Data Specifications

The page contains a full description of the data products accompanying the public release of the Auriga Project data: the snapshots containing raw particle/cell data; the group catalogues that hold information about halos and subhalos for each snapshot; the merger trees; and supplementary data.

Snapshots

globus path structure: level?/<suite_name>/halo_Z/snapdir_X/snapshot_X.Y.hdf5

Each Auriga simulation stores a number of snapshots containing the raw data of each particle and cell. Each snapshot (denoted by number X) is split across Y files within a snapdir_X directory. The number of snapshots varies between the different simulation sets (see the table on the data download page). In total, there are 4 different output lists used. The collapsible tables below list the scale factor and redshift values of snapshots for each of these output lists.

Output list (64) ▾
Output number Expansion factor redshift
0 0.021931844.596
1 0.024058340.5657
2 0.026391136.8916
3 0.028950133.5422
4 0.031757230.4889
5 0.034836527.7055
6 0.038214525.1681
7 0.041920122.8549
8 0.045985120.7462
9 0.050444418.8238
10 0.055336417.0713
11 0.060703 15.4737
12 0.066590414.0172
13 0.073049412.6894
14 0.080135711.4788
15 0.087910710.3752
16 0.0964416 9.36897
17 0.105803 8.45154
18 0.116076 7.61502
19 0.127352 6.85222
20 0.139731 6.15658
21 0.153325 5.52211
22 0.168255 4.94334
23 0.184663 4.41527
24 0.202703 3.93332
25 0.222553 3.4933
26 0.244416 3.09139
27 0.267669 2.73596
28 0.290221 2.44564
29 0.312097 2.20413
30 0.333412 1.99929
31 0.35426 1.82279
32 0.374717 1.66868
33 0.39485 1.53261
34 0.414712 1.41131
35 0.434353 1.30228
36 0.453814 1.20355
37 0.473132 1.11358
38 0.492342 1.03111
39 0.511473 0.955137
40 0.530554 0.884821
41 0.549611 0.81947
42 0.568666 0.758501
43 0.587743 0.701425
44 0.606861 0.647824
45 0.626041 0.597339
46 0.645301 0.549663
47 0.664659 0.50453
48 0.684132 0.461706
49 0.703736 0.420987
50 0.723487 0.382196
51 0.743399 0.345173
52 0.763488 0.309779
53 0.783767 0.275889
54 0.804251 0.243392
55 0.824954 0.212189
56 0.845888 0.182189
57 0.867067 0.153313
58 0.888504 0.125487
59 0.910212 0.0986451
60 0.932203 0.0727278
61 0.95449 0.0476804
62 0.977084 0.023453
63 1 0
Output list (128) ▾
Output number Expansion factor redshift
0 0.02094 46.7554
1 0.021931844.596
2 0.022970442.5342
3 0.024058340.5657
4 0.025197738.6861
5 0.026391136.8916
6 0.027641 35.1782
7 0.028950133.5422
8 0.030321231.9803
9 0.031757230.4889
10 0.033261329.065
11 0.034836527.7055
12 0.036486526.4074
13 0.038214525.1681
14 0.040024523.9847
15 0.041920122.8549
16 0.043905621.7761
17 0.045985120.7462
18 0.048163219.7627
19 0.050444418.8238
20 0.052833817.9273
21 0.055336417.0713
22 0.057957516.254
23 0.060703 15.4737
24 0.063578514.7286
25 0.066590414.0172
26 0.069745113.3379
27 0.073049412.6894
28 0.076510512.0701
29 0.080135711.4788
30 0.083933110.9143
31 0.087910710.3752
32 0.0920772 9.86046
33 0.0964416 9.36897
34 0.101014 8.89967
35 0.105803 8.45154
36 0.11082 8.02363
37 0.116076 7.61502
38 0.121583 7.22483
39 0.127352 6.85222
40 0.133397 6.4964
41 0.139731 6.15658
42 0.146369 5.83206
43 0.153325 5.52211
44 0.160614 5.22609
45 0.168255 4.94334
46 0.176265 4.67326
47 0.184663 4.41527
48 0.193469 4.1688
49 0.202703 3.93332
50 0.21239 3.70832
51 0.222553 3.4933
52 0.233219 3.28781
53 0.244416 3.09139
54 0.256093 2.90483
55 0.267669 2.73596
56 0.279038 2.58374
57 0.290221 2.44564
58 0.301236 2.31966
59 0.312097 2.20413
60 0.322818 2.09772
61 0.333412 1.99929
62 0.343889 1.90791
63 0.35426 1.82279
64 0.364533 1.74324
65 0.374717 1.66868
66 0.384821 1.59861
67 0.39485 1.53261
68 0.404812 1.47028
69 0.414712 1.41131
70 0.424558 1.35539
71 0.434353 1.30228
72 0.444103 1.25173
73 0.453814 1.20355
74 0.463488 1.15755
75 0.473132 1.11358
76 0.482748 1.07147
77 0.492342 1.03111
78 0.501915 0.992368
79 0.511473 0.955137
80 0.521018 0.919318
81 0.530554 0.884821
82 0.540084 0.851564
83 0.549611 0.81947
84 0.559137 0.78847
85 0.568666 0.758501
86 0.5782 0.729504
87 0.587743 0.701425
88 0.597295 0.674214
89 0.606861 0.647824
90 0.616442 0.622212
91 0.626041 0.597339
92 0.63566 0.573168
93 0.645301 0.549663
94 0.654967 0.526794
95 0.664659 0.50453
96 0.67438 0.482842
97 0.684132 0.461706
98 0.693917 0.441095
99 0.703736 0.420987
100 0.713592 0.401361
101 0.723487 0.382196
102 0.733422 0.363472
103 0.743399 0.345173
104 0.75342 0.32728
105 0.763488 0.309779
106 0.773603 0.292653
107 0.783767 0.275889
108 0.793983 0.259473
109 0.804251 0.243392
110 0.814575 0.227635
111 0.824954 0.212189
112 0.835391 0.197044
113 0.845888 0.182189
114 0.856446 0.167615
115 0.867067 0.153313
116 0.877753 0.139273
117 0.888504 0.125487
118 0.899324 0.111947
119 0.910212 0.0986451
120 0.921171 0.0855744
121 0.932203 0.0727278
122 0.943309 0.0600986
123 0.95449 0.0476804
124 0.965748 0.0354671
125 0.977084 0.023453
126 0.988501 0.0116324
127 1 0
Output list (252) ▾
Output number Expansion factor redshift
0 0.020442247.9184
1 0.024475139.8578
2 0.028347734.2762
3 0.032369629.8932
4 0.036268126.5725
5 0.040252823.843
6 0.044254 21.5968
7 0.048194119.7494
8 0.052236818.1436
9 0.056084716.8302
10 0.060215915.6069
11 0.064041714.6148
12 0.068110613.682
13 0.072095612.8705
14 0.075953 12.166
15 0.080016711.4974
16 0.083899410.919
17 0.087970510.3674
18 0.0918032 9.89287
19 0.0958028 9.43811
20 0.0999766 9.00234
21 0.103839 8.63028
22 0.107851 8.27206
23 0.111488 7.96957
24 0.115795 7.63593
25 0.1197 7.35419
26 0.123737 7.08164
27 0.127306 6.85512
28 0.131599 6.59885
29 0.135394 6.38586
30 0.139298 6.17884
31 0.143315 5.97762
32 0.147448 5.78204
33 0.150983 5.62325
34 0.155337 5.4376
35 0.159061 5.28688
36 0.162875 5.13968
37 0.167572 4.96759
38 0.170778 4.85555
39 0.174872 4.71845
40 0.179065 4.58457
41 0.183358 4.45381
42 0.186866 4.35142
43 0.191346 4.22613
44 0.195008 4.12801
45 0.198739 4.03173
46 0.202541 3.93726
47 0.206417 3.84457
48 0.210366 3.75361
49 0.214392 3.66436
50 0.218494 3.57679
51 0.222674 3.49086
52 0.226935 3.40655
53 0.230184 3.34435
54 0.234588 3.26279
55 0.239077 3.18275
56 0.2425 3.12372
57 0.245971 3.06551
58 0.250678 2.98918
59 0.254267 2.93288
60 0.257907 2.87737
61 0.262842 2.80457
62 0.266605 2.75087
63 0.270421 2.69793
64 0.274293 2.64574
65 0.27822 2.59428
66 0.282203 2.54355
67 0.286243 2.49353
68 0.290341 2.44423
69 0.294498 2.39561
70 0.298714 2.34769
71 0.301558 2.31611
72 0.305875 2.26931
73 0.310254 2.22316
74 0.313209 2.19276
75 0.317693 2.1477
76 0.322241 2.10327
77 0.325309 2.074
78 0.329966 2.03061
79 0.333108 2.00203
80 0.337877 1.95966
81 0.341094 1.93174
82 0.345977 1.89036
83 0.349272 1.8631
84 0.354272 1.82269
85 0.357645 1.79607
86 0.361051 1.76969
87 0.36622 1.7306
88 0.369707 1.70485
89 0.373227 1.67934
90 0.376781 1.65406
91 0.382175 1.6166
92 0.385814 1.59192
93 0.389487 1.56748
94 0.393196 1.54326
95 0.39694 1.51927
96 0.400719 1.49551
97 0.404535 1.47197
98 0.408387 1.44866
99 0.412275 1.42556
100 0.416201 1.40269
101 0.420164 1.38002
102 0.424164 1.35758
103 0.428203 1.33534
104 0.43228 1.31331
105 0.436396 1.29149
106 0.440552 1.26988
107 0.442644 1.25915
108 0.446859 1.23784
109 0.451114 1.21674
110 0.455409 1.19583
111 0.457572 1.18545
112 0.461929 1.16484
113 0.466327 1.14442
114 0.470767 1.12419
115 0.473003 1.11415
116 0.477507 1.09421
117 0.482054 1.07446
118 0.484343 1.06465
119 0.488955 1.04518
120 0.491277 1.03551
121 0.495955 1.01631
122 0.500677 0.997294
123 0.503055 0.987853
124 0.507845 0.969104
125 0.510257 0.959796
126 0.515116 0.941311
127 0.517562 0.932134
128 0.52249 0.913911
129 0.524972 0.904863
130 0.529971 0.886897
131 0.532488 0.877977
132 0.537558 0.860265
133 0.540111 0.851471
134 0.542676 0.842719
135 0.547844 0.825339
136 0.550446 0.81671
137 0.555687 0.799575
138 0.558326 0.791068
139 0.560978 0.782602
140 0.566319 0.765788
141 0.569009 0.757441
142 0.571712 0.749134
143 0.577155 0.732636
144 0.579896 0.724446
145 0.582651 0.716294
146 0.588198 0.700106
147 0.590992 0.69207
148 0.593799 0.684071
149 0.599453 0.668187
150 0.6023 0.660302
151 0.605161 0.652453
152 0.608035 0.644642
153 0.613825 0.62913
154 0.61674 0.621429
155 0.619669 0.613764
156 0.622612 0.606136
157 0.628541 0.590987
158 0.631526 0.583466
159 0.634525 0.575981
160 0.637539 0.568531
161 0.64361 0.553737
162 0.646666 0.546392
163 0.649738 0.539082
164 0.652824 0.531807
165 0.655924 0.524566
166 0.65904 0.517359
167 0.665315 0.503048
168 0.668475 0.495942
169 0.67165 0.488871
170 0.67484 0.481833
171 0.678045 0.474828
172 0.681266 0.467857
173 0.684501 0.460918
174 0.691019 0.447139
175 0.694301 0.440298
176 0.697598 0.433489
177 0.700912 0.426713
178 0.704241 0.419969
179 0.707586 0.413257
180 0.710946 0.406576
181 0.714323 0.399927
182 0.717716 0.393309
183 0.72455 0.380168
184 0.727991 0.373644
185 0.731448 0.36715
186 0.734923 0.360688
187 0.738413 0.354256
188 0.74192 0.347854
189 0.745444 0.341482
190 0.748985 0.335141
191 0.752542 0.32883
192 0.756116 0.322548
193 0.759707 0.316296
194 0.763316 0.310074
195 0.766941 0.303881
196 0.770584 0.297718
197 0.774244 0.291583
198 0.777921 0.285478
199 0.781616 0.279401
200 0.785328 0.273353
201 0.789058 0.267334
202 0.792806 0.261343
203 0.796571 0.255381
204 0.800354 0.249446
205 0.804156 0.24354
206 0.807975 0.237662
207 0.811813 0.231811
208 0.815668 0.225988
209 0.819542 0.220193
210 0.823435 0.214425
211 0.827346 0.208684
212 0.831275 0.202971
213 0.835224 0.197284
214 0.839191 0.191624
215 0.843176 0.185992
216 0.847181 0.180385
217 0.851205 0.174805
218 0.855248 0.169252
219 0.85931 0.163725
220 0.863391 0.158224
221 0.867492 0.152749
222 0.871612 0.1473
223 0.875752 0.141876
224 0.879911 0.136478
225 0.88409 0.131106
226 0.888289 0.125759
227 0.892508 0.120438
228 0.896747 0.115141
229 0.901006 0.10987
230 0.905286 0.104623
231 0.909586 0.0994018
232 0.913906 0.0942048
233 0.918246 0.0890324
234 0.922608 0.0838844
235 0.92699 0.0787608
236 0.931392 0.0736614
237 0.935816 0.0685861
238 0.940261 0.0635348
239 0.944727 0.0585073
240 0.949214 0.0535036
241 0.953722 0.0485236
242 0.958252 0.0435672
243 0.962803 0.0386341
244 0.967376 0.0337244
245 0.97197 0.0288379
246 0.976587 0.0239744
247 0.981225 0.019134
248 0.985886 0.0143164
249 0.990568 0.00952167
250 0.995273 0.00474955
251 1 2.22045e-16
Output list (418) ▾
Output number Expansion factor redshift
0 0.02094 46.7554
1 0.021931844.596
2 0.022970442.5342
3 0.024058340.5657
4 0.025197738.6861
5 0.026391136.8916
6 0.027641 35.1782
7 0.028950133.5422
8 0.030321231.9803
9 0.031757230.4889
10 0.033261329.065
11 0.034836527.7055
12 0.036486526.4074
13 0.038214525.1681
14 0.040024523.9847
15 0.041920122.8549
16 0.043905621.7761
17 0.045985120.7462
18 0.048163219.7627
19 0.050444418.8238
20 0.052833817.9273
21 0.055336417.0713
22 0.057957516.254
23 0.060703 15.4737
24 0.063578514.7286
25 0.066590414.0172
26 0.069745113.3379
27 0.073049412.6894
28 0.076510512.0701
29 0.080135711.4788
30 0.083933110.9143
31 0.087910710.3752
32 0.0920772 9.86046
33 0.0964416 9.36897
34 0.101014 8.89967
35 0.105803 8.45154
36 0.11082 8.02363
37 0.116076 7.61502
38 0.121583 7.22483
39 0.127352 6.85222
40 0.133397 6.4964
41 0.139731 6.15658
42 0.146369 5.83206
43 0.153325 5.52211
44 0.160614 5.22609
45 0.168255 4.94334
46 0.176265 4.67326
47 0.184663 4.41527
48 0.193469 4.1688
49 0.202703 3.93332
50 0.21239 3.70832
51 0.222553 3.4933
52 0.233219 3.28781
53 0.244416 3.09139
54 0.256093 2.90483
55 0.267669 2.73596
56 0.279038 2.58374
57 0.290221 2.44564
58 0.301236 2.31966
59 0.312097 2.20413
60 0.322818 2.09772
61 0.333412 1.99929
62 0.343889 1.90791
63 0.35426 1.82279
64 0.364533 1.74324
65 0.374717 1.66868
66 0.384821 1.59861
67 0.39485 1.53261
68 0.404812 1.47028
69 0.414712 1.41131
70 0.424558 1.35539
71 0.434353 1.30228
72 0.444103 1.25173
73 0.453814 1.20355
74 0.463488 1.15755
75 0.473132 1.11358
76 0.482748 1.07147
77 0.492342 1.03111
78 0.49718 1.01134
79 0.49868 1.00529
80 0.5002 0.9992
81 0.501915 0.992368
82 0.50328 0.986966
83 0.5048 0.980983
84 0.50634 0.974958
85 0.50786 0.969047
86 0.5094 0.963094
87 0.51092 0.957254
88 0.511473 0.955137
89 0.51246 0.951372
90 0.51398 0.945601
91 0.51552 0.939789
92 0.51704 0.934086
93 0.51856 0.928417
94 0.5201 0.922707
95 0.521018 0.919318
96 0.52162 0.917104
97 0.52314 0.911534
98 0.52466 0.905996
99 0.5262 0.900418
100 0.52772 0.894944
101 0.52924 0.889502
102 0.53076 0.884091
103 0.53228 0.87871
104 0.5338 0.873361
105 0.53532 0.868042
106 0.53684 0.862752
107 0.53836 0.857493
108 0.540084 0.851564
109 0.5414 0.847063
110 0.54292 0.841892
111 0.54444 0.83675
112 0.54594 0.831703
113 0.54746 0.826617
114 0.54898 0.82156
115 0.549611 0.81947
116 0.5505 0.81653
117 0.55202 0.811529
118 0.55352 0.806619
119 0.55504 0.801672
120 0.55656 0.796751
121 0.55806 0.791922
122 0.55958 0.787055
123 0.5611 0.782214
124 0.5626 0.777462
125 0.56412 0.772672
126 0.56564 0.767909
127 0.56714 0.763233
128 0.568666 0.758501
129 0.57018 0.753832
130 0.57168 0.74923
131 0.5732 0.744592
132 0.5747 0.740038
133 0.57622 0.735448
134 0.5782 0.729504
135 0.57924 0.7264
136 0.58074 0.721941
137 0.58226 0.717446
138 0.58376 0.713033
139 0.58528 0.708584
140 0.58678 0.704216
141 0.587743 0.701425
142 0.5883 0.699813
143 0.5898 0.69549
144 0.59132 0.691132
145 0.59282 0.686853
146 0.59434 0.682539
147 0.59584 0.678303
148 0.59736 0.674032
149 0.59886 0.669839
150 0.60038 0.665612
151 0.60188 0.661461
152 0.60338 0.65733
153 0.6049 0.653166
154 0.606861 0.647824
155 0.60792 0.644953
156 0.60942 0.640904
157 0.61094 0.636822
158 0.61244 0.632813
159 0.61396 0.628771
160 0.61546 0.624801
161 0.616442 0.622212
162 0.61698 0.620798
163 0.61848 0.616867
164 0.62 0.612903
165 0.6215 0.60901
166 0.623 0.605136
167 0.62452 0.60123
168 0.626041 0.597339
169 0.62754 0.593524
170 0.62904 0.589724
171 0.63056 0.585892
172 0.63208 0.582078
173 0.63358 0.578333
174 0.6351 0.574555
175 0.63566 0.573168
176 0.6366 0.570845
177 0.63812 0.567103
178 0.63962 0.563428
179 0.64114 0.559722
180 0.64264 0.556081
181 0.64416 0.552409
182 0.64568 0.548755
183 0.64718 0.545165
184 0.6487 0.541545
185 0.65022 0.537941
186 0.65172 0.534401
187 0.65324 0.530831
188 0.654967 0.526794
189 0.65626 0.523786
190 0.65778 0.520265
191 0.6593 0.51676
192 0.6608 0.513317
193 0.66232 0.509844
194 0.66384 0.506387
195 0.664659 0.50453
196 0.66536 0.502946
197 0.66688 0.49952
198 0.66838 0.496155
199 0.6699 0.49276
200 0.67142 0.489381
201 0.67294 0.486017
202 0.67446 0.482668
203 0.67598 0.479334
204 0.6775 0.476015
205 0.67902 0.472711
206 0.68054 0.469421
207 0.68206 0.466147
208 0.68358 0.462887
209 0.684132 0.461706
210 0.6851 0.459641
211 0.68662 0.45641
212 0.68814 0.453193
213 0.68966 0.44999
214 0.69118 0.446801
215 0.6927 0.443626
216 0.69424 0.440424
217 0.69576 0.437277
218 0.69728 0.434144
219 0.6988 0.431025
220 0.70034 0.427878
221 0.70186 0.424786
222 0.703736 0.420987
223 0.70492 0.418601
224 0.70644 0.415548
225 0.70796 0.412509
226 0.7095 0.409443
227 0.71102 0.40643
228 0.71256 0.403391
229 0.71408 0.400403
230 0.71562 0.39739
231 0.71714 0.394428
232 0.71868 0.39144
233 0.72022 0.388465
234 0.72174 0.38554
235 0.723487 0.382196
236 0.72482 0.379653
237 0.72636 0.376728
238 0.72788 0.373853
239 0.72942 0.370952
240 0.73096 0.368064
241 0.7325 0.365188
242 0.733422 0.363472
243 0.73404 0.362324
244 0.73558 0.359471
245 0.73712 0.356631
246 0.73866 0.353803
247 0.7402 0.350986
248 0.74174 0.348181
249 0.743399 0.345173
250 0.74482 0.342606
251 0.74638 0.3398
252 0.74792 0.337041
253 0.74946 0.334294
254 0.75102 0.331522
255 0.75256 0.328798
256 0.75342 0.32728
257 0.7541 0.326084
258 0.75566 0.323346
259 0.7572 0.320655
260 0.75876 0.31794
261 0.7603 0.31527
262 0.76186 0.312577
263 0.763488 0.309779
264 0.76496 0.307258
265 0.76652 0.304597
266 0.76808 0.301948
267 0.76962 0.299343
268 0.77118 0.296714
269 0.77274 0.294096
270 0.773603 0.292653
271 0.7743 0.291489
272 0.77586 0.288892
273 0.77742 0.286306
274 0.77898 0.28373
275 0.78054 0.281164
276 0.7821 0.278609
277 0.783767 0.275889
278 0.78524 0.273496
279 0.7868 0.270971
280 0.78836 0.268456
281 0.78994 0.265919
282 0.7915 0.263424
283 0.79306 0.260939
284 0.793983 0.259473
285 0.79464 0.258431
286 0.7962 0.255966
287 0.79778 0.253478
288 0.79936 0.251001
289 0.80092 0.248564
290 0.8025 0.246106
291 0.804251 0.243392
292 0.80564 0.241249
293 0.80722 0.23882
294 0.8088 0.2364
295 0.81038 0.233989
296 0.81196 0.231588
297 0.81354 0.229196
298 0.814575 0.227635
299 0.81512 0.226813
300 0.81672 0.22441
301 0.8183 0.222046
302 0.81988 0.219691
303 0.82146 0.217345
304 0.82306 0.214978
305 0.824954 0.212189
306 0.82624 0.210302
307 0.82782 0.207992
308 0.82942 0.205662
309 0.831 0.203369
310 0.8326 0.201057
311 0.8342 0.198753
312 0.83578 0.196487
313 0.83738 0.194201
314 0.83898 0.191924
315 0.84058 0.189655
316 0.84218 0.187395
317 0.84378 0.185143
318 0.84538 0.1829
319 0.845888 0.182189
320 0.84698 0.180665
321 0.8486 0.178412
322 0.8502 0.176194
323 0.8518 0.173985
324 0.85342 0.171756
325 0.85502 0.169563
326 0.85662 0.167379
327 0.85824 0.165175
328 0.85986 0.16298
329 0.86146 0.16082
330 0.86308 0.158641
331 0.8647 0.15647
332 0.86632 0.154308
333 0.867067 0.153313
334 0.86794 0.152153
335 0.86956 0.150007
336 0.87118 0.147868
337 0.8728 0.145738
338 0.87442 0.143615
339 0.87604 0.1415
340 0.877753 0.139273
341 0.8793 0.137268
342 0.88092 0.135177
343 0.88254 0.133093
344 0.88418 0.130991
345 0.88582 0.128898
346 0.88744 0.126837
347 0.888504 0.125487
348 0.88908 0.124758
349 0.89072 0.122687
350 0.89234 0.120649
351 0.89398 0.118593
352 0.89562 0.116545
353 0.89726 0.114504
354 0.899324 0.111947
355 0.90056 0.11042
356 0.9022 0.108402
357 0.90384 0.106391
358 0.90548 0.104387
359 0.90714 0.102366
360 0.90878 0.100376
361 0.91044 0.09837
362 0.91208 0.0963951
363 0.91374 0.0944032
364 0.9154 0.0924186
365 0.91706 0.0904412
366 0.91872 0.0884709
367 0.92038 0.0865077
368 0.921171 0.0855744
369 0.92204 0.0845516
370 0.9237 0.0826026
371 0.92536 0.0806605
372 0.92702 0.0787254
373 0.92868 0.0767972
374 0.93036 0.0748527
375 0.932203 0.0727278
376 0.9337 0.0710078
377 0.93536 0.0691071
378 0.93704 0.0671903
379 0.93872 0.0652804
380 0.94038 0.0633999
381 0.94206 0.0615035
382 0.94374 0.0596139
383 0.94542 0.057731
384 0.9471 0.0558547
385 0.94878 0.0539851
386 0.95048 0.0521
387 0.95216 0.0502437
388 0.95384 0.0483939
389 0.95449 0.0476804
390 0.95554 0.0465287
391 0.95722 0.0446919
392 0.95892 0.0428399
393 0.9606 0.041016
394 0.9623 0.039177
395 0.964 0.0373444
396 0.965748 0.0354671
397 0.9674 0.0336986
398 0.9691 0.0318853
399 0.9708 0.0300783
400 0.9725 0.0282776
401 0.9742 0.0264833
402 0.97592 0.0246742
403 0.977084 0.023453
404 0.97762 0.0228923
405 0.97934 0.0210958
406 0.98104 0.0193264
407 0.98276 0.0175424
408 0.98448 0.0157647
409 0.98618 0.0140137
410 0.9879 0.0122482
411 0.988501 0.0116324
412 0.98962 0.0104889
413 0.99134 0.00873565
414 0.99306 0.0069885
415 0.9948 0.00522718
416 0.99652 0.00349215
417 0.99824 0.0017631
418 1 0

The particle/cell data in any given snapshot is organized according to their group/subgroup membership, as per the FoF or Subfind algorithms. For each particle type, the sort order is: GroupNumber, SubgroupNumber, BindingEnergy, where particles belonging to the group but not to any of its subgroups ("fuzz") are included after the last subgroup. The following figure provides a schematic view of the particle organization within a snapshot, for one particle type. Note that the truncation of a snapshot in chunks is arbitrary, thus halos may happen to be stored across multiple, subsequent chunks. Similarly, the different particle types of a halo can be stored in different sets of chunks.

Every HDF5 snapshot contains several groups: "Header", "Parameters", "Configuration", and five "PartTypeX" groups, for the following particle types (the DM only runs have a single PartType1 group):

  • gas cells: PartType0
  • high-resolution dark matter particles: PartType1
  • low-resolution dark matter particles: PartType2 & PartType3
  • star particles & wind particles: PartType4
  • black holes: PartType5
  • tracer particles: PartType6

The Header information can be viewed easily with the following command:

h5dump -g Header snapshot_127.0.hdf5

where the snapshot file corresponds to the block 0 of snapshot 127.

The most important information held in the Header group is:

Header attributes ▾
Field Dim's Units Description
BoxSize 1 $$ ckpc/h $$ Spatial extent of the periodic box (in comoving units; set to 67.77).
MassTable 6 $$ 10^{10} M_\odot/h $$ Masses of particle types which have a constant mass (only DM).
NumPart_ThisFile 6 - Number of particles (of each type) included in this (sub-)file.
NumPart_Total 6 - Total number of particles (of each type) across all (sub-)files of this snapshot.
NumPart_Total_HighWord 6 - Total number of particles (of each type) across all (sub-)files of this snapshot.
HubbleParam 1 - Dimensionless Hubble parameter (set to 0.6777)
Omega0 1 - The cosmological density parameter for matter (set to 0.307).
OmegaLambda 1 - The cosmological density parameter for the cosmological constant (set to 0.693).
Redshift 1 - The redshift corresponding to the current snapshot.
Time 1 - The scale factor a (=1/(1+z)) corresponding to the current snapshot.
NumFilesPerSnapshot 1 - Number of file chunks per snapshot.

The data fields/attributes belonging to each PartTypeX group can be similarly checked with command line interface hdf5 script. For example, the following command shows the fields for high resolution dark matter particles:

$ h5ls snapshot_127.0.hdf5/PartType1
Coordinates              Dataset {1311009, 3} 
ParticleIDs              Dataset {1311009} 
Potential                Dataset {1311009} 
Velocities               Dataset {1311009, 3} 
        

The system of units used in Auriga is:

UnitLength          3.085678e24        ;  1.0 Mpc
            UnitMass            1.989e43           ;  1.0e10 solar masses
            UnitVelocity        1e5                   ;  1 km/sec
        

The following table lists the most important data fields in the snapshot for each of the PartTypeX groups, including dimensions, units and descriptions. For an extensive list, we refer the reader to IllustrisTNG website (but note that the UnitLength is 1 kiloparsec for those simulations, not 1 Megaparsec as used in Auriga).

Snapshot data attributes ▾
Common to all PartTypes
Field Dim's Units Description
Coordinates N,3 Spatial position of the center of mass. Comoving coordinate.
Potential N Gravitational potential energy of the cell/particle.
ParticleIDs N - The unique ID of the cell/particle.
Velocities {N,3} Spatial velocity. Multiply this value by to obtain peculiar velocity.
Fields for low resolution dark matter particles - PartType2 & PartType3
Masses N These are larger than the mass of PartType1 dark matter and are always outside of the Lagrangian region of the simulation (typically ≥ 1 Mpc away from the main halo).
Fields for gas cells - PartType0
Density N Comoving mass density of cell (calculated as mass/volume).
DivergenceOfMagneticField N Comoving mass density of cell (calculated as mass/volume).
ElectronAbundance N Fractional electron number density with respect to the total hydrogen number density.
EnergyDissipation N The dissipated energy rate (amount of kinetic energy irreversibly transformed into thermal energy).
GFM_AGNRadiation N Bolometric intensity (physical units) at the position of this cell arising from the radiation fields of nearby AGN.
GFM_CoolingRate N The instantaneous net cooling rate experienced by this gas cell.
GFM_Metallicity N - The ratio where is the total mass all metal elements (above He). To convert to solar metallicity, divide by 0.0127 (the primordial solar metallicity).
GFM_Metals N,9

(or N,14)

- Individual abundances of nine species: H, He, C, N, O, Ne, Mg, Si, Fe (in this order). Each is the dimensionless ratio of mass in that species to the total gas cell mass.

(additional s-process elements are included in the low-mass Milky Way and dwarf simulations only)

GFM_RProcess N,12 - r-process element abundances from different models (Neutron star mergers and rare core-collapse supernovae). See van de Voort et al. (2020) for details.

(only in the low-mass Milky Way and dwarf simulations)

HighResGasMass N A tracer of the mass in a cell that should be 'High resolution gas', which ensures the gas is refined if needed to reach the target gas mass resolution.
InternalEnergy N Internal (thermal) energy per unit mass for this gas cell.
Machnumber N The Mach number for this gas cell.
MagneticField N,3 The (comoving) magnetic field 3-vector of this gas cell. Multiply by the same Unit factor to get CGS units (Gauss).
Masses N Gas mass in this cell (usually within a factor of 2 of the target gas mass).
NeutralHydrogenAbundance N - Fraction of the hydrogen cell mass (or density) in neutral hydrogen.
NumTracers N - Number of tracer particles in this gas cell.

(only in the low-mass Milky Way and dwarf simulations)

StarFormationRate N Instantaneous star formation rate of this gas cell.
Volume N Volume of the gas cell.
Fields for star & wind particles - PartType4
BirthDensity N The density of the gas cell in which this star particle was born.

(only in the dwarf simulations)

BirthPos N,3 The coordinates of the star particle at birth.

(only in the low-mass Milky Way and dwarf simulations)

BirthVel N,3 The velocity of the star particle at birth.

(only in the low-mass Milky Way and dwarf simulations)

GFM_InitialMass N The mass of the star particle when it was formed (either equal to or less than Masses field owing to mass loss from stellar evolution).
GFM_Metallicity N - Inherited metallicity from the gas cell it formed from (see PartType0).
GFM_Metals N,9

(or N,14)

- Inherited chemical abundances from the gas cell it formed from (see PartType0).
GFM_NSNS_Count N,12 - Number of Neutron star mergers that have occured in this star particle. See van de Voort et al. (2020) for details.

(only in the low-mass Milky Way and dwarf simulations)

GFM_RProcess N,12 - r-process element abundances from different models (Neutron star mergers and rare core-collapse supernovae). See van de Voort et al. (2020) for details.

(only in the low-mass Milky Way and dwarf simulations)

GFM_StellarFormationTime N - If negative, it represents a wind particle. If positive, it is the scale factor at which the star particle was formed.
GFM_StellarPhotometrics N,8 mag Stellar magnitudes in bands U, B, V, K, g, r, i, z.
NumTracers N - Number of tracer particles in this star particle.

(only in the low-mass Milky Way and dwarf simulations)

Fields for black hole particles - PartType5
BH_CumEgyInjection_QM N Cumulative amount of thermal AGN feedback energy injected into surrounding gas in the high accretion-state (quasar) mode, total over the entire lifetime of this blackhole. Field summed during BH-BH merger.
BH_CumEgyInjection_RM N Cumulative amount of thermal AGN feedback energy injected into surrounding gas in the low accretion-state (radio) mode, total over the entire lifetime of this blackhole. Field summed during BH-BH merger.
BH_CumMassGrowth_QM N Cumulative mass accreted onto the BH in the high accretion-state (quasar) mode, total over the entire lifetime of this blackhole. Field summed during BH-BH merger.
BH_CumMassGrowth_RM N Cumulative mass accreted onto the BH in the low accretion-state (radio) mode, total over the entire lifetime of this blackhole. Field summed during BH-BH merger.
BH_Density N Local comoving gas density averaged over the nearest neighbors of the BH.
BH_Hsml N The comoving radius of the sphere enclosing the nearest neighbors of the BH.
BH_Mass N The mass of the black hole particle.
BH_Mdot N Instantaneous mass accretion rate.
BH_Mdot_Quasar N Instantaneous mass accretion rate in the quasar mode.
BH_Mdot_Radio N Instantaneous mass accretion rate in the radio mode.
BH_Pressure N Physical gas pressure (in comoving units) near the BH, defined as , where is the local comoving gas density (BH_Density, as above) is BH_U (defined below).
BH_Progs N Total number of BHs that have merged into this BH.
BH_U N Thermal energy per unit mass in quasar-heated bubbles near the BH. Used to define the BH_Pressure.
HostHaloMass N Mass of the (sub)halo in which the black hole is located.
NumTracers N - Number of tracer particles in this black hole particle.

(only in the low-mass Milky Way and dwarf simulations)

Fields for tracer particles - PartType6
ParentID N - The unique ID (uint64) of the parent of this tracer. Could be a gas cell, star, wind phase cell, or BH.

(only in the low-mass Milky Way and dwarf simulations)

TracerID N - The unique ID (uint64) of this tracer.

(only in the low-mass Milky Way and dwarf simulations)

In addition to the snapshots described above, there exist high-cadence (5 Myr) snapshots containing only star particle information for the dwarf galaxy simulation suites: Halos_1e11msol/4, Halos_1e11msol/3, and Halos_1e10msol/3.



Group Catalogues

globus path structure: level?/<suite_name>/halo_Z/groups_X/fof_subhalo_tab_X.Y.hdf5

One group catalogue exists for each snapshot. The catalogues are built from two main algorithms: Friends of Friends (FOF) and SUBFIND. FOF is applied to dark matter particles only and aims to group particles of virial overdensity. SUBFIND identifies gravitationally bound substructures within each FOF group and is run on all particle types. The subhalos identified by SUBFIND are ordered in rank of descending total mass, such that the most massive subhalo of a group comes first.

In Auriga, the first subhalo of the first FOF group (FOF=0; SUBFIND=0) is usually the main Milky Way-mass halo of interest. All other subhaloes (SUBFIND>0) in the FOF are then satellites of the main halo of that FOF group. However, owing to the stochasticity in the growth of individual halos, a satellite of the main Milky Way halo may be given the SUBFIND=0 index if it temporarily becomes more massive. For this reason, it is best to use the merger trees (see below) to ensure the main halo is consistently tracked over time.

Some of the more important fields in the group catalaogues are:

Group catalogue attributes ▾
FOF group data fields
Field Dimensions Units Description
GroupBHMass N Sum of the mass of all blackholes (type 5) in this group.
GroupBHMdot N Sum of the mass accretion rate of all blackholes (type 5) in this group.
GroupCM (N,3) Comoving position of the center of mass of the group (computed from all particle types in the group).
GroupFirstSub N - Index into the Subhalo table of the most massive Subfind group within this FoF group.
GroupGasMetalFractions (N,9) - Total mass fraction locked up in the following elements: H, He, C, N, O, Ne, Mg, Si, Fe (in this order) of all gas cells in the FoF group.
GroupGasMetallicity N - Mass-weighted average metallicity of all gas cells in the FoF group.
GroupLen N - The total number of particles/cells of all types in this group.
GroupLenType (N,6) - The total number of each particle type in this group.
GroupMass N Sum of the individual masses of every particle/cell, of all types, in this group.
GroupMassType (N,6) Sum of the individual masses of every particle/cell, split into the six different types, in this group.
GroupNsubs N - Number of subhalos in this FOF group.
GroupPos (N,3) Position of this FOF group.
GroupSFR N Sum of the individual star formation rates of all star-forming gas cells in this group.
GroupStarMetalFractions (N,9) - Total mass fraction locked up in the following elements: H, He, C, N, O, Ne, Mg, Si, Fe (in this order) of all star particles in the FoF group.
GroupStarMetallicity N - Mass-weighted average metallicity of all star particles in the FoF group.
GroupVel (N,3) Velocity of the group, computed as the sum of the mass weighted velocities of all particles/cells in this group, of all types. The peculiar velocity is obtained by multiplying this value by 1/a.
GroupWindMass N Sum of the individual masses of all wind phase gas cells (negative GFM_FormationTime) in this group.
Group_M_Crit200 N of this FOF group: Total Mass of this group enclosed in a sphere whose mean density is 200 times the critical density of the Universe, at the time the halo is considered.
GroupNsubs N - Count of the total number of Subfind groups within this FoF group.
Group_R_Crit200 N - of this FOF group.
Subhalo data fields
SubhaloBHMass N Sum of the mass of all blackholes (type 5) of this subhalo.
SubhaloBHMdot N Sum of the mass accretion rate of all blackholes (type 5) of this subhalo.
SubhaloCM (N,3) Comoving position of the center of mass of the subhalo (computed from all particle types in the subhalo).
SubhaloGasMetalFractions (N,9) - Total mass fraction locked up in the following elements: H, He, C, N, O, Ne, Mg, Si, Fe (in this order) of all gas cells in the subhalo.
SubhaloGasMetallicity N - Mass-weighted average metallicity of all gas cells in the subhalo.
SubhaloGrNr N - Index into the Group table of the FOF host/parent of this subhalo.
SubhaloHalfmassRad N Comoving radius containing half of the total mass (SubhaloMass) of this subhalo.
SubhaloHalfmassRadType (N,6) Comoving radius containing half of the total mass (SubhaloMass) of this subhalo in each individual particle type.
SubhaloIDMostbound N - The ID of the particle with the smallest binding energy (could be any type).
SubhaloLen N - Total number of all particles/cell in this subhalo.
SubhaloLenType (N,6) - Number of particles/cell in this subhalo for each PartType.
SubhaloMass N The total mass of of all particles/cell in this subhalo.
SubhaloMassType (N,6) The mass of each PartType of this subhalo.
SubhaloMassInHalfRad N The total mass of of all particles/cell within the half mass radius of this subhalo.
SubhaloMassInHalfRadType (N,6) The mass of each PartType within the half mass radius of this subhalo.
SubhaloMassInMaxRad N The total mass of all particles/cell within the radius at which the maximum circular velocity is attained for this subhalo.
SubhaloMassInMaxRadType (N,6) The mass of each PartType within the radius at which the maximum circular velocity is attained for this subhalo.
SubhaloMassInRad N The total mass of of all particles/cell within twice the half mass radius of this subhalo.
SubhaloMassInRadType (N,6) The mass of each PartType within twice the half mass radius of this subhalo.
SubhaloPos (N,3) The coordinates of this subhalo.
SubhaloSFR N Sum of the individual star formation rates of all star-forming gas cells in this subhalo.
SubhaloSFRinHalfRad N Sum of the individual star formation rates of all star-forming gas cells within the half mass radius of this subhalo.
SubhaloSFRinMaxRad N Sum of the individual star formation rates of all star-forming gas cells in this subhalo.
SubhaloSFRinRad N Sum of the individual star formation rates of all star-forming gas cells within the radius at which the maximum circular velocity is attained for this subhalo.
SubhaloSpin (N,3) Total spin per axis, computed for each as the mass weighted average of the relative coordinate times relative velocity of all member particles/cells. Also known as specific angular momentum.
SubhaloStarMetalFractions (N,9) - Total mass fraction locked up in the following elements: H, He, C, N, O, Ne, Mg, Si, Fe (in this order) of all star particles in the subhalo.
SubhaloStarMetallicity N - Mass-weighted average metallicity of all star particles in the subhalo.
SubhaloStellarPhotometrics (N,8) mag Magnitudes (U, B, V, K, g, r, i, z) calculated from the summed luminosities of all star particles in the subhalo.
SubhaloStellarPhotometricsMassInRad N Sum of the mass of the member star particles within the radius SubhaloStellarPhotometricsRad (see below) of this subhalo.
SubhaloStellarPhotometricsRad N Radius at which the surface brightness profile of this subhalo drops below the limit of 20.7 mag arcsec in the K band (in comoving units).
SubhaloVel (N,3) The velocity of this subhalo.
SubhaloVelDisp N One-dimensional velocity dispersion of all the member particles/cells (the 3D dispersion divided by the square-root of 3).
SubhaloVelMax N Maximum value of the spherically-averaged rotation curve.
SubhaloVmaxRad N Comoving radius at which the maximum rotation velocity is achieved.
SubhaloWindMass N Total mass of wind particles in this subhalo.


Merger Trees

globus path structure: level?/<suite_name>/mergertrees/halo_Z/trees_sf1_X.Y.hdf5

The merger trees for the Auriga simulations are produced in post-processing using the code developed by Springel et al. 2005, and are very similar to the LHaloTree data product of the IllustrisTNG simulations. They provide useful linking indices that connect individual objects catalogued by FOF and SUBFIND both within the same snapshot and over different snapshots. This is important, because subhalos are not always listed in the same order between snapshots: as they are ordered by mass, 2 objects of similar mass can overtake each other over time and consequently their subhalo index can change.

The schematic diagram below illustrates how the linking indices given in the merger trees work. The most important linking indices are the 'FirstProgenitor', 'Descendent', and 'NextProgenitor' ones. In particular, 'Descendent' allows one to walk foward in time and identify the same object at the next output. On the other hand, 'FirstProgenitor' allows one to talk backward in time by identifying an object's most massive progenitor at preceding outputs. Finally, 'NextProgenitor' moves sideways to identify other progenitors in the preceding output that have the same descendant as each other (if this is more than one, a merger has occurred). Traversing the tree in any direction (forward, backward, or sideways) can be done recursively until an index of -1 is returned, which indicates the end of the branch. We provide an example of walking the tree on the Analysis Code & Examples page.

The mergertree output is split across several HDF5 files called trees_sf1_127.[chunknum].hdf5. In each file there are a number of groups named TreeX, where X is an integer which increases from zero to the number of tree groups in that file chunk. For the Auriga zoom-in simulations, Tree0 is the relevant tree group. The following tables summarise the data fields held in the tree.

Merger Trees ▾
Tree Header
Field Dimensions Units Description
Redshifts N snaps - List of redshifts of the snapshots used to create this merger tree.
TotNsubhalos N snaps - Equal to the number of Subfind/Subhalo groups in the group catalog, for each snapshot used to create this merger tree.
Tree Data
SubhaloNumber N - The SUBFIND ID of this subhalo at a given snapshot.
Descendant N - The index of the subhalo's descendant within the merger tree, if any (-1 otherwise).
FirstProgenitor N - The index of the subhalo's first progenitor within the merger tree, if any (-1 otherwise). The first progenitor is defined as the most massive one (-1 if none).
NextProgenitor N - The index of the next subhalo from the same snapshot which shares the same descendant, if any (-1 if this is the last).
FirstHaloInFOFGroup N - The index of the main subhalo (i.e. the most massive one) from the same FOF group.
NextHaloInFOFGroup N - The index of the next subhalo from the same FOF group (-1 if this is the last).
SnapNum N - The snapshot in which this subhalo was found.

In addition to the above, many of the fields stored in the Group and subhalo catalogues are also stored in the tree for convenience.

It is useful to note that the python analysis package (available at this bitbucket repository) automatically converts the units of many snapshot, group catalogue, and merger tree fields to physical units upon loading the data.



Accreted Particle lists

globus path structure: level?/<suite_name>/accretedlists/halo_Z/halo_ZstarID_accreted_all_newmtree_X.hdf5

We provide additional information about the star particles found within the of the main halo at redshift zero. This information is designed to be particularly useful for understanding the origin and accretion history of star particles that were born elsewhere and later accreted into the main halo, and that exist in the final snapshot as either disrupted debris or part of a satellite galaxy. These data can be structured in a series of files, one for each snapshot of the simulation that contains only the star particles born in that snapshot. Thus, all files should be loaded to get a complete list of all the star particles found within the of the halo at redshift zero; an example of how to do this can be found on the Analysis Code & Examples page. The data fields are described in the table below.

Accreted particle lists ▾
Header
Field Dimensions Units Description
n_ins 1 - Number of star particles born in-situ.
n_acc 1 - Number of star particles born ex-situ.
Insitu
ParticleIDs N_in - The ID of the star particle.
Exsitu
AccretedFlag N_ex - Indicates whether the star particle belong to an existing satellite (1) or the main halo (0) at redshift zero.
BirthFofIndex N_ex - The FOF group in the corresponding snapshot in which the star particle first appeared after birth.
BirthSubhaloIndex N_ex - The SUBFIND subhalo index in the corresponding snapshot in which the star particle first appeared after birth.
BoundFirstTime N_ex scale factor, The first time at which the star particle becomes bound to the main halo.
ParticleIDs N_ex - The ID of the star particle.
PeakMassIndex N_ex - The tree index of the progenitor object at its most massive (in stars).
PeakMassInfalltime N_ex scale factor, The time at which the progenitor in which the star particle was born crosses inside for the first time.
RootIndex N_ex - The first entry in the 'FirstProgenitor' branch of the progenitor object in which the star particle was born.

Note that, for a minority of star particles, some of the ex-situ fields can have negative values if not applicable: for example, BirthSubhaloIndex is negative if a star particle is not associated with a subhalo at its time of birth.



Published high level data

High level data are the outcome of analysis of the simulations, such as various galaxy properties, and are often tabulated in publications. In this section, we make high level data available in a convenient form, such as .txt files that can be easily read by, for example, numpy.

i) Milky Way galaxy main properties [download]

Table 1 of Grand et al. (2017) that lists properties such as the mass and scale lengths of the stellar disc and bulge of the main galaxy in the Milky Way mass simulations at redshift zero. Quantities and units are listed in the downloadable file. A citation to this paper is requested if these data are used and/or referenced.

ii) Milky Way galaxy HI gas disc properties [download]

Table 1 of Marinacci et al. (2017) that lists the mass and sizes of the HI gas discs of the main galaxy in the Milky Way mass simulations at redshift zero. Quantities and units are listed in the downloadable file. A citation to this paper is requested if these data are used and/or referenced.

iii) Milky Way satellite & subhalo properties [download]

Table 1 of Simpson et al. (2018) that lists the mass, maximum rotation velocity, number of subhalos, and their fraction of quenched and HI-poor satellite galaxies and subhalos of Milky Way mass hosts at redshift zero. Quantities and units are listed in the downloadable file. A citation to this paper is requested if these data are used and/or referenced.