Съдържание

IAO 2002, Практически тур, Група β — Задача 7. Hubble's law in the nearby Universe

Оригинал на условието (изображение)Съобщи за грешка

Всички материали от IAO 2002

Practical round. Problem to solve · 22 октомври 2002 г.

Условие

Look at the maps of the nearby Universe. A circle within radius of 5 Mpc is clipped out from the "pancake" of Local supercluster. Fig.1 demonstrates a view in its plane (top view). Fig.2 demonstrates a view in its edge (front view). Each point is a single galaxy. Majority of galaxies are dwarfs, mostly detected and investigated in the Special Astrophysical observatory by I.D.Karachentsev with colleagues. One can separate several group in this supercluster: Local group including our Galaxy Milky Way (MW) and M31 and M33 galaxies, a cluster of galaxies in Centaurus and M81 with environment. A Local Void is visible on the upper part of Fig.2, where no galaxy was detected.

Fig. 1 and Fig. 2. Original nearby-Universe maps, galaxy positions, labels and Local Void.

What is the Hubble's law dependence (radial velocity versus distance) today ? In the table given is the last data obtained by the Karachentsev group are presented: distance of separate galaxies and their radial velocities relative to the center of gravity of the Local group.

$d$ , Mpc		$V_r$ , km/s
0.10		-55
0.15		-37
0.42		-140
0.60		20
0.63		-75
0.70		-5
0.70		-90
0.73	M31	-35
0.82	M33	37
0.82		22
0.82		-62
1.00		23
1.30		63
1.40		93
1.60		87
1.65		107
1.92		127
1.92		80
2.18		118
2.24		170
2.43		150
2.50		220
2.50		172
2.58		195
2.63		250
2.80		260
2.82		278
2.96		290
3.02		256
3.08		302
3.20		337
3.20		303
3.20		287
3.30		317
3.30		262
3.40		330
3.40		315
3.40		278
3.40		245
3.40		227
3.50		232
3.52	M82	342
3.52		150
3.60		360
3.60		320
3.60		270
3.60		250
3.60		170
3.60	M81	112
3.70		270
3.70		176
3.70		120
3.80		180
3.80		160
3.90		240
3.90		190
4.00		200
4.00		80
4.20		247
4.27		305
4.30		272
4.30		213
4.40		288
4.50		300
4.50		263
4.60		355
4.60		300
4.60		262
4.62		332
4.70		353
4.80		348
4.80		295
4.90		305
5.00		385
5.20		430
5.20		350
5.20		320

Tasks

Using the tabular data, plot the profile $V_r$ vs $(d)$ on the cross-bar paper.
By fitting the function on the straight line, find the Hubble's constant from the law of Hubble.
If your profile includes systematic deviation of points from the line (take into account the intervals of $d$ from 0 up to 1 Mpc and from 2.5 up to 4.5 Mpc), please, explain them.

Решение

Внимание: Непълно решение

В архива няма официално решение на тази задача.

Оригинал в Архива: betapract1.jpg · допълнителни данни: betapract2.jpg · допълнителни данни: betapractdata.jpg