J/ApJ/390/108 Galactic Worms (Koo+, 1992)
Galactic worms. I. Catalog of worm candidates.
Koo B.-C., Heiles C., Reach W.T.
<Astrophys. J., 390, 108-132 (1992)>
=1992ApJ...390..108K 1992ApJ...390..108K
ADC_Keywords: H I data ; Galactic plane ; Radio continuum ; H II regions ;
Interstellar medium
Keywords: Catalogs; ISM: Bubbles ; ISM: HII Regions ;
Radio Continuum: Interstellar ; Radio Lines: Atomic
Abstract:
A catalog of candidates for the Galactic Worms that are possibly the
walls surrounding the superbubbles is compiled; 118 isolated
structures that appear both in HI and in IR (60 and 100µm). 52 are
possibly associated with HII regions. It is found that the 100-µm
emissivity increases systematically toward the Galactic interior,
which is consistent with the increase of the general interstellar
radiation field. The 100-µm emissivity of the structures associated
with the HII regions is larger than that of the structures without
associated HII regions. The 60-100µm ratio is large, 0.28±0.03,
which may indicate that the grains associated with the atomic gas have
a relatively large population of small grains. 35 structures appear in
the 408MHz continuum. The IR and the radio continuum properties
suggest that the 408MHz continuum emission in those structures is very
likely thermal. The implications of these results on the ionization of
gas far from the Galactic plane are discussed.
Description:
118 structures catalogued as "worm candidates" are found on the basis
of the maps in HI-21cm, IRAS 100 and 60µm. The 21cm maps of the
Galactic Plane (b < 10°) result from available surveys (Kerr et
al. 1986A&AS...66..373K 1986A&AS...66..373K; Weaver & Williams 1973A&AS....8....1W 1973A&AS....8....1W, Cat.
VIII/11) and from new observations near the Galactic center during
1989 and 1990 using the Hat Creek 26m telescope.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 150 118 Catalog of Worm Candidates
table3.dat 76 35 Worm candidates with associated radio continuum
emission (at 485MHz)
table5.dat 155 52 Worm candidates near HII regions
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/118] Running number, used in Fig.2
5- 6 A2 --- --- [GW]
8- 16 A9 --- GW Galactic Worm name (G1)
18- 21 F4.1 deg Dl [1/15] Angular size in longitude
23- 25 F3.1 deg Db [1/9] Angular size in latitude
28- 33 F6.1 km/s V.min [-131/71] Minimum velocity of structure (2)
34 A1 --- u_V.min [?] double or multiple peaks (2)
36- 40 F5.1 km/s V.max [-83/109] Maximum velocity of structure (2)
41 A1 --- u_V.max [?] double or multiple peaks (2)
43- 46 F4.1 kpc Rg [1.5/19]?=- Galactocentric radius of
structure (3)
47 A1 --- u_Rg [?] Uncertainty flag on Rg (3)
49- 52 F4.1 kpc d [0.1/11.1]?=- Distance to structure (4)
53 A1 --- u_d [?] Uncertainty flag on d
55- 59 I5 pc z.min [-1680/520]?=- Minimum height above the
Galactic plane
60 A1 --- u_z.min [?] Uncertainty flag on z.min
62- 66 I5 pc z.max [-1310/1580]?=- Maximum height above the
Galactic plane
67 A1 --- u_z.max [?] Uncertainty flag on z.max
69- 72 F4.1 deg2 A(HI) [1.3/32] Area of the structure in HI
75- 78 F4.1 10+20cm-2 N(HI) Average HI column density
80- 84 F5.1 10+20cm-2 e_N(HI) rms deviation of NHI
86- 93 E8.2 Msun M(HI) ?=- HI mass
95- 98 F4.1 deg2 A(IR) [1.3/45] Area of the structure at 100µm
100-103 F4.2 --- r [0/1] cross-correlation HI/100µm (G2)
105-109 F5.1 MJy/sr I100 Average 100µm surface brightness
111-115 F5.1 MJy/sr e_I100 rms deviation of I100
117-121 F5.1 MJy/sr I60 Average 60µm surface brightness
123-127 F5.1 MJy/sr e_I60 rms deviation of I60
130-133 F4.2 --- 60/100 [0/1.2] Median value of the 60 to 100µm
surface brightness ratio (5)
135-138 F4.2 --- e_60/100 rms deviation of 60/100
141-144 F4.1 aJy.m2/sr Em median value of the 100µm emissivity (6)
146-150 F5.1 aJy.m2/sr e_Em rms deviation of the 100µm emissivity (6)
--------------------------------------------------------------------------------
Note (2): these columns contain the minimum and the maximum velocities
determined at the half-maximum of the Gaussian fitting, respectively.
The velocities of those structures with double or multiple peaks are
listed with a question mark.
Note (3): the Galactocentric radius is calculated assuming R☉=8.5kpc
and a flat rotation curve with v☉=220km/s. The velocities of
some structures are forbidden by the flat Galactic rotation model,
and for these the Galactocentric radius could not be determined. The
Galactocentric radii of those structures with uncertain velocities are
listed with question marks, as also for the other distance-dependent
physical parameters.
Note (4): For structures in the inner Galaxy, we always take the "near"
distance. With our method in this paper, it is hard to detect
structures on the other side of the Galaxy unless they are very large
(see Sect. 4.1; see also some possible exceptions in Sect. 5).
Note (5): obtained by the pixel-by-pixel comparison
Note (6): the emissivity is defined as the median of I(100µm)//N(HI),
expressed in MJy.sr-1/(1020cm-2) = 10-18Jy.m2.sr-1.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [GW]
4- 12 A9 --- GW Galactic Worm name
14- 17 F4.1 deg2 Area Area of the structure in HI
19- 23 F5.1 K Tb 408MHz brightness temperature
25- 29 F5.1 K e_Tb rms deviation of Tb
31- 34 F4.2 --- r(HI) [0/1] cross-correlation 408MHz/HI (G2)
37- 40 F4.1 10-24K.m2 Tb/NHI ?=- 408MHz emissivity Tb/N(HI)
42- 45 F4.1 10-24K.m2 e_Tb/NHI ?=- rms deviation of Em
47- 50 F4.2 --- r(100) [0/1] cross-correlation 408MHz/100µm
53- 56 F4.2 K.sr/MJy Tb/I100 ?=- Median value of Tb/I(100µm)
58- 61 F4.2 K.sr/MJy e_Tb/I100 ?=- rms deviation of Tb/I100
63- 66 F4.2 --- r(60) [0/1] cross-correlation 408MHz/60µm
68- 71 F4.1 K.sr/MJy Tb/I60 Median value of Tb/I(60µm)
73- 76 F4.1 K.sr/MJy e_Tb/I60 rms deviation of Tb/I100
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [GW]
4- 12 A9 --- GW Galactic Worm name (G1)
14- 16 A3 -- n_GW [a, b] Notes (1)
18- 57 A40 --- Overlap Comma-separated list of HII regions
that overlap (2)
61-155 A95 --- Plane Comma-separated list of HII regions
at the plane (2)
--------------------------------------------------------------------------------
Note (1): the note means:
a = velocity of the worm candidate is uncertain
b = velocities of BFS HII sources is based on CO observations of Blitz et al.
(1982ApJS...49..183B 1982ApJS...49..183B, VII/216)
Note (2): the lists are from:
S = Sharpless (1959ApJS....4..257S 1959ApJS....4..257S, Sh-2 in Simbad)
BFS = Blitz, Fich & Stark (1982ApJS...49..183B 1982ApJS...49..183B, VII/50)
RCW = Roger, Campbell & Whiteoak (1960MNRAS.121..103R 1960MNRAS.121..103R, VII/216)
--------------------------------------------------------------------------------
Global Notes:
Note (G1): the GW name specifies the longitude and latitude of the center
of the structure. The central position is determined by averaging the
positions of all pixels in the structure in three wavebands. All these
names are written here with leading zeroes for longitudes<100°.
Note (G2): the cross-correlation coefficient is defined from the areas of
the structures A and B at different wavelengths as:
r = area(A∩B)/sqrt(area(A).area(B))
History:
Prepared originally by H. Andernach (R2247 in his collection)
(End) Francois Ochsenbein [CDS] 22-Feb-2016