2020A&A...634A.139W


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.28CET06:23:41

2020A&A...634A.139W - Astronomy and Astrophysics, volume 634A, 139-139 (2020/2-1)

Cloud formation in the atomic and molecular phase: H I self absorption (HISA) towards a giant molecular filament.

WANG Y., BIHR S., BEUTHER H., RUGEL M.R., SOLER J.D., OTT J., KAINULAINEN J., SCHNEIDER N., KLESSEN R.S., GLOVER S.C.O., McCLURE-GRIFFITHS N.M., GOLDSMITH P.F., JOHNSTON K.G., MENTEN K.M., RAGAN S., ANDERSON L.D., URQUHART J.S., LINZ H., ROY N., SMITH R.J., BIGIEL F., HENNING T. and LONGMORE S.N.

Abstract (from CDS):

Molecular clouds form from the atomic phase of the interstellar medium. However, characterizing the transition between the atomic and the molecular interstellar medium (ISM) is a complex observational task. Here we address cloud formation processes by combining HI self absorption (HISA) with molecular line data. Column density probability density functions (N-PDFs) are a common tool for examining molecular clouds. One scenario proposed by numerical simulations is that the N-PDF evolves from a log-normal shape at early times to a power-law-like shape at later times. To date, investigations of N-PDFs have been mostly limited to the molecular component of the cloud.In this paper, we study the cold atomic component of the giant molecular filament GMF38.1-32.4a (GMF38a, distance = 3.4kpc, length∼230pc), calculate its N-PDFs, and study its kinematics. We identify an extended HISA feature, which is partly correlated with the 13CO emission. The peak velocities of the HISA and 13CO observations agree well on the eastern side of the filament, whereas a velocity offset of approximately 4km/s is found on the western side. The sonic Mach number we derive from the linewidth measurements shows that a large fraction of the HISA, which is ascribed to the cold neutral medium (CNM), is at subsonic and transonic velocities. The column density of the CNM part is on the order of 1020 to 1021cm–2. The column density of molecular hydrogen, traced by 13CO, is an order of magnitude higher. The N-PDFs from HISA (CNM), HI emission (the warm and cold neutral medium), and 13CO (molecular component) are well described by log-normal functions, which is in agreement with turbulent motions being the main driver of cloud dynamics. The N-PDF of the molecular component also shows a power law in the high column-density region, indicating self-gravity. We suggest that we are witnessing two different evolutionary stages within the filament. The eastern subregion seems to be forming a molecular cloud out of the atomic gas, whereas the western subregion already shows high column density peaks, active star formation, and evidence of related feedback processes.

Abstract Copyright: © Y. Wang et al. 2020

Journal keyword(s): ISM: atoms - ISM: clouds - ISM: molecules - radio lines: ISM - stars: formation

VizieR on-line data: <Available at CDS (J/A+A/634/A139): list.dat fits/*>

CDS comments: G34.133+ 0.471 not in SIMBAD.

Simbad objects: 22

goto Full paper

goto View the reference in ADS

Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Per Region reg 03 37 00.0 +31 15 00           ~ 234 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3641 0
3 IC 2599 HII 10 37.7 -58 39           ~ 35 2
4 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3839 2
5 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11996 0
6 PMN J1822-0939 Rad 18 22 28.70 -09 38 57.0           ~ 32 1
7 SNR G030.8-00.0 SNR 18 47 32 -01 56.5           ~ 457 0
8 NVSS J185146+003532 Rad 18 51 46.72295 +00 35 32.3649           ~ 56 1
9 [WWB83] G033.91+0.11 HII 18 52 50.4 +00 55 29           ~ 90 1
10 GPSR5 34.255+0.145 Rad 18 53 20.08 +01 14 39.2           ~ 2 0
11 [WBH2005] G033.810-0.190 HII 18 53 42.9 +00 41 43           ~ 2 1
12 NVSS J185535+025119 Rad 18 55 35.43646 +02 51 19.5629           ~ 14 1
13 GPSR5 36.056+0.356 Rad 18 55 52.21 +02 56 32.6           ~ 2 0
14 [KJB2003] G35.574+0.068 HII 18 56 01.0 +02 22 54           ~ 4 1
15 SNR G034.6-00.5 SNR 18 56 10.650 +01 13 21.30           ~ 845 2
16 [ERG2015] 6197 cor 18 57 08.7097 +01 39 05.647           ~ 13 0
17 AGAL G036.406+00.021 smm 18 57 42 +03 06.1           ~ 7 0
18 NVSS J185802+031316 Rad 18 58 02.35260055 +03 13 16.3012572           ~ 20 1
19 AGAL G036.839-00.022 cor 18 58 39 +03 28.0           ~ 7 0
20 AGAL G036.666-00.114 Y*O 18 58 40 +03 16.2           ~ 7 0
21 AGAL G036.826-00.039 Y*O 18 58 41 +03 26.8           ~ 9 0
22 [RHT2014] GMF G038.1-32.4a ISM 20 57 -10.2           ~ 6 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2020A&A...634A.139W and select 'bookmark this link' or equivalent in the popup menu


2021.02.28-06:23:41

© Université de Strasbourg/CNRS

    • Contact