1997A&A...322...19N

Query : 1997A&A...322...19N

1997A&A...322...19N - Astronomy and Astrophysics, volume 322, 19-28 (1997/6-1)

A radio continuum survey of Shapley-Ames galaxies at λ 2.8cm. II. Separation of thermal and non-thermal radio emission.

NIKLAS S., KLEIN U. and WIELEBINSKI R.

Abstract (from CDS):

The radio continuum spectra of 74 galaxies were used to separate thermal and non-thermal radio emission. The thermal fraction fth1GHz at 1GHz and the non-thermal spectral index αnth of the radio continuum emission were determined. The mean values are <fth1GHz≥ 0.08±0.01 and <αnth≥0.83±0.02. Even at 10 GHz the radio continuum emission of most of the galaxies is dominated by the synchrotron component. Using Hα data the thermal radio flux densities were independently estimated and the non-thermal spectral indices were recalculated. Good agreement was found between the results of the two methods and the mean internal extinction was determined to be AHα≃0.8mag. Early-type spirals and irregulars tend to have flatter non-thermal spectra as the thermal fraction is independent of morphological type. Galaxies with strong star formation activity are found to have flatter non-thermal spectral indices.

Abstract Copyright: ∼

Journal keyword(s): galaxies: spiral - infrared: galaxies - radio continuum: galaxies - ISM: cosmic rays

Simbad objects: 76

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Number of rows : 76
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 NGC 157 Sy2 00 34 46.7879913696 -08 23 47.273597952   11.0 19.00 10.03 10.7 ~ 351 0
2 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3332 2
3 NGC 278 H2G 00 52 04.3452013728 +47 33 01.675026036   10.5       ~ 234 1
4 NGC 520 AG? 01 24 34.90 +03 47 29.4 12.41 12.24 11.42     ~ 513 3
5 NGC 660 Sy2 01 43 02.350 +13 38 44.45   12.02 11.16     ~ 556 2
6 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1666 2
7 NGC 1055 GiP 02 41 45.233 +00 26 35.45 11.59 11.40 10.59 10.5 10.7 ~ 283 2
8 M 77 Sy2 02 42 40.7091669408 -00 00 47.859690204 9.70 9.61 8.87 10.1 9.9 ~ 4599 2
9 NGC 1084 GiG 02 45 59.926 -07 34 43.10 11.22 11.59 10.73 10.55 11.1 ~ 368 2
10 NGC 1309 GiG 03 22 06.5548977432 -15 23 59.791692912   12.08   12.5 11.7 ~ 221 0
11 NGC 1421 EmG 03 42 29.2806642840 -13 29 16.951034724   12.38       ~ 192 0
12 NGC 1569 IG 04 30 49.186 +64 50 52.52 11.72 11.86 11.03     ~ 1241 3
13 NGC 2207 AG? 06 16 22.0336889136 -21 22 21.759218400   11.48 10.65 10.21 11.9 ~ 288 3
14 NGC 2146 SBG 06 18 37.710 +78 21 25.27 11.67 11.38 10.59     ~ 720 2
15 NGC 2276 AG? 07 27 14.485 +85 45 16.20   12.3       ~ 375 0
16 NGC 2905 H2G 09 32 10.111 +21 30 02.99 10.44 9.75 9.07 8.68   ~ 1116 3
17 NGC 2964 GiP 09 42 54.251 +31 50 49.97   12.0       ~ 275 1
18 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4446 3
19 M 82 AGN 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5855 6
20 NGC 3079 Sy2 10 01 57.8789863992 +55 40 47.449758324 11.57 11.54 10.86     ~ 1391 3
21 NGC 3166 GiP 10 13 45.7270131936 +03 25 29.310401424   11.2       ~ 234 0
22 NGC 3227 Sy1 10 23 30.5765149296 +19 51 54.282206700   12.61 11.79     ~ 1703 1
23 NGC 3310 AGN 10 38 45.85707 +53 30 11.8940   12.45 12.15     ~ 773 1
24 M 95 GiP 10 43 57.7313485800 +11 42 13.301191332 10.71 10.51 9.73 9.48   ~ 1121 2
25 NGC 3504 LIN 11 03 11.3 +27 58 21   13.48 12.93     ~ 524 2
26 NGC 3521 G 11 05 48.5680991376 -00 02 09.245076540 10.06 9.83 9.02 10.1 9.6 ~ 817 2
27 M 108 SBG 11 11 30.967 +55 40 26.84   10.70       ~ 471 1
28 NGC 3593 GiG 11 14 36.9731893800 +12 49 05.497790664   11.8       ~ 359 2
29 M 66 GiP 11 20 15.0 +12 59 29 9.85 9.65 8.92     ~ 1386 4
30 NGC 3628 GiP 11 20 17.018 +13 35 22.16   10.42 9.48 9.22   ~ 826 3
31 NGC 3675 GiG 11 26 08.5641089832 +43 35 09.587062464   11.04   9.57   ~ 284 1
32 NGC 3810 GiG 11 40 58.7615811624 +11 28 15.808680696   11.4       ~ 335 2
33 NGC 3893 GiP 11 48 38.207 +48 42 38.84   11.23 10.67     ~ 369 1
34 NGC 3982 Sy1 11 56 28.1445516072 +55 07 30.859586652   12.20 11.70 11.18   ~ 550 1
35 NGC 4030 GiP 12 00 23.6102390784 -01 06 00.197099136   11.42   10.3 10.4 ~ 340 1
36 NGC 4038 EmG 12 01 53.002 -18 52 03.32   10.91   9.74 11.0 ~ 1331 1
37 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1690 0
38 NGC 4039 GiP 12 01 53.51 -18 53 10.3   11.08   9.77   ~ 1159 1
39 NGC 4051 Sy1 12 03 09.6101337312 +44 31 52.682601288   11.08 12.92 9.94   ~ 2165 1
40 NGC 4088 GiP 12 05 34.2230093952 +50 32 21.064017876   11.2       ~ 407 1
41 NGC 4102 Sy2 12 06 23.0 +52 42 40   11.8       ~ 422 1
42 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3688 2
43 M 98 LIN 12 13 48.2910686976 +14 54 01.953475200 11.25 10.95 10.14     ~ 481 1
44 M 99 H2G 12 18 49.625 +14 24 59.36 10.45 10.44 9.87     ~ 918 2
45 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2362 3
46 M 100 AGN 12 22 54.9299993592 +15 49 20.296257960 10.04 10.05 9.35     ~ 1845 2
47 NGC 4388 Sy2 12 25 46.820 +12 39 43.45 11.91 11.76 11.02     ~ 1340 2
48 NGC 4414 GiG 12 26 27.1276893168 +31 13 24.626206488 11.12 10.96 10.12     ~ 566 2
49 NGC 4438 LIN 12 27 45.6705493536 +13 00 31.708096380 11.37 11.02 10.17     ~ 635 2
50 NGC 4449 EmG 12 28 11.118 +44 05 36.81 10.11 9.98 9.64 9.45   ~ 1125 1
51 NGC 4490 GiP 12 30 34.5 +41 38 26 10.03 10.22 9.79     ~ 574 3
52 M 88 Sy2 12 31 59.1525062448 +14 25 13.148971824   14.33 13.18     ~ 804 1
53 NGC 4527 GiP 12 34 08.4 +02 39 15   12.4       ~ 532 2
54 NGC 4565 LIN 12 36 20.804 +25 59 14.61   13.61 12.43     ~ 956 0
55 NGC 4568 GiP 12 36 34.292 +11 14 19.07   12.11 11.19     ~ 380 2
56 M 90 Sy2 12 36 49.8009839880 +13 09 46.523813040 10.56 10.26 9.54     ~ 898 1
57 NGC 4631 GiP 12 42 08.009 +32 32 29.44   9.78 9.19 9.10   ~ 1095 2
58 NGC 4654 GiP 12 43 56.638 +13 07 34.86   11.8       ~ 566 1
59 NGC 4666 EmG 12 45 08.676 -00 27 42.88   11.7   11.5 10.7 ~ 387 1
60 M 94 SyG 12 50 53.0737971432 +41 07 12.900884628 9.15 8.96 8.24 7.78   ~ 1386 2
61 NGC 4984 Sy1 13 08 57.2555329728 -15 30 58.743722520   12   10.92   ~ 135 0
62 NGC 5005 GiP 13 10 56.312 +37 03 32.19   14.67 13.67     ~ 541 2
63 NGC 5033 Sy2 13 13 27.535 +36 35 37.14   11.01 12.03 9.73   ~ 869 3
64 M 63 LIN 13 15 49.2741893928 +42 01 45.728076108   9.34 8.59 8.35   ~ 1223 2
65 NGC 5054 Sy1 13 16 58.488 -16 38 05.46   11.3   10.36 10.7 ~ 196 1
66 M 51 Sy2 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4329 4
67 M 83 SBG 13 37 00.91920 -29 51 56.7400 8.85 8.11 7.52 7.21   ~ 2571 2
68 NGC 5248 GiG 13 37 32.0145074088 +08 53 06.496982448   11.4       ~ 507 0
69 NGC 5383 GiG 13 57 04.9709727768 +41 50 46.419238680   12.5   10.95   ~ 339 0
70 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 2914 2
71 NGC 5676 GiG 14 32 46.853 +49 27 28.11   11.7       ~ 254 1
72 NGC 5792 Sy2 14 58 22.709 -01 05 27.89   11.8   11.8 11.1 ~ 183 0
73 NGC 5906 GiG 15 15 53.687 +56 19 43.86   11.4       ~ 767 1
74 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2527 2
75 NGC 7331 LIN 22 37 04.0506038088 +34 24 56.800076508 10.65 10.35 9.48     ~ 1227 2
76 NGC 7479 Sy2 23 04 56.6432243448 +12 19 22.357387020 11.74 11.60 10.85 10.47 9.66 ~ 742 2

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