2008ApJS..178....1S

Query : 2008ApJS..178....1S

2008ApJS..178....1S - Astrophys. J., Suppl. Ser., 178, 1-19 (2008/September-0)

The fractal distribution of H II regions in disk galaxies.

SANCHEZ N. and ALFARO E.J.

Abstract (from CDS):

It is known that interstellar gas has a fractal structure in a wide range of spatial scales with a fractal dimension that seems to be a constant around Df≃2.7. It is expected that stars forming from this fractal medium exhibit similar fractal patterns. Here we address this issue by quantifying the degree to which star-forming events are clumped. We develop, test, and apply a precise and accurate technique to calculate the correlation dimension Dc of the distribution of H II regions in a sample of disk galaxies. We find that the determination of Dc is limited by the number of H II regions, since if there are ≲100 regions available, then a bias tending to underestimate the dimension is produced. The reliable results are distributed in the range 1.5≲Dc≲2.0 with an average value <Dc≥1.81. This corresponds to a three-dimensional dimension of <Df≥2.73, very similar to the value measured in the interstellar clouds. However, we get significant variations in the fractal dimension among galaxies, contrary to the universal picture sometimes claimed in literature. The fractal dimension exhibits a weak but significant correlation with the absolute magnitude and, to a lesser extent, with the galactic radius. The faintest galaxies tend to distribute their H II regions in more clustered (less uniform) patterns. The fractal dimension for the brightest H II regions within the same galaxy seems to be smaller than for the faintest ones, suggesting some kind of evolutionary effect, but the obtained correlation remains unchanged if only the brightest regions are taken into account.

Abstract Copyright: ∼

Journal keyword(s): Catalogs - Galaxies: Structure - ISM: H II Regions - Stars: Formation

VizieR on-line data: <Available at CDS (J/ApJS/178/1): table2.dat table3.dat hii/*>

Nomenclature: Catalogue: [SA2008] DDO NNN +XX.xx+YY.yy, [SA2008] ESO 377-24 +XX.xx+YY.yy, [SA2008] IC NNNN +XX.xx+YY.yy, [SA2008] NGC NNNN +XX.xx+YY.yy, N=-.

Status at CDS : All or part of tables of objects will not be ingested in SIMBAD.

Simbad objects: 103

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Number of rows : 103
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 IC 10 rG 00 20 17.33520 +59 18 13.6480   13.6 9.5     ~ 1185 1
2 NGC 210 GiP 00 40 34.9927609368 -13 52 21.999585108   11.8   11.00 11.4 ~ 181 0
3 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
4 NGC 337A LSB 01 01 33.987 -07 35 18.75 12.57 12.70 12.17 12.8 12.5 ~ 81 1
5 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 6226 1
6 M 74 G 01 36 41.7451236624 +15 47 01.107512304 10.52 10.00 9.46 9.16   ~ 1934 1
7 NGC 864 H2G 02 15 27.641 +06 00 09.43   12.00       ~ 235 1
8 NGC 1042 SyG 02 40 23.9724818544 -08 26 00.736256616 11.47 11.56 11.02 11.7 11.4 ~ 286 1
9 M 77 Sy2 02 42 40.7091669408 -00 00 47.859690204 9.70 9.61 8.87 10.1 9.9 ~ 4897 2
10 NGC 1073 EmG 02 43 40.598 +01 22 33.13   11.3   11.3 11.8 ~ 335 0
11 NGC 1097 LIN 02 46 19.059 -30 16 29.68 10.46 9.97 9.48 8.72 9.8 ~ 1448 3
12 NGC 1156 GiG 02 59 42.8528847264 +25 14 28.352017320 12.13 12.32 11.74     ~ 323 1
13 NGC 1300 Sy2 03 19 41.0462219928 -19 24 40.187565432   11.16 10.42 9.90 10.7 ~ 616 0
14 NGC 1566 Sy1 04 20 00.3968473248 -54 56 16.624708764 10.29 10.19 9.73 9.21 10.1 ~ 1051 2
15 NGC 1672 SyG 04 45 42.552 -59 14 50.68 10.29 10.53 9.68 9.53 10.2 ~ 461 2
16 NGC 1808 Sy2 05 07 42.343 -37 30 46.98 11.05 10.80 9.94 9.36 10.2 ~ 756 3
17 NGC 2363A HII 07 28 42.8 +69 11 21           ~ 588 3
18 NGC 2366 H2G 07 28 52.4529 +69 12 38.859 12.25 11.86 11.39 11.33   ~ 801 0
19 Z 87-30 G 07 41 56.3059298112 +16 48 07.451632188   15.4       ~ 233 0
20 UGC 4305 IG 08 19 04.9864630512 +70 43 13.086910452 12.06 11.72 11.39 11.11   ~ 812 2
21 NGC 2775 AG? 09 10 20.1334093488 +07 02 16.874157048   11.417 10.481 9.920 8.994 ~ 377 0
22 NGC 2805 GiP 09 20 20.3891233968 +64 06 10.716485004   11.9       ~ 226 1
23 NGC 2997 GiG 09 45 38.7542237472 -31 11 27.345810192   9.97 9.41 8.84 9.9 ~ 454 1
24 IC 2510 Sy2 09 47 43.3494 -32 50 10.975   15.5       ~ 52 0
25 NGC 2985 Sy2 09 50 22.233 +72 16 43.13   11.37 10.61     ~ 269 1
26 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4725 3
27 NGC 3081 Sy2 09 59 29.5437024336 -22 49 34.747341960   13.06 13.55 11.67 12.1 ~ 509 0
28 NGC 3169 SyG 10 14 15.0379414272 +03 27 57.941639856   13.46 12.41     ~ 381 1
29 IC 2560 Sy2 10 16 18.7073057664 -33 33 49.720274676   12.53 13.31 11.25 12.2 ~ 283 1
30 NGC 3180 GiG 10 18 16.985 +41 25 27.77   10.4       ~ 777 0
31 NGC 3227 Sy1 10 23 30.5765149296 +19 51 54.282206700   12.61 11.79     ~ 1807 2
32 NGC 3344 EmG 10 43 31.150 +24 55 19.99 10.38 10.54 9.86 9.71   ~ 434 1
33 M 95 GiP 10 43 57.7313485800 +11 42 13.301191332 10.71 10.51 9.73 9.48   ~ 1238 2
34 NGC 3367 Sy1 10 46 34.9528432440 +13 45 03.081157488 11.89 12.05 11.50     ~ 285 1
35 NGC 3359 EmG 10 46 36.845 +63 13 25.10 10.83 11.03 10.57     ~ 380 1
36 M 96 GiP 10 46 45.744 +11 49 11.78 10.42 10.15 9.25 8.99   ~ 862 1
37 NGC 3393 Sy2 10 48 23.4653152920 -25 09 43.487648784   13.10 13.95 11.67 12.2 ~ 471 1
38 NGC 3486 Sy2 11 00 23.946 +28 58 29.35 10.89 11.11 10.53 10.40   ~ 373 1
39 MCG-06-25-013 Sy1 11 12 33.3615 -36 25 30.836   13.54 13.11 11.98   ~ 33 0
40 NGC 3631 AG? 11 21 02.8871865144 +53 10 10.415331660   11.0       ~ 385 1
41 NGC 3660 Sy2 11 23 32.2781260536 -08 39 30.730097016   15.34 14.45     ~ 185 0
42 NGC 3726 G 11 33 21.1367545656 +47 01 45.280222428   11.11   10.02   ~ 374 0
43 NGC 3783 Sy1 11 39 01.7096819040 -37 44 19.009642992   12.46 13.43 11.33 12.1 ~ 1765 1
44 NGC 3810 GiC 11 40 58.7615811624 +11 28 15.808680696   11.4       ~ 351 2
45 NGC 3982 Sy2 11 56 28.1445516072 +55 07 30.859586652   12.20 11.70 11.18   ~ 588 1
46 NGC 4030 EmG 12 00 23.6102390784 -01 06 00.197099136   11.42   10.3 10.4 ~ 361 1
47 NGC 4051 Sy1 12 03 09.6101337312 +44 31 52.682601288   11.08 12.92 9.94   ~ 2270 1
48 NGC 4123 AGN 12 08 11.1187718376 +02 52 41.781736956   13.1       ~ 352 2
49 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3938 2
50 NGC 4228 SBG 12 15 39.174 +36 19 36.80 10.63 10.30 9.93 9.74   ~ 1017 1
51 M 99 H2G 12 18 49.625 +14 24 59.36 10.45 10.44 9.87     ~ 1004 2
52 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2512 4
53 M 61 Sy2 12 21 54.9282582888 +04 28 25.597367184 10.07 10.18 9.65     ~ 1084 1
54 M 100 AGN 12 22 54.9299993592 +15 49 20.296257960 10.04 10.05 9.35     ~ 1963 2
55 NGC 4395 Sy2 12 25 48.8633109888 +33 32 48.700168152 10.84 10.54 10.11 9.98   ~ 1286 1
56 NGC 4487 EmG 12 31 04.4731449720 -08 03 14.548820040   11.7   11.9 11.6 ~ 189 0
57 NGC 4535 H2G 12 34 20.3443516704 +08 11 51.908488116   11.1       ~ 679 0
58 M 91 LIN 12 35 26.4446761320 +14 29 46.760333748   14.63 13.57     ~ 639 0
59 NGC 4507 Sy2 12 35 36.6338976888 -39 54 33.710416272   12.95 13.54 11.70 12.4 ~ 532 1
60 M 58 Sy2 12 37 43.59747 +11 49 05.1240 10.80 10.48 9.66     ~ 1140 2
61 NGC 4593 Sy1 12 39 39.4435107024 -05 20 39.034988448   13.95 13.15     ~ 1179 0
62 NGC 4602 Sy2 12 40 36.848 -05 07 58.84   12.34   11.40 11.8 ~ 156 0
63 IC 3639 Sy1 12 40 52.8344884344 -36 45 21.057011172   13.01 13.50 11.87 12.7 ~ 262 1
64 NGC 4618 GiP 12 41 32.8976471760 +41 09 03.185175528 11.03 11.22 10.78     ~ 344 2
65 NGC 4639 Sy1 12 42 52.3785000336 +13 15 26.706153600   13.62 12.72     ~ 642 0
66 NGC 4689 H2G 12 47 45.5568088416 +13 45 46.135889100   12.8       ~ 418 0
67 NGC 4699 EmG 12 49 02.186 -08 39 51.49   10.8   10.01 10.3 ~ 226 0
68 NGC 4725 Sy2 12 50 26.5716367992 +25 30 02.733090588   13.45 12.44     ~ 727 2
69 M 94 SyG 12 50 53.0737971432 +41 07 12.900884628 9.15 8.96 8.24 7.78   ~ 1476 2
70 NGC 4789A GiC 12 54 05.248 +27 08 58.67 14.37 14.23 13.95 13.84   ~ 614 1
71 NGC 4939 Sy2 13 04 14.3280524928 -10 20 22.300454724   14.81 13.80 10.92   ~ 332 1
72 NGC 4995 Sy2 13 09 40.6390105944 -07 50 00.223871892   12   10.94   ~ 133 0
73 NGC 5033 Sy2 13 13 27.535 +36 35 37.14   11.01 12.03 9.73   ~ 909 1
74 Z 245-36 AG? 13 14 27.997 +45 55 11.14 13.63 13.26 13.02 12.81   ~ 297 0
75 M 51 Sy2 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4565 4
76 NGC 5248 G 13 37 32.0145074088 +08 53 06.496982448   11.4       ~ 554 0
77 NGC 5247 EmG 13 38 03.0183262176 -17 53 02.645511252   10.77   9.96 10.5 ~ 228 0
78 NGC 5334 LSB 13 52 54.4632396696 -01 06 52.604999568   12.0   12.3 12.1 ~ 177 0
79 NGC 5390 LIN 13 55 39.9385716624 +40 27 42.380606592   12.81 11.93 10.04   ~ 373 1
80 NGC 5364 GiP 13 56 12.004 +05 00 52.06   13.2       ~ 273 0
81 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 3138 2
82 APG 271 IG 14 03 25.45 -06 02 59.9           ~ 209 0
83 NGC 5427 Sy1 14 03 26.0408044536 -06 01 50.682790236   14.67 13.96 11.54   ~ 307 0
84 NGC 5474 GiP 14 05 01.608 +53 39 43.95   11.28 10.79     ~ 475 1
85 NGC 5643 Sy2 14 32 40.778 -44 10 28.60   11.03 13.60 9.92 10.6 ~ 652 1
86 NGC 5681 GiG 14 35 42.8685615528 +08 18 02.133470196   14.3       ~ 38 0
87 NGC 5850 LIN 15 07 07.6828131840 +01 32 39.513281352   11.5   10.79 11.1 ~ 330 1
88 NGC 5921 AG? 15 21 56.561 +05 04 13.94   12.7       ~ 286 0
89 NGC 5964 EmG 15 37 36.2103407496 +05 58 26.360661972   12.45 11.82 11.48 10.89 ~ 133 0
90 NGC 6070 AG? 16 09 58.6908501624 +00 42 33.266922696   12.1   12.3 12.0 ~ 166 0
91 NGC 6140 AG? 16 20 58.162 +65 23 25.98   12.6       ~ 122 0
92 NGC 6118 EmG 16 21 48.6065282088 -02 17 00.680742060   13.20   12.0 11.7 ~ 213 0
93 NGC 6221 Sy2 16 52 46.329 -59 13 00.99   10.90 13.45 9.68 10.4 ~ 328 0
94 NGC 6300 Sy2 17 16 59.5418094960 -62 49 13.946588832   10.88 13.08 9.44 10.2 ~ 478 1
95 NGC 6384 AG? 17 32 24.2848390896 +07 03 37.531624968   13.2       ~ 313 0
96 NGC 6814 Sy1 19 42 40.5862186152 -10 19 25.108718844   15.33 14.21 11.7 11.3 ~ 866 0
97 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2661 2
98 NGC 7314 Sy2 22 35 46.1985355872 -26 03 01.564993476   11.62 13.11 10.61 11.4 ~ 601 0
99 NGC 7331 LIN 22 37 04.0506038088 +34 24 56.800076508 10.65 10.35 9.48     ~ 1284 2
100 NGC 7479 Sy2 23 04 56.6432243448 +12 19 22.357387020 11.74 11.60 10.85 10.47 9.66 ~ 783 2
101 NGC 7552 Sy1 23 16 10.66 -42 35 04.7 11.34 11.22 10.57 10.08 11.1 ~ 574 3
102 NGC 7590 Sy1 23 18 54.7949760192 -42 14 20.515300476   12.12 13.76 11.06 11.8 ~ 290 1
103 NGC 7741 GiP 23 43 54.375 +26 04 32.07 11.70 11.84 11.31     ~ 303 1

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