H I lines), B does not scale with density. This suggests that diffuse clouds are assembled by flows along magnetic field lines, which would increase the density but not the magnetic field strength. We further find strong evidence for B in molecular clouds being randomly distributed between very small values and a maximum that scales with volume density n as B ∝ n 0.65 for n>300/cm3, with an uncertainty at the 50% level in the power-law exponent of about ±0.05. This break-point density could be interpreted as the average density at which parsec-scale clouds become self-gravitating. Both the uniform PDF of total field strengths and the scaling with density suggest that magnetic fields in molecular clouds are often too weak to dominate the star formation process. The stochasticity of the total field strength B implies that many fields are so weak that the mass/flux ratio in many clouds must be significantly supercritical. A two-thirds power law comes from isotropic contraction of gas too weakly magnetized for the magnetic field to affect the morphology of the collapse. On the other hand, our study does not rule out some clouds having strong magnetic fields with critical mass/flux ratios.

Abstract Copyright:

Journal keyword(s): ISM: magnetic fields - polarization - stars: formation

Simbad objects: 95

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Number of rows : 95

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 3C 18.0 Sy2 00 40 50.5 +10 03 27   18.5       ~ 140 2
2 NAME W 3 OH HII 02 27 04.1 +61 52 22           ~ 928 2
3 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 942 3
4 LDN 1457S DNe 02 56 05.9 +19 25 05           ~ 4 0
5 3C 75 PaG 02 57 41.64 +06 01 28.0           ~ 279 1
6 NGC 1218 Sy1 03 08 26.22380280 +04 06 39.3008111   12.84       ~ 335 1
7 LDN 1448 DNe 03 22.5 +30 35           ~ 459 0
8 LDN 1455 DNe 03 28 00.6480 +30 07 58.800           ~ 167 1
9 NGC 1333 SFR 03 28 55 +31 22.2   10.9       ~ 1181 1
10 Barnard 1 MoC 03 33 16.3 +31 07 51           ~ 244 0
11 NAME [BM89] B5 DNe 03 47 38.3 +32 52 43           ~ 220 0
12 LDN 1471 DNe 03 48.0 +32 54           ~ 275 0
13 2C 349 Sy2 03 58 54.4385123848 +10 26 02.820631972   16.68 15.41     ~ 317 2
14 LDN 1495W DNe 04 13.1 +28 10           ~ 22 0
15 NAME Taurus 16 PoC 04 18.1 +28 23           ~ 7 0
16 [OMK96] 6 PoC 04 18.4 +28 24           ~ 5 0
17 IRAS 04191+1523 Y*O 04 22 00.439 +15 30 21.21           ~ 182 0
18 [LM99] B217-2 cor 04 28 08.6 +26 20 53           ~ 14 0
19 LDN 1521F DNe 04 28 39.3 +26 51 43           ~ 176 1
20 [DB2002b] G173.42-16.34 cor 04 29 18.6 +24 31 34           ~ 6 0
21 NAME [BM89] L1521E DNe 04 29 21.0 +26 14 19           ~ 82 1
22 [LM99] L1524-4 cor 04 30 05.7 +24 25 16           ~ 11 0
23 Bad 16 Y*O 04 30 50.280 +23 00 08.85   18.08   14.95   F1 132 0
24 [LM99] L1551S-1 cor 04 31 47.8 +18 07 36           ~ 4 0
25 NAME Tau G PoC 04 31.9 +24 25           ~ 6 0
26 LDN 1521 DNe 04 33.1 +26 06           ~ 47 0
27 Mrk 1506 Sy1 04 33 11.0958197353 +05 21 15.617543663   15.72 15.05 10.08   ~ 1805 2
28 [LM99] 46 cor 04 35 51.3 +24 09 21           ~ 15 0
29 NAME Per B AGN 04 37 04.37510272 +29 40 13.8184969   21.7       ~ 458 2
30 Barnard 220 DNe 04 41 38.8 +26 00 42           ~ 119 0
31 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1326 0
32 LDN 1534 DNe 04 41 46 +25 41.4           ~ 42 0
33 [LM99] L1507A1 cor 04 42 38.6 +29 43 45           ~ 7 0
34 LDN 1507 MoC 04 43 32 +29 40.0           ~ 32 0
35 3C 131 Rad 04 53 23.3 +31 29 24           ~ 64 1
36 3C 132 rG 04 56 42.922 +22 49 23.06   18.5       ~ 141 1
37 ICRF J050258.4+251625 AGN 05 02 58.47478439 +25 16 25.2761557   20       ~ 155 1
38 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 652 0
39 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 434 1
40 HD 33189 * 05 08 37.4732604515 +01 16 34.841537460   8.70 8.71     A0V 13 0
41 ICRF J052109.8+163822 Sy1 05 21 09.88592749 +16 38 22.0517668   19.37 18.84 18.480   ~ 726 1
42 3C 142.1 rG 05 31 29.40 +06 30 25.0   21       ~ 81 1
43 M 1 SNR 05 34 31.94 +22 00 52.2           ~ 5486 4
44 NAME OMC 1S PoC 05 35 14.5 -05 25 49           ~ 67 1
45 NAME OMC-N4 Y*? 05 35 16.8 -05 19 19           ~ 13 0
46 NAME OMC-N1 PoC 05 35 20.5 -05 17 33           ~ 3 0
47 NGC 2024 Cl* 05 41 43 -01 50.5           ~ 1057 1
48 LDN 1647 DNe 05 42.4 -09 58           ~ 24 1
49 NAME SH 2-255 IRS 1 Y*O 06 12 54.0060 +17 59 22.958           ~ 310 0
50 IC 2162 HII 06 13 04.1 +17 58 44           ~ 333 2
51 ICRF J084047.5+131223 Sy1 08 40 47.58841798 +13 12 23.5641152   18.58 18.15 17.622   ~ 377 1
52 3C 225 rG 09 42 15.4 +13 45 51   19 20.0     ~ 115 2
53 3C 225B Rad 09 42 15.41 +13 45 51.0           ~ 24 0
54 3C 237.0 rG 10 08 00.0529 +07 30 16.830   21       ~ 170 0
55 VV 204 AGN 15 04 57.120 +26 00 58.46   15.24       ~ 272 0
56 4C 26.47 AGN 15 13 40.0227468596 +26 07 23.710955469   16.30       ~ 216 1
57 3C 318.0 QSO 15 20 05.4779632581 +20 16 05.487892990   21.93 20.9     ~ 171 1
58 LDN 134 MoC 15 53 36.3 -04 35 26           ~ 193 0
59 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 674 1
60 3C 333 Rad 16 17 15.7 +21 07 29           ~ 28 1
61 NAME rho Oph 1 PoC 16 27.3 -24 34           ~ 7 0
62 NAME rho Oph 2 PoC 16 27.5 -24 18           ~ 6 0
63 NAME Hercules A BiC 16 51 08.024 +04 59 34.91     18.25     ~ 426 1
64 2C 1473 AGN 17 20 28.147 -00 58 47.12   15.36       ~ 295 1
65 NGC 6357 HII 17 26.5 -34 12           ~ 244 0
66 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11004 0
67 NAME Sgr B2 (North) Rad 17 47 20.2 -28 22 21           ~ 493 1
68 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1851 1
69 NAME Sgr B2 Main Rad 17 47 20.5 -28 23 06           ~ 321 1
70 4C 13.65 Rad 17 58 31.00 +13 28 34.0           ~ 23 1
71 SSTGLMC G010.6243-00.3840 Rad 18 10 28.80 -19 55 48.5           ~ 4 0
72 NAME M17SWn Cld 18 20 22.9 -16 11 32           ~ 5 0
73 NAME M17SWs Cld 18 20 24.9 -16 13 42           ~ 5 0
74 LBN 028.77+03.43 HII 18 31 26.5 -02 04 22           ~ 178 2
75 4C 13.67 Rad 18 37 29.10 +13 30 14.0           ~ 15 1
76 W 49b SNR 19 11 09.000 +09 06 24.00           ~ 384 1
77 LDN 723 DNe 19 18 12 +19 13.6           ~ 153 0
78 LDN 771 DNe 19 20 50 +23 29.9           ~ 18 0
79 LDN 774 DNe 19 22.9 +23 26           ~ 6 0
80 LDN 663 DNe 19 36 55 +07 34.4           ~ 535 0
81 LDN 694 DNe 19 40.7 +10 57           ~ 26 0
82 LDN 810 DNe 19 45 23.8630 +27 50 57.840           ~ 62 0
83 SH 2-88 B HII 19 46 47.329 +25 12 45.62           ~ 150 2
84 3C 409 Rad 20 14 27.6 +23 34 53           ~ 79 1
85 3C 410 QSO 20 20 06.5624875736 +29 42 14.183853306   19.5       ~ 106 0
86 LDN 889 DNe 20 27 13.1 +40 05 54           ~ 11 0
87 SH 2-106 HII 20 27 26.8 +37 22 49           ~ 406 2
88 NAME S106-OH Cld 20 27 28.4 +37 22 41           ~ 2 0
89 NAME S106-CN PoC 20 27 29.5 +37 22 54           ~ 4 0
90 NAME DR 21(OH) MM 2 Mas 20 39 00.4 +42 22 44           ~ 39 0
91 NAME DR 21(OH) MM 1 Mas 20 39 01.1 +42 22 49           ~ 41 0
92 2MASX J21234458+2504272 Sy2 21 23 44.582 +25 04 27.23   17.660 16.350     ~ 297 0
93 SH 2-140 OpC 22 19 07.8 +63 17 07           ~ 628 2
94 IRAS 22176+6303 SFR 22 19 17.978 +63 18 52.92           ~ 587 0
95 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2439 2

    Equat.    Gal    SGal    Ecl

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2019.10.20-12:22:04

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