2015A&A...581L...5G


Query : 2015A&A...581L...5G

2015A&A...581L...5G - Astronomy and Astrophysics, volume 581, L5-5 (2015/9-1)

Application of the mid-IR radio correlation to the G^ sample and the search for advanced extraterrestrial civilisations.

GARRETT M.A.

Abstract (from CDS):

Wright et al. (2014ApJ...792...26W) have embarked on a search for advanced Karadashev Type III civilisations via the compilation of a sample of sources with extreme mid-IR emission and colours. The aim is to furnish a list of candidate galaxies that might harbour an advanced Kardashev Type III civilisation; in this scenario, the mid-IR emission is then primarily associated with waste heat energy by-products. I apply the mid-IR radio correlation to this Glimpsing Heat from Alien Technology (G) sample, a catalogue of 93 candidate galaxies compiled by Griffith et al., 2015ApJS..217...25G. I demonstrate that the mid-IR and radio luminosities are correlated for the sample, determining a k-corrected value of q22=1.35±0.42 . By comparison, a similar measurement for 124 galaxies drawn from the First Look Survey (FLS) has q22=0.87±0.27. The statistically significant difference of the mean value of q22 for these two samples, taken together with their more comparable far-IR properties, suggests that the G sample shows excessive emission in the mid-IR. The fact that the G sample largely follows the mid-IR radio correlation strongly suggests that the vast majority of these sources are associated with galaxies in which natural astrophysical processes are dominant. This simple application of the mid-IR radio correlation can substantially reduce the number of false positives in the G catalogue since galaxies occupied by advanced Kardashev Type III civilisations would be expected to exhibit very high values of q. I identify nine outliers in the sample with q22>2 of which at least three have properties that are relatively well explained via standard astrophysical interpretations e.g. dust emission associated with nascent star formation and/or nuclear activity from a heavily obscured AGN. The other outliers have not been studied in any great detail, and are deserving of further observation. I also note that the comparison of resolved mid-IR and radio images of galaxies on sub-galactic (kpc) scales can also be useful in identifying and recognising artificial mid-IR emission from less advanced intermediate Type II/III civilisations. Nevertheless, from the bulk properties of the G sample, I conclude that Kardashev Type III civilisations are either very rare or do not exist in the local Universe.

Abstract Copyright:

Journal keyword(s): astrobiology - galaxies: general - galaxies: star formation - radio continuum: galaxies - infrared: general

VizieR on-line data: <Available at CDS (J/A+A/581/L5): table1.dat>

Simbad objects: 92

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Number of rows : 92
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 NPM1G +40.0002 Sy2 00 08 20.3675391072 +40 37 55.922085984     16.8     ~ 45 0
2 MCG-02-01-051 Sy2 00 18 50.898 -10 22 36.49   14.81 14.33     ~ 141 3
3 IRAS 00321-0018 Sy2 00 34 43.5012933672 -00 02 27.032963604   16.26 15.67     ~ 45 0
4 ESO 350-38 Sy2 00 36 52.489 -33 33 17.23   14.31 14.41 13.49   ~ 378 0
5 6dFGS gJ004250.1-365241 EmG 00 42 50.11 -36 52 40.9   14.83   13.79   ~ 4 0
6 MCG+12-02-001 AG? 00 54 03.943 +73 05 05.23   16       ~ 109 1
7 NGC 449 Sy2 01 16 07.2128 +33 05 21.652   15.90 14.96     ~ 286 4
8 Z 436-30 LIN 01 20 02.654 +14 21 41.73   14.9       ~ 153 0
9 6dFGS gJ020805.4-291433 G 02 08 05.397 -29 14 32.48   16.91   15.74   ~ 2 0
10 NGC 814 AG? 02 10 37.6066894944 -15 46 25.244209812   14   13.61   ~ 45 1
11 2MASX J02414325+4546272 G 02 41 43.2496631232 +45 46 26.652302616           ~ 10 0
12 LEDA 175473 Sy2 02 45 06.4235562168 -02 07 28.357445064   16.16   15.03   ~ 10 0
13 MCG+08-06-022 G 02 56 00.3372147024 +47 48 15.118994952   15.7       ~ 13 0
14 6dFGS gJ025609.8-153946 Sy2 02 56 09.780 -15 39 42.91   16.61   15.85   ~ 4 0
15 NGC 1156 rG 02 59 42.8528847264 +25 14 28.352017320 12.13 12.32 11.74     ~ 313 1
16 2MASX J03044511+0747394 G 03 04 45.1238944104 +07 47 39.158800188           ~ 11 0
17 NGC 1377 GiG 03 36 39.077 -20 54 08.14   13.38   12.12   ~ 224 0
18 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1513 1
19 2MASX J04285125+6934469 G 04 28 51.255 +69 34 46.91           ~ 9 0
20 NGC 1614 Sy1 04 34 00.027 -08 34 44.57   14.66 13.99     ~ 666 0
21 UGC 3097 AG? 04 35 48.4302410280 +02 15 29.990712312   15.6       ~ 45 0
22 ESO 552-5 Sy1 04 47 38.386 -17 26 02.35   14.43   13.95 15.0 ~ 14 0
23 2MASX J04551070+0535126 GiC 04 55 10.708 +05 35 12.69           ~ 6 0
24 NGC 1739 EmG 05 01 47.338 -18 10 00.29   14.24   13.22 14.0 ~ 25 0
25 ESO 486-39 EmG 05 15 21.381 -26 28 17.55   15.26   14.58   ~ 13 0
26 6dFGS gJ051646.2-122100 Sy2 05 16 46.24 -12 20 59.8   15.06   13.66   ~ 4 0
27 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17416 0
28 2MASX J05432362+5400439 G 05 43 23.6393211960 +54 00 43.963023888           ~ 9 0
29 LEDA 2816499 Sy2 05 44 21.5650855248 -13 53 11.964062292   16.01   14.99   ~ 9 0
30 6dFGS gJ054738.7-103552 EmG 05 47 38.688 -10 35 52.12   18.39   17.31   ~ 5 0
31 UGCA 116 H2G 05 55 42.645 +03 23 32.23 10.74 11.68 11.46   11.82 ~ 538 0
32 2MASXI J0556522-052308 LSB 05 56 52.269 -05 23 08.71   16.46   15.89 15.3 ~ 11 0
33 ESO 490-11 G 06 32 26.0716457280 -24 32 08.412329400   15.34   13.97   ~ 8 0
34 2MASX J06433935-2712180 GiG 06 43 39.3208038816 -27 12 17.828830512   15.55   14.12   ~ 11 0
35 Z 204-12 AG? 06 45 40.974 +43 34 06.96   15.5       ~ 8 0
36 2MASX J08353838-0114072 G 08 35 38.4016944384 -01 14 07.047484008   16.55   15.20   ~ 10 0
37 LEDA 26611 EmG 09 23 38.196 -25 16 34.35   15.78   14.65   ~ 7 0
38 ESO 434-13 EmG 09 35 48.860 -29 19 54.63   15.67   14.73   ~ 8 0
39 NVSS J093929+062610 rG 09 39 30.1514689200 +06 26 13.256647908   15.2       ~ 10 0
40 NGC 3094 AG? 10 01 25.9394231904 +15 46 12.175678236   13.5       ~ 115 0
41 MCG-03-27-005 Sy2 10 20 50.9296043856 -17 18 59.420474568   15   14.07   ~ 14 0
42 NGC 3239 AG? 10 25 04.867 +17 09 49.21   13.5       ~ 182 0
43 IC 630 GiP 10 38 33.6291893352 -07 10 14.528232696   13.3   12.9 12.3 ~ 66 0
44 IC 649S GiG 10 50 52.0 +01 09 43   14.9       ~ 4 0
45 ESO 318-23 AG? 10 54 16.7205883751 -39 40 19.691641352   15.28   13.73   ~ 10 0
46 LEDA 33083 LIN 10 59 18.128 +24 32 34.74   15.7       ~ 274 1
47 IRAS 11215-2806 Sy2 11 24 02.7219289536 -28 23 15.489126168   15.7       ~ 61 0
48 LEDA 36667 EmG 11 45 43.561 -11 47 12.10   14.82   13.80   ~ 13 0
49 LEDA 38612 G 12 09 13.8678693840 +26 52 37.029523152           ~ 12 0
50 LEDA 39024 LIN 12 13 46.107 +02 48 41.50           ~ 354 1
51 NGC 4228 SBG 12 15 39.174 +36 19 36.80 10.63 10.30 9.93 9.74   ~ 965 1
52 NGC 4355 Sy2 12 26 54.6206739120 -00 52 39.421212996   14.21 13.37     ~ 489 2
53 IRAS 12468-1107 Sy2 12 49 30.1522742016 -11 24 03.586500360   16.66   15.37   ~ 22 0
54 NGC 4747 GiP 12 51 45.592 +25 46 30.12   13.2       ~ 170 1
55 6dFGS gJ125324.2-234546 EmG 12 53 24.1496037624 -23 45 45.745729524   16.33   15.18 15.07 ~ 7 0
56 MCG-02-33-099 GiG 13 02 20.3897926848 -15 45 59.619522384   18   13.16   ~ 29 0
57 PKS 1306-241 Sy1 13 08 42.01125890 -24 22 57.9385806   15.54   14.93 14.43 ~ 63 1
58 IC 860 LIN 13 15 03.51 +24 37 07.8   14.8       ~ 217 0
59 2MASX J13202200-2332256 EmG 13 20 21.9731480688 -23 32 26.057587092   16.81   15.51 14.89 ~ 10 0
60 NGC 5253 AGN 13 39 55.990 -31 38 24.11 11.48 10.94 10.49 10.33 13.47 ~ 1365 4
61 Mrk 273 Sy2 13 44 42.1781 +55 53 12.819   15.68 14.91     ~ 911 3
62 2MASX J13454733+7004455 G 13 45 47.4207584472 +70 04 45.822061416   15.6       ~ 13 0
63 Z 103-77 G 14 07 36.9866088384 +16 01 21.346305600   15.4       ~ 13 0
64 ESO 326-24 Sy1 14 28 37.0435942752 -39 48 44.036894916   16.37   15.29   ~ 7 0
65 2MASX J15002897-2626487 H2G 15 00 28.971 -26 26 48.72   14.70   13.98   ~ 7 0
66 NVSS J150253+165507 rG 15 02 53.244 +16 55 08.74   15.2       ~ 23 0
67 Z 221-50 SyG 15 18 06.1187 +42 44 45.086   15.0 15     ~ 219 1
68 LEDA 90205 G 15 23 09.7027844688 -39 34 48.603242388   17.2       ~ 15 0
69 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2957 4
70 ESO 515-7 Sy1 15 48 13.3600093848 -24 53 09.752098452   14.95   13.67   ~ 16 0
71 2MASX J16183392+1324253 G 16 18 33.9325011192 +13 24 24.963915456           ~ 5 0
72 2MASX J16360060+1013396 G 16 36 00.6041581272 +10 13 39.706638096           ~ 8 0
73 6dFGS gJ173428.9-040542 G 17 34 28.843 -04 05 41.61   18.98   18.39   ~ 3 0
74 2MASX J17343177+4713010 G 17 34 31.8039246960 +47 13 01.463603664   15.5       ~ 7 0
75 2MASX J17380143+5613257 Sy2 17 38 01.5136985352 +56 13 25.857992136     15.2     ~ 25 0
76 Z 142-9 AG? 18 10 41.3030266488 +25 07 23.738567844   15.2       ~ 8 0
77 LEDA 165761 AG? 18 16 03.1834071432 +47 37 05.361825252           ~ 8 0
78 2MASX J18255272+3752416 G 18 25 52.7530079736 +37 52 41.798600220           ~ 8 0
79 LEDA 90310 Sy1 18 52 22.4339501064 -29 36 20.913483456   16.27   14.84   ~ 12 0
80 ESO 459-7 EmG 19 12 27.3324923880 -29 02 35.868621156   15.41   14.36   ~ 14 0
81 2MASX J19411289+6305430 G 19 41 12.8267007888 +63 05 43.061714196           ~ 6 0
82 Z 324-2 AG? 19 46 05.4125265984 +64 08 50.028243864   15.2       ~ 13 0
83 MCG-05-47-012 Sy2 19 57 51.914 -32 21 28.46   15.45   14.47   ~ 14 0
84 ESO 400-28 EmG 20 28 25.3246299312 -33 04 28.772591160   14.19   13.19   ~ 17 0
85 Z 448-20 G 20 57 23.62800 +17 07 44.5980   15.2       ~ 165 0
86 2MASX J22215143+3950240 G 22 21 51.3995738808 +39 50 24.169426008           ~ 6 0
87 2MASX J22445816-0145589 G 22 44 58.1666542368 -01 45 59.192041140   16.26   15.12   ~ 7 0
88 Mrk 309 AGN 22 52 34.7122076328 +24 43 49.401829632   15.69 15.22     ~ 99 0
89 2MASX J22545096+3742205 G 22 54 51.0369142032 +37 42 20.863575000           ~ 6 0
90 LEDA 95346 Sy1 23 26 10.584 -30 31 06.17   16.270   15.104   ~ 7 0
91 NGC 7714 GiP 23 36 14.1257730600 +02 09 18.197422668   14.91 14.36     ~ 765 1
92 MCG+02-60-017 Sy2 23 47 09.1963447944 +15 35 48.271844760   15.12 14.4     ~ 43 0

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