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22.11.02. astro-ph za 18 - 22 noyabrya 2002 goda: izbrannye stat'i |
Ochen' chasto sozdateli bol'shih proektov obeshayut "otkryt' vse na svete", "naiti otvety na poslednie voprosy" i t.p. Yasno, chto eto preuvelichenie, a potomu ne greh zadumat'sya " a chto zhe dal'she?" V dannoi korotkoi zametke avtor pytaetsya rasskazat', chto eshe mozhno budet sdelat' v izuchenii mikrovolnovogo fona posle obrabotki dannyh sputnika MAP. Na samom dele yasno, chto posle MAP budet Planck. No i krome etogo avtor rassmatrivaet razlichnye eksperimenty, i obsuzhdaet, chto im "ostanetsya" otkryt'.
Authors: R.X. Xu Commets: 8 page and no figure, IAU Symposium No.214, or at http://vega.bac.pku.edu.cn/~rxxu/publications/index_P.htm Prostoi obzor po kvarkovym zvezdam, gde vse dovol'nl ponyatno razlozheno po polochkam.
Authors: E. Waxman Commets: 10 pages, Invited talk, Neutrino 2002 (Munich) Obsuzhdayutsya istochniki neitrino vysokih energii i neitrinnye teleskopy, sposobnye ih zaregistrirovat'. Ocenki pokazyvayut, chto teleskopy dolzhny byt' Gigatonnymi, chto sootvetstvuet vodyanomu (ledyanomu) kubu s rebrom 1 km. Takie teleskopy i planiruetsya postroit' v nedalekom budushem.
Authors: Neil Gehrels et al Commets: 24 pages, 4 Postscript figures, to appear in The Astrophysical Journal, 2003 March 10, vol. 585 Rassmotreno vozdeistvie vspyshki blizkoi sverhnovoi na ozonovyi sloi Zemli. Avtory pokazali, chto blizkaya (<8 pk) sverhnovaya svoim zhestkim izlucheniem mozhet umen'shit' soderzhanie ozona v 2 raza na srok v neskol'ko let. Proishodit eto iz-za rezkogo uvelicheniya v atmosfere soderzhaniya molekul oksidov azota, kotorye intensivno reagiruyut s ozonom i razrushayut ego. Chastota takih vspyshek ocenivaetsya v 1.5.10-9 let-1.
Authors: O.M.Blaes Commets: in "Accretion Disks, Jets, and High Energy Phenomena in Astrophysics", Proceedings of Session LXXVIII of Les Houches Summer School, Chamonix, France, August 2002, F.Menard, G. Pelletier, G.Henri, V. Beskin, and J. Dalibard eds. (EDP Science: Paris and Springer: Berlin), in preparation Omer Blaes - ochen' izvestnyi astrofizik, a, mozhet byt', uzhe i klassik nauki. Ego nebol'shoi kurs lekcii posvyashen teorii akkrecionnyh diskov s osobym uporom na processy proishodyashie v yarkih rentgenovskih istochnikah, soderzhashih chernye dyry. V kurse rassmotreny: standartnaya model' Shakury-Syunyaeva, formirovanie spektrov izlucheniya, perenos uglovogo momenta v diske, rol' irradiacii (oblucheniya diska central'nym istochnikom) i magnitogidrodinamicheskih processov. Slozhnyh formul kurs ne soderzhit.
Authors: G. R. Filewood Commets: Latex2e document. 3 pages Ochen' korotkaya zametka: esli postoyannaya tonkoi struktury (alpha=e2/hc) menyaetsya so vremenem (sm., naprimer, zdes'), to zakon sohraneniya energii narushaetsya, esli net raspada protonov.
Authors: Martin Elvis and Margarita Karovska Commets: 13 pages, with 3 figures. ApJ Letters, in press (Dec 20, 2002) Avtory predlagayut novyi metod izmereniya rasstoyanii do kvazarov, pohozhii po sheme na "perevernutyi" metod geometricheskih parallaksov (sm. risunok). Peremennoe izluchenie, ishodyashee iz yadra kvazara, otrazhaetsya ot ego bolee vneshnih chastei (tak nazyvaemoi zony shirokih emissionnyh linii (BELR)). Svetimost' etoi zony takzhe menyaetsya, no s nekotoroi zaderzhkoi po sravneniyu s izlucheniem yadra. Eta zaderzhka ravna t=dBELR/c. Esli my izmerim, ugol, pod kotorym zona shirokih emissionnyh linii kvazara vidna s Zemli, to smozhem opredelit' i rasstoyanie do nego. No dlya etogo nuzhno ochen' vysokoe uglovoe razreshenie - 10-5 uglovoi sekundy dlya kvazara s z=2.
Authors: Hideki Asada, Takashi Hamana, Masumi Kasai Commets: 5 pages; accepted for publication in A&A Esli gravitacionnaya linza ne obladaet sfericheskoi simmetriei, no sozdavaemye ei izobrazheniya imeyut dostatochno slozhnyi vid. Zato eta situaciya sushestvenno bolee obshaya, chem sluchai sfericheskoi linzy. I ee okazyvaetsya mozhno opisat' odnim algebraicheskim uravneniem! Interesuyushiesya gravitacionnymi linzami - vpered (no prigotov'tes' k slozhnoi matematike).
Authors: G.S. Bisnovatyi-Kogan Commets: 5 pages, no figures U poverhnosti Zemli sushestvuet nebol'shoe elektricheskoe pole. Zemlya otricatel'no zaryazhena. Vse eto horosho izvestnye fakty. Neizvestno kak eto poluchilos'. V ochen' korotkoi zametke avtor pytaetsya obrisovat' vozmozhnyi mehanizm poyavleniya polya u Zemli i u drugih nebesnyh tel. Poyavlenie polya elektricheskogo svyazyvaetsya s medlennymi variaciyami magnitnogo polya etih ob'ektov.
Authors: Christofer Gunnarsson and Ariel Goobar (Stockholm University) Commets: 9 pages, 16 figures, submitted to A&A Skoplenie galaktik na z~0.3-0.5 mozhet sdelat' sushestvenno yarche raspolozhennuyu za nim sverhnovuyu. Na skol'ko? Kak chasto eto budet proishodit'? V kakom fil'tre ih luchshe nablyudat'? Eti i ryad drugih voprosov rassmotreny v dannoi stat'e.
Authors: Adam Burrows, Todd A. Thompson Commets: 46 pages, including 9 figures. To be published as a Chapter in "Core Collapse of Massive Stars," ed. C.L. Fryer, Kluwer Academic Publ Bol'shaya poluobzornaya rabota na styke nauk. Avtory dayut obzor po vzaimodeistviyu neitrino s veshestvom pri parametrah, sootvetstvuyushih kollapsiruyushemu yadru sverhnovoi. Stat'ya dovol'no special'naya, a potomu vryad li budet interesna ochen' shirokoi publike. Odnako, ona mozhet byt' interesna fizikam, kotorye redko soprikasayutsya s astrofizikoi.
Authors: S. T. Holland (Notre Dame) Commets: 12 pages, 7 figures, uses econfmacros.tex, to appear in the NBSI conference proceedings for Beaming and Jets in Gamma-Ray Bursts V stat'e dan korotkii obzor opticheskih poslesvechenii gamma-vspleskov. Rassmotrena kak klassicheskaya model' faerbola, tak i ryad al'ternativnyh modelei ("pushechnogo yadra", zaderzhannogo vzryva).
Authors: J.E. Grindlay et al. Commets: 14 pages, 8 figures, 2 tables. PDF file only. Presented at SPIE (Aug. 2002) and to appear in Proc. SPIE, vol. 4851 EXIST - Energetic X-ray Imaging Survey Telescope. Eto, na moi vzglyad, ochen' mnogoobeshayushii kosmicheskii proekt. Nesmotrya na to, chto seichas v kosmose nahodyatsya tri otlichnye observatorii, rabotayushie v zhestkom diapazone, nam nuzhna eshe odna - dlya obzora. Chandra i N'yuton - prekrasnye instrumenty dlya izucheniya otdel'nyh istochnikov i glubokih polei. No neobhodimy i obzory novogo pokoleniya. EXIST kak raz dlya etogo i prednaznachen. Sputnik budet davat' obzor neba kazhdye 95 minut (period orbity) v diapazone 10-600 kEv. Uglovoe razreshenie - neskol'ko uglovyh minut. Stoimost' proekta 380 mln.doll.
Authors: Yoel Rephaeli Commets: 15 pages, 3 figures, invited review, proceedings of NATO ASI, Palermo, September 2002 Effekt Syunyaeva-Zel'dovicha (chasto li vy vstrechali abbreviaturu takogo vida - S-Z?) byl priduman v 1980 g. Zaklyuchaetsya on v sleduyushem - skopleniya galaktik okruzheny oblakami ochen' goryachego (108 K) ionizovannogo gaza. On imeet takuyu vysokuyu temperaturu dlya togo, chtoby nahoditsya v ravnovesii v gravitacionnom pole skopleniya. Elektrony, stalkivayas' s nizkochastotnymi fotonami reliktovogo izlucheniya prevrashayut ih v rentgenovskie kvanty (tak nazyvaemyi obratnyi kompton effekt). Takoe rentgenovskoe izluchenie ot skoplenii galaktik nablyudaetsya. No iz-za etogo effekta chislo kvantov, prihodyashih so storony skopleniya umen'shitsya, chto budet proyavlyat'sya kak ponizhenie temperatury reliktovogo izlucheniya. Eto snizhenie temperatury i est' effekt Syunyaeva-Zel'dovicha. Poslednee vremya chislo rabot posvyashennyh issledovaniyu kosmologicheskih parametrov nashei Vselennoi s pomosh'yu effekta Syunyaeva-Zel'dovicha bystro rastet. Okazyvaetsya s ego pomosh'yu mozhno opredelit' ochen' mnogo raznyh kosmologicheskih parametrov. Podrobnosti - v stat'e.
Authors: James M. Cline and J\'er\'emie Vinet Commets: 8 pages, revtex4 Kak bylo ustanovleno v poslednie neskol'ko let (i poka eshe proveryaetsya) nasha Vselennaya rasshiryaetsya s uskoreniem. Schitaetsya, chto takoi hod rasshireniya opredelyaetsya tem, chto vselennaya zapolnena, v osnovnom, temnoi energiei - sredoi s ochen' bol'shim po modulyu otricatel'nym davleniem (ravnym ili pochti ravnym plotnosti energii etoi substancii). No okazyvaetsya vse eto mozhno ob'yasnit' bez takoi materii v ramkah mnogomernoi teorii, esli razmery dopolnitel'nyh kompaktnyh izmerenii menyayutsya so vremenem.
Authors: Michael F. Bode Commets: 12 pages, 8 figures. Invited review in the Proceedings of the Conference "Classical Nova Explosions" (Sitges, May 2002), M. Hernanz and J. Jose eds., published by the American Institute of Physics Journal-ref: AIP Conference Proceedings, Volume 637, Issue 1, pp. 497-508 (2002) Novye ne tak grandiozny kak Sverhnovye. No oni tozhe vspyhivayut, pri etih vspyshkah tozhe vybrasyvaetsya veshestvo. A kak potom evolyucioniruyut ostatki novyh? Ob etom - o teorii i o nablyudeniyah - dannyi obzor.
Authors: I.F. Mirabel et al Commets: Published in Astronomy and Astrophysics. 5 pages, 2 color figures. Color figure and animation can be found at http://www.iafe.uba.ar/astronomia/mirabel/mirabel.html or ftp://ftp.cea.fr/incoming/y2k01/mirabel Eto ta samaya stat'ya o toi samoi chernoi dyre, kotoraya porodila sensaciyu na etoi nedele. O nei uzhe mnogo i po-raznomu napisano: astronet, rambler, cnews. Dannaya sistema yavlyaetsya tesnoi dvoinoi soderzhashei chernuyu dyru. Osnovnoi rezul'tat, poluchennyi v stat'e, - izmerena prostranstvennaya skorost' sistemy i postroena traektoriya ee dvizheniya v Galaktike. Eta skorost' (okolo 100 km/s otnositel'no blizkih k nei zvezd) dostatochno velika, a galakticheskaya orbita imeet zametnyi ekscentrisitet. Oba etih faktora ukazyvayut na to, chto pri rozhdenii chernaya priobrela dopolnitel'nuyu skorost' (etot effekt eshe nazyvayut otdacha ili kik). Eto pervaya chernaya dyra s yavnymi priznakami anizotropii vspyshki sverhnovoi i imenno eto avtory stat'i schitayut samym vazhnym svoim vyvodom.
Authors: A. Morales Commets: 19 pages, 6 figures, Invited Review Talk given at the XXX International Meeting on Fundamental Physics, IMFP2002, February 2002, Jaca, Spain. To appear in Nucl. Phys. B (Proc. Suppl.) Dovol'no emkii obzor po eksperimentam, prizvannym obnaruzhit' chasticy temnoi materii. Rassmatrivayutsya detektory vseh tipov, krome kriogennyh. Poka polozhitel'nyh rezul'tatov net, krome 3-sigma signala v eksperimente DAMA (no tut eshe nado vse proveryat' pereproveryat').
Authors: Shizuka Akiyama, J. Craig Wheeler Commets: 18 pages, 4 figures. To appear in conference proceedings "Core Collapse of Massive Stars," ed. C. L. Fryer, Kluwer Academic Pub V principe yasno, chto magnitnye polya dolzhny igrat' bol'shuyu rol' pri vzryve sverhnovoi. Svyazano eto ne tol'ko (i ne stol'ko) s tem, chto vo vzryvayusheisya zvezde uzhe bylo pole, a eshe i s faktom generacii polya pri kollapse. Odnako, raschety vseh etih processov ochen' slozhny. My i bez ucheta polya kak sleduet poschitat' sverhnovuyu ne mozhem (raschety takih vzryvov po vsei vidimosti yavlyayutsya odnoi iz samyh slozhnyh sovremennyh schetnyh zadach). V stat'e krome svoih original'nyh rezul'tatov avtory dayut dovol'no horoshii obzor sostoyaniya del v dannoi oblasti, privodya okolo 70 ssylok (v osnovnom na detal'nye raschety).
Authors: Abraham Loeb, P.J.E. Peebles Commets: 5 pages, Sumitted to ApJ Ochen' krasivaya vesh' - naiti prostoe ob'yasneniyu nekotoromu horosho izvestnomu (no ne do konca ponyatomu) yavleniyu. Imenno eto avtory i pytayutsya sdelat'. Dispersiya skorostei bol'shih ellipticheskih galaktik 200 km/s (rech' idet o zvezdah v galaktikah). Bolee 400 km/s prakticheski nikogda ne byvaet. Okolo 200 - dovol'no rezkii maksimum. Eto daet sil'noe ogranichenie na massu, zaklyuchennuyu v "svetyasheisya" chasti galaktiki. Avtory ob'yasnyayut eto processom formirovaniya galaktik v standartnoi na segodnyashnii den' modeli s holodnoi temnoi materiei i kosmologicheskim chlenom. Dlya ob'yasneniya vvodyatsya dve razumnye gipotezy. Pervaya: zvezdy obrazuyutsya na z=6 eshe do okonchatel'nogo formirovaniya galaktiki. Vtoraya: raspredelenie temnogo veshestva v novoobrazovavshemsya galo "ne pomnit" takih detalei processa, kak malaya dolya besstolknovitel'nogo "zvezdnogo" veshestva v plotnyh oblastyah bolee rannih galo. Rezul'taty raschetov v sootvetstvii s etimi gipotezami podtverzhdayutsya dannymi Sloanovskogo obzora neba.
Authors: Jozef Klacka Effekt Robertsona-Pointinga (v nashei literature obychno ispol'zuetsya takoi poryadok imen) zaklyuchaetsya v sleduyushem: izluchenie Solnca tormozit tela i chasticy, obrashayushiesya vokrug nego. Esli peresest' na takuyu chasticu, to iz-za aberracii sveta Solnce "okazhetsya" na strogo sboku, a neskol'ko vperedi i davlenie ego izlucheniya budet tormozit' chasticu (t.e. na chasticu budet deistvovat' sila, protivopolozhnaya ee skorosti). A dlya nepodvizhnogo nablyudatelya dvizhushayasya po orbite chastica rasseivaet bol'she fotonov v napravlenii svoego dvizheniya, chem v protivopolozhnom, i teryaet svoi impul's. Pod deistviem takoi sily chastica teryaet uglovoi orbital'nyi moment i energiyu i perehodit na orbitu, raspolozhennuyu blizhe k Solncu (odnako pri etom ee orbital'naya skorost' vozrastaet - po teoreme viriala). Vpervye etot effekt byl predlozhen dlya opisaniya dinamiki pyli vblizi ot Solnca. No okazyvaetsya etot mehanizm mozhet okazat' zametnoe vozdeistvie i na meteoroidy.
Authors: C.L. Carilli Commets: 9 pages, Elsevier Science format: 'Radio galaxies past, present future', ed. Jarvis Posle korotkogo vvedeniya, posvyashennogo rentgenovskim nablyudeniyam blizkih radiogalaktik (Lebed' A i dr.) avtor perehodit k rezul'tatam issledovanii chetyreh dalekih ob'ektov, nablyudavshihsya na sputnike Chandra. Istochniki na bol'shih krasnyh smesheniyah okazyvayutsya nemnogo nepohozhimi na blizkie, chto svyazyvayut s bol'shim vozrastom poslednih. Obsuzhdayutsya razlichnye svoistva rentgenovskogo izlucheniya v dalekih radiogalaktikah, a takzhe ih korrelyacii s radiosvoistvami i prichiny vozniknoveniya takih svyazei.
Authors: Almudena Alonso-Herrero Commets: 4 pages, in `AGN: from Central Engine to Host Galaxy'', ASP Conference Series, in press (Edited by S. Collin, F. Combes and I. Shlosman)
Daetsya korotkii obzor poslednih dannyh po IK nablyudeniyam blizkih
seifertovskih galaktik. Bol'shaya chast' iz nih pokazyvaet tochechnyi istochnik
v yadre. Izluchenie ot etogo istochnika peremenno v 9 sluchayah
iz 14, dlya kotoryh est' povtornye nablyudeniya. Eto govorit o nezvezdnoi
prirode izlucheniya (yasno, chto skoplenie zvezd ne mozhet dat' zametnoi
peremennosti). Avtory takzhe provodyat sravnenie IK svoistv seifertovskih
galaktik s parametrami ih zhestkogo rentgenovskogo izlucheniya i nahodyat vazhnye
korrelyacii, pozvolyayushie ispol'zovat' IK dannye dlya opredeleniya polnoi
svetimosti yadra. Veroyatno, IK svetimost' neposredstvenno svyazana s massoi
central'noi chernoi dyry.
Arhiv statei, voshedshih v predydushie vypuski.
Razdely arhiva (s iyulya 2002 g.): Poleznye astronomicheskie ssylki. Obzornye stat'i v astro-ph s 2001 g. |
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