Rambler's Top100Astronet    
  po tekstam   po klyuchevym slovam   v glossarii   po saitam   perevod   po katalogu
 

The R.A.P. Project (Reviews of Astro-Ph)

Akkreciya
(Arhiv Akkreciya:
v.2, 2003, v.1, 2002-2003)

Vypusk 197. 13-19 oktyabrya 2008

obzor arxiv:0810.2690 Giperakkrecionnye diski vokrug chernyh dyr (Hyper-accreting black holes)
Authors: Andrei M. Beloborodov
Comments: 20 pages

Giperakreciya na chernye dyry mozhet realizovyvat'sya srazu posle kollapsa ili zhe posle sliyaniya dvuh kompaktnyh ob'ektov. Kak izvestno, imenno v takih sistemah, soglasno sovremennoi kartine, voznikayut gamma-vspleski.

Obzor napisan ochen' ponyatno, poetomu ego mozhno smelo vsem rekomendovat'. Takzhe pro akkreciyu na chernuyu dyru, no tol'ko posle sliyanii, sm. svezhuyu original'nuyu stat'yu arxiv:0810.2535.


Vypusk 193. 15-31 avgusta 2008

arxiv:0808.2034 Rentgenovskie pul'sary glazami INTEGRAL (X-ray pulsars through the eyes of INTEGRAL)
Authors: A. Lutovinov, S. Tsygankov
Comments: 12 pages, 8 figures

Daetsya obzor rezul'tatov po nablyudeniyam rentgenovskih pul'sarov na sputnike INTEGRAL. Naibolee interesno opisanie zavisimosti energii ciklotronnoi linii ot svetimosti (eto izmereno dlya treh istochnikov). Takzhe rassmatrivaetsya evolyuciya periodov i zavisimost' doli pul'siruyushego ot razlichnyh parametrov.


Vypusk 190. 09-21 iyulya 2008

arxiv:0807.2427 Obnaruzhenie vspyhivayushih struktur vblizi Sgr A* po nablyudeniyam na VLBI v (sub)millimetrovom diapazone (Detecting Flaring Structures in Sagittarius A* with (Sub)Millimeter VLBI)
Authors: Vincent L. Fish et al.
Comments: 4 pages PDF including 1 color figure, accepted for presentation at the XXIX URSI General Assembly

Izvestno, chto central'naya chernaya dyra nashei Galaktiki - Sgr A* - demonstriruet vspyshechnuyu aktivnost' v raznyh diapazonah. V stat'e avtory govoryat o vozmozhnosti obnaruzhenii struktur, nahodyashihsya sovsem blizko k gorizontu sobytii, po nablyudeniyam na submillimetrovyh volnah s pomosh'yu interferometrov s bol'shoi bazoi. Poka takie interferencionnye sistemy eshe ne zarabotali, no eto delo sovsem nedalekogo budushego.


Vypusk 187. 01-09 iyunya 2008

obzor arxiv:0806.1073 Fizika akkrecii iz zvezdnogo vetra (The Physics of Wind-Fed Accretion)
Authors: Christopher W. Mauche et al.
Comments: 9 pages including 5 color encapsulated postscript figures; LaTeX format, uses aipproc.cls, aip-6s.clo, and aipxfm.sty; submitted for inclusion in the proceedings of "Cool Discs, Hot Flows: The Varying Faces of Accreting Compact Objects," ed. M. Axelsson (New York: AIP)

Avtory chislenno issleduyut akkreciyu iz zvezdnogo vetra na kompaktnyi istochnik v tesnyh dvoinyh sistemah. Osoboe vnimanie udelyaetsya sisteme Vela X-1. Avtory ne tol'ko detal'no schitayut gidrodinamiku, no i akkuratno modeliruyut spektr.


Vypusk 186. 16-31 maya 2008

arxiv:0805.4492 Rentgenovskoe mikrolinzirovanie v RXJ1131-1231 i HE1104-1805 (X-ray Microlensing in RXJ1131-1231 and HE1104-1805)
Authors: G. Chartas, C. S. Kochanek, X. Dai, S. Poindexter, G. Garmire
Comments: 20 pages, includes 8 figures, submitted to ApJ

Ne ustayu udivlyat'sya, kakie vozmozhnosti daet gravitacionnoe mikrolinzirovanie dlya izucheniya nerazlichimyh s pomosh'yu sovremennyh priborov ob'ektov. Ideya prosta, prodstav'te sebe linzirovanie dalekogo kvazara: est' kvazar, est' my, a mezhdu nami galaktika, vystupayushaya v roli linzy. No v etoi galaktike est' zvezdy. I oni mogut davat' effekt mikrolinzirovaniya. Istochnikom v dannom sluchae yavlyaetsya akkrecionnyi disk vokrug sverhmassivnoi chernoi dyry v kvazare. V rezul'tate, my mozhem poluchat' ocenki razmera izluchayushei chasti diska. Eto ispol'zovalos' dlya proverki modelei diska (model' Shakury-Syunyaeva horosho podhodit), dlya izucheniya korrelyacii razmera diska s massoi cherynoi dyry i t.d. V ocherednoi stat'ei avtory izuchayut linzirovanie v rentgenovskom diapazone, chto dovol'no netrivial'no. Mozhno ocenit' razmer izluchayushei oblasti. Rezul'tat (menee 6 gravradiusov) nalagaet sushestvennye ogranicheniya na modeli koron diskov v aktivnyh yadrah.


Vypusk 184. 21-30 aprelya 2008

obzor arxiv:0804.3096 Teoriya zamagnichennyh dzhetov (Theory of magnetically powered jets)
Authors: H.C. Spruit
Comments: 24 pages

Rassmatrivayutsya astrofizicheskie dzhety i rol' magnitnogo polya v ih formirovanii, a takzhe ego vliyaniya na nablyudaemye svoistva. V chastnosti, rol' magnitnogo polya velika v "zapuske" dzheta: energiya gravitacionnogo polya perekachivaetsya v energiyu vrasheniya v osnovanii dzheta, a ta, s pomosh'yu magnitnogo polya, uzhe perehodit v kineticheskuyu energiyu strui.

Sushestvenno, chto Spruitu opyat' udaetsya sochetat' strogoe izlozhenie s ponyatnym opisaniem s pomosh'yu prostyh formul.


Vypusk 183. 01-20 aprelya 2008

arxiv:0804.1063 Akkrecionnyi disk vokrug chernoi dyry v NGC 4258: odna iz samyh krasivyh dinamicheskih sistem v prirode (The Black Hole Accretion Disk in NGC 4258: One of Nature's Most Beautiful Dynamical Systems)
Authors: James M. Moran
Comments: 14 pages, 12 figures, accepted and to appear in "Frontiers of Astrophysics - A Celebration of NRAO's 50th Anniversary," ASP Conference Series, eds. Alan H. Bridle, James J. Condon and Gareth C. Hunt

V galaktike NGC 4258 blagodarya nalichiyu mazernyh istochnikov v akkrecionnom diske vokrug chernoi dyry, my mozhem poluchat' horoshie dannye o vnutrennem parseke. Eto dovol'no redkii sluchai, t.k., izuchiv sotni galaktik, drugih podobnyh sistem naideno malo (vsego megamazernyh galaktik izvestno okolo sotni - pyat' procentov ot issledovannyh, - no stol' "kachestvennyh" - 4-5 shtuk. Issledovaniya takih megamazernyh sistem v diske pozvolyaet poluchat' ochen' tochnye ocenki mass chernyh dyr i opredelyat' rasstoyaniya do galaktik.


Vypusk 181. 01-17 marta 2008 goda

arxiv:0803.0003 Poyarchenie akkrecionnogo diska za schet vyazkoi dissipacii gravitacionnyh voln pri sliyanii sverhmassivnyh chernyh dyr (Brightening of an Accretion Disk Due to Viscous Dissipation of Gravitational Waves During the Coalescence of Supermassive Black Holes)
Authors: Bence Kocsis, Abraham Loeb
Comments: 4 pages, 2 figures, submitted to Physical Review Letters

Krasivyi rezul'tat. Avtory pokazyvayut, chto pri sliyanii dvuh sverhmassivnyh chernyh dyr budut interesnye nablyudatel'nye effekty v elektro-magnitnom izluchenii.

Sverhmassivnye chernye dyry slivayutsya pri sliyaniyah galaktik. Poetomu vokrug dyr ne pusto - mnogo gaza. Sootvetstvenno, budet akkrecionnyi disk. Imenno v diske i budet proishodit' dissipaciya energii gravvoln. Okazyvaetsya, chto hotya volny budut ochen' slabo "raskachivat'" disk, tem ne menee etogo dostatochno, chtoby za nedeli (a to i gody) do polnogo sliyaniya voznikal nablyudaemyi signal. Krome togo, konechno zhe dolzhen byt' signal i ot samogo sliyaniya. Interesno, chto on pridet k nam na neskol'ko chasov (ili dazhe dnei) pozzhe gravitacionnogo signala (poka tam disk perekonvertiruet gravitacionnye volny v elektro-magnitnye).

Tak chto avtory polagayut, chto vo-pervyh, mozhno nadeyat'sya uvidet' slivayushiesya chernye dyry i do LISA (hotya, razumeetsya, LISA tut nichem ne zamenish': uvidet' signal, kosvenno svyazannyi so sliyaniem, sovsem ne tozhe samoe, chto uvidet' sam gravitacionno-volnovoi signal). Vo-vtoryh, uzhe posle zapuska LISA stoit lovit' elektro-magnitnye signaly, sootvetstvuyushie nablyudayushimsya gravitacionno-volnovym.


Vypusk 179. 01-14 fevralya 2008 goda

miniobzor arxiv:0802.0391 Izuchenie akkreciruyushih neitronnyh zvezd i chernyh dyr s pomosh'yu vremennyh ryadov: za stepennym spektrom (Studying accreting black holes and neutron stars with time series: beyond the power spectrum)
Authors: S. Vaughan, P. Uttley
Comments: 13 pages, 6 figures, in "Noise and Fluctuations" Proc. SPIE vol. 6603

Akkreciya na neitronnye zvezdy i chernye dyry idet ne rovnym spokoinym potokom. Est' turbulentnye dvizheniya, razlichnye neustoichivosti i tp. Vse eto otrazhaetsya na krivoi bleska istochnika, na taiminge i td. Razumeetsya, astronomy "oborachivayut" zadachu: po taimingu, po nablyudeniyam fluktuacii svetimosti i drugim menyayushimsya harakteristikam oni pytayutsya uznat' chto-to novoe o processe akkrecii. O nekotoryh novostyah v takih issledovaniyah mozhno uznat' ih obzora.

Sm. takzhe stat'yu arxiv:0802.0376, posvyashennuyu analogichnomu voprosu, no tol'ko isklyuchitel'no dlya sistem s chernymi dyrami.


Vypusk 176. 20 dekabrya 2007-09 yanvarya 2008 goda

miniobzor arxiv:0801.0953 Zagadochnye slabye akkreciruyushie neitronnye zvezdy v nashei Galaktike (Enigmatic sub-luminous accreting neutron stars in our Galaxy)
Authors: Rudy Wijnands
Comments: 6 pages, Conference proceedings from 'A Population Explosion: The Nature and Evolution of X-ray Binaries in Diverse Environments', 28 Oct - 2 Nov, St. Petersburg Beach, FL

Razvitie tehniki nablyudenii v rentgenovskom diapazone pozvolyaet detal'no izuchat' dostatochno slabye istochniki v dvoinyh sistemah so svetimost'yu poryadka 1035 erg/s. Sredi nih est' i sil'no peremennye istochniki, i ob'ekty s dostatochno stabil'noi svetimost'yu. Po-vidimomu, bol'shinstvo yavlyaetsya neitronnymi zvezdami. Nekotorye iz nih mogut yavlyat'sya praroditelyami millisekundnyh radiopul'sarov. Etot poslednii moment delaet takie sistemy osobenno interesnymi. Krome togo, v nekotoryh sluchayah my mozhem poluchat' informaciyu o vnutrennem stroenii neitronnyh zvezd, esli nablyudaetsya teplovoe izluchenie, svyazannoe ne s akkreciei, a s zapasennym teplom i piknoyadernymi reakciyami.


Vypusk 175. 14-19 dekabrya 2007

arxiv:0712.2877 Rentgenovskaya, IK i submillimetrovaya vspyshka Sagittarius A* (An X-ray, IR, and Submillimeter Flare of Sagittarius A*)
Authors: D. P. Marrone et al.
Comments: Submitted to ApJ. Comments welcome

Kak izvestno, v centre nashei galaktiki nahoditsya sverhmassivnaya chernaya dyra (s massoi neskol'ko millionov solnechnyh). Kak izvestno, dyra nasha ves'ma neaktivna: ee svetimost' mala v sravnenii s eddingtonovskim predelom dlya takoi massy. Kak izvestno, s nei svyazan istochnik Sagittarius A*. Kak izvestno, etot istochnik vspyhivaet. Kak izvestno, prichina vspyshek neizvestna.

Avtoram udalos' otnablyudat' odnu iz vspyshek srazu v chetyreh diapazonah s pomosh'yu pervoklassnyh instrumentov. Mozhno nadeyat'sya, chto eti dannye taki pomogut teoretikam postroit' okonchatel'nuyu model' vspyshek.

Sm. takzhe arxiv:0712.2882, gde "konkuriruyushaya firma" obsuzhdaet tu zhe vspyshku. Etoi gruppe udalos' otnablyudat' ee i na VLA.


Vypusk 173. 20-30 noyabrya 2007

arxiv:0711.4078 Kvazizvezdy: akkreciruyushie chernye dyry v massivnyh obolochkah (Quasistars: Accreting black holes inside massive envelopes)
Authors: Mitchell C. Begelman, Elena M. Rossi, Philip J. Armitage
Comments: 11 pages, 9 figures, MNRAS submitted. Resubmitted version after referee review

Sushestvuet takaya problema: kak bystro vyrastit' iz zarodyshevyh chernyh dyr sverhmassivnye ob'ekty v centrah galaktik? Delo v tom, chto prosto "napihat'" veshestvo vnutr' dyry za schet akkrecii nel'zya, t.k. pri akkrecii vydelyaetsya energiya, i etot potok izlucheniya ostanovit akkreciyu (tochnee otreguliruet ee v sootvetstvii s t.n. Eddingtonovskim predelom, opredelyaemym massoi chernoi dyry).

Avtory rassmatrivayut akkreciyu na chernuyu dyru iz plotnoi gazovoi obolochki. Eto pohozhe na situaciyu, v kotoroi nachinaetsya rost massy chernyh dyr v centrah molodyh galaktik. Za schet otvoda energii konvekciei, avtoram udaetsya obespechit' dostatochno vysokii rost massy. Tak mozhno dorastit' massu do neskol'kih tysyach solnechnyh za million let. Potom obolochka, v kotoroi idet konvekciya, rasseivaetsya. Eto vazhnyi etap v processe uvelicheniya massy chernyh dyr. Veroyatno, nablyudeniya na kosmicheskom teleskope sleduyushego pokoleniya mogut dat' otvet na vopros realizuetsya li takoi scenarii v deistvitel'nosti.


Vypusk 165. 01-13 avgusta 2007

obzor arxiv:0708.0148 Modelirovanie povedeniya akkrecionnyh techenii v rentgenovskih dvoinyh (Modelling the behaviour of accretion flows in X-ray binaries)
Authors: Chris Done, Marek Gierlinski, Aya Kubota
Comments: 76 pages, accepted for publication in Astronomy and Astrophysics Reviews

Bol'shoi podrobnyi obzor. Prichinoi dlya ego napisaniya posluzhil rost dannyh po tesnym dvoinym sistemam s kompaktnymi ob'ektami. Blagodarya mnogovolnovym nablyudeniyam - ot radio do gamma - udaetsya poluchat' dannye o povedenii i diskov, i dzhetov. Chto, v svoyu ochered', pozvolyaet stroit' modeli, v kotoryh zavyazana evolyuciya diska i dzheta.


Vypusk 163. 01-19 iyulya 2007

arxiv:0707.0003 Prostranstvennaya struktura akkrecionnogo (The Spatial Structure of An Accretion Disk)
Authors: Shawn Poindexter, et al.
Comments: 5 pages, 4 figures, submitted to ApJ

Po dannym o mikrolinzirovanii na volnah ot 0.4 do 8 mikron udalos' opredelit' razmer diska kvazara HE1104-1805 na raznyh dlinah voln (sm. takzhe sleduyushuyu stat'yu).


arxiv:0707.0305 Razmer akkrecionnogo diska kvazara - otnoshenie k masse chernoi dyry (The Quasar Accretion Disk Size - Black Hole Mass Relation)
Authors: Christopher W. Morgan et al.
Comments: 5 pages, 3 figures, submitted to ApJL

Sovershenno porazitel'noe, s moei tochki zreniya, delo! Udaetsya proshupyvat' (v optike!) akkrecionnye diski kvazarov. Rech' idet o nablyudenie struktur razmerom menee 1016 santimetrov s rasstoyanii bolee 1026 santimetrov. Udaetsya eto blagodarya mikrolinzirovaniyu.

My privykli k tomu, chto mikrolinzirovanie nablyudaetsya u nas v Galaktike ili v ee blizhaishih sputnikah. No, okazyvaetsya, ono mozhet srabotat' i v drugih situaciyah.

Nablyudayutsya kvazary, linziruemye galaktikami. Eto sil'noe linzirovanie. No v galaktikah est' zvezdy. I imenno oni mogut davat' effekt mikrolinzirovaniya, pozvolyayushii proshupat' disk kvazara!

Bolee togo, udaetsya pokazat', chto razmer diska kvazara svyazan s massoi chernoi dyry.

Obsudit' v ZhZh-soobshestve ru_astroph.
Obsudit' na Astroforume v Nauchnoi panorame.


arxiv:0707.1880 Sverhorbital'naya peremennost' rentgenovskogo i radioizlucheniya ot Cyg X-1: I. Anizotropiya izlucheniya precessiruyushih istochnikov (Superorbital variability of X-ray and radio emission of Cyg X-1. I. Emission anisotropy of precessing sources)
Authors: A. Ibragimov et al.
Comments: 10 pages, 9 figures and 2 tables, accepted to MNRAS

U izvestnogo kandidata v chernye dyry Cyg X-1 sushestvuet modulyaciya izlucheniya s periodom okolo 150 dnei. Eto mnogo bol'she orbital'nogo perioda. Blagodarya novym dannym avtory poluchili vozmozhnost' dostatochno podrobno issledovat' etu peremennost'. Veroyatnee vsego, my imeem delo s precessiei akkrecionnogo diska. Takoe yavlenie nablyudaetsya i u drugoi izvestnoi sistemy - SS 433. Voobshe, sistemy ochen' pohozhi! Tol'ko rezhimy akkrecii raznye.


Vypusk 161. 09-19 iyunya 2007

miniobzor arxiv:0706.2562 Rentgenovskie nablyudeniya ul'tramoshnyh istochnikov (X-ray observations of ultraluminous X-ray sources)
Authors: T.P. Roberts
Comments: Invited talk at the 5th Stromlo Symposium. 10 pages, 4 figures. Accepted for publication in Astrophysics & Space Science

Nebol'shoi obzor po rentgenovskim nablyudeniyam UMI. Razumeetsya, avtor obsuzhdaet obe gipotezy o prirode etih istochnikov (chernye dyry promezhutochnyh mass ili zhe obychnye "zvezdnye" chernye dyry), no obzor vse-taki imenno chto nablyudatel'nyi, i v etom ego dostoinstvo. Ne zashishaya ni odnu iz gipotez, avtor izlagaet osnovnye fakty i rassmatrivaet, kak oni ukladyvayutsya (ili ne ukladyvayutsya) v ramki modelei.


Vypusk 157. 01-11 maya 2007

obzor arxiv:0705.0030 Vysokochastotnye QPO u neitronnyh zvezd i chernyh dyr: zondirovanie plotnogo veshestva i sil'nyh gravitacionnyh polei (High Frequency QPOs in Neutron Stars and Black Holes: Probing Dense Matter and Strong Gravitational Fields)
Authors: Frederick K. Lamb
Comments: 30 pages, 8 figures, published in "From X-Ray Binaries to Gamma-ray Bursts", proceedings of a symposium held in memory of Jan van Paradijs 6-9 June 2001, eds. E.P.J. van den Heuvel, L. Kaper, E. Roi, & R.A.M.J. Wijers

QPO - kvaziperiodicheskie oscillyacii. Yavlenie sostoit v tom, chto v akkreciruyushih istochnikah nablyudaetsya peremennost' na nekotoryh zarakternyh chastotah, no chastota "plyvet". T.e., eto ne pul'sarnaya chastota, a chto-to menee regulyarnoe. Chto - do konca ne yasno. Sushestvuet dostatochno mnogo modelei. Est' nadezhda, chto pravil'no ponimanie prirody QPO privedet k tomu, chto my poluchim novyi kanal informacii o neitronnyh zvezdah i chernyh dyrah.

Vtoroi obzor Freda Lemba neskol'ko peresekaetsya s QPOshnym i posvyashen akkrecii na neitronnye zvezdy v malomassivnyh dvoinyh sistemah.


Vypusk 136. 01 iyunya - 15 iyunya 2006

astro-ph/0606195 Trehmernoe modelirovanie sfericheskoi akkrecii s malomasshtabnymi magnitnymi polyami (Three-Dimensional Simulations of Spherical Accretion Flows with Small-Scale Magnetic Fields)
Authors: Igor V. Igumenshchev
Comments: 31 pages, 7 figures attached in jpg-format; to appear in ApJ

Teoriya akkrecii razvivaetsya uzhe dostatochno davno. Tem ne menee, dazhe dlya dostatochno prostyh techenii ne dostignuto polnoe ponimanie. Kak yasno iz nazvaniya stat'i, v nei providitsya chislennoe issledovanie trehmernoi sfericheski-simmetrichnoi akkrecii s uchetom magnitnyh polei.

Kak i v bolee rannih issledovaniyah (v tom chisle i samogo avtora stat'i) temp akkrecii konechno zhe men'she, chem v sluchae klassicheskoi akkrecii Bondi. Vazhnym novym vyvodom yavlyaetsya nevozmozhnost' ustanovleniya stacionarnogo sverhzvukovogo sfericheski-simmetrichnogo techeniya pri nalichii melkomasshtabnyh magnitnyh polei.


Vypusk 131. 13-21 marta 2006

kniga astro-ph/0603390 Dzhety i sverhkriticheskii akkrecionnyi disk u SS433 (The Jets and and Supercritical Accretion Disk in SS433)
Authors: Sergei Fabrika
Comments: 100 pages, 19 figures; Astrophysics and Space Physics Reviews (2004), 12, pp. 1-153

Sergei Fabrika iz SAO davno i uspeshno zanimaetsya izucheniem sistemy SS433. I vot, napisal o nei celuyu knigu.

Konechno, rech' tam ne tol'ko ob odnom edinstvennom ob'ekte. Mnogie soobrazheniya primenimy i k drugim istochnikam, naprimer k ul'tramoshnym rentgenovskim istochnikam. Sergei schitaet, chto oni yavlyayutsya analogami SS433.


Vypusk 120. 12-30 noyabrya 2005

astro-ph/0511486 Slabeishie akkretory (The faintest accretors)
Authors: Andrew King, Rudy Wijnands
Comments: Andrew King, Rudy Wijnands

Prodolzhaem temu rentgenovskih dvoinyh. Poslednie dannye nablyudenii pokazali nalichie ochen' slabyh istochnikov, yavlyayushihsya rentgenovskimi dvoinymi, v kotoryh idet akkreciya. Priroda sistem neyasna. Avtory rassmatrivayut neskol'ko idei. Svyazany oni s akkreciei s ochen' malomassivnogo kompan'ona. Vozmozhno, chto takie sistemy yavlyayutsya reliktami naseleniya III, t.e. ochen' starymi sistemami, v zvezdah kotoryh malo tyazhelyh elementov.


Vypusk 119. 29 oktyabrya - 11 noyabrya 2005

astro-ph/0510809 Tendencii v kosmicheskoi astronomii i Obraz Kosmosa 2015-2025 (Trends in Space astronomy and Cosmic vision 2015-2025)
Authors: Catherine Turon et al.
Comments: 6 pages.

V stat'e predstavleny osnovnye napravleniya razvitiya evropeiskih kosmicheskih proektov, svyazannyh s astronomiei.

Nedavno ESA byl ob'yavlen konkurs na proekty, osushestvlenie kotoryh otnositsya k 2015-2025 gg., a takzhe na chut' bolee dalekuyu perspektivu. Bylo podano bolee 150 zayavok, iz nih 47 imeyut pryamoe otnoshenie k astronomii. Bezuslovno podderzhka proektov osnovana na nekotorom anlize naibolee perspektivnyh napravlenii. Ih bylo vydeleno tri.
1. Drugie miry i zhizn' vo Vselennoi
a) Ekzoplanety
b) Zhizn'
c) Obrazovanie zvezd i planet
2. Rannyaya Vselennaya
a) Temnaya energiya
b) Inflyaciya
c) Obrazovanie struktur
3. Evolyuciya yarostnoi (violent) Vselennoi
a) Povedenie veshestva v ekstremal'nyh usloviyah
b) Chernye dyry
c) Sverhnovye

Zatem etot spisok byl sveden k chetyrem osnovnym voprosam, na kotorye dolzhna otvetit' astronomiya v blizhaishie dva desyatiletiya.
1. Kakovy usloviya dlya obrazovaniya planet i poyavleniya zhizni?
2. Kak poyavilas' Solnechnaya sistema?
3. Kakovy fundamental'nye zakony Vselennoi?
4. Kak poyavilas' nablyudaemaya Vselennaya i iz chego ona sdelana?

Pozhalui, krome pervyh dvuh, voprosy slishkom obshie. Tem ne menee, odobrennye proekty dolzhny pomoch' naiti na nih otvety, ili hotya by prodvinut'sya v ih ponimanii.

V blizhaishee vremya prodvizhenie v ponimanii ustroistva Vselennoi svyazyvaetsya s takimi proektami:
1. Corot (ESA) i Kepler (USA). Eti missii prednaznacheny dlya poiska planet tipa Zemli.
2. Herschel (ESA) i JWST (USA-ESA-others). Eti moshnye infrakrasnye observatorii pozvolyat luchshe razobrat'sya v processah obrazovaniya zvezd i planetnyh sistem.
3. GAIA (ESA) i SIM (USA). Eti astrometricheskie missii, krome vsego prochego, pomogut rezko uvelichit' chislo izvestnyh planet-gigantov.

V neskol'ko bolee otdalennom budushem evropeiskie astronomy poluchat kosmicheskii interferometr, rabotayushii v IK diapazone. On budet nuzhen dlya detal'nogo issledovaniya planet tipa Zemli. V chastnosti, mozhno budet napryamuyu izuchat' ih atmosfery. Krome togo, budet postroen bol'shoi kosmicheskii infrakrasnyi teleskop.

Posle missii Planck, prdnaznachennoi dlya izucheniya mikrovolnovogo fona (t.e. reliktovogo izlucheniya) budet postroen eshe bolee moshnyi pribor, nuzhnyi dlya detal'nogo issledovaniya polyarizacii relikta. Eto pozvolit ponyat', kakoi byla Vselennaya srazu posle stadii inflyacii.

Nakonec budet postroena novaya rentgenovskaya observatoriya, kotoraya pridet na smenu XMM-Newton. A chut' pozzhe i gamma-observatoriya, kotoraya prizvana zamenit' sputnik INTEGRAL.

Kak vidno, evropeiskuyu astronomiyu zhdet blestyashee budushee.


Vypusk 118. 17-28 oktyabrya 2005

astro-ph/0510410 Akkreciya Bondi-Hoila iz turbulentnoi sredy (Bondi-Hoyle Accretion in a Turbulent Medium)
Authors: Mark R. Krumholz et al.
Comments: Accepted for publication in ApJ; 13 pages, 9 figures, emulateapj

Klassicheskaya formula akkrecii Bondi neprimenima v sluchae sil'no turbulizovannoi sredy. Avtory obsuzhdayut, kak sil'naya sverhzvukovaya turbulentnost' povliyaet na temp akkrecii. Effekty turbulentnosti dostatochno slozhno uchest'. Dazhe vyvody raboty trudno chetko i kratko sformulirovat'. Vozmozhna situaciya, kogda temp budet vyshe, chem formal'no vychislennyi po formule Bondi, vozmozhna i obratnaya situaciya.

Otmechu, chto avtory prenebregali rol'yu magnitnyh polei. Uchest' srazu i turbulentnost' i polya budet ochen' slozhno dazhe v chislennyh raschetah.

Avtory prilagayut svoi raschety k formirovaniyu molodyh zvezd (sm. bolee podrobno stat'yu teh zhe avtorov nizhe - astro-ph/0510412) i akkrecii na zvezdy do stadii glavnoi posledovatel'nosti. Pokazano, chto dlya massivnyh ob'ektov vozmozhno sushestvennoe izmenenie po-sravneniyu s bolee rannimi modelyami. Krome togo, kratko rassmotrena akkreciya na sverhmassivnye chernye dyry v centrah galaktik.


Vypusk 110. 15-30 iyunya 2005

astro-ph/0506298 Primenenie modeli "hudogo" diska v UMI: sluchai istochnika H-8 v M33 (The application of slim disk models to ULX: the case of M33 X-8)
Authors: L. Foschini et al.
Comments: 6 pages, 4 figures, accepted for publication on Advances in Space Research, Special Issue Proceedings of 35th COSPAR (Paris, France, 18-25 July 2004)

Prodolzhayutsya popytki ponyat' prirodu ul'tramoshnyh rentgenovskih istochnikov (UMI).

Sushestvuet neskol'ko modelei, opisyvayushih akkrecionnye diski. Sredi nih i t.n. "hudye" (slim) diski. Avtory prilagayut dannuyu model' v istochniku H-8 v galaktike v Treugol'nike (M33). Po-mneniyu avtorov nablyudeniya horosho opisyvayutsya v ramkah sushestvovaniya tesnoi dvoinoi sistemy s chernoi dyroi obychnoi (zvezdnoi) massy, akkreciruyushei so sverheddingtonovskim (t.e. sverhkriticheskim) tempom.


Vypusk 105. 21-30 aprelya 2005

dissertaciya astro-ph/0504498 Gamma-izluchenie ot mikrokvazarov (Gamma-Ray Emission from Microquasars)
Authors: M.M. Kaufman Bernado
Comments: PhD Thesis supervised by G.E. Romero and presented at the University of Buenos Aires (UBA) on December 15th, 2004

V dissertacii mikrokvazary (akkreciruyushie dvoinye s relyativistskimi dzhetami) obsuzhdayutsya kak vozmozhnye neotozhdestvlennye istochniki, nablyudavshiesya priborom EGRET.


Vypusk 103. 01-10 aprelya 2005

miniobzor astro-ph/0504185 Sostoyaniya chernyh dyr: akkreciya i dzhety (Black Hole States: Accretion and Jet Ejection)
Authors: Tomaso Belloni
Comments: 8 pages, 3 figures, in "Interacting Binaries: Accretion, Evolution and Outcomes", eds. L. A. Antonelli, et al., Procs. Interacting Binaries Meeting, Cefalu, Italy, June 2004, in press (AIP)

Chernye dyry v tesnyh dvoinyh sistemah nablyudayutsya kak rentgenovskie istochniki blagodarya akkrecii. Nablyudenii pokazali nalichie raznyh rezhimov, otlichayushihsya (s nablyudatel'noi tochki zreniya) po spektral'nym harakteristikam, moshnosti izlucheniya, modulyacii izlucheniya i t.p.

V obzore summiruetsya klassifikaciya sostoyanii istochnikov s chernymi dyrami. Kratko obsuzhdayutsya fizicheskie usloviya v kazhdom iz sostoyanii.

Raspechatyvaya stat'yu bud'te vnimatel'ny! Poslednie 24 stranicy (iz 40) pustye, t.k. bol'shie risunki nel'zya bylo pomestit' v Arhiv iz-za ogranicheniya na ob'em.


Vypusk 99. 15-28 fevralya 2005

astro-ph/0502266 Rezhim propellera pri diskovoi akkrecii na bystrovrashayushuyusya zamagnichennuyu zvezdu (The Propeller Regime of Disk Accretion to a Rapidly Rotating Magnetized Star)
Authors: Marina M. Romanova et al.
Comments: 5 pages with 4 figures, LaTeX, macros: emulapj.sty, avi movies are available at http://www.astro.cornell.edu/us-russia/disk_prop.htm; Journal-ref: ApJ Letters, 616, L151-L154, 2004

Chestno govorya, vsegda nravilis' kartinki i fil'my, demonstriruyushie diskovuyu akkreciyu.
Rassmotren rezhim propellera pri diskovoi akkrecii na zamagnichennuyu zvezdu. Rezul'taty mogut primenyat'sya kak dlya akkrecii na neitronnye zvezdy i belye karliki, tak i dlya issledovaniya zvezd tipa T Tel'ca.

Na pervoi serii risunkov pokazano, kak izmenyaetsya konfiguraciya magnitnogo polya. Na levom risunke (T=0, vremya otschityvaetsya v uslovnyh edinicah, sootvetstvuyushih odnomu oborotu s keplerovskoi skorost'yu na rasstoyanii 2.86 radiusa zvezdy) pokazana nachal'naya konfiguraciya polya. Zatem nachinaetsya raschet, i vidno, kak silovye linii formiruyut "magnitnye bashni". V nizhnei chasti dano uvelichennoe izobrazhenie linii vblizi diska dlya T=70.


Na vtoroi serii risunkov prodemonstrirovano, chto nesmotrya na to, chto sistema nahoditsya na stadii propellera, kogda bystrovrashayusheesya magnitnoe pole prepyatstvuet proniknoveniya veshestva na poverhnost' zvezdy, nekotoraya akkreciya tem ne menee vozmozhna. Na srednem risunke otchetlivo vidno eto "proniknovenie".



Vypusk 95. 22-31 dekabrya 2004

katalog astro-ph/0412331 WWW baza dannyh modelei akkrecionnyh diskov, obluchaemyh central'noi zvezdoi (WWW Database of Models of Accretion Disks Irradiated by The Central Star)
Authors: Paola D'Alessio (CRyA) et al.
Comments: 7 pages, 1 table

Eto anons novoi versii kataloga fizicheskih modelei akkrecionnyh diskov s uchetom oblucheniya (irradiacii) central'noi zvezdoi. Katalog soderzhit okolo 3000 modelei s razlichnymi central'nymi zvezdami, razmerami i naklonom diskov, raznymi obiliyami pyli i tempami akkrecii. Dlya kazhdoi modeli privedeny zavisimosti fizicheskih parametrov ot radiusa i sinteticheskie spektry. Katalog dostupen po sleduyushim adresam:
http://www-cfa.harvard.edu/youngstars/dalessio/ (SShA),
http://www.astrosmo.unam.mx/~dalessio/ (Meksika) i
http://www.laeff.esa.es/models/dalessio/ (Ispaniya).


Vypusk 91. 01-14 noyabrya 2004

obzor astro-ph/0411185 Sverheddingtonovskaya akkreciya na chernye dyry: "pol'skie ponchiki" i slim-diski (Super-Eddington black hole accretion: Polish doughnuts and slim disks)
Authors: Marek A. Abramowicz
Comments: 17 pages, 3 figures

Eshe odin obzor, napisannyi klassikom Marekom Abramovicom, iz pod pera kotorogo vyshel celyi ryad shiroko izvestnyh rabot po akkrecii.

Teoriya sushestvenno sverheddingtonovskoi akkrecii na chernye dyry byla razrabotana v 80-h godah v Varshave gruppoi Bogdana Pachin'skogo v terminah "pol'skih ponchikov": opticheski tolstyh vrashayushihsya potokov so slaboi vyazkost'yu. Drugoi podhod slim-diski byl pozdnee predlozhen Abramovicem i Lasotoi, no on deistvuet tol'ko dlya umerennogo prevysheniya eddingtonovskogo predela.


obzor astro-ph/0411200 Teoriya istechenii iz kataklizmicheskih peremennyh (Theory of Outflows in Cataclysmic Variables)
Authors: Daniel Proga
Comments: 15 pages, 4 figures

V obzore rassmatrivaetsya istechenie veshestva iz akkrecionnogo diska v kataklizmicheskih peremennyh pod deistviem davleniya izlucheniya v liniyah. Rassmatrivaetsya kak chisto gidrodinamicheskii, tak i magnitogidrodinamicheskie mehanizmy. Obsuzhdayutsya fizicheskie principy i ih realizaciya v chislennyh shemah.


Vypusk 90. 25-31 oktyabrya 2004

obzor astro-ph/0410551 Obzor bystroi peremennosti v rentgenovskih (A review of rapid X-ray variability in X-ray binaries)
Authors: M. van der Klis
Comments: 73 pages, 21 figures, no color to appear in Compact stellar X-ray sources, Lewin & van der Klis (eds), Cambridge University Press

Eshe odna glava iz "Compact stellar X-ray sources".

van der Klis yavlyaetsya, pozhalui, samym krupnym ekspertom po QPO - kvaziperiodicheskim oscillyaciyam, Etot tip peremennosti nablyudaetsya u akkreciruyushih neitronnyh zvezd i chernyh dyr. Po QPO mozhno poluchat' vazhnuyu informaciyu o parametrah sistem.


Vypusk 88. 11-17 oktyabrya 2004

astro-ph/0410313 Seismologiya akkreciruyushih belyh karlikov (Seismology of Accreting White Dwarfs)
Authors: Phil Arras, Dean Townsley, Lars Bildsten
Comments: 6 pages, 2 figures.

Pul'sacii akkreciruyushih belyh karlikov, vhodyashih v sostav nekotoryh kataklizmicheskih peremennyh, byli zaregistrirovany dostatochno nedavno (eto slozhnaya nablyudatel'naya zadacha). V principe, po takim kolebaniyam mozhno izuchat' vnutrennyuyu strukturu pul'siruyushih zvezd. No poka v etoi oblasti poluchen tol'ko odin rezul'tat: dlya sistemy GW Lib na osnove izucheniya ee pul'sacii polucheny ocenka massy belogo karlika (MWD=1.05Mo) i massy obolochki akkrecirovannogo veshestva (Menv=0.4x10-4 Mo).


astro-ph/0410343 Poslesvechenie ot sliyaniya massivnyh chernyh dyr (The Afterglow of Massive Black Hole Coalescence)
Authors: Milos Milosavljevic, E. S. Phinney
Comments: 4 pages, 2 figures

Sliyaniya dvoinyh (sverh)massivnyh chernyh dyr s massami 105-107 Mo budut s legkost'yu registrirovat'sya kosmicheskim lazernym interferometrom LISA (Laser Interferometer Space Antenna) dazhe s krasnyh smeshenii z=20.

Odnako dannoe gravitacionnoe sobytie ne proidet nezamechennym i v drugih diapazonah: ono budet soprovozhdat'sya elektromagnitnym "poslesvecheniem", voznikayushim po sleduyushei prichine:

  • Zadolgo do sliyaniya chernye dyry nachinayut "sgrebat'" okruzhayushii ih gaz, kotoryi v vyazkoi shkale vremeni formiruet disk vokrug (snaruzhi ot) dvoinoi sistemy (circumbinry disc).
  • Vnutrennyaya granica diska primerno sovpadaet s tochkoi, gde prilivnye sily ot dvoinoi sistemy sravnivayutsya s deistvuyushimi v diske vyazkimi silami.
  • Vnachale vnutrennii krai diska sleduet za chernymi dyrami po mere ih sblizheniya, no na poslednem etape skorost' sblizheniya komponent sistemy rezko vozrastaet i disk ot etogo processa "otstaet".
  • Posle sliyaniya obrazuetsya odinochnaya chernaya dyra, okruzhennaya diskom.
  • Cherez nekotoroe vremya pod deistviem vyazkih sil vnutrennii krai diska priblizhaetsya k chernoi dyre i v sisteme voznikaet rentgenovskii istochnik so svetimost'yu do 1044 erg/s i vremenem zhizni poryadka desyati let (dlya massy chernoi dyry 106 mass solnca).

    Eto i est' "poslesvechenie" slivshihsya chernyh dyr.


Vypusk 87. 01-10 oktyabrya 2004

astro-ph/0410053 Pochemu net dzhetov u kataklizmicheskih peremennyh? (Why there are no jets from cataclysmic variable stars)
Authors: Jean-Pierre Lasota, Noam Soker
Comments: 6 pages

Avtory obrashayut vnimanie na to, chto teplovaya model' formirovaniya dzhetov, razrabotannaya dlya protozvezdnyh ob'ektov okruzhennyh diskom, prekrasno podhodit i dlya kataklizmicheskih peremennyh: dvoinyh zvezd v kotoryh prisutstvuet belyi karlik okruzhennyi akkrecionnym diskom. Primenenie teplovoi modeli k etomu novomu tipu sistem pozvolyaet estestvennym obrazom otvetit' na vopros pochemu u nih otsutstvuyut dzhety. Prichinoi etogo okazyvaetsya otnositel'naya slabost' vliyaniya magnitnyh polei na disk v kataklizmicheskih peremennyh.


Vypusk 83. 01-31 avgusta 2004

astro-ph/0408209 Mul'titemperaturnyi chernotel'nyi spektr tonkogo akkrecionnogo diska s i bez usloviya nulevogo momenta sil na vnutrennei granice (Multi-Temperature Blackbody Spectra of Thin Accretion Disks With and Without a Zero-Torque Inner Boundary Condition)
Authors: E.R.Zimmerman et al.

V osesimmetrichnom akkrecionnom diske kazhdoe ego kol'co ispuskaet teplovoe chernotel'noe izluchenie. No temperatura izlucheniya u raznyh kolec otlichaetsya. V itoge summarnyi spektr imeet v shirokom intervale chastot stepennoi vid. Do togo, kak v 1969 godu Lindenbell vpervye rasschital spektr akkrecionnogo diska, schitalos', chto stepennoi spektr mozhet proizvodit'sya tol'ko neteplovymi istochnikami izlucheniya. V posledstvii k podobnym istochnikam izlucheniya stal primenyat'sya termin "mul'titemperaturnyi".

V "standartnoi" teorii akkrecionnyh diskov, kotoruyu razrabotali Shakura i Syunyaev, predpolagalos', chto na vnutrennem krae diska vyazkie natyazheniya obrashayutsya v nol'. Segodnya dlya diskov vokrug chernyh dyr chashe primenyaetsya model', v kotoroi k veshestvu na vnutrennem krae diska prilozhen nekotoryi moment sil. Avtory dannoi raboty sravnili dve ukazannye modeli na primere horosho izuchennyh sputnikom RXTE kandidatov v chernye dyry: 4U 1543-47, XTE J1550-564 i GRO J1655-40. Ih vyvod takov: obe modeli horosho opisyvayut nablyudaemye spektry, tol'ko v klassicheskoi modeli radius vnutrennei granicy dolzhen byt' v 2.2 raza men'she. Etot rezul'tat vazhen dlya opredeleniya uglovogo momenta chernyh dyr i tempa akkrecii na nih.


Vypusk 81. 20-30 iyunya 2004

obzor astro-ph/0406466 Akkrecionnyi disk vokrug chernoi dyry s uchetom magnitnyh polei (Accretion disks around black holes with account of magnetic fields)
Authors: G.S. Bisnovatyi-Kogan
Comments: 24 pages, 18 figures.

Esli akkreciruyushee veshestvo neset vmorozhennoe v sebya magnitnoe pole, to davlenie polya rastet bystree, chem davlenie samogo veshestva. I esli v nachale pole ne bylo ochen' ochen' slabym, to mozhet nastupit' moment, kogda osnovnuyu rol' v dinamike akkrecii stanut igrat' imenno magnitnye polya. Teoriya dannyh processov otlichaetsya ot togo, chto predskazyvaet kak standartnaya al'fa-model', tak i modeli advekcionnyh diskov.


Shematichnoe izobrazhenie struktury diska s magnitnym polem

V obzore podrobno rassmotreny vse aspekty dannoi teorii.


Vypusk 80. (01) - 12-20 iyunya 2004

astro-ph/0406353 Energetika sistem chernaya dyra - akkrecionnyi disk s magnitnoi svyaz'yu pri nizkih tempah akkrecii (Energetics of Black Hole-Accretion Disk System with Magnetic Connection: Limit of Low Accretion Rate)
Authors: Li-Xin Li
Comments: 28 pages, including 11 figures; accepted in PASJ

Rassmotrena model' chernoi dyry, okruzhennoi akkrecionnym diskom, s umerenno sil'noi magnitnoi svyaz'yu, kogda samaya vnutrennyaya chast' akkrecionnogo diska vrashaetsya tverdotel'no iz-za krupnomasshtabnogo magnitnogo polya. Pokazano, chto esli moment vrasheniya chernoi dyry prevoshodit nekotoroe kriticheskoe znacheniya

a > acr = 0.3594 M,

to energiya vrasheniya chernoi dyry nachinaet vkachivat'sya v disk i mozhet povysit' ego svetimost' na poryadki velichiny.

V protivopolozhnom sluchae (pri a < acr) dvizhenie vnutrennei oblasti diska opredelyaetsya magnitnym polem, a ego vnutrennyaya granica raspolagaetsya na radiuse korotacii (tam, gde Keplerovskaya orbital'naya uglovaya skorost' stanovitsya ravnoi skorosti vrasheniya chernoi dyry). Svetimost' diska v etom sluchae rezko snizhaetsya po sravneniyu so standartnoi (al'fa) model'yu.


Vypusk 77. 01-12 maya 2004

astro-ph/0405099 Forma i polozhenie teni chernoi dyry v akkrecionnom diske i vrashenie chernoi dyry (Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes)
Authors: Rohta Takahashi
Comments: 13 pages, 6 figures, accepted in ApJ

Mozhno li opredelit' spinovyi parametr ("skorost' vrasheniya") chernoi dyry prosto glyadya na nee? Da, po forme i polozheniyu ee "teni" na fone yarkogo akkrecionnogo diska ("ten'" - oblast' otkuda k nam ne prihodyat fotony), hotya takoe opredelenie inogda ne daet odnoznachnogo rezul'tata.

Formy tenei chernyh dyr pri razlichnyh parametrah. Belaya tochka ukazyvaet polozhenie centra chernoi dyry, seraya liniya - sovpadayushie osi vrasheniya chernoi dyry i akkrecionnogo diska. Gorizontal'noe napravlenie kazhdogo iz risunkov vybrano tak, chtoby shirina teni byla maksimal'noi.


Vypusk 75. 12-19 aprelya 2004

astro-ph/0404214 Rastekanie akkreciruemogo veshestva po belym karlikam (Spreading of Accreted Material on White Dwarfs)
Authors: Anthony L. Piro (UCSB), Lars Bildsten (KITP, UCSB)
Comments: 14 pages, 3 pages

Esli u belogo karlika slaboe magnitnoe pole, a akkrecionnyi disk tonkii (tolshina vnutrennego kraya v neskol'ko raz men'she razmera zvezdy), to disk dohodit do poverhnosti zvezdy v oblasti ekvatora vrasheniya. Skorost' veshestva diska tam vyshe, chem skorost' poverhnosti zvezdy. Veshestvo tormozitsya i rastekaetsya po poverhnosti, obrazuya tak nazyvaemyi "pogranichnyi sloi", v kotorom vydelyaetsya prakticheski stol'ko zhe energii, kak vo vsem ostal'nom akkrecionnom diske v celom. Veshestvo rastekaetsya po poverhnosti zvezdy, priblizhayas' k polyusam, ego skorost' i temperatura postepenno sravnivayutsya s parametrami zvezdy.

Etot process vyglyadit takzhe, kak mnogokratno ranee opisannoe obrazovanie pogranichnogo sloya u akkreciruyushei neitronnoi zvezdy so slabym magnitnym polem. Dlya belyh karlikov chislennoe modelirovanie (provedennoe v stat'e) delaetsya, kazhetsya, vpervye.


Vypusk 73. 16-31 marta 2004

astro-ph/0403329 Akkreciya vetra v dvoinyh sistemah - I. (Wind accretion in binary stars - I. Mass accretion ratio)
Authors: T.Nagae et al.
Comments: 8 pages, accepted in Astron. Astroph.

Esli zvezda v tesnoi dvoinoi sisteme ne zapolnyaet polost' Rosha, no blizka k etomu, i, odnovremenno, obladaet moshnym zvezdnym vetrom, to akkreciya mozhet byt' dostatochno moshnoi, a ee fizika - ochen' interesnoi.

V dannoi rabote privedeny rezul'taty trehmernogo gidrodinamicheskogo modelirovaniya, provedennye gruppoi yaponskih issledovatelei. Tehnicheskaya storona (sobstvenno samo chislennoe modelirovanie) v stat'e rassmotrena ochen' kratko, zato mnogo graficheskih illyustracii. Osoboe vnimanie avtory udelyayut voprosu kachestvennomu razlichiyu struktury potokov pri akkrecii iz vetra (sil'noe nedozapolnenie polosti Rosha), pri techenii cherez tochku Lagranzha (polost' Rosha zapolnena) i v promezhutochnyh sluchayah (maloe otklonenie ot polosti Rosha).

Sleva tipichnaya geometriya potoka pri akkrecii iz zvezdnogo vetra,
sprava - pri zapolnenii polosti Rosha.


astro-ph/0403407 Kineticheskaya teoriya vyazkosti (Kinetic theory viscosity)
Authors: C.J. Clarke, J. E. Pringle
Comments: 8 pages, 0 figures, Accepted in MNRAS

Stat'ya, v kotoroi vyazkie Keplerovskie akkrecionnye diski opisyvayutsya v ramkah kineticheskoi teorii. Dostatochno interesno s teoreticheskoi tochki zreniya.


Vypusk 71. 23-29 fevralya 2004

istoricheskii obzor astro-ph/0402562 Issledovanie processov akkrecii na chernye dyry: pyat'desyat let raboty (Study of Accretion Processes on Black Holes: Fifty Years of Developments)
Authors: Sandip K. Chakrabarti

Pervoi rabotoi, otnosyasheisya k dannomu napravleniyu, avtor schitaet vyshedshuyu v 1952 godu nazad stat'yu Bondi (Bondi) o sfericheskoi akkrecii. [50 let etoi stat'e ispolnilos' v 2002, kogda i byl opublikovan dannyi obzor.] S etogo vremeni potok statei ros eksponencial'no i bylo sdelano ochen' mnogo.


Vypusk 68. 01-07 fevralya 2004

miniobzor astro-ph/0402013 Vysokochastotnye QPO kak fizicheskaya problema: nelineinyi rezonans (High-frequency QPOs as a problem in physics: non-linear resonance)
Authors: Wlodek Kluzniak, Marek A. Abramowicz, William H. Lee
Comments: 4 pages, presented at X-ray Timing 2003: Rossi and Beyond, Boston, November 2003

QPO - kvaziperiodicheskie oscillyacii. Eto vazhnyi fenomen, nablyudayushiisya v akkreciruyushih tesnyh dvoinyh sistemah s neitronnymi zvezdami i chernymi dyrami. Prichiny vozniknoveniya QPO neyasny. Est' dostatochno mnogo modelei i vse vremya poyavlyayutsya novye (sm. samuyu poslednyuyu v svezhei rabote The MHD Alfven wave oscillation model of kHz Quasi Periodic Oscillation of Accreting X-ray Binaries).

Zdes' zhe avtory rassmatrivayut QPO kak nelineinyi rezonans (sm. takzhe ih stat'yu Resonance in forced oscillations of an accretion disk and kHz QPOs). Poskol'ku yavlenie nablyudaetsya i u sistem s neitronnymi zvezdami, i u sistem s chernymi dyrami, to, polagayut avtory, nado smotret' na to obshee, chto u nih est'. U chernyh dyr net ni poverhnosti, ni magnitnogo polya. Znachit, ostaetsya akkrecionnyi disk. I imenno on igraet klyuchevuyu rol' v ih modeli: QPO - eto rezonansnye kolebaniya akkrecionnogo diska.

V otdel'noi stat'e (astro-ph/0402012) avtory rassmatrivayut QPO v sistemah s chernymi dyrami, nadeyas' s pomosh'yu etogo instrumenta poluchit' otvet o prirode ul'tramoshnyh rentgenovskih istochnikov.


miniobzor astro-ph/0402059 Chto my mozhem uznat' iz kartirovaniya zatmenii akkrecionnyh diskov? (What can we learn from Accretion Disc Eclipse Mapping experiments?)
Authors: Raymundo Baptista
Comments: 5 pages, 3 postscript figures, 2 links for animated gif files, coded with AN latex style file. To appear in Astron. Nachrichten

Dlya kataklizmicheskih peremennyh (dvoinye sistemy s belym karlikom) mozhno pytat'sya stroit' izobrazheniya akkrecionnogo diska, esli nablyudayutsya ego zatmeniya vtoroi zvezdoi. Metod predlozhen davno, i davno uzhe primenyaetsya. Ob osnovah metodiki, osnovnyh rezul'tatah i planah kak raz mozhno uznat' iz etogo korotkogo obzora.

A eshe mozhno posmotret' animashki:
http://www.astro.ufsc.br/~bap/anslide1.gif
http://www.astro.ufsc.br/~bap/anslide2.gif
http://www.astro.ufsc.br/~bap/slide0.gif
http://www.astro.ufsc.br/~bap/ipmovie.gif.


Vypusk 67. 26-31 yanvarya 2004

astro-ph/0401476 Glitch akkreciruyushego pul'sara (A Frequency Glitch in an Accreting Pulsar)
Authors: D.K. Galloway et al.
Comments: 10 pages, 4 figures; submitted to ApJ

Glitch - eto sboi perioda vrasheniya. Nablyudayutsya oni u obychnyh radiopul'sarov (naprimer, u pul'sara v Krabe) i nedavno byli otkryty u anomal'nyh rengenovskih pul'sarov. No nikogda glitchi ne nablyudalis' u akkreciruyushih neitronnyh zvezd v tesnyh dvoinyh sistemah.

Pri glitche skachkom menyaetsya period vrasheniya. Menyaetsya na neznachitel'nuyu velichinu. Svyazyvayut eto ili s izmeneniem momenta inercii kory zvezdy, ili s otryvom vihrevyh nitei, kotorye "pricepleny" k kore iznutri.

Avtory etoi raboty privodyat dannye o rezkom (zavedomo menee 10 chasov) izmenenii perioda neitronnoi zvezdy v sisteme KS 1947+300. Eto dvoinaya s Ve-zvezdoi. Period vrasheniya neitronnoi zvezdy 18.7 sekundy. Vvidu slozhnosti povedeniya perioda vrasheniya akkreciruyushih neitronnyh zvezd v dvoinyh sistemah avtory rassmatrivayut razlichnye prichiny skachka perioda. Odnako, po ih mneniyu, glitch - samaya veroyatnaya. Tem ne menee otmetim, chto delo eto poka temnoe. Tem bolee, chto glitch poluchaetsya ochen' netipichnym kak po velichine, tak i po posleduyushei evolyucii vrasheniya neitronnoi zvezdy. V lyubom sluchae, avtoram udalos' uvidet' ochen' interesnoe yavlenie.


Vypusk 65. 12-19 yanvarya 2004

astro-ph/0401141 Necentral'noe zazhiganie ugleroda v bystrovrashayushihsya akkreciruyushih Uglerodno-kislorodnyh belyh karlikah (Off-Center Carbon Ignition in Rapidly Rotating, Accreting Carbon-Oxygen White Dwarfs)
Authors: Hideyuki Saio and Ken'ichi Nomoto
Comments: 7 pages, 4 figures

Termoyadernoe gorenie belogo karlika vyzyvaet vzryv sverhnovoi tipa Ia. Nachinaetsya etot process v samyh plotnyh sloyah zvezdy: v ee centre. Eto utverzhdenie sovershenno verno dlya nevrashayushihsya, sfericheski simmetrichnyh karlikov. Ono ostaetsya vernym pri medlennom i umerenno bystrom ih vrashenii. No kogda skorost' vrasheniya na ekvatore stanovitsya sravnimoi s Keplerovoi, situaciya menyaetsya: gorenie mozhet nachat'sya ne v centre zvezdy, a na nekotorom rasstoyanii ot nego.

Krome togo bystro vrashayushiesya belye karliki dol'she ne zagorayutsya. Iz etogo avtory raboty delayut vyvod, chto sliyaniya dvoinyh belyh karlikov ne dolzhny privodit' k sverhnovym Ia (t.e. takie sverhnovye porozhdayutsya iz medlenno vrashayushihsya belyh karlikov v tesnyh sistemah s normal'nymi kompan'onami).

Smotrite, takzhe, stat'yu na svyazannuyu temu "Explosion models for thermonuclear supernovae resulting from different ignition conditions" (astro-ph/0401230).


astro-ph/0401212 Evolyuciya spektral'nyh sostoyanii Aql X-1 vo vremya vspleska 2000 g. (Evolution of Spectral States of Aql X-1 during the 2000 Outburst)
Authors: D. Maitra, C. D. Bailyn
Comments: 25 pages, 11 figures. Accepted for publication in ApJ

V astronomii pochti vsegda poluchaetsya tak: ishut, gde yarche. Naprimer, esli otkryt novyi tip istochnikov, to kakoi-nibud' odin stanovitsya naibolee izuchennym, "standartnym" i t.d. i t.p. Dlya myagkih rentgenovskih tranzientov (eto malomassivnye rentgenovskie dvoinye s neitronnymi zvezdami) takovoi yavlyaetsya sistema Aql X-1.

Eto dvoinaya s orbital'nym periodom okolo 19 chasov, nahodyashayasya na rasstoyanii 4-7 kpk ot nas. Malomassivnyi komponent - zvezda klassa K, zapolnyayushaya polost' Rosha. Primerno raz v god istochnik vspyhivaet.

Osen'yu 2000 g. vo vremya ocherednoi vspyshki provodilis' sovmestnye nablyudeniya v optike i rentgene (sputnik RXTE). Takie issledovaniya ochen' vazhny, t.k. fizika processov v myagkih rentgenovskih tranzientah ostaetsya do konca neponyatoi.


Vypusk 64. 01-11 yanvarya 2004

miniobzor astro-ph/0401100 Akkrecionnye potoki vokrug chernyh dyr zvezdnyh mass i neitronnyh zvezd (Accretion flows around stellar mass black holes and neutron stars)
Authors: Didier Barret
Comments: 12 pages, 9 figures

Na 12 stranicah (vklyuchaya risunki) avtor uspevaet uspeshno upomyanut':

  • o vysokom i nizkom (myagkom i zhestkom) sostoyanii akkreciruyushih istochnikov;
  • o teplovoi i neteplovoi komptonizacii fotonov;
  • ob istochnike myagkih fotonov;
  • ob otrazhenii rentgenovskogo izlucheniya ot poverhnosti zvezdy, diska i ih korony;
  • o peremennosti izlucheniya - kvaziperiodicheskih oscillyaciyah;
Odin iz vyvodov avtora: neitronnye zvezdy byvaet ochen' trudno otlichit' ot chernyh dyr.


(Arhiv Akkreciya:
v.2, 2003, v.1, 2002-2003)

Publikacii s klyuchevymi slovami: astrofizika - obzory - astro-ph
Publikacii so slovami: astrofizika - obzory - astro-ph
Sm. takzhe:
Vse publikacii na tu zhe temu >>

Ocenka: 3.4 [golosov: 102]
 
O reitinge
Versiya dlya pechati Raspechatat'

Astrometriya - Astronomicheskie instrumenty - Astronomicheskoe obrazovanie - Astrofizika - Istoriya astronomii - Kosmonavtika, issledovanie kosmosa - Lyubitel'skaya astronomiya - Planety i Solnechnaya sistema - Solnce


Astronet | Nauchnaya set' | GAISh MGU | Poisk po MGU | O proekte | Avtoram

Kommentarii, voprosy? Pishite: info@astronet.ru ili syuda

Rambler's Top100 Yandeks citirovaniya