2018A&A...619A..36C


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.14CET01:00:34

2018A&A...619A..36C - Astronomy and Astrophysics, volume 619A, 36-36 (2018/11-1)

LOFAR MSSS: Flattening low-frequency radio continuum spectra of nearby galaxies.

CHYZY K.T., JURUSIK W., PIOTROWSKA J., NIKIEL-WROCZYNSKI B., HEESEN V., VACCA V., NOWAK N., PALADINO R., SURMA P., SRIDHAR S.S., HEALD G., BECK R., CONWAY J., SENDLINGER K., CURYLO M., MULCAHY D., BRODERICK J.W., HARDCASTLE M.J., CALLINGHAM J.R., GURKAN G., IACOBELLI M., ROTTGERING H.J.A., ADEBAHR B., SHULEVSKI A., DETTMAR R.-J., BRETON R.P., CLARKE A.O., FARNES J.S., ORRU E., PANDEY V.N., PANDEY-POMMIER M., PIZZO R., RISELEY C.J., ROWLINSON A., SCAIFE A.M.M., STEWART A.J., VAN DER HORST A.J. and VAN WEEREN R.J.

Abstract (from CDS):


Aims. The shape of low-frequency radio continuum spectra of normal galaxies is not well understood, the key question being the role of physical processes such as thermal absorption in shaping them. In this work we take advantage of the LOFAR Multifrequency Snapshot Sky Survey (MSSS) to investigate such spectra for a large sample of nearby star-forming galaxies.
Methods. Using the measured 150 MHz flux densities from the LOFAR MSSS survey and literature flux densities at various frequencies we have obtained integrated radio spectra for 106 galaxies characterised by different morphology and star formation rate. The spectra are explained through the use of a three-dimensional model of galaxy radio emission, and radiation transfer dependent on the galaxy viewing angle and absorption processes.
Results. Our galaxies' spectra are generally flatter at lower compared to higher frequencies: the median spectral index αlow measured between ~=50MHz and 1.5GHz is -0.57±0.01 while the high-frequency one αhigh, calculated between 1.3GHz and 5GHz, is -0.77±0.03. As there is no tendency for the highly inclined galaxies to have more flattened low-frequency spectra, we argue that the observed flattening is not due to thermal absorption, contradicting the suggestion of Israel & Mahoney (1990ApJ...352...30I). According to our modelled radio maps for M 51-like galaxies, the free-free absorption effects can be seen only below 30MHz and in the global spectra just below 20MHz, while in the spectra of starburst galaxies, like M 82, the flattening due to absorption is instead visible up to higher frequencies of about 150MHz. Starbursts are however scarce in the local Universe, in accordance with the weak spectral curvature seen in the galaxies of our sample. Locally, within galactic disks, the absorption effects are distinctly visible in M 51-like galaxies as spectral flattening around 100-200MHz in the face-on objects, and as turnovers in the edge-on ones, while in M 82-like galaxies there are strong turnovers at frequencies above 700MHz, regardless of viewing angle.
Conclusions. Our modelling of galaxy spectra suggests that the weak spectral flattening observed in the nearby galaxies studied here results principally from synchrotron spectral curvature due to cosmic ray energy losses and propagation effects. We predict much stronger effects of thermal absorption in more distant galaxies with high star formation rates. Some influence exerted by the Milky Way's foreground on the spectra of all external galaxies is also expected at very low frequencies.

Abstract Copyright: © ESO 2018

Journal keyword(s): galaxies: evolution - radio continuum: galaxies - galaxies: statistics

Simbad objects: 137

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Number of rows : 137

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 UGC 12914 LIN 00 01 38.304 +23 29 01.18   13.2       ~ 131 1
2 IC 10 G 00 20 23.16 +59 17 34.7   13.6 9.5     ~ 983 0
3 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2862 2
4 NGC 278 H2G 00 52 04.3422973787 +47 33 01.649350749   10.5       ~ 215 1
5 NGC 520 IG 01 24 35.071 +03 47 32.68 12.41 12.24 11.42     ~ 480 3
6 M 74 G 01 36 41.772 +15 47 00.46 10.52 10.00 9.46 9.16   ~ 1342 1
7 NGC 660 LIN 01 43 02.350 +13 38 44.45   12.02 11.16     ~ 501 2
8 NGC 693 GiC 01 50 30.847 +06 08 42.76 13.39 13.24 12.44     ~ 97 2
9 NGC 772 GiP 01 59 19.5556685548 +19 00 27.476398641 11.35 11.09 10.31 10.23 9.38 ~ 299 1
10 NGC 828 rG 02 10 09.5458704337 +39 11 25.220114583   13.0       ~ 148 1
11 NGC 876 GiG 02 17 53.327 +14 31 17.91   16.5       ~ 52 0
12 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1491 2
13 UGC 1845 GiG 02 24 07.9832706371 +47 58 10.743777802   15.7       ~ 70 1
14 NGC 935 IG 02 28 11.146 +19 35 56.83   13.56 12.82     ~ 85 0
15 IC 1801 GiP 02 28 12.753 +19 34 59.96   14.73 13.98     ~ 44 0
16 NGC 972 rG 02 34 13.385 +29 18 40.47   12.1 13.63     ~ 154 2
17 NGC 1055 GiP 02 41 45.233 +00 26 35.45 11.59 11.40 10.59 10.5 10.7 ~ 253 2
18 3C 84 Sy2 03 19 48.1597607660 +41 30 42.114155434   13.10 12.48 11.09   ~ 3463 3
19 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1363 1
20 UGC 2855 H2G 03 48 20.731 +70 07 58.37   14.6       ~ 121 2
21 NGC 1530 G 04 23 27.102 +75 17 44.05   13.40       ~ 250 1
22 NGC 1569 IG 04 30 49.186 +64 50 52.52 11.72 11.86 11.03     ~ 1137 3
23 UGC 3293 GiG 05 20 40.788 +08 48 31.41   16.0       ~ 26 0
24 NGC 1961 LIN 05 42 04.775 +69 22 42.17   11.73 10.99     ~ 298 3
25 UGC 3350 GiP 05 45 39.48816 +58 35 59.1684   16.0       ~ 12 1
26 UGC 3351 Sy2 05 45 47.836 +58 42 03.83   16.0       ~ 85 2
27 UGC 3405 GiP 06 13 57.524 +80 28 34.66   15.17 13.95     ~ 45 0
28 NGC 2339 H2G 07 08 20.5341674864 +18 46 48.807046146   12.3       ~ 134 1
29 NGC 2276 IG 07 27 14.485 +85 45 16.20   12.3       ~ 337 0
30 NGC 2403 AGN 07 36 51.396 +65 36 09.17 9.31 8.84 8.38 8.19   ~ 1571 1
31 NGC 2623 LIN 08 38 24.016 +25 45 16.29 14.10 13.99 13.36     ~ 427 1
32 NGC 2639 Sy1 08 43 38.093 +50 12 19.94 12.90 12.56 11.65     ~ 375 2
33 NGC 2633 GiP 08 48 04.6279110889 +74 05 55.032130996   12.4       ~ 146 1
34 NGC 2683 AGN 08 52 41.345 +33 25 18.48 11.57 10.68 9.79 9.38   ~ 374 1
35 NGC 2748 GiG 09 13 43.037 +76 28 31.23   11.7       ~ 171 0
36 NGC 2782 Sy2 09 14 05.120 +40 06 49.68 12.29 12.30 11.63     ~ 428 3
37 NGC 2841 LIN 09 22 02.655 +50 58 35.32 10.43 10.09 9.22     ~ 964 1
38 NGC 2905 H2G 09 32 10.111 +21 30 02.99 10.44 9.75 9.07 8.68   ~ 968 3
39 NGC 2964 GiP 09 42 54.251 +31 50 49.97   12.0       ~ 252 1
40 NGC 2976 GiP 09 47 15.458 +67 54 58.97 11.77 11.03 10.16 9.51   ~ 567 1
41 NGC 2985 Sy1 09 50 22.233 +72 16 43.13   11.37 10.61     ~ 215 1
42 NGC 3044 G 09 53 40.884 +01 34 46.74   12.7   12.7 12.3 ~ 190 1
43 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3893 5
44 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5221 6
45 UGC 5376 G 10 00 27.070 +03 22 27.51   14.5       ~ 64 0
46 NGC 3079 Sy2 10 01 57.80342 +55 40 47.2428 11.57 11.54 10.86     ~ 1220 3
47 NGC 3147 Sy2 10 16 53.632 +73 24 02.34   11.43 10.61     ~ 414 2
48 NGC 3180 GiG 10 18 16.985 +41 25 27.77   10.4       ~ 609 0
49 NGC 3221 G 10 22 19.988 +21 34 10.56   14.3       ~ 110 1
50 NGC 3226 GiP 10 23 27.0067240562 +19 53 54.682329315   14.32 13.33     ~ 389 1
51 NVSS J102332+522031 rG 10 23 32.582 +52 20 30.89   15.0       ~ 29 1
52 NGC 3294 G 10 36 16.2545096912 +37 19 29.023196163   11.5       ~ 177 0
53 NGC 3310 AGN 10 38 45.857 +53 30 11.89   12.45 12.15     ~ 720 1
54 NGC 3359 EmG 10 46 36.845 +63 13 25.10 10.83 11.03 10.57     ~ 338 1
55 NGC 3395 GiP 10 49 50.116 +32 58 58.22   12.1 12.10     ~ 255 2
56 NGC 3424 GiP 10 51 46.322 +32 54 02.44   13.2       ~ 117 1
57 NGC 3432 IG 10 52 31.132 +36 37 07.60   11.81 11.67 11.29   ~ 245 1
58 NGC 3437 EmG 10 52 35.746 +22 56 02.82   12.575 11.961 11.474 10.818 ~ 150 1
59 NGC 3448 IG 10 54 39.240 +54 18 18.82   12.2       ~ 182 1
60 NGC 3486 Sy2 11 00 23.946 +28 58 29.35 10.89 11.11 10.53 10.40   ~ 311 1
61 NGC 3504 LIN 11 03 11.191 +27 58 20.77   13.48 12.93     ~ 476 2
62 M 108 SBG 11 11 30.967 +55 40 26.84   10.70       ~ 402 1
63 NGC 3583 GiP 11 14 10.979 +48 19 06.16   11.6       ~ 170 1
64 NGC 3593 GiG 11 14 36.9733686308 +12 49 05.505076217   11.8       ~ 323 2
65 M 66 GiP 11 20 15.026 +12 59 28.64 9.85 9.65 8.92     ~ 1122 4
66 NGC 3628 GiP 11 20 17.018 +13 35 22.16   10.42 9.48 9.22   ~ 736 3
67 NGC 3631 IG 11 21 02.944 +53 10 09.95   11.0       ~ 318 1
68 NGC 3646 GiP 11 21 43.107 +20 10 10.35 11.76 11.78 11.13     ~ 132 1
69 NGC 3655 Sy2 11 22 54.6353248122 +16 35 24.232295688   12.575 11.904 11.366 10.732 ~ 150 0
70 NGC 3735 Sy2 11 35 57.327 +70 32 08.13   12.4       ~ 163 2
71 NGC 3799 LIN 11 40 09.3865107582 +15 19 38.397936289   14.4       ~ 62 0
72 NGC 3810 GiG 11 40 58.737 +11 28 16.07   11.4       ~ 301 1
73 NGC 3893 GiP 11 48 38.207 +48 42 38.84   11.23 10.67     ~ 324 1
74 NGC 3938 GiG 11 52 49.453 +44 07 14.63 10.80 10.90 10.38     ~ 454 1
75 NGC 3949 GiG 11 53 41.7329679734 +47 51 31.426105104   10.9       ~ 290 1
76 NGC 3982 Sy1 11 56 28.169 +55 07 31.30   12.20 11.70 11.18   ~ 475 1
77 NGC 3987 AGN 11 57 20.907 +25 11 43.63   14.4       ~ 102 0
78 NGC 4041 SyG 12 02 12.2373728821 +62 08 14.095878409   11.6       ~ 223 1
79 NGC 4051 Sy1 12 03 09.6098828919 +44 31 52.693714606   11.08 12.92 9.94   ~ 1954 1
80 NGC 4088 GiP 12 05 34.2188954517 +50 32 21.031900467   11.2       ~ 356 1
81 NGC 4096 GiG 12 06 01.161 +47 28 42.09   11.61   10.86   ~ 213 0
82 NGC 4100 GiG 12 06 08.602 +49 34 56.32   11.7       ~ 206 0
83 NGC 4102 LIN 12 06 23.115 +52 42 39.42   11.8       ~ 364 1
84 NGC 4157 GiP 12 11 04.365 +50 29 04.85 12.48 12.15 11.35     ~ 300 2
85 NGC 4194 AGN 12 14 09.615 +54 31 35.93   13.79 13.30     ~ 402 2
86 NGC 4217 GiG 12 15 50.900 +47 05 30.44   12.4       ~ 243 2
87 M 99 H2G 12 18 49.625 +14 24 59.36 10.45 10.44 9.87     ~ 740 2
88 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2060 3
89 M 100 AGN 12 22 54.9318850854 +15 49 20.294302163 10.04 10.05 9.35     ~ 1620 2
90 NGC 4414 GiG 12 26 27.089 +31 13 24.76 11.12 10.96 10.12     ~ 506 2
91 NGC 4449 EmG 12 28 11.118 +44 05 36.81 10.11 9.98 9.64 9.45   ~ 993 1
92 NGC 4490 GiP 12 30 36.368 +41 38 37.07 10.03 10.22 9.79     ~ 514 3
93 NGC 4532 GiP 12 34 19.329 +06 28 03.73   12.3       ~ 243 2
94 NGC 4559 H2G 12 35 57.6399424117 +27 57 35.859639262   10.46 10.01     ~ 521 1
95 NGC 4565 LIN 12 36 20.804 +25 59 14.61   13.61 12.43     ~ 845 0
96 NGC 4631 GiP 12 42 08.009 +32 32 29.44   9.78 9.19 9.10   ~ 943 2
97 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1182 3
98 NGC 4793 SBG 12 54 40.6134238572 +28 56 19.232232841   12.50 11.93     ~ 158 2
99 M 64 SyG 12 56 43.696 +21 40 57.57   9.36 8.52     ~ 791 2
100 NGC 5005 GiP 13 10 56.312 +37 03 32.19   14.67 13.67     ~ 489 2
101 NGC 5033 Sy1 13 13 27.535 +36 35 37.14   11.01 12.03 9.73   ~ 783 3
102 M 63 LIN 13 15 49.2738527699 +42 01 45.726078017   9.34 8.59 8.35   ~ 1024 2
103 IC 883 SBG 13 20 35.380 +34 08 21.84   14.8       ~ 361 1
104 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 3691 4
105 NGC 5248 GiG 13 37 32.069 +08 53 06.22   11.4       ~ 438 0
106 NGC 5256 PaG 13 38 17.8 +48 16 41   14.1 13.42     ~ 393 2
107 Mrk 273 Sy2 13 44 42.070 +55 53 13.17   15.68 14.91     ~ 814 3
108 NGC 5390 LIN 13 55 40.023 +40 27 42.37   12.81 11.93 10.04   ~ 313 1
109 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 2475 2
110 NGC 5678 AGN 14 32 05.5716657614 +57 55 17.157051439   12.10       ~ 203 1
111 NGC 5676 GiG 14 32 46.853 +49 27 28.11   11.7       ~ 228 1
112 NGC 5775 GiP 14 53 57.653 +03 32 40.10   13.0 11.34     ~ 383 2
113 NGC 5900 GiP 15 15 05.017 +42 12 35.47   14.43 13.39     ~ 90 0
114 UGC 9794 G 15 16 10.847 +10 30 34.85   14.3       ~ 36 0
115 NGC 5929 GiP 15 26 06.158 +41 40 14.40   13.0 14.00     ~ 408 0
116 NGC 5936 H2G 15 30 00.846 +12 59 21.55   13.0       ~ 144 1
117 NGC 5953 GiP 15 34 32.402 +15 11 37.80   13.23 12.45     ~ 330 1
118 NGC 5962 GiP 15 36 31.6808963190 +16 36 27.929023082 12.04 11.98 11.34     ~ 219 1
119 NGC 6052 IG 16 05 12.8707837896 +20 32 32.613940524 13.01 13.44 13.00     ~ 329 2
120 NGC 6181 GiG 16 32 20.969 +19 49 35.77   12.7       ~ 221 0
121 NGC 6217 AGN 16 32 39.2277115994 +78 11 53.468793359   14.37 13.88     ~ 275 0
122 NGC 6285 GiG 16 58 24.016 +58 57 21.23   15.3       ~ 95 0
123 UGC 11041 G 17 54 51.7609789831 +34 46 34.561150178   13.9       ~ 76 0
124 NGC 6574 GiG 18 11 51.2462161679 +14 58 54.740459628   12.5       ~ 168 0
125 NGC 6643 G 18 19 46.370 +74 34 06.23   11.80       ~ 282 1
126 NGC 6701 G 18 43 12.429 +60 39 12.13   12.9       ~ 114 1
127 NGC 6764 LIN 19 08 16.348 +50 55 59.14   15.00 14.32     ~ 268 1
128 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2184 2
129 NGC 6951 Sy2 20 37 14.1181441937 +66 06 20.078027288   11.64 10.65     ~ 490 2
130 NGC 7331 LIN 22 37 04.102 +34 24 57.31 10.65 10.35 9.48     ~ 1085 2
131 NGC 7448 IG 23 00 03.589 +15 58 49.31   12.0       ~ 210 0
132 NGC 7479 Sy2 23 04 56.668 +12 19 22.36 11.74 11.60 10.85 10.47 9.66 ~ 652 2
133 NGC 7541 GiP 23 14 43.857 +04 32 02.04   12.7       ~ 292 1
134 NGC 7625 IG 23 20 30.132 +17 13 32.16 13.31 13.23 11.98 11.25   ~ 238 0
135 NGC 7674 Sy2 23 27 56.6974755223 +08 46 44.238278540 13.84 13.92 13.23 12.64   ~ 620 4
136 NGC 7678 AGN 23 28 27.8602784329 +22 25 16.572970163   15.3       ~ 182 0
137 NGC 7770 GiG 23 51 22.610 +20 05 48.56   14.5       ~ 93 1

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2019.11.14-01:00:34

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