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21.07.02. astro-ph za 15-19 iyulya 2002 goda: izbrannye stat'i |
V stat'e predstavlen novyi kod dlya parallel'nyh vychislenii v mnogomernoi
radiacionnoi gidrodinamike (RHD). Uchityvaetsya anizotropnyi harakter polei
izlucheniya i neravnovesnye processy. Predstavleny rezul'taty testovyh
vychislenii.
Authors: J. Farihi, E. E. Becklin, B. Zuckerman Comments: 21 pages, 7 figures, 3 tables, accepted to ApJ
Opisyvaetsya otkrytie samogo holodnogo ($T_{\rm eff}=3650$ K) belogo karlika
s gelievoi atmosferoi. Rasstoyanie do ob'ekta neizvestno.
On byl otkryt kak sputnik drugogo belogo karlika (GD248A).
Vozmozhno vozrast GD248B poryadka 8.6 milliardov let, i togda on yavlyaetsya
samym starym (iz izvestnyh) belym karlikom v diske Galaktiki.
Authors: Michael D. Albrow et al. Comments: 31 pages including 11 figures, accepted by ApJ
S pomosh'yu Kosmicheskogo teleskopa vpervye udalos' detal'no izuchit' funkciyu
mass v yadre sharovogo skopleniya. Vnutri yadra obnaruzhen sushestvennyi izbytok
zvezd s massami 0.5-0.8 mass solnca po sravneniyu s ih kolichestvom vne yadra.
Funkciya mass skopleniya vcelom bolee ploskaya chem solpiterovskaya i ne mozhet
byt' predstavlena edinym stepennym zakonom.
Authors: Marek A. Abramowicz, Wlodek Kluzniak, Jean-Pierre Lasota Comments: 4 pages, no figures, submitted to A&A Letters
Pochemu do sih por nikto ne poluchil Nobelevskuyu premiyu za otkrytie chernoi
dyry? Oin iz vozmozhnyh variantov otveta takov: nikto ne dokazal
sushestvovanie gorizonta u kakogo-libo iz t.n. "kandidatov chernye dyry".
Kak mozhno dokazat' nalichie gorizonta? Avtory stat'i schitayut, chto nikak!
Authors: Johan Bleeker, Mariano Mendez Comments: 7 pages, 6 figures, to appear in Proc. Symp. ew Visions of the X-ray Universe in the XMM-Newton and Chandra Era', ESA SP-488 Opisyvaetsya budushii rentgenovskii sputnik XEUS. Osnovnye zadachi apparata: izuchenie prevyh sverhmassivnyh chernyh dyr, izuchenie obrazovaniya gravitacionno svyazannyh sistem iz temnogo veshestva, issledovanie evolyucii obrazovaniya tyazhelyh elementov, izuchenie mezhgaoakticheskogo veshestva.
Rentgenovskii teleskop budet imet' ochen' bol'shuyu sobirayushuyu ploshad',
a takzhe otlichnoe spektral'noe i uglovoe razreshenie. Poslednee budet
dostignuto za schet gigantskogo fokusnogo rasstoyaniya: 50 metrov!
Dlya etogo sputnik budet sdelan iz dvuh nesvyazannyh mezhdu soboi chastei.
Author: L. Guzzo Comments: 13 pages LateX, style files included, 4 PS figures. Review to appear in "DARK2002", 4th Heidelberg Int. Conference on Dark Matter in Astro- and Particle Physics, (Cape Town, February 2002), H.-V. Klapdor-Kleingrothaus & R. Viollier eds., Springer
Obsuzhdayutsya noveishie dannye po krupnomasshtabnoi strukture, poluchennye
v obzorah galaktik i ih skoplenii (2dF, REFLEX).
Rezul'taty horosho opisyvayutsya v ramkah modeli s nizkoi plotnost'yu
materii ($\Omega_M\simeq 0.3$).
Author: David Langlois Comments: Invited review talk given at the 11th Workshop on General Relativity and Gravitation, Waseda University, Tokyo, Japan (Jan 2002); 14 pages; Latex; one figure
V obzore opisyvayutsya rezul'taty issledovanii v oblasti brannoi kosmologii
(sm. takzhe stat'yu "Transdimensional physics and inflation"
hep-ph/0207145).
Author: S.E. Deustua et al. Comments: Invited review for the Symposium`The Future of Particle Physics'', Snowmass 2001. 16 pages, 4 jpeg figures, 3 postscript figures, uses revtex4
Daetsya obzor sovremennyh dannyh po osnovnym kosmologicheskim parametram,
temnoi energii i krupnomasshtabnoi strukture. V nachale obsuzhdayutsya
kosmologicheskie parametry: chto eto takoe i kak oni izmeryayutsya. Zatem
obsuzhdaetsya temnaya energiya: pochemu my uvereny v ee sushestvovanii,
kakova vozmozhnaya priroda etoi energii i t.d. Nakonec obsuzhdaetsya
krupnomasshtabnaya struktura: kak ona obrazuetsya, i kak sovremennye nablyudeniya
krupnomasshtabnoi struktury mogut nakladyvat' ogranicheniya na kosmologicheskie
parametry.
Author: Michael S. Turner Comments: 10 pages LaTeX (newpasp.sty). To appear in "Hubble's Science Legacy: Future Optical-Ultraviolet Astronomy from Space", eds. K.R. Sembach, J.C. Blades, G.D. Illingworth, & R.C. Kennicutt, ASP Conference Series Seichas pochti ustoyalas' standartnaya kartina temnoi materii i energii vo Vselennoi (3.5% +/- 1% barionov, 29% +/- 4% holodnoi temnoi materii, 66% +/- 6% temnoi energii i nemnogo neitrino). Teper', polagaet avtor stat'i, nado skoncentrirovat'sya na sleduyushih voprosah: (1) V kakoi forme nahodyatsya temnye bariony? (2) Iz chego (iz kakih chastic) sostoit holodnaya temnaya materiya? (3) Kakova priroda temnoi energii?
Otvetov na eti voprosy net, chto i obsuzhdaetsya v obzore.
Author: James E. Taylor, Joseph Silk Comments: 8 pages, 6 figures; submitted to MNRAS Sovremennye dannye ukazyvayut na to, chto znachitel'naya chast' temnogo veshestva yavlyaetsya t.n. "holodnoi" temnoi materiei. Eto mogut byt' slabovzaimodeistvuyushie massivnye chasticy (WIMP). Takaya temnaya materiya dolzhna nahodit'sya v galo galaktik. Odnako, raspredelenie veshestva v galo mozhet byt' ne odnorodnym, a komkovatym. Eto mozhet byt' vazhno pri raschete nablyudaemyh effektov vzaimodeistviya chastic temnoi materii, v pervuyu ochered' ih annigilyacii.
Avtory raschityvayut (na baze minimal'nyh SUSY modelei) potok gamma-kvantov
ot galo. Okazyvaetsya, chto sovremennyi potok kvantov, rodivshihsya posle
annigilyacii chastic temnoi materii, mozhet byt' na poryadok vyshe, chem schitalos'
ranee. Obsuzhdaetsya vozmozhnost' nablyudeniya etogo izlucheniya na budushih
apparatah.
Author: Donald F. Figer Comments: IAU 212 V oblasti galakticheskogo centra sosredotocheno 10% massivnyh zvezd Galaktiki. Bol'shaya chast' iz etih massivnyh zvezd nahodyatsya v treh skopleniyah, obrazovavshihsya v poslednie 5 millionov let (eti skopleniya raspolozheny menee chem v 30 pk ot galakticheskogo centra). Est' osnovaniya polagat', chto
stol' burnoe zvezdoobrazovanie proishodilo v central'noi chasti Mlechnogo puti
i ran'she. V stat'e avtor issleduet massivnoe zvezdnoe naselenie centra
Galaktiki, i vyskazyvaet argumenty v pol'zu bolee-menee nepreryvnogo
zvezdoobrazovaniya v etoi oblasti.
Author: Martin Loidl Comments: 9 pages, 4 figures, to appear in Proceedings of the XXXVIIth Rencontres de Moriond Krome izvestnogo protivorechiya mezhdu fizikami i lirikami, est' zametnaya raznica mezhdu astrofizikami i fizikami. Naprimer, esli astrofiziki uvereny v sushestvovanii temnoi materii i issleduyut ee global'nye svoistva i sledstviya iz etih svoistv vytekayushie, to fizikam interesno "poimat' neitrino za borodu": obnaruzhit' chasticy temnoi materii v laboratorii.
V stat'e avtor opisyvaet popytki zaregistrirovat' slabovzaimodeistvuyushie
massivnye chasticy (WIMP). Poka polozhitel'nogo rezul'tata net, sootvetstvenno
predstavleny verhnie predely.
Author: Piet Hut et al. Comments: workshop summary, submitted to New Astronomy, 34 pages, 3 figures
Avtory summiruyut rezul'taty, predstavlennye na konferencii MODEST-1
(MOdeling DEnse STellar systems). Ideya sostoit v rasshirenii tradicionnyh
modelei populyacionnogo sinteza za schet vklyucheniya effektov dinamicheskogo
vzaimodeistviya (vzaimodeistvie otdel'nyh zvezd, dvoinyh i kratnyh sistem).
Cel'yu yavlyaetsya provedenie vychislenii, kotorye vklyuchali by v sebya i
zvezdnuyu evolyuciyu, i zvezdnuyu dinamiku, i zvezdnuyu gidrodinamiku.
S etoi cel'yu na konferenciyu byli priglasheny specialisty, rabotayushte vo vseh
etih oblastyah.
Author: Tiziana Di Matteo, Rosalba Perna, Ramesh Narayan Comments: 23 pages including 6 figures, accepted by ApJ Seichas mnogie modeli gamma-vspleskov vklyuchayut v sebya, v kachestve mehanizma vzryva, akkreciyu bol'shogo kolichestva veshestva (neskol'ko mass solnca s tempom desyatye doli massy solnca v sekundu) na chernuyu dyru. Popham et al. i Narayan et al. pokazali, chto pri tempe akkrecii bol'she 0.1 massy solnca v sekundu ohlazhdenie v osnovnom obespechivaetsya neitrino. V dannoi rabote avtory utochnyayut eti vychisleniya, vklyuchaya processy perenosa neitrino.
Pokazano, chto potok stanovitsya opticheski tolstym dlya neitrino vnutri oblasti
6-40 shvarcshil'dovskih radiusov (temp akkrecii 0.1-10 mass solnca v sekundu).
Dlya tempa bol'she 1 massy solnca v sekundu neitrino zahvatyvayutsya potokom i
stanovitsya vazhnym advekcionnoe ohlazhdenie. Vazhnoi okazyvaetsya annigilyaciya
neitrino.
Author: W. Coburn et al. Comments: 36 Pages, 9 Figures, 9 Tables, ApJ in press Odnim iz vazhneishii parametrov neitronnyh zvezd yavlyaetsya velichina ih magnitnogo polya. Dlya radiopul'sarov pole opredelyaetsya v osnovnom po tempu zamedleniya v predpolozhenii magnito-dipol'nogo izlucheniya. Dlya rentgenovskih pul'sarov (o kotoryh i idet rech' v stat'e) mozhno ispol'zovat' kak dannye po uskoreniyu i zamedleniyu, tak i pryamye spektral'nye dannye. Togda po ciklotronnoi linii mozhno opredelit' velichinu polya.
V stat'e avtory ispol'zuyut dannye, poluchennye na sputnike RXTE, dlya 10
rentgenovskih pul'sarov. Krome dannyh po magnitnym polyam avtory issledovali
korrelyacii mezhdu razlichnymi parametrami, naprimer izuchalos' vlichnie
magnitnogo polya na harakteristkii rentgenovskogo izlucheniya.
Author: P. J. E. Peebles, Bharat Ratra Comments:
Temnaya energiya ... V obzore podrobno izlagayutsya osnovnye fizicheskie ponyatiya i
astronomicheskie dannye, svyazannye s etim fenomenom; daetsya istoricheskii
ocherk razvitiya sootvetstvuyushih idei; opisyvayutsya sovremennye nablyudeniyai
obsuzhdayutsya budushie. Avtory privodyat svoi kriticheskie kommentarii po povodu
fundamental'nyh teoreticheskih voprosov, svyazannyh s temnoi energiei.
Author: Pasquale Blasi Comments: 15 pages, Invited Review Talk, to appear in the Proc. of "Matter and Energy in Clusters of Galaxies", April 23-27 2002, Taiwan Interesnyi obzor, nachinayushiisya s samyh azov. Gamma-izluchenie ot soplenii galaktik poka ne zaregistrirovano. Odnako, est' vse osnovaniya polagat', chto budushie kosmicheskie i/ili nazemnye teleskopy smogut ego otkryt'. Osnovaniya sleduyut iz nablyudenii v rentgenovskom, UF i radio diapazonah. Vse eti dannye govoryat o nalichie neteplovyh chastic v skopleniyah galaktik.
V obzore podrobno obsuzhdaetsya vozmozhnoe proishozhdenie neteplovyh chatsic,
metody uskoreniya i t.p.
Author: Samir Salim, Andrew Gould Comments: 5 pages, full catalog available at http://www.astronomy.ohio-state.edu/~gould/NLTT/
NLTT - New Luyten Catalogue of Stars With Proper Motions Larger than
Two Tenths of an Arcsecond.
T.o. eto katalog zvezd s bol'shimi sobstvennymi dvizheniyami.
V stat'e opisyvaetsya novaya versiya kataloga, osnovannaya na uluchshennyh
astrometricheskih dannyh i na novyh fotometricheskih izmereniyah v optike i IK.
Author: P. Grandclement, V. Kalogera, A. Vecchio Comments: Submitted to Phys. Rev. D V stat'e rassmatrivaetsya interesnaya fizicheskaya zadacha: kakovo vliyanie precessii orbity slivayusheisya dvoinoi sistemy (za schet relyativistskogo spin-orbital'nogo vzaimodeistviya) na gravitacionno-volnovoi signal. Gravitacionno-volnovaya astronomiya zhdet epohi buri i natiska: zapuska VIRGO i LIGO. Poka zhe natisk idet na "nevidimom", t.e. teoreticheskom, fronte (sm. nedavnii obzor Grishuka i dr. v UFN 2001 nomer 1). Odnim iz vazhnyh rezul'tatov avtorov yavlyaetsya umen'shenie (na poryadok!) tempa registracii sliyanii dlya sistem s bol'shim otnosheniem mass, esli ne uchityvat' effektov precessii v raschete formu signala (po vsei vidimosti eto dolzhno byt' vazhno dlya sistem neitronnaya zvezda plyus chernaya dyra, kotorye, po raschetam Lipunova i dr. mogut dominirovat' sredi pervyh zaregistrirovannyh sobytii). Izuchaetsya diapazon parametrov dvoinyh sistem, gde etot effekt sushestvenen.
Author: Olivier Dore et al. Comments: 4 pages, 3 figures, submitted to ApJ Letters Etu stat'yu ya vklyuchil v svyazi s diskussiei na Forume po MOND (modificirovannoi n'yutonovskoi dinamike). Seichas astronomy umeyut neploho opredelyat' gravitacionnyi potencial dlya samyh raznyh sistem. Temnaya materiya uspeshno vse eto ob'yasnyaet, chego ne skazhesh' o MOND. V opisyvaemoi stat'e avtory predlagayut analiticheskii metod opredeleniya potenciala na bol'shih rasstoyaniyah (bol'she razmera skoplenii galaktik) po pekulyarnym skorostyam skoplenii, a takzhe po slabomu mikrolinzirovaniyu. Pekulyarnye skorosti skoplenii galaktik mozhno opredelyat' s tochnost'yu poryadka 100 km/s po effektu Syunyaeva-Zel'dovicha. V etom sluchae izmeryaemaya skorost' svyazana s radial'nym dvizheniem otnositel'no reliktovogo fona. Etot metod horosh dlya otnositel'no bol'shih krasnyh smeshenii (0.2 i bol'she). Dlya bolee blizkih skoplenii mozhno opredelyat' rasstoyanie, a zatem vychitat' iz skorosti t.n. habblovskii potok. Izmereniya, svyazannye s linzirovaniem, dopolnyayut etu kartinu, t.k. svyazany ne s radial'nymi gradientami gravitacionnogo potenciala, a s tangencial'nymi. Avtory podrobno obsuzhdayut vozmozhnye istochniki pogreshnostei metoda.
Author: S. G.Korzennik et al. Comments: 55 pages, 35 figures -- low resolution figures to allow upload to astro-ph High-resolution version at http://www-sgk.harvard.edu:1080/~sylvain/preprints/. Manuscript submitted to ApJ
Gelioseismologiya
seichas yavlyaetsya odnim iz osnovnyh istochnikov informacii o nedrah Solnca.
V stat'e avtory predstavlyayut metody i
rezul'taty obrabotki nablyudenii na sputnike
SOHO (Solar and Heliospheric Observatory), poluchennye v period s 1996 po
1999 gg., a takzhe podrobno obsuzhdayut poluchennye rezul'taty i metodiku.
Voobshe rabota v osnovnom posvyashena imenno obrabotke dannyh, a potomu
neskol'ko suhovata.
Author: Jeremy Kepner, Stan Ahalt Comments: submitted to Supercomputing 2002; 10 pages; 8 figures MatlabMPI nikak ne svyazan s institutami Maksa Planka, eto Message Passing Interface (MPI) standart. On pozvolyaet ispol'zovat' MatLab na mnogoprocessornym komp'yuterah. Avtory podrobno opisyvayut testy, provedennye na raznyh platformah (MatlabMPI idet vezde, gde idet sam MatLab). Obeshayut, chto ves' soft budet dostupen.
Chestno govorya, ya tol'ko ne ponyal, pochemu rebyata polozhili stat'yu v astro-ph.
;)
Author: G. Fiorentini, B. Ricci Comments: 9 pages with 3 ps figures included, to appear on the Proc. of ESO-CERN-ESA Symposium on Astronomy, Cosmology and Fundamental Physics, Garching bei Munchen, Germany March 4-7, 2002 Daetsya obzor nablyudenii po proverke postoyannosti postoyannoi tonkoi struktury. Obsuzhdayutsya novye vozmozhnye istochniki dannyh.
Napomnyu, chto u nas v strane etoi tematikoi davno i uspeshno
zanimaetsya
gruppa
Varshalovicha v FTI im. Ioffe v Peterburge.
Author: Axel Brandenburg, Wolfgang Dobler Comments: 6 pages, 4 figures, Astron Nachr (accepted; proceedings of "1st Potsdam Thinkshop on Sunspots and Starspots", Potsdam, Germany, May 2002) 19 iyulya poyavilos' srazu tri stat'i Aleksa Brandenburga, posvyashennye problemam dinamo mehanizmov na Sonce i zvezdah (astro-ph/0207392-4). V obsuzhdaemoi rabote na 6 stranicah daetsya korotkii obzor nedavnih dostizhenii v etoi oblasti.
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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