2025ApJ...983..128D

Query : 2025ApJ...983..128D

2025ApJ...983..128D - Astrophys. J., 983, 128 (2025/April-3)

The Spectral Variation Behavior of Fermi-LAT Blazars.

DENG J. and JIANG Y.

Abstract (from CDS):

In this study, we analyze the ∼16 yr Fermi-Large Area Telescope data of 160 blazars consisting of 92 flat-spectrum radio quasars (FSRQs), 64 BL Lacertae (BL Lac)-type objects, and 4 blazar-candidates-of-unknown-type objects, and investigate their spectral variation. By fitting a linear model (y = kx + b) to the monthly binned flux-index plots, we find that most of the FSRQs (∼89%) display a harder-when-brighter trend (k > 0), while the majority of BL Lac-type objects (∼64%) exhibit a softer-when-brighter trend (k < 0). By plotting their slope (k) versus their variability index and inverse Compton (IC) peak frequency, we find a moderate positive correlation between k and the variability index and a moderate negative correlation between k and the IC peak frequency, which we name as the gamma-ray variability sequence of blazars. Additionally, eight blazars may not follow the linear variation trend, particularly in PKS 0537-441, AP Librae, and PKS 1510-089. Additional very-high-energy gamma-ray emission components may be the cause of the nonlinear variation trend.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Blazars

Simbad objects: 159

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Number of rows : 159
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 7C 0059+5808 Bla 01 02 45.76237340 +58 24 11.1366164   20.09 19.22 18.57 17.90 ~ 262 1
2 4C 01.02 Bla 01 08 38.77110544 +01 35 00.3171844   18.54 18.39 19.05   ~ 589 1
3 QSO B0109+224 BLL 01 12 05.8247044608 +22 44 38.785880796   16.00 15.66 15.47   ~ 373 2
4 4C 31.03 Bla 01 12 50.3328920232 +32 08 17.435303556     18.0 18.1   ~ 140 1
5 QSO B0116-219 Bla 01 18 57.26217841 -21 41 30.1402631   19.40 19.0 19.37   ~ 144 1
6 QSO B0130-17 Bla 01 32 43.48746292 -16 54 48.5220804   18.75 18.44 15.44   ~ 247 1
7 QSO B0131-522 Bla 01 33 05.76250002 -52 00 03.9454078   18.68 20.3 18.63   ~ 129 1
8 6C 013354+473615 Bla 01 36 58.59480326 +47 51 29.1000720     19.50 19.25 15.21 ~ 537 1
9 1RXS J014126.8-092857 BLL 01 41 25.83216015 -09 28 43.6742470   16.94 16.55 17.21   ~ 302 1
10 ICRF J014433.5+270503 BLL 01 44 33.55384903 +27 05 03.1179726       18.6   ~ 104 1
11 QSO B0208-512 BLL 02 10 46.2004407600 -51 01 01.893013392   17.10 16.93 14.82   ~ 485 1
12 ICRF J021113.1+105134 BLL 02 11 13.1774921592 +10 51 34.798753116 13.96 13.63 13.40 15.42   ~ 161 1
13 QSO J0217+0144 Bla 02 17 48.95475095 +01 44 49.6990271   16.74 16.09 18.51 13.29 ~ 455 1
14 6C 021803+354230 BLL 02 21 05.4920852208 +35 56 13.848581904   20.0 20.0 19.60   ~ 603 3
15 3C 66A BLL 02 22 39.6114771888 +43 02 07.799534304   15.71 15.21 14.5   ~ 942 2
16 QSO B0226-559 Bla 02 28 21.5992002288 -55 46 03.292197564     19.0 19.76   ~ 55 1
17 4C 28.07 Bla 02 37 52.40567519 +28 48 08.9899986     19.30 16.99   ~ 654 1
18 QSO B0235+1624 BLL 02 38 38.93010450 +16 36 59.2745528   16.46 15.50 15.92   ~ 1614 2
19 QSO B0244-470 Bla 02 46 00.1179456480 -46 51 17.232749496     18.5 17.9   ~ 104 1
20 ICRF J025247.9-221925 Bla 02 52 47.95365568 -22 19 25.4659009       19.83   ~ 130 1
21 PKS J0303-2407 BLL 03 03 26.5025589984 -24 07 11.426291220   16.55 16.18     ~ 249 1
22 QSO B0308-611 Bla 03 09 56.09914475 -60 58 39.0564095   19.00 18.5 18.18   ~ 154 1
23 QSO B0332-403 BLL 03 34 13.65448823 -40 08 25.3979928 18.54 18.35 17.87 17.5   ~ 349 1
24 ICRF J033415.4-372543 BLL 03 34 15.4249837080 -37 25 43.063647672 16.95 16.71 16.56     ~ 80 1
25 QSO B0336-0156 Bla 03 39 30.93778633 -01 46 35.8041892   18.96 18.41 17.33   ~ 598 1
26 QSO J0403-3605 Bla 04 03 53.74990003 -36 05 01.9131880   17.04 17.17 16.67   ~ 313 1
27 QSO B0420-0127 Bla 04 23 15.80072217 -01 20 33.0656073   17.50 17.00 16.28   ~ 1263 3
28 WISEA J042840.41-375619.3 BLL 04 28 40.4241894720 -37 56 19.580735832   18.96 19.0 17.21   ~ 343 1
29 QSO B0440-003 Bla 04 42 38.66072366 -00 17 43.4209582   19.59 19.22 17.85   ~ 433 1
30 PKS J0449-4350 BLL 04 49 24.6981911928 -43 50 08.960970948 14.95 17.52 15.24 16.27   ~ 190 1
31 QSO J0457-2324 Bla 04 57 03.1791422424 -23 24 52.021129572   18.85 18.5 16.56   ~ 435 1
32 4C -02.19 Bla 05 01 12.80988538 -01 59 14.2564557   19.1 18.06 19.04   ~ 624 1
33 QSO B0502+049 Bla 05 05 23.18472514 +04 59 42.7245008   18.7 19.0 17.58   ~ 188 1
34 PMN J0509+0541 BLL 05 09 25.9644373872 +05 41 35.333820420 15.32 14.95 14.78 15.12   ~ 589 2
35 QSO B0507+179 Bla 05 10 02.36912937 +18 00 41.5815635   20.0 19.0 19.09   ~ 470 1
36 QSO B0516-621 BLL 05 16 44.92617055 -62 07 05.3894029 18.50 18.09 17.85 17.46   ~ 139 1
37 RX J0521.7+2112 BLL 05 21 45.9657388992 +21 12 51.452786736           ~ 162 1
38 QSO B0524-485 Bla 05 26 16.67131784 -48 30 36.7919695     20.0 19.36   ~ 107 1
39 QSO B0529+075 Bla 05 32 38.9985483000 +07 32 43.344156480   19.0 19.00 17.50   ~ 252 1
40 6C 052927+482100 Bla 05 33 15.86579115 +48 22 52.8077787     19.90     ~ 150 1
41 QSO B0537-441 BLL 05 38 50.36155950 -44 05 08.9390233   15.77 16.48 16   ~ 924 2
42 NVSS J060723+473947 BLL 06 07 23.2550008416 +47 39 46.944292500       16.38   ~ 91 1
43 NVSS J061251+412237 BLL 06 12 51.1851596976 +41 22 37.408102212       15.71   ~ 99 2
44 2MASS J07003124-6610452 BLL 07 00 31.2536435688 -66 10 45.229749384 16.38 15.99 15.89     ~ 86 3
45 7C 071604.59+331243.00 BLL 07 19 19.41966120 +33 07 09.7087082   17.66 17.05     ~ 130 1
46 8C 0716+714 BLL 07 21 53.4482942664 +71 20 36.363846516   15.5 15.50 14.27   ~ 1388 1
47 4C 14.23 BLL 07 25 16.80776465 +14 25 13.7465925       17.48   ~ 170 1
48 QSO J0730-116 Bla 07 30 19.11247452 -11 41 12.6006642     20.30 20.3   ~ 323 1
49 QSO J0738+1742 BLL 07 38 07.39375312 +17 42 18.9981506   16.76 16.22 15.78   ~ 1045 1
50 QSO B0736+01 Bla 07 39 18.03389906 +01 37 04.6177501   16.90 16.47 16.19   ~ 738 1
51 6C 073840+545153 BLL 07 42 39.79069953 +54 44 24.6671050     16.90     ~ 138 1
52 QSO B0805-077 Bla 08 08 15.53603763 -07 51 09.8865298     19.80 16.71   ~ 291 1
53 RX J0809.8+5218 BLL 08 09 49.1868285744 +52 18 58.249938744   16.11 15.59 14.6   ~ 302 1
54 QSO B0808+019 BLL 08 11 26.70731711 +01 46 52.2201568   17.58 17.2 17.96   ~ 281 1
55 7C 081451.89+423206.00 BLL 08 18 15.99961476 +42 22 45.4148987   18.88 18.18 17.81   ~ 429 1
56 QSO B0823-223 BLL 08 26 01.5730900658 -22 30 27.204409684   16.11 16.20     ~ 224 1
57 QSO B0829+047 BLL 08 31 48.8770033992 +04 29 39.086842884   17.10 16.4 14.55   ~ 511 2
58 4C 71.07 Bla 08 41 24.36528508 +70 53 42.1730435     17.30 16.8   ~ 818 1
59 ATO J132.5014+48.9163 Bla 08 50 00.3513461725 +48 54 58.673579470       18.3   ~ 45 1
60 [VV98] J085009.6-121334 Bla 08 50 09.63563375 -12 13 35.3761390     16.80 16.02   ~ 162 1
61 PG 0851+202 BLL 08 54 48.8749846272 +20 06 30.639583620   15.649 15.146 15.446   ~ 2513 1
62 QSO B0903-573 BLL 09 04 53.1791655231 -57 35 05.782508724           ~ 131 1
63 QSO B0907-023 Bla 09 09 44.9240838552 -02 31 30.358736220   19.1 18.56 18.2   ~ 92 1
64 6C 091740+445437 Bla 09 20 58.45848666 +44 41 53.9850947   18.40 18.16 16.55   ~ 407 1
65 6C 091739+622838 Bla 09 21 36.23107643 +62 15 52.1803510   19.76 19.26 18.96   ~ 394 1
66 4C 55.17 Bla 09 57 38.1839604096 +55 22 57.754950636   18.24 17.89     ~ 459 1
67 6C 095456+654857 BLL 09 58 47.2451872176 +65 33 54.819354600     17.0 15.75   ~ 771 1
68 QSO B1004-217 Bla 10 06 46.4138565672 -21 59 20.411032848   17.05 16.89 16.29   ~ 111 1
69 RX J1015.0+4926 BLL 10 15 04.1396533776 +49 26 00.706055496   16.56 16.15 14.58   ~ 400 3
70 6C 103031+610629 Bla 10 33 51.4290959304 +60 51 07.334442756   19.31 18.86 20.24   ~ 195 2
71 RX J1037.7+5711 BLL 10 37 44.3078432736 +57 11 55.629345156   17.05 16.54 16.7   ~ 131 1
72 6C 104451+715930 Bla 10 48 27.61992778 +71 43 35.9384142     19.0 17.49   ~ 270 1
73 4C 01.28 BLL 10 58 29.60520810 +01 33 58.8237454   18.74 18.28 16.68   ~ 828 2
74 NVSS J105912-113422 BLL 10 59 12.4263597024 -11 34 22.779475140     17.5 16.2   ~ 89 1
75 MRC 1101-536 BLL 11 03 52.22168463 -53 57 00.6966389   18.30 17.9     ~ 91 1
76 Z 184-50 BLL 11 04 27.3140835504 +38 12 31.798495872   13.50 12.90 8.31   ~ 2841 1
77 QSO B1124-186 Bla 11 27 04.39245388 -18 57 17.4418445   19.17 18.65 19.23   ~ 254 1
78 ICRF J113245.6+003427 BLL 11 32 45.6184743144 +00 34 27.830851248 18.98 18.54 18.08 17.5   ~ 131 1
79 6C 114419+401458 Bla 11 46 58.29791724 +39 58 34.3043988   18.80 18.45 18.58   ~ 261 1
80 QSO B1144-3755 BLL 11 47 01.37071212 -38 12 11.0235229   19.03 16.2 16.72   ~ 320 1
81 Ton 599 Bla 11 59 31.83391383 +29 14 43.8268224   14.80 14.41 17.652 13.39 ~ 989 1
82 6C 120623+545839 Bla 12 08 54.25643167 +54 41 58.1632900   19.55 19.18 19.5   ~ 117 1
83 RX J1217.8+3007 BLL 12 17 52.0819904040 +30 07 00.634936872   16.07 15.62 13.47   G7 516 1
84 6C 121746+712158 Bla 12 20 03.62842109 +71 05 31.1335587       19.8   ~ 73 2
85 PG 1218+304 BLL 12 21 21.9426947832 +30 10 37.158534012   16.50 15.85 15.7   ~ 497 1
86 7C 1219+2830 BLL 12 21 31.6904439888 +28 13 58.500308172   16.81 16.11 14.24   ~ 924 1
87 7C 122223.5+213929 Bla 12 24 54.4583146056 +21 22 46.385507388   17.56 17.50 18.2   ~ 770 2
88 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 6022 1
89 RX J1230.2+2518 BLL 12 30 14.0893292232 +25 18 07.136022996   15.6   14.78   ~ 177 1
90 [VV2006] J123932.7+044305 Bla 12 39 32.75568115 +04 43 05.2330218   20.81 20.56 18.1   ~ 191 2
91 QSO J1246-2547 Bla 12 46 46.80203943 -25 47 49.2889822   17.65 17.41 16.96 15.5 ~ 314 1
92 LB 2449 BLL 12 48 18.7847605224 +58 20 28.717260720   16.10 15.78 15.19   ~ 215 1
93 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 3205 2
94 [VV2006] J132111.2+221613 Bla 13 21 11.20255812 +22 16 12.1083023   19.59 19.23 19.37   ~ 133 1
95 NAME VLBI 1325-558 QSO 13 29 01.14491196 -56 08 02.6655453           ~ 84 3
96 QSO J1332-0509 Bla 13 32 04.46468002 -05 09 43.3058094     18.5 18.37   ~ 169 1
97 ICRF J133239.2-125615 Bla 13 32 39.25140566 -12 56 15.3435472       18.7   ~ 90 1
98 7C 134328.69+450758.00 Bla 13 45 33.17247907 +44 52 59.5725560       19.6   ~ 138 1
99 SDSS J141828.58+354249.4 Bla 14 18 28.5815939688 +35 42 49.461956028           ~ 47 1
100 PSO J214.8439-08.6422 Bla 14 19 22.5559897046 -08 38 32.139347932           ~ 50 1
101 PG 1424+240 BLL 14 27 00.3917926224 +23 48 00.037510776 14.52 14.34 14.95 14.5   ~ 420 1
102 QSO B1424-41 Bla 14 27 56.29756617 -42 06 19.4376238   18.48 17.7 16.30   ~ 547 1
103 7C 1441+2514 Bla 14 43 56.89220390 +25 01 44.4907165   19.5   19.7   ~ 179 1
104 PKS J1443-3908 BLL 14 43 57.1974184800 -39 08 40.053885612       14.7   ~ 105 1
105 RX J1454.4+5124 BLL 14 54 27.1245711624 +51 24 33.731127900   18.76 18.35     ~ 103 1
106 QSO J1457-3539 BLL 14 57 26.71171449 -35 39 09.9716148   17.95 19.50 18.93   ~ 167 1
107 QSO B1502+1041 Bla 15 04 24.97978391 +10 29 39.1985309   18.97 18.56 18.94   ~ 634 1
108 6C 150412+374224 Bla 15 06 09.52997529 +37 30 51.1325012   21.2 21.2 20.60   ~ 213 1
109 QSO J1512-0906 Bla 15 12 50.53293048 -09 05 59.8297908   16.74 16.54     ~ 1409 1
110 ESO 514-1 BLL 15 17 41.8134049824 -24 22 19.482207024   15.13 14.00 13.95   ~ 815 3
111 7C 1520+3154 Bla 15 22 09.99173254 +31 44 14.3819383   20.45 19.89 19.87   ~ 230 1
112 QSO B1542+614 BLL 15 42 56.9436243096 +61 29 55.346749080   16.9 16.25 16.6   ~ 159 1
113 PG 1553+113 BLL 15 55 43.0440048528 +11 11 24.365649948 14.91 14.72 14.57 13.99   ~ 672 1
114 7C 1603+5722 Bla 16 04 37.3548559224 +57 14 36.660126444   18.02 17.79 17.70   ~ 120 1
115 4C 38.41 Bla 16 35 15.49297809 +38 08 04.5005995   18.14 17.97 17.25   ~ 906 1
116 Z 225-7 BLL 16 53 52.21668403 +39 45 36.6088754 14.09 14.15 13.29 8.26   ~ 2304 2
117 6C 170021+683437 Bla 17 00 09.29285259 +68 30 06.9591278     17.00 18.47   ~ 143 1
118 6C 170807+432136 Bla 17 09 41.08658310 +43 18 44.5325307   19.99 19.25 19.67   ~ 113 2
119 ASASSN -14ct Bla 17 23 50.8444548552 -77 13 50.548166148           ~ 59 2
120 7C 172601.30+453309.00 BLL 17 27 27.65080202 +45 30 39.7312530   19.0 18.10 16.64   ~ 233 2
121 7C 173240.70+385949.00 BLL 17 34 20.57853650 +38 57 51.4430945   19.5 19 19.00   ~ 232 1
122 4C 51.37 Bla 17 40 36.97784792 +52 11 43.4073694   18.16 18.70 16.73   ~ 441 1
123 RX J1748.5+7005 BLL 17 48 32.8402992264 +70 05 50.768819304   17.46 17.01 15.48   ~ 456 2
124 4C 09.57 BLL 17 51 32.81857326 +09 39 00.7284066   17.46 16.78 15.57   ~ 1007 1
125 ATO J268.5491+32.2064 BLL 17 54 11.7992994912 +32 12 23.055857100           ~ 62 1
126 1RXS J180043.6+782806 BLL 18 00 45.6838528560 +78 28 04.018028016   16.4 15.90 16.134   ~ 793 1
127 ICRF J180242.6-394007 Bla 18 02 42.68005300 -39 40 07.9081646       17.3   ~ 126 1
128 Z 340-35 BLL 18 06 50.6802916920 +69 49 28.109609256   14.77 14.22 11.39   ~ 909 1
129 4C 56.27 BLL 18 24 07.06837171 +56 51 01.4908155   18.9 19.30 16.48   ~ 510 1
130 ICRF J182912.4-581355 Bla 18 29 12.40235306 -58 13 55.1618061   19.26   18.80   ~ 50 1
131 QSO B1830-211 Bla 18 33 39.9399138048 -21 03 39.368838780     18.70 21   ~ 724 1
132 6C 184914+670207 Bla 18 49 16.07228484 +67 05 41.6802599     16.90 17.45   ~ 305 2
133 QSO B1908-202 Bla 19 11 09.65289294 -20 06 55.1090664   18.21   18.14   ~ 306 1
134 QSO B1936-623 QSO 19 41 21.76858343 -62 11 21.0567014   22.5       ~ 81 1
135 QSO B1954-388 Bla 19 57 59.81927491 -38 45 06.3558881   18.47 17.07 16.73   ~ 239 1
136 QSO B1959+650 BLL 19 59 59.8520303688 +65 08 54.652536492     12.8 11.21   ~ 699 2
137 8C 2007+777 BLL 20 05 30.9987913056 +77 52 43.248139536     16.5 17.36   ~ 474 1
138 QSO B2022-077 BLL 20 25 40.6602562440 -07 35 52.688047128   18.5       ~ 234 3
139 QSO B2052-474 Bla 20 56 16.35980507 -47 14 47.6277179   18.29 19.1 18.07   ~ 341 1
140 QSO J2115+295 Bla 21 15 29.41345155 +29 33 38.3669390     19.5 19.26   ~ 201 1
141 QSO B2136-428 BLL 21 39 24.1733820912 -42 35 20.465859048   16.50 16.2 15.7   ~ 97 1
142 PMN J2141-6411 rG 21 41 46.4409715032 -64 11 14.476312320           ~ 15 1
143 QSO B2141+1730 Bla 21 43 35.54456275 +17 43 48.7875890   15.91 15.73 15.17   ~ 418 1
144 QSO J2147-7536 Bla 21 47 12.73063669 -75 36 13.2249063   17.79 17.30     ~ 167 1
145 PKS J2158-3013 BLL 21 58 52.0652249880 -30 13 32.118447792   13.36 13.09 12.62   ~ 1829 1
146 QSO B2201+1711 BLL 22 03 26.89368237 +17 25 48.2477620     19.50 14.76   ~ 221 1
147 QSO B2227-0848 Bla 22 29 40.08433313 -08 32 54.4355294   17.80 17.41 17.81   ~ 391 1
148 4C 11.69 Bla 22 32 36.40890093 +11 43 50.9040592   17.75 17.33     ~ 1205 2
149 QSO B2233-148 BLL 22 36 34.08715104 -14 33 22.1896043 19.53 19.13 18.66 18.05   ~ 172 1
150 NVSS J224354+202103 BLL 22 43 54.7436079792 +20 21 03.775386276       16.1   ~ 116 1
151 ICRF J224412.7+405713 BLL 22 44 12.7311667056 +40 57 13.619816316       19.7   ~ 110 1
152 QSO B2247-283 BLL 22 50 44.49237710 -28 06 39.3295239   21.71   19.3   ~ 90 1
153 3C 454.3 Bla 22 53 57.7480438728 +16 08 53.561508864   16.57 16.10 15.22   ~ 3004 2
154 QSO B2255-2814 Bla 22 58 05.96287687 -27 58 21.2567572   17.34 16.77 17.20   ~ 397 1
155 6C 230840+340844 Bla 23 11 05.32880063 +34 25 10.9049514     19.5 19.2   ~ 138 1
156 ICRF J232154.9+320407 Bla 23 21 54.95598750 +32 04 07.6225103     18 20   ~ 115 1
157 QSO B2320-035 Bla 23 23 31.95375055 -03 17 05.0238540   18.6   18.16   ~ 229 2
158 QSO B2326-502 Bla 23 29 20.8816086312 -49 55 40.657964772   19.0 19.0 20.86   ~ 114 1
159 QSO J2345-1555 BLL 23 45 12.4622049264 -15 55 07.836801888   19.21   18.48   ~ 202 1

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