Ụyọkọ kpakpando Satellite
ụyọkọ kpakpando Satellite bụ ụyọkọ kpakbando ibe ya nke na agagharị na gburugburu n'ime ikike ndọda nke ụyọkọ ụyọkọkọ kpakpadas buru ibu ma na egbuke egbuke (nke a makwaara dị ka ụyọkọ nke isi). [1] Ụyọkọ kpakpando Satellite na ihe ndị mejupụtara ha na ejikọta na ụyọkọ kpakpi ha, n'otu ụzọ ahụ na mbara ala ndị dị n'ime Usoro Anyanwụ na ejikarị ike ndọda ejikọta na Anyanwụ.[2] Ọ bụ ezie na ọtụtụ ụyọkọ kpakpando satellite bụ ụyọkọ ụyọkọ ndị dị obere, ụyọkọ Satellite nke nnukwu ụyọkọkọ kpakpinda nwere ike ịdị ukwuu karịa.[3] Ihe dị ka ụyọkọ kpakpando satellite iri ise na agba Milky Way gburugburu, nke kachasị ukwuu n'ime ha bụ Nnukwu Igwe ojii Magellanic.
Ọzọkwa, ụyọkọ kpakpando satellite abụghị naanị ihe ndị dị na mbara igwe nke na ejikọta na ụyọkọ ụyọkọ ndị buru ibu (lee ụyọkọ globular). N'ihi nke a, ndị na enyocha mbara igwe akọwaala ụyọkọ kpakpando dị ka nchịkọta kpakpando ndị nwere ikike ndọda nke na egosipụta njirimara ndị a na apụghị ịkọwa site na njikọta nke ihe baryonic (ya bụ ihe nkịtị) na iwu Newton nke ike ndọdịrị.[4] Dịka ọmụmaatụ, ọnụọgụ nke ọsọ nke kpakpando na gas n'ime ụyọkọ kpakpando ndị na-agba gburugburu na eme ka ọsọ ọsọ nke na agbanwe nke ukwuu site na amụma amụma. Nchọpụta a akpaliwo nkọwa dị iche iche dị ka ozizi nke ihe gbara ọchịchịrị na mgbanwe na Newtonian dynamics.[1] Ya mere, n'agbanyeghị na ha bụkwa satellites nke ụyọkọ kpakpando, a gaghị echefu ụyọkọ globular maka ụyọkọ satellite. Ọ bụghị naanị na ụyọkọ kpakpando Satellite dịkwuo ogologo ma gbasaa ma e jiri ya tụnyere ụyọkọ globular, kamakwa a na ekpuchi ha na nnukwu ihe gbara ọchịchịrị nke a na eche na e nyere ha n'oge usoro nhazi.[5]
Ụyọkọ kpakpando Satellite na ebukarị ndụ ọgba aghara n'ihi mmekọrịta ha na ụyọkọ kpakbando buru ibu na satellites ndị ọzọ. Dịka ọmụmaatụ, ụyọkọ kpakpando nwere ike imebi satellites na agba gburugburu site na iwepu nrụgide mmiri na nke ram. Mmetụta gburugburu ebe obibi ndị a nwere ike iwepu nnukwu gas oyi site na satellites (ya bụ, mmanụ maka mmepụta kpakpando), nke a nwere ike ime ka satellites bụrụ ndị na adịghị ike n'echiche na ha akwụsịla ịmepụta kpakpando.[6] Ọzọkwa, satellites nwekwara ike imegide ụyọkọ kpakpando ha na akpata obere njikọta (ya bụ, njikọta n'etiti ụyọkọ ụyọkọ nke ịdị arọ dị iche iche). N'aka nke ọzọ, satellites nwekwara ike ijikọ ibe ha na akpata nnukwu njikọta (ya bụ, njikọta n'etiti ụyọkọ kpakpando nke ịdị arọ yiri). Ụyọkọ kpakpando na ejikarị ohere efu, gas na uzuzu, ya mere njikọta ụyọkọ kpakpa anaghị agụnye mgbagwoju anya n'etiti ihe sitere n'otu ụyọkọkọ kpakpade na ihe sitere na nke ọzọ, Otú ọ dị, ihe omume ndị a na akpata ọtụtụ ụyọkọ. N'ihi ya, ndị na enyocha mbara igwe na achọ igbochi ọnụego nke obere na nnukwu njikọta na eme iji ghọtakwuo mmepụta nke nnukwu ihe ndị jikọtara ụyọkọ kpakpando dịka ìgwè ụyọkọ ụyọkọ.[7][8]
Akụkọ ihe mere eme
[dezie | dezie ebe o si]Ná mmalite narị afọ nke 20
[dezie | dezie ebe o si]Tupu narị afọ nke 20, echiche ahụ bụ na ụyọkọ kpakpando dị karịa Milky Way abụghị nke a kwadoro nke ọma. N'ezie, echiche ahụ bụ ihe arụmụka n'oge ahụ nke mere ka ihe a na akpọsa ugbu a dị ka "Shapley Curtis Great Debate" nke a kpọrọ aha ndị na enyocha mbara igwe Harlow Shapley na Heber Doust Curtis bụ ndị rụrịtara ụka banyere ọdịdị nke "nebulae" na nha nke Milky Way na National Academy of Sciences na Eprel 26, 1920. Shapley kwuru na Milky Way bụ eluigwe na ala dum (nke gafere ihe karịrị 100,000 lightyears ma ọ bụ 30 kiloparsec gafee) nakwa na "nebulae" niile a hụrụ (nke a maara ugbu a dị ka ụyọkọ kpakpando) bi n'ime mpaghara a. N'aka nke ọzọ, Curtis kwuru na Milky Way dị obere karịa nakwa na nebulae ndị a hụrụ bụ n'ezie ụyọkọ kpakpando yiri Milky Way.[9] Arụmụka a akwụsịghị ruo na ngwụcha afọ 1923 mgbe onye na enyocha mbara igwe Edwin Hubble tụrụ anya anya M31 (nke a maara ugbu a dị ka ụyọkọ kpakpando Andromeda) site na iji kpakpando Cepheid Variable. Site n'ịtụle oge nke kpakpando ndị a, Hubble nwere ike ịtụle ìhè ha dị n'ime ma mgbe ọ jikọtara nke a na oke ha, o mere atụmatụ na ọ dị anya nke 300 kpc, nke bụ usoro nke ịdị ukwuu karịa oke nke eluigwe na ala nke Shapley mere. Nnyocha a gosipụtara na ọ bụghị naanị na eluigwe na ala buru ibu karịa ka a tụrụ anya ya na mbụ, kamakwa ọ gosipụtara na nebula ndị a hụrụ bụ n'ezie ụyọkọ kpakpando dị anya nwere ọdịdị dịgasị iche iche (lee Usoro Hubble). [9]
Oge Ndị A
[dezie | dezie ebe o si]N'agbanyeghị nchọpụta Hubble na eluigwe na ala jupụtara na ụyọkọ kpakpando, ọtụtụ n'ime ụyọkọ Satellite nke Milky Way na Local Group nọgidere na enweghị nchọpụta ruo mgbe ọbịbịa nke nyocha mbara igwe nke oge a dị ka Sloan Digital Sky Survey (SDSS) na Dark Energy Survey (DES).[10][11] Karịsịa, a maara Milky Way ugbu a na ọ na anabata ụyọkọ kpakpando satellite 59 (lee ụyọkọ satellite nke Milky Way), nke abụọ n'ime ha a maara dị ka Nnukwu Igwe Magellanic na Obere Igwe Magelanic ka a na ahụ na Southern Hemisphere na anya na enweghị enyemaka kemgbe oge ochie. Ka o sina dị, echiche nke oge a nke usoro mbara igwe na evolushọn na ebu amụma ọnụ ọgụgụ dị ukwuu nke ụyọkọ kpakpando satellite karịa ihe a hụrụ (lee Nsogbu Satellite na efu efu).[12] Otú ọ dị, simulations dị elu na nso nso a egosila na ọnụ ọgụgụ nke satellites a hụrụ ugbu a anaghị eme ka echiche a na ahụkarị nke mmalite ụyọkọ kpakpando ghara ịdị egwu. [13][14]
Ihe na akpali ịmụ ụyọkọ kpakpando satellite
[dezie | dezie ebe o si]Spectroscopic, photometric na kinematic observations nke ụyọkọ kpakpando satellite emeela ka e nwee ọtụtụ ozi e ji mụọ, n'etiti ihe ndị ọzọ, nhazi na evolushọn nke ụyọyọkọ kpakpi, mmetụta gburugburu ebe obibi nke na eme ka ọnụego nke mmepụta kpakpando n'ime ụyọkọkọ kpakpadas na nkesa nke ihe gbara ọchịchịrị n'ime halo. N'ihi ya, ụyọkọ kpakpando satellite na eje ozi dị ka ebe nnwale maka amụma nke ụdị mbara igwe mere. [13] [15][16]
Nchịkọta nke ụyọkọ kpakpando satellite
[dezie | dezie ebe o si]Dị ka e kwuru n'elu, a na ekewa ụyọkọ kpakpando satellite dị ka ụyọkọ ụyọkọ nke dwarf ma ya mere soro atụmatụ nhazi Hubble yiri nke ahụ dị ka onye na elekọta ha na obere mgbakwunye nke obere "d" n'ihu ụdị dị iche iche iji kọwaa ọnọdụ ụyọkọ dwarf. Ụdị ndị a gụnyere dwarf irregular (dI), dwarf spheroidal (dSph), dwarf elliptical (dE) na dwarf spiral (dS). Otú ọ dị, n'ime ụdị ndị a niile, a kwenyere na dwarf spirals abụghị satellites, kama ọ bụ obere ụyọkọ kpakpando ndị a na ahụ naanị n'ọhịa.[17]
Ụyọkọ kpakpando ndị na adịghị mma
[dezie | dezie ebe o si]A na akọwa ụyọkọ kpakpando satellite ndị na adịghị mma site na ọdịdị ha na-enweghị atụ, obere gas fractions, ọnụ ọgụgụ dị elu nke kpakpando na obere metallicity.[18] Atọ n'ime satellites ndị dị nso na Milky Way gụnyere Small Magellanic Cloud, Canis Major Dwarf, na Antlia 2 a chọpụtara ọhụrụ.
ụyọkọ kpakpando
[dezie | dezie ebe o si]A na akọwa ụyọkọ kpakpando satellite ndị dị obere site na ọdịdị ha dị ka oval n'eluigwe, mmegharị nke kpakpando ndị mejupụtara ya, nke dị n'etiti na nke dị ala, obere gas na ọnụ ọgụgụ kpakpando ochie. Ụyọkọ kpakpando dwarf elliptical dị na Local Group gụnyere NGC 147, NGC 185, na NGC 205, nke bụ satellites nke ụyọkọ kpakbando Andromeda dị nso.[18][19]
Ụyọkọ kpakpando
[dezie | dezie ebe o si]A na akọwa ụyọkọ kpakpando satellite ndị dị obere site na ọdịdị ha dị iche iche, obere ìhè elu, oke oke na ìhè (ya bụ, ihe gbara ọchịchịrị na achịkwa), obere metallicity, obere gas fractions na ọnụ ọgụgụ kpakpando ochie.[1] Ọzọkwa, dwarf spheroidals mejupụtara ọnụ ọgụgụ kachasị ukwuu nke ụyọkọ kpakpando satellite a maara nke Milky Way. Ụfọdụ n'ime satellites ndị a gụnyere Hercules, Pisces II na Leo IV, nke a na akpọ aha ya site na Ìgwè kpakpando ebe a na-ahụ ha.[18]
Ụdị mgbanwe
[dezie | dezie ebe o si]N'ihi obere njikọta na mmetụta gburugburu ebe obibi, a na ekewa ụfọdụ ụyọkọ kpakpando dị ka ụyọkọ ụyọkọ satellite dị n'etiti ma ọ bụ nke na agafe agafe. Dịka ọmụmaatụ, a na ekewa Phoenix na LGS3 dị ka ụdị dị n'etiti nke yiri ka ọ na agbanwe site na dwarf irregular gaa na dwarf spheroidals. Ọzọkwa, a na ewere nnukwu igwe ojii Magellanic ka ọ na agbanwe site na obere okirikiri gaa na obere okpomọkụ.[18]
Ọdịdị nke ụyọkọ kpakpando satellite
[dezie | dezie ebe o si]Dabere na ụkpụrụ ụkpụrụ nke Cosmology (nke a maara dị ka ụdị ΛCDM), mmepụta nke ụyọkọ kpakpando satellite nwere njikọ dị mgbagwoju anya na nnukwu ọdịdị nke eluigwe na ala. N'ụzọ doro anya, ihe nlereanya ΛCDM dabeere n'echiche na usoro a hụrụ nke buru ibu bụ nsonaazụ nke usoro nhazi nke malitere mgbe oge recombination nke e guzobere atọm Hydrogen na anọpụ iche na eletrik n'ihi na electrons na protons nwere onwe ha na ejikọta ọnụ. Ka ọnụọgụ nke hydrogen na anọpụ iche na protons na electrons na enweghị onwe ha na eto, otú ahụ ka mgbanwe na njupụta nke baryonic. Mgbanwe ndị a toro ngwa ngwa ruo n'ókè nke na ha ghọrọ ihe a pụrụ iji tụnyere mgbanwe nke ihe gbara ọchịchịrị. Ọzọkwa, obere mgbanwe ndị ahụ toro na nonlinearity, ghọrọ virialized (ya bụ, ruru nguzozi ike ndọda), wee bụrụ ndị a chịkọtara n'ime usoro ndị buru ibu.[20]
Gas dị n'ime usoro ndị a na ejikọta ma na-ajụ oyi ngwa ngwa n'ime Ihe gbara ọchịchịrị na ajụ okpomọkụ nke na-abawanye n'ogo site na ijikọta ọnụ ma na agbakọta gas ọzọ site na usoro a maara dị ka accretion. A maara ihe ndị kachasị ukwuu sitere na usoro a dị ka superclusters, dị ka Virgo Supercluster, nke nwere obere ụyọkọ kpakpando nke onwe ha gbara gburugburu ọbụna obere ụyọnụ kpakpando. Ọzọkwa, n'ime ihe nlereanya a, a na ewere ụyọkọ kpakpando ndị dị obere dị ka ihe owuwu bụ isi nke na ebute ụyọkọkọ kpakpade ndị buru ibu karị, na satellites ndị a na ahụ gburugburu ụyọkọ ndị a bụ ndị dị obere nke onye nwe ha ka na eri.[21]
Nchịkọta nke ịdị arọ na halo nke ihe gbara ọchịchịrị
[dezie | dezie ebe o si]Usoro crured ma bara uru iji chọpụta ka ihe gbara ọchịchịrị na eji nwayọọ nwayọọ na enweta oke site na njikọ nke obere halos nwere ike ịkọwa site na iji njem nlegharị anya set formalism, nke a makwaara dị ka agbatị Press-Schechter formalism (EPS). Tinyere ihe ndị ọzọ, enwere ike iji usoro EPS mee ihe iji mee ka ọ dị ntakịrị 𝑀2 nke sitere na ihe dara ada nke otu oke n'oge mbụ 𝑡1 < 𝑡2 site n'itinye ọnụ ọgụgụ nke Markovian random ije na trajectories nke uka ọcha na (𝑆,𝛿) -oghere, ebe 𝑆=𝜎2(𝑀) na 𝛿=𝜌(𝑥)-𝜌 Ihe 𝜌 Ihe na anọchi anya nnukwu ọdịiche na oke njupụta, n'otu n'otu.
Karịsịa EPS formalism tọrọ ntọala na ansatz nke na ekwu na "obere akụkụ nke trajectories na mbụ upcrossing nke mgbochi ahụ.
𝛿𝑆=𝛿𝑐𝑟𝑖𝑡𝑖𝑐𝑎𝑙 (t) na 𝑆 >𝑆1 =𝜎2(𝑀1 )hà nhata na ntakiri uka n'oge
𝑡 nke a na etinye na halos na masses 𝑀<𝑀1 "[1]
N'ihi ya, ansatz a na eme ka a mata na trajectory ọ bụla ga agafe ihe mgbochi ahụ. 𝛿𝑆=𝛿𝑐𝑟𝑖𝑡𝑖𝑐
𝑎𝑙(𝑡) nyere ụfọdụ nnukwu aka ike 𝑆, na n'ihi ya, ọ na ekwe nkwa na nke ọ bụla mass element ga emecha bụrụ akụkụ nke a halo.[1]
Ọzọkwa, akụkụ nke ịdị arọ M2 nke sitere na ihe ndị dara ada nke otu oke n'oge gara aga t1 < t2 enwere ike iji ya chọpụta nkezi ọnụ ọgụgụ ndị nne na nna n'oge t1 n'ime oghere (Ọ bụ ezie na ọ bụ ezie na M1, M1 + dM1) nke jikọtara ọnụ iji mepụta halo nke M2 n'oge t2 . A na-eme nke a site n'ịtụle mpaghara dị gburugburu nke ịdị arọ M2 na ọdịiche dị n'etiti S2= σ2 (M2) na oke oke oke δ2 = δc( t2 ) =δc / D ( t2 ) ebe D ( t2 ) bụ ọnụọgụ uto nke a na eme ka ọ dị n'otu n'oge t2 na δc bụ oke oke oke nke mpaghara mbụ ahụ dị gburugburu adaala iji mepụta ihe na eme ka ọ bụrụ ihe. Na mgbakọ na mwepụ, a na egosipụta ọrụ nna nna dị ka: N (M1, t1 / M2, t2 ) dM1 = M2 /M1 *fPS (ν12) dIn(v12)/ dIn(M1) dM1ebe ν12 = δ1 − δ2 / S1 − S2 na fPS (ν12 ) = 2/π ν12 exp ( − ν2 12 /2) bụ ọrụ mmụba nke Press-Schechter nke na-akọwa akụkụ nke ịdị arọ metụtara halo n'etiti In(ν12 ).[22]
Ntụnyere dị iche iche nke ọrụ nna nna na simulations ọnụọgụ ekwuola na a na enweta nkwekọrịta dị mma n'etiti ozizi na simulations naanị mgbe Δt =t2 − t1 dị obere, ma ọ bụghị ya, a na eleda oke oke n'ime ndị nne na nna dị elu anya nke ukwuu, nke a nwere ike ịkọwa na echiche ndị na enweghị isi dị ka iche na eche na ihe nlereanya zuru oke nke ọdịda na iji mpaghara njupụta njupụta dị iche iche dị iche na mpaghara njupụta na abụghị nke na aga n'ihu iji gosipụta ihe ndị dara.[23][24] Ka o sina dị, uru nke usoro EPS bụ na ọ na-enye usoro nhazi maka ịchọpụta njirimara nke ihe gbara ọchịchịrị.
Ọnụ ọgụgụ njikọta Halo
[dezie | dezie ebe o si]Uru ọzọ nke usoro EPS bụ na enwere ike iji ya chọpụta ọnụego nke halo nke ibu mbụ M na agwakọta na halo nke oke dị n'etiti M na M + ΔM.[22] Ọnụ ego a na enye site na
![{\displaystyle {\mathcal {P}}(\Delta M|M,t)\operatorname {d} \ln \Delta M\operatorname {d} \ln t={\frac {1}{\sqrt {2\pi }}}{\Bigg [}{\frac {S_{1}}{(S_{1}-S_{2})}}{\Bigg ]}^{3/2}\exp {\Bigg [}-{\frac {\delta _{c}^{2}(S_{1}-S_{2})}{2S_{1}S_{2}}}{\Bigg ]}{\Bigg |}{\frac {\operatorname {d} \ln \delta _{c}}{\operatorname {d} \ln t}}{\Bigg |}{\Bigg |}{\frac {\operatorname {d} \ln S_{2}}{\operatorname {d} \ln \Delta M}}{\Bigg |}{\frac {\delta _{c}}{\sqrt {S_{2}}}}\mathrm {d} \ln t\,\mathrm {d} \ln \Delta M}](https://wikimedia.org/api/rest_v1/media/math/render/svg/765079cd941eef5e97ce8b13b6e84f4dbdc2e2a6)
ebe S1 = σ2 (M), S2= σ2 (M + Δ M) N'ozuzu mgbanwe n'ìgwè, ΔM, bụ ngụkọta nke ọtụtụ obere njikọta. Ka o sina dị, nyere obere oge na enweghị njedebe Ọ bụ n'oge ọ bụ ihe ezi uche dị na ya ịtụle mgbanwe ahụ n'ìgwè ka ọ bụrụ n'ihi otu ihe jikọtara ọnụ nke M1 mgbanwe gaa na M2 .[22]
Galactic cannibalism (obere njikọta)
[dezie | dezie ebe o si]
N'oge ndụ ha niile, ụyọkọ kpakpando satellite na agba gburugburu n'ime ihe gbara ọchịchịrị halo na enwe mkpakọ dị egwu ma si otú a gbadaa n'ime ikike ndọda nke onye na elekọta ha n'ihi mbibi nke okirikiri. N'oge niile a na agbadata, a na ewepụ kpakpando dị na mpaghara mpụga nke satellite n'ihi Ike ebili mmiri sitere na ụyọkọ kpakpando. Usoro a, nke bụ ihe atụ nke obere njikọta, na aga n'ihu ruo mgbe ụyọkọ kpakpando na elekọta ya mebiri satellite kpamkpam ma rie ya.[25] Enwere ike ịhụ ihe akaebe nke usoro mbibi a na mpempe akwụkwọ kpakpando gburugburu ụyọkọ kpakpando ndị dị anya.
Ọnụ ọgụgụ nke ọdịda nke Orbital
[dezie | dezie ebe o si]Ka satellites na agba gburugburu onye na elekọta ha ma na emekọrịta ihe, ha na eji nwayọọ nwayọọ na efunahụ obere ike na nkuku n'ihi mkpakọ dị ike. N'ihi ya, anya dị n'etiti onye na elekọta ya na satellite na eji nwayọọ nwayọọ na ebelata iji chekwaa ike nkuku. Usoro a na aga n'ihu ruo mgbe satellite na ụyọkọ kpakpando na elekọta ya jikọtara. Ọzọkwa, Ọ bụrụ na anyị eche na onye ọbịa ahụ bụ otu isothermal sphere (SIS) na satellite ahụ bụ SIS nke a na ebibi nke ọma na radius nke ọ na amalite ịgba ọsọ na onye ọbịa (nke a maara dị ka Jacobi radius), mgbe ahụ oge t fric 2.34 σ2 M /In ^σ3 s ri= 2.7 Gyr /In^ ri /30 kpc (σ M / 200km/ s−1)^2 (100km / σs ) ebe ri bụ radius mbụ na t = 0 , σM bụ ọsọ nke mgbasa nke ụyọkọ kpakpando, σs bụ ọsọ nke satellite na In^ bụ Coulomb logarithm akọwapụtara dị ka In^= In( bmax/ max (rh,GM / v2 typ ) ) na bmax ,rh na v2typ na-anọchite anya ọnụọgụ kachasị elu, ọkara radius na ọsọ ọsọ. Ọzọkwa, ma ọkara radius na ọsọ ọsọ nwere ike idegharị na usoro radius na mgbasa ọsọ dị ka nke rh = σs/ 2 3/2 σM r na GM /v2typ= 2σ2s / σ3M *r . N'iji mmekọrịta Faber-Jackson, enwere ike ịtụle ọsọ ọsọ nke satellites na onye na-elekọta ha n'otu n'otu site na ìhè ha hụrụ. Ya mere, site na iji usoro dị n'elu, ọ ga-ekwe omume ịkọ oge ọ na-ewe maka ụyọkọ kpakpando satellite ka ụyọkọ ụyọkọkọ kpakpadas na-eri.[25]
Obere njikọta na-akpali mmepụta kpakpando
[dezie | dezie ebe o si]N'afọ 1978, ọrụ ọsụ ụzọ nke gụnyere ịtụle agba nke njikọta nke ndị na enyocha mbara igwe Beatrice Tinsley na Richard Larson mere ka echiche ahụ dị na njikọta na eme ka ọdịdị kpakpando dịkwuo mma. Ihe ha chọpụtara gosiri na a na ejikọta ụcha na acha anụnụ anụnụ na ihe ndị fọdụrụ na njikọta ahụ. Tupu nchọpụta a, ndị na enyocha mbara igwe ekewapụlarị kpakpando (lee nhazi kpakpando) ma amaara na kpakpando ndị na eto eto, ndị buru ibu na acha anụnụ anụnụ n'ihi ìhè ha na enwu na obere oge. Ọzọkwa, a makwaara na kpakpando ndị a na adị ndụ dị mkpirikpi n'ihi ngwa ngwa ha na eri mmanụ ụgbọala iji nọgide na nguzozi mmiri. Ya mere, nchọpụta na a na ejikọta ihe ndị fọdụrụ na ọnụ ọgụgụ buru ibu nke kpakpando na eto eto, nnukwu na-atụ aro na njikọta na akpata mmepụta kpakpando ngwa ngwa (lee ụyọkọ kpakpando). [26] Kemgbe e mere nchọpụta a, nchọpụta dị iche iche emeela ka njikọta na akpata mmepụta kpakpando siri ike.[25] N'agbanyeghị na nnukwu njikọta dị irè karịa na akwọta mmepụta kpakpando karịa obere njikọta, a maara na obere njikọta dị iche iche karịa nnukwu njikọta ya mere mmetụta nchịkọta nke obere njikọta n'Oge mbara igwe na-ekwukwa na ọ ga enye aka nke ukwuu na mgbawa nke mmepụta kpakwando.[27]
Obere njikọta na mmalite nke ihe ndị dị na diski buru ibu
[dezie | dezie ebe o si]Nnyocha nke ụyọkọ kpakpando ndị dị n'akụkụ na atụ aro ọnụnọ zuru ụwa ọnụ nke obere diski, nnukwu diski na akụkụ halo nke ụyọdị kpakpando. N'agbanyeghị ihe doro anya nke ihe ndị a, a ka na eme nchọpụta iji chọpụta ma ọ bụrụ na nnukwu diski na obere diski bụ ihe dị iche iche.[28] Ka o sina dị, a tụwo aro ọtụtụ echiche iji kọwaa mmalite nke akụkụ diski dị arọ, na n'etiti echiche ndị a bụ otu nke na emetụta obere njikọta. Karịsịa, a na eche na akụkụ diski dị arọ nke ụyọkọ kpakpando na ekpo ọkụ n'oge obere njikọta ma n'ihi ya, diski dị warara na agbasa iji mepụta akụkụ diski ka ukwuu.[29]
Hụkwa
[dezie | dezie ebe o si]- 1 2 3 Binney, James (2008). Galactic dynamics, Tremaine, Scott, 1950-, 2nd, Princeton: Princeton University Press. ISBN 9781400828722. OCLC 759807562.
- ↑ What Is a Satellite Galaxy? (en). NASA Spaceplace. Retrieved on 10 April 2016.
- ↑ Dwarf Galaxies. www.cfa.harvard.edu. Retrieved on 2018-06-10.
- ↑ Willman (2012-09-01). ""Galaxy," Defined". The Astronomical Journal 144 (3): 76. DOI:10.1088/0004-6256/144/3/76. ISSN 0004-6256.
- ↑ Forbes (2009-06-29). "Globular Clusters and Satellite Galaxies: Companions to the Milky Way". Mercury 38 (2): 24–27.
- ↑ Wetzel (2015-07-22). "Rapid Environmental Quenching of Satellite Dwarf Galaxies in the Local Group". The Astrophysical Journal 808 (1): L27. DOI:10.1088/2041-8205/808/1/L27. ISSN 2041-8213.
- ↑ Our Galaxy and its Satellites Link for sharing this page on Facebook (en). Cseligman. Retrieved on 8 April 2016.
- ↑ HubbleSite: News - Astronomers Pin Down Galaxy Collision Rate. hubblesite.org. Retrieved on 2018-06-14.
- 1 2 Binney, James (1998). Galactic astronomy, Merrifield, Michael, 1964-, Princeton, NJ: Princeton University Press. ISBN 978-0691004020. OCLC 39108765.
- ↑ The DES Collaboration (2015-11-04). "Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey". The Astrophysical Journal 813 (2): 109. DOI:10.1088/0004-637X/813/2/109. ISSN 1538-4357.
- ↑ Wang (2018-05-15). "The shape alignment of satellite galaxies in galaxy pairs in SDSS". Monthly Notices of the Royal Astronomical Society 484 (3): 4325–4336. DOI:10.1093/mnras/stz285.
- ↑ Klypin (September 1999). "Where Are the Missing Galactic Satellites?". The Astrophysical Journal 522 (1): 82–92. DOI:10.1086/307643. ISSN 0004-637X.
- 1 2 Wetzel (2016-08-11). "Reconciling dwarf galaxies with LCDM cosmology: Simulating a realistic population of satellites around a Milky Way-mass galaxy". The Astrophysical Journal 827 (2): L23. DOI:10.3847/2041-8205/827/2/L23. ISSN 2041-8213.
- ↑ Kim (2018). "There is No Missing Satellites Problem". Physical Review Letters 121 (21): 211302. DOI:10.1103/PhysRevLett.121.211302. PMID 30517791.
- ↑ Li (2017-11-22). "Determination of Dark Matter Halo Mass from Dynamics of Satellite Galaxies". The Astrophysical Journal 850 (2): 116. DOI:10.3847/1538-4357/aa94c0. ISSN 1538-4357.
- ↑ Wojtak (2013-01-21). "Physical properties underlying observed kinematics of satellite galaxies". Monthly Notices of the Royal Astronomical Society 428 (3): 2407–2417. DOI:10.1093/mnras/sts203. ISSN 1365-2966.
- ↑ Schombert (November 1995). "Dwarf Spirals". The Astronomical Journal 110: 2067. DOI:10.1086/117669. ISSN 0004-6256.
- 1 2 3 4 Sparke (2007). Galaxies in the universe : an introduction, 2nd, Cambridge: Cambridge University Press. ISBN 978-0521855938. OCLC 74967110.
- ↑ Hensler (2011). "The Morphological Origin of Dwarf Galaxies". EAS Publications Series 48: 383–395. DOI:10.1051/eas/1148086. ISSN 1633-4760.
- ↑ Blumenthal (October 1984). "Formation of galaxies and large-scale structure with cold dark matter". Nature 311 (5986): 517–525. DOI:10.1038/311517a0. ISSN 0028-0836.
- ↑ Kravtsov (2010). "Dark matter substructure and dwarf galactic satellites". Advances in Astronomy 2010: 281913. DOI:10.1155/2010/281913. ISSN 1687-7969.
- 1 2 3 Houjun. (2010). Galaxy formation and evolution, Van den Bosch, Frank, 1969-, White, S. (Simon D. M.), Cambridge: Cambridge University Press. ISBN 9780521857932. OCLC 460059772. Kpọpụta njehie: Invalid
<ref>tag; name ":1" defined multiple times with different content - ↑ Somerville (December 1999). "Semi-Analytic Modelling of Galaxy Formation: The Local Universe". Monthly Notices of the Royal Astronomical Society 310 (4): 1087–1110. DOI:10.1046/j.1365-8711.1999.03032.x. ISSN 0035-8711.
- ↑ Zhang (2008-10-01). "How to Grow a Healthy Merger Tree". Monthly Notices of the Royal Astronomical Society 389 (4): 1521–1538. DOI:10.1111/j.1365-2966.2008.13671.x.
- 1 2 3 Binney, James (2008). Galactic dynamics, Tremaine, Scott, 1950-, 2nd, Princeton: Princeton University Press, 705. ISBN 9781400828722. OCLC 759807562.
- ↑ Larson (January 1978). "Star formation rates in normal and peculiar galaxies". The Astrophysical Journal 219: 46. DOI:10.1086/155753. ISSN 0004-637X.
- ↑ Kaviraj (2014-06-01). "The importance of minor-merger-driven star formation and black-hole growth in disk galaxies". Monthly Notices of the Royal Astronomical Society 440 (4): 2944–2952. DOI:10.1093/mnras/stu338. ISSN 1365-2966.
- ↑ Bovy (2012). "The Milky Way Has No Distinct Thick Disk". The Astrophysical Journal 751 (2): 131. DOI:10.1088/0004-637X/751/2/131. ISSN 0004-637X.
- ↑ Di Matteo (January 2011). "The formation of a thick disk through the heating of a thin disk: Agreement with orbital eccentricities of stars in the solar neighborhood". Astronomy & Astrophysics 525: L3. DOI:10.1051/0004-6361/201015822. ISSN 0004-6361.