2012A&A...541A..58L


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.19CET15:28:11

2012A&A...541A..58L - Astronomy and Astrophysics, volume 541A, 58-58 (2012/5-1)

Imaging diffuse clouds: bright and dark gas mapped in CO.

LISZT H.S. and PETY J.

Abstract (from CDS):

We wish to relate the degree scale structure of galactic diffuse clouds to sub-arcsecond atomic and molecular absorption spectra obtained against extragalactic continuum background sources. We used the ARO 12 m telescope to map J=1-0 CO emission at 1' resolution over 30' fields around the positions of 11 background sources occulted by 20 molecular absorption line components, of which 11 had CO emission counterparts. We compared maps of CO emission to sub-arcsec atomic and molecular absorption spectra and to the large-scale distribution of interstellar reddening. 1) The same clouds, identified by their velocity, were seen in absorption and emission and atomic and molecular phases, not necessarily in the same direction. Sub-arcsecond absorption spectra are a preview of what is seen in CO emission away from the continuum. 2) The CO emission structure was amorphous in 9 cases, quasi-periodic or wave-like around B0528+134 and tangled and filamentary around BL Lac. 3) Strong emission, typically 4-5K at EB–V≤0.15mag and up to 10-12K at EB–V≲0.3mag was found, much brighter than toward the background targets. Typical covering factors of individual features at the 1K.km/s level were 20%. 4) CO-H2 conversion factors as much as 4-5 times below the mean value N(H2)/WCO=2x1020H2/cm2/(K.km/s) are required to explain the luminosity of CO emission at/above the level of K.km/s. Small conversion factors and sharp variability of the conversion factor on arcminute scales are due primarily to CO chemistry and need not represent unresolved variations in reddening or total column density. Like Fermi and Planck we see some gas that is dark in CO and other gas in which CO is overluminous per H2. A standard CO-H2 conversion factor applies overall owing to balance between the luminosities per H2 and surface covering factors of bright and dark CO, but with wide variations between sightlines and across the faces of individual clouds.

Abstract Copyright:

Journal keyword(s): ISM: clouds - ISM: molecules

Simbad objects: 27

goto Full paper

goto View the reference in ADS

Number of rows : 27

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 6C 021252+733537 BLL 02 17 30.8143057005 +73 49 32.612359669     19.0 18.97   ~ 400 1
2 6C 022440+670742 QSO 02 28 50.05148948 +67 21 03.0293039   19.5   18.1   ~ 224 1
3 4C 50.11 QSO 03 59 29.74726473 +50 57 50.1615765           ~ 388 1
4 3C 111 Sy1 04 18 21.2773655604 +38 01 35.801523843   19.75 18.05     ~ 841 1
5 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1327 0
6 Barnard 30 DNe 05 30.3 +12 46           ~ 39 0
7 QSO J0530+13 QSO 05 30 56.41672 +13 31 55.1495     20.0 19.35   ~ 871 1
8 * lam Ori ** 05 35 08.27761 +09 56 02.9611 2.45 3.48 3.66 3.72 3.89 O8IIIf+B0.5V 261 1
9 NAME lam Ori Molecular Ring HII 05 35.3 +09 56           ~ 64 1
10 NAME ORI MOL CLOUD MoC 05 56 -01.8           ~ 812 1
11 QSO J0730-116 QSO 07 30 19.11247420 -11 41 12.6005110     20.30 20.3   ~ 249 1
12 [DB2002b] G171.83+26.72 MoC 07 35.9 +46 41           ~ 12 0
13 QSO B0736+01 QSO 07 39 18.03389693 +01 37 04.6178588   16.90 16.47 16.19   ~ 613 1
14 NAME M 81-82 Group GrG 09 55 +69.1           ~ 616 0
15 SAMS 2 MoC 09 57.0 +69 20           ~ 2 0
16 6C 095456+654857 BLL 09 58 47.2452838930 +65 33 54.821524491     17.0 15.75   ~ 605 1
17 SAMS 1 MoC 10 03 30.3 +68 41 42           ~ 2 0
18 NAME Polaris Flare MoC 11 00 14.8 +86 10 52           ~ 158 1
19 * zet Oph Be* 16 37 09.5390545 -10 34 01.529471 1.73 2.58 2.56 2.46 2.50 O9.2IVnn 1709 2
20 QSO B1730-130 QSO 17 33 02.70578476 -13 04 49.5481484   18 18.5 18.78   ~ 957 1
21 ICRF J192748.4+735801 Sy1 19 27 48.4944745594 +73 58 01.571908984     15.5 15.11   ~ 484 2
22 QSO B1954+513 QSO 19 55 42.73826837 +51 31 48.5461210     18.5 17.34   ~ 208 1
23 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 1975 1
24 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2441 2
25 MBM 53 MoC 23 08 07.3 +22 56 15           ~ 41 0
26 [DB2002b] G89.19-40.94 MoC 23 08 24 +15 05.3           ~ 77 0
27 NAME Local Bubble ISM ~ ~           ~ 663 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2012A&A...541A..58L and select 'bookmark this link' or equivalent in the popup menu


2019.11.19-15:28:11

© Université de Strasbourg/CNRS

    • Contact