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1. Vvedenie
Razdely
1.1 Opredeleniya i standartnye oboznacheniya
Cel'yu poverhnostnoi fotometrii yavlyaetsya izmerenie raspredeleniya yarkosti po poverhnosti protyazhennogo ob'ekta (galaktiki, tumannosti, HII oblasti i t.d.). Esli izuchaetsya tol'ko raspredelenie yarkosti bez privyazki k kakim-libo absolyutnym standartam, to eto nazyvaetsya otnositel'noi fotometriei. Absolyutnaya poverhnostnaya fotometriya stavit svoei zadachei naiti yarkost', vyrazhennuyu v nekotoroi absolyutnoi sisteme edinic.
Yarkost' ob'ekta v dannom napravlenii opredelyaetsya kak energiya,
izluchaemaya v edinicu vremeni vnutri edinichnogo telesnogo ugla
elementom poverhnosti, proekciya kotorogo na perpendikulyarnuyu
vybrannomu napravleniyu ploskost' imeet edinichnuyu ploshad'.
Dlya protyazhennyh ob'ektov opredelyaemuyu takim obrazom yarkost'
chasto nazyvayut poverhnostnoi yarkost'yu. Budem oboznachat' ee v
dal'neishem bukvoi .
Pri issledovanii konkretnyh galaktik sistemu otscheta udobno
vybirat' tak, chtoby yadro galaktiki sovpadalo s nachalom otscheta.
Togda raspredelenie poverhnostnoi yarkosti galaktiki yavlyaetsya
funkciei dvuh peremennyh --
, gde
-- eto rasstoyanie
ot centra galaktiki, a ugol
otschityvaetsya ot kakogo-libo
fiksirovannogo napravleniya (naprimer, ot napravleniya bol'shoi osi
galaktiki), ili
, gde
i
-- pryamougol'nye koordinaty.
Vo vnegalakticheskoi astronomii poverhnostnaya yarkost' obychno
izmeryaetsya vidimoi zvezdnoi velichinoi poverhnosti ploshad'yu v
1 kv. sek. dugi. Yarkost', vyrazhennaya v takih edinicah,
kak pravilo oboznachaetsya grecheskoi bukvoi . Soglasno opredeleniyu
shkaly zvezdnyh velichin, svyaz'
i
daetsya prosto kak
lg
const.
Poverhnostnuyu yarkost' v astronomii takzhe chasto izmeryayut v
svetimostyah Solnca () s ploshadi v 1 kvadratnyi
parsek (pk
). Vyrazhaemaya takim obrazom yarkost' svyazana
s
sleduyushim sootnosheniem:










V stacionarnom ploskom prostranstve poverhnostnaya yarkost' ne zavisit
ot rasstoyaniya do galaktiki. V rasshiryayusheisya Vselennoi
, gde
-- krasnoe smeshenie ob'ekta
(sm. p. 9.2).
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Publikacii s klyuchevymi slovami:
Fotometricheskaya sistema - slabye galaktiki - Skoplenie galaktik - fotometriya
Publikacii so slovami: Fotometricheskaya sistema - slabye galaktiki - Skoplenie galaktik - fotometriya | |
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