2012ApJ...748...75L


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.06CET13:52:29

2012ApJ...748...75L - Astrophys. J., 748, 75 (2012/April-1)

A high-resolution study of the H I-H2 transition across the Perseus molecular cloud.

LEE M.-Y., STANIMIROVIC S.Z., DOUGLAS K.A., KNEE L.B.G., DI FRANCESCO J., GIBSON S.J., BEGUM A., GRCEVICH J., HEILES C., KORPELA E.J., LEROY A.K., PEEK J.E.G., PINGEL N.M., PUTMAN M.E. and SAUL D.

Abstract (from CDS):

To investigate the fundamental principles of H2 formation in a giant molecular cloud, we derive the H I and H2 surface density (Σ_H I _ and ΣH2) images of the Perseus molecular cloud on sub-pc scales (∼0.4 pc). We use the far-infrared data from the Improved Reprocessing of the IRAS Survey and the V-band extinction image provided by the COMPLETE Survey to estimate the dust column density image of Perseus. In combination with the H I data from the Galactic Arecibo L-band Feed Array H I Survey and an estimate of the local dust-to-gas ratio, we then derive the ΣH2 distribution across Perseus. We find a relatively uniform Σ_ H I_∼ 6-8 M/pc2 for both dark and star-forming regions, suggesting a minimum H I surface density required to shield H2 against photodissociation. As a result, a remarkably tight and consistent relation is found between ΣH2/Σ_ H I_and Σ_H I_+ ΣH2. The transition between the H I- and H2-dominated regions occurs at N(H I) + 2N(H2) ∼ (8-14)x1020/cm2. Our findings are consistent with predictions for H2 formation in equilibrium, suggesting that turbulence may not be of primary importance for H2formation. However, the importance of a warm neutral medium for H2shielding, an internal radiation field, and the timescale of H2 formation still remain as open questions. We also compare H2and CO distributions and estimate the fraction of "CO-dark" gas, fDG∼ 0.3. While significant spatial variations of fDG are found, we do not find a clear correlation with the mean V-band extinction.

Abstract Copyright:

Journal keyword(s): dust, extinction - infrared: ISM - ISM: individual: Perseus - ISM: molecules - radio lines: ISM

Simbad objects: 26

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Number of rows : 26

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 V* VX Cas Ae* 00 31 30.6816836826 +61 58 50.982831889 11.83 11.59 10.50 11.19 10.94 A0Vep 125 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9131 1
3 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 603 2
4 LDN 1448 DNe 03 22.5 +30 35           ~ 459 0
5 BD+30 540 *iN 03 25 50.1005913741 +30 55 54.160508084   9.49 9.22     B8V 22 1
6 LDN 1451 DNe 03 26.1 +30 10           ~ 41 0
7 LDN 1455 DNe 03 28 00.6480 +30 07 58.800           ~ 168 1
8 HD 21483 * 03 28 46.6535161214 +30 22 31.233721714 7.080 7.390 7.070     B3III 134 0
9 NGC 1333 SFR 03 28 55 +31 22.2   10.9       ~ 1184 1
10 BD+30 549 Y*O 03 29 19.7770675177 +31 24 57.044403187 10.81 10.95 10.47 10.587   B8:p 91 1
11 Barnard 1 MoC 03 33 16.3 +31 07 51           ~ 248 0
12 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1011 0
13 4C 32.14 QSO 03 36 30.10760600 +32 18 29.3422210     17.50 16.6   ~ 568 1
14 NAME Per B1-E PoC 03 36 45.0 +31 12 40           ~ 27 0
15 NAME Per Region reg 03 37 00.0 +31 15 00           ~ 223 0
16 HD 278942 ** 03 39 55.6857366532 +31 55 33.189050871   10.25 9.15     O9.5-B0 43 1
17 * o Per * 03 42 22.6455526 +33 57 54.089323 4.13 4.912 4.972     B0.5V 279 0
18 * omi Per ** 03 44 19.13204 +32 17 17.6929 3.13 3.88 3.83 3.71 3.71 B1III 572 0
19 IC 348 OpC 03 44 34 +32 09.8           ~ 1206 1
20 HD 281159 Y*? 03 44 34.197 +32 09 46.27 9.19 9.21 8.53   7.850 B5V 199 2
21 NAME [BM89] B5 DNe 03 47 38.3 +32 52 43           ~ 220 0
22 LDN 1471 DNe 03 48.0 +32 54           ~ 276 0
23 3CR 93.1 Sy2 03 48 46.9076031514 +33 53 15.460411800   20.723   19.110   ~ 124 1
24 NAME Tau-Aur Region SFR 04 30 +25.0           ~ 1183 1
25 NAME Taurus Dark Cloud SFR 04 41.0 +25 52           ~ 3333 0
26 IRAS 23545+6508 * 23 57 05.2 +65 25 11           B 49 0

    Equat.    Gal    SGal    Ecl

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2019.12.06-13:52:29

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