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<< 5.2 Vertikal'naya struktura diskov | Oglavlenie | 6. Mnogokomponentnye galaktiki >>
5.3 Trehmernye diski
S ispol'zovaniem (43) i (54) opticheskuyu strukturu
diskov spiral'nyh galaktik mozhno predstavit' v vide
![$I(r,z)\,=\,0$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img496.gif)
![$r > r_{max}$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img470.gif)
Dlya prostoty chasto ispol'zuyut takzhe predstavlenie v vide
dvoinogo eksponencial'nogo diska:
Esli disk (57) viden ''plashmya'' (), to ego
central'naya poverhnostnaya yarkost'
. V
polozhenii ''s rebra'' (
)
.
Sledovatel'no,
ili
Iz (59,60) sleduet, chto, esli diski galaktik svobodny ot poglosheniya (''prozrachny''), to nablyudaemye znacheniya
![$\mu_0^{edge-on}$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img504.gif)
![$\mu_0^{face-on}$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img505.gif)
![$h/z_0 \approx 5$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img506.gif)
![$^m$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img50.gif)
![$^m$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img50.gif)
Po etoi zhe prichine -- integrirovanie izlucheniya vdol' lucha zreniya -
diski vidimyh ''s rebra'' galaktik budut imet' bol'shii diametr (esli
diametr izmeryat' v predelah fiksirovannogo urovnya poverhnostnoi
yarkosti). Naprimer, esli rassmotret' disk, opisyvaemyi uravneniem
(57), s
i
, to s pomosh'yu
(51) mozhno ocenit', chto ego vidimyi diametr, opredelyaemyi
po izofote
, pri izmenenii naklona ot
do
uvelichitsya na
90%. Pri izmerenii diametra
po izofote
rost budet sostavlyat'
70%.
Kogda galaktika vidna pod proizvol'nym uglom k luchu zreniya
(to est'
), nablyudaemaya central'naya
poverhnostnaya yarkost' ee diska (
) obychno
pereschityvaetsya k znacheniyu, kotoroe bylo by u galaktiki v polozhenii
''plashmya'' pri otsutstvii vnutrennego poglosheniya [39]:
![$a/b$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img514.gif)
![$a/b$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img514.gif)
![$i$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img224.gif)
![$i$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img224.gif)
![$i$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img224.gif)
![$i$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img224.gif)
![$b/a$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img135.gif)
V rabote [117] dlya ispravleniya nablyudaemoi central'noi
poverhnostnoi yarkosti diska za naklon galaktiki, raspolozhennoi pod bol'shim
uglom k nablyudatelyu, predlozhena formula, kotoraya mozhet
byt' zapisana sleduyushim obrazom:
![$h_z/h$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img516.gif)
![$\mu_0^{face-on} - \mu_0^{obs}$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img517.gif)
![$i > 70^{\rm o}$](https://images.astronet.ru/pubd/2006/08/23/0001215351/img518.gif)
![]() |
Privedennye vyshe formuly osnovyvayutsya na predpolozhenii, chto diski galaktik svobodny ot poglosheniya. Real'nye spiral'nye galaktiki soderzhat znachitel'noe kolichestvo gaza i pyli i dlya nih neobhodimo primenyat' bolee slozhnye modeli, uchityvayushie processy poglosheniya i rasseyaniya izlucheniya (sm. dalee p. 7).
<< 5.2 Vertikal'naya struktura diskov | Oglavlenie | 6. Mnogokomponentnye galaktiki >>
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