Name: ______Date: ______

LARGE SCALE STRUCTURE OF THE UNIVERSE PRE-LAB

Answer each question in complete sentences. Be sure to define any relevant terms.

1. What is Hubble’s law and what does it tell us?

2. Define Right Ascension, Declination, and redshift.

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² COLLECTING DATA FOR A WEDGE PLOT Now we collect the data for the wedge plot. Your instructor will tell you which galaxies you should measure.

1. Enter the names and positions of your galaxies into table 1. 2. Move the telescope to each of your galaxies, in turn, using the set coordinates button. Record a spectrum for each galaxy as you go. Some of the dimmer galaxies will require a great deal of time to measure the spectrum. You can, by selecting Telescope from the menu bar, request time on a larger telescope. If granted, you can switch to the larger telescope at any time. If denied, you have to request again later. The larger telescopes are quite busy and do not always have available time. 3. Calculate each of the quantities necessary to fill in the chart as you proceed through your mea- surements. Record each measurement on the computer as you go. 4. When you have recorded everything, print your data to share with the class. You can use the computer to store your results for plotting. Select File and then data and save results for plot. The computer will let you know if anything is missing and will save everything to a file. You can select File, Data, Review to look at your data and make changes.

PLOTTING A WEDGE DIAGRAM Your instructor will tell you how to make your data available for the project.

We will begin the project by making the assumption that all of our galaxies lie at about the same declination. In other words, we are looking at a thin slice of the universe. We will plot out a graph of Right Ascension and velocity on a wedge graph.

From the telescope control window of the program, select File from the menu bar. Then click on wedge plot. This will open our plotting tool.

From the Plot Module window, select File and then open file. If you saved your data correctly, you should see the file listed there to be opened. Now select Plot from the menu bar and Plot current file. This should plot your data points on your graph. You can also select to enter the data points manually. This will allow you to enter points from other groups so you have a more complete graph if you did not record all of the data yourself.

Once you have plotted all of the available points, you can adjust the appearance of your graph by selecting options. Your instructor may have a preferred appearance, so you should consult with him or her.

When you are satisfied with the appearance of your graph, you may print it by selecting Plot and then print the plot from the menu bar.

1. Does matter in the universe appear to be randomly distributed on the large scale, or are there clumps and voids?

24–7 2. The most densely populated region of the diagram looks like a human stick figure. It is the core of the Coma Cluster of galaxies. What are the approximate Right Ascension and velocity coordi- nates of this feature?

3. You can use Hubble’s redshift-distance relation to determine the distances of objects in the chart.

v = H × D where H is the Hubble constant which tells you how fast a galaxy at a given distance is receding due to the expansion of the universe. The value of H is not well known, and there is a great deal of dispute about it, but a value of 75 kilometers/sec/megaparsecs is reasonable. (1 megaparsec = 106 parsecs)

Using the value of H, calculate the distance to the Coma Cluster.

4. Using the redshift-distance relation, how far is the farthest galaxy included in this study? How much smaller is this distance than the limit of the observable universe, which is about 4.6 × 109 parsecs?

5. Discuss the problem of completeness of the sample, which is based on a catalog of galaxies identified on photographs. What sorts of objects might be missing from our survey? How could we improve the completeness?

24–8 Beyond the Coma Cluster there is a loose band of galaxies stretching from east to west across the entire survey volume. It is called the “Great Wall”.

6. Using the Hubble redshift-distance relations, calculate the distance to the Great Wall.

7. One can use simple trigonometry to estimate the length of the Great Wall. If D is the distance of the Great Wall, and q is the angle it spans in the skies (in degrees), then

Length of the great wall = 2/D × e / 360

Use this formula to estimate the length of the Great Wall (which is just a lower limit, since it may extend beyond the boundaries of our survey.) Give your answer in megaparsecs and light years (3.26 ly = 1 parsec).

8. What other observations do astronomers need to make to confirm that the Great Wall is indeed a wall and not just a line or filament of galaxies?

9. Attach your wedge plot to this write-up when you turn it in.

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REDSHIFT DATA FOR LARGE SCALE STRUCTURE OF DATA REDSHIFT

Name RA NGC4278 12h17m36.2s Dec S/N mag

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TARGET GALAXIES IN THE PC RESHIFT SURVEY THE PC RESHIFT GALAXIES IN TARGET

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1 1202+3127 12 2 10 31 27 20 27 NGC 4286 12 18 12 29 38 0

23 NGC 40804 NGC 4104 125 NGC 4131 2 12 NGC 4132 19 4 12 27 6 12 6 16 12 6 28 29 30 15 27 29 35 10 31 0 0 28 NGC 4308 29 30 12 NGC 4310 31 NGC 4314 19 12 24 NGC 4359 12 19 30 54 12 20 20 29 0 21 42 0 29 30 31 0 10 48 0 0

67 NGC 41348 1206+3151 129 NGC 4136 12 6 NGC 4150 6 36 12 29 36 6 12 31 27 48 8 51 30 0 0 12 0 30 0 41 0 32 33 NGC 4375 34 NGC 4393 12 NGC 4414 12 35 22 31 23 12 IC 3376 18 28 24 27 12 0 50 50 25 31 6 18 0 30 27 0 16 0

10 NGC 417311 NGC 417412 12 NGC 417513 9 12 NGC 418514 48 9 12 NGC 4196 29 54 9 12 29 10 29 59 12 48 29 11 25 0 28 54 26 0 28 47 48 42 0 0 36 37 NGC 4448 38 IC 3407 12 39 NGC 4475 25 40 NGC 4495 12 12 48 1229+2959 12 27 26 28 12 18 30 28 54 54 29 27 28 18 0 29 32 4 29 25 0 0 59 0 0

15 NGC 4211A16 12 1214+290017 13 NGC 4245 1218 4 14 NGC 4251 12 28 12 15 12 29 27 6 15 18 0 36 29 28 27 53 27 0 0 41 NGC 4514 42 12 NGC 4525 43 44 30 12 NGC 4556 6 NGC 4559 31 12 18 30 12 33 30 33 0 18 30 34 27 0 28 0 11 14 0 0

19 NGC 425320 IC 77721 12 NGC 4274 1522 56 NGC 4272 12 12 30 17 16 12 18 54 5 17 29 28 18 26 30 53 35 37 0 0 0 45 NGC 4585 47 46 12 48 1240+2800 IC 3651 35 1242+2845 12 42 12 12 40 29 36 38 42 13 18 12 28 0 27 28 0 44 0 0 35 0

23 NGC 427524 NGC 427825 12 NGC 4283 17 12 24 17 12 27 36 17 29 54 50 29 33 0 35 31 12 49 50 NGC 4670 51 NGC 4673 12 IC 821 12 42 43 50 12 8 27 45 27 23 0 20 56 30 3 4 0 26 1217+3127 12 17 54 31 27 0 52 1245+2715 12 45 16 27 15 12

No Name RA Dec ' " Mag v

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53 NGC 469254 1250+283 955 12 12 NGC 4789 45 50 29 12 24 27 51 28 29 55 39 27 48 0 20 18 81 82 NGC 4926 83 NGC 4929 12 NGC 4931 13 59 29 13 0 27 0 20 53 37 28 36 28 18 18 48 2

56 NGC 479357 NGC 479858 12 NGC 4807 5259 12 16 NGC 4816 5260 12 29 36 NGC 4819 53 12 27 12 6 53 12 41 48 30 27 54 28 0 0 47 1 27 0 15 0 0 84 NGC 4944 85 13 NGC 4952 86 87 1 13 NGC 4957 88 26 NGC 4961 2 13 28 NGC 4966 36 13 2 27 13 29 49 3 13 24 24 3 27 54 28 0 50 29 12 0 20 0 0

61 NGC 482762 1254+3059B63 12 12 NGC 4839 5464 54 18 1255+2749 12 36 27 54 12 30 27 59 55 59 27 0 0 0 46 27 49 0 0 89 90 NGC 4983 1306+2827 91 13 13 NGC 5000 92 6 6 NGC 5004 13 0 30 13 7 28 28 24 8 27 35 29 42 0 0 10 29 54 0 0

65 NGC 4841A66 12 NGC 4841B67 55 12 NGC 484868 7 55 NGC 485369 12 28 9 NGC 4860 55 12 28 44 42 56 12 28 45 48 10 56 27 31 40 6 28 52 0 23 0 36 93 1309+3146 94 13 95 NGC 5032 96 9 NGC 5041 13 97 18 NGC 5052 13 11 NGC 5056 31 13 0 12 13 46 12 13 28 13 12 30 0 4 48 29 58 31 0 55 0 12 0 0

70 NGC 486571 NGC 487272 12 NGC 4874 5673 12 55 NGC 4892 57 12 28 10 57 12 28 21 11 57 28 13 36 12 27 13 9 10 48 0 98 NGC 5057 99 100 13 NGC 5065 NGC 5074 101 14 13 13 NGC 5081 6 15 16 13 12 31 6 16 31 17 48 31 20 0 28 44 0 46 0 0

74 NGC 488975 NGC 489576 12 IC 842 5777 12 44 NGC 4907 57 28 53 12 12 28 14 58 58 28 24 12 46 28 29 12 25 17 0 0 102 NGC 5089 103 1318+3147 13 13 105 17 104 18 18 1319+3130 1319+3137 0 30 13 13 31 31 19 19 24 18 47 0 31 31 0 30 37 0 0

78 NGC 491179 NGC 4921 12 58 12 30 59 28 0 3 28 9 0 0 106 NGC 5116 107 13 NGC 5117 20 13 36 20 27 36 15 28 0 35 0 80 NGC 4923 12 59 7 28 6 54 108 IC 4234 13 20 42 27 23 0

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No Name RA Dec ' " Mag v

109 NGC 5127110 NGC 5131 13111 NGC 5187 21 13 24 21 13 31 37 27 31 50 30 31 14 0 23 53 17 137 138 IC 4395A IC 4403 139 1418+2705 14 15 14 14 6 16 18 18 6 27 27 31 5 5 53 15 0 0

112 1327+3135113 1328+3153 13114 27 NGC 5251 13115 58 28 1337+2801 13 31 8 35 13 35 31 37 5 25 27 52 27 28 43 40 1 25 47 140 IC 4408 141 IC 4409 142 14 IC 4422 143 IC 4425 19 14 0 19 14 18 14 30 23 31 42 24 13 30 49 30 0 27 42 0 25 0 0

116 NGC 5263117 NGC 5280 13118 1340+3036 37 13119 37 NGC 5282 40 13120 28 36 40 1345+3035 13 30 52 39 41 13 30 45 10 7 6 35 0 30 0 19 30 20 35 0 0 144 1424+3144 145 146 14 IC 1012 1426+2729 24 147 14 49 NGC 5635 148 14 26 31 IC 4442 25 18 14 44 1 27 26 20 14 18 31 29 26 27 10 0 34 38 17 29 0 11 16

121 1348+2824122 1348+2937 13123 48 NGC 5375 13124 12 48 1355+2902 13 28 12 54 13 29 24 30 55 37 29 4 0 25 29 0 0 2 23 149 NGC 5639A 150 NGC 5642 14 151 NGC 5641 26 14 152 42 IC 4447 27 14 30 0 27 38 14 5 30 7 27 15 29 6 0 2 31 36 3 0

125 IC 4355126 1357+2819127 13 1358+3019 13128 55 57 1358+2948 13129 48 24 58 1358+2946 13 28 28 30 58 13 30 40 18 42 58 29 19 48 13 0 29 48 0 46 0 0 154 153 NGC 5653 1427+2745 155 NGC 5657 14 14 156 1428+2727 157 28 27 14 IC 4450 59 0 14 28 27 30 28 31 14 56 45 29 26 29 27 24 0 17 54 27 0 28 30 46 0

130 1400+2816131 1402+2809 14132 1405+3006 0 14133 IC 4384 48 2 14 28 18 5 28 14 16 42 30 9 17 9 36 6 0 27 49 21 0 158 IC 4452 159 160 NGC 5672 14 1431+2816 14 30 161 14 1431+2810 12 30 31 30 27 14 30 31 39 31 28 53 54 0 16 28 0 22 10 0

134 NGC 5512135 1411+2714 14 10 14 24 11 31 1 27 5 14 0 30 162 163 1432+3146 IC 4459 14 32 14 12 32 31 18 46 31 0 11 0 136 1411+2940 14 11 30 29 40 0 164 IC 4460 14 32 24 30 30 0

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No Name RA Dec ' " Mag v

165 NGC 5685166 NGC 5709 14167 1436+3110 34 14 0 36 14 36 36 30 30 48 7 31 39 10 0 0 0 192 193 IC 4546 194 1527+3039 1528+2716 15 15 15 27 24 38 28 54 12 30 29 27 39 1 16 23 0 0

168 1437+3143169 1438+3135 14170 37 1439+3151 14171 54 38 NGC 5735 14 31 24 39 14 31 43 18 40 31 35 12 0 51 28 0 56 0 0 195 NGC 5958 196 1533+2730 197 15 NGC 5961 15 198 32 1533+3058 42 33 15 6 15 28 33 12 33 50 27 15 31 30 0 30 1 0 58 0 0

172 IC 4497173 1443+3038174 14 1447+2759A 14175 14 42 43 1447+2759176 47 18 6 IC 4514 14 6 30 28 47 27 37 18 45 14 59 27 48 54 0 42 59 0 27 12 46 0 200 199 NGC 5974 201 1534+3050 202 IC 4568 15 15 1538+2831A 37 15 34 15 203 0 18 38 IC 4569 38 24 31 30 0 28 55 50 15 28 31 47 0 38 19 0 42 0 28 28 0

177 NGC 5771178 NGC 5773 14179 1452+3025A 50 14180 14 NGC 5780 0 50181 52 18 NGC 5789 30 14 0 30 52 14 3 30 12 0 54 25 29 0 24 0 30 0 9 25 0 0 204 205 1539+2809 206 IC 4570 IC 4572 15 207 39 208 15 IC 4580 15 18 1541+2835 39 39 28 15 18 15 48 9 41 28 41 28 42 6 23 0 18 28 20 28 0 35 31 0 0

182 NGC 5798183 1457+2719 14184 IC 4533 55 14185 30 57 1502+2711 30 24 15 15 27 10 2 2 19 22 30 0 27 27 0 59 11 13 0 209 210 IC 4581 IC 4582 211 15 212 1544+3025 15 41 1544+3110 15 54 43 15 36 44 28 44 18 28 26 45 30 15 31 0 25 0 9 0 53

186 1503+3121187 1515+3052 15188 1517+3133 3 15189 15 1519+2844 33 15 57 31 17 15 30 48 19 21 31 52 12 20 28 33 13 44 0 0 213 214 NGC 6001 1546+2746 215 15 15 1548+2847 216 45 46 1552+3018 15 42 54 15 48 28 27 30 52 48 46 28 6 0 0 47 30 0 18 0

190 NGC 5924 15 19 54 31 24 0 217 NGC 6016 15 53 54 27 7 0

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