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08.11.02. astro-ph za 04 oktyabrya - 08 noyabrya 2002 goda: izbrannye stat'i |
Na 76-metrovom radioteleskope im.Lovella observatorii Dzhordell Benk regulyarno provodyatsya nablyudeniya bolee chem 500 radiopul'sarov. Bolee chem dlya 300 pul'sarov ryady nablyudenii dlyatsya bolee 6 let (samyi dolgii - 34 goda). Po eti dannym modno opredelit' period pul'sara i ego izmenenie, a takzhe ego polozhenie na nebe s ochen' vysokoi tochnost'yu. V stat'e izlozhena tehnika obrabotki taiminga pul'sarov (momentov prihoda impul'sov k nablyudatelyu). Predlozhen novyi podhod, pozvolyayushii po vremennoi informacii pouchit' sobstvennye dvizheniya pul'sarov. Etim metodom vpervye opredeleny znacheniya sobstvennyh dvizhenii dlya 111 pul'sarov (no sami eti znacheniya v stat'e ne privedeny).
Authors: I. H. Stairs et al. Comments: 4 pages; to appear in proceedings of "Radio Pulsars," eds. M. Bailes, D. J. Nice, S. E. Thorsett Kak mozhno tochno dokazat', chto vy otkryli imenno chernuyu dyru? Akkreciruyushie sistemy ne dayut takoi odnoznachnosti (hotya my, na samom dele, i uvereny v sushestvovanii chernyh dyr v tesnyh dvoinyh i v yadrah galaktik). Gravitacionnye detektory (LIGO, VIRGO) eshe ne zarabotali. Mikrolinzirovanie? Vozmozhno, no tut vy ne mozhete otozhdestvit' ob'ekt posle nablyudenii. Vladimir Mihailovich Lipunov uzhe davno propogandiroval ideyu o tom, chto luchshii sposob - eto naiti dvoinuyu sistemu radiopul'sar + chernaya dyra. Po raschetam s pomosh'yu "Mashiny Scenariev" poluchalos', chto takie sistemy dolzhny vstrechat'sya v kolichestve odna shtuka na 1000 radiopul'sarov. Ne tak uzh i malo! My znaem seichas bol'she 1000 pul'sarov. No otkrytie takoi dvoinoi - delo sluchaya. Odnako, ideya pronikla v massy, i potomu radioastronomy ne zabyvayut o tom, chto u nih est' shans poluchit' nobelevskuyu premiyu (navernyaka, za otkrytie takoi sistemy, tochnee za dokazatel'stvo sushestvovaniya chernyh dyr, premiyu mogut dat'). Potomu, otkrytyi v 1997 g. pul'sar 1740-3052 privlekal vnimanie. Delo v tom, chto u nego yavno est' massivnyi kompan'on, no nablyudayushayasya v napravlenii etogo pul'sara zvezdochka po svoim svoistvam emu " ne para". Potomu v svoei stat'e 2001 g. Sterz i dr. predpolozhili, chto vtorym kompan'onom mozhet byt' chernaya dyra. Drugaya vozmozhnost', kotoraya takzhe byla ukazana avtorami - eto massivnaya V-zvezda (kstati, takie pary uzhe obnaruzhivalis', i ih tozhe zapodozrivali v "chernodyrnosti"). V obsuzhdaemoi zametke avtory vse-taki pokazyvayut, chto eto i v samom dele V-zvezda, a ne chernaya dyra. Avtory obnaruzhili sushestvennoe uvelichenie mery dispersii, chto estestvennym obrazom ob'yasnyaetsya vetrom ot massivnoi V-zvezdy. Zhal', znachit otkrytiya radiopul'sara v pare s chernoi dyroi nado eshe zhdat'.... No avtoram dolzhno byt' eshe bolee pechal'no - oni-to mogli rasschityvat' na Nobelevskuyu premiyu :)
Authors: D. R. Lewis et al. Comments: 4 pages, 2 figures, to appear in proceedings of "Radio Pulsars," Chania, Crete, August 2002 (ASP conference series) V Avstralii, na gore Udovol'stviya (Mt. Pleasant) s pomosh'yu 26-metrovoi antenny provoditsya regulyarnyi monitoring 10 molodyh radiopul'sarov s cel'yu obnaruzheniya sboev perioda (glitchei). Esli udast'sya obnaruzhit' takoi sboi, to srazu zhe nachnutsya nablyudeniya posleglitchevogo progreva v drugih diapazonah (v pervuyu ochered' - v rentgenovskom). Krome togo, uzhe 21 god idut nablyudeniya pul'sara Vela na 14-metrovoi antenne (18 chasov v den'!), a takzhe pul'sara PSR B1641-45. Vela daet sboi primerno kazhdye 1000 dnei. U etogo istochnika obnaruzheno uzhe nemalo glitchei. Takie nablyudeniya neobhodimy potomu, chto sboi perioda i ego posleduyushee vosstanovlenie - eto unikal'naya vozmozhnost' uznat' chto-nibud' o "vnutrennostyah" neitronnyh zvezd.
Authors: Gerry Gilmore Commets: review for Cozumel conference, Galaxy Evolution: Theory and Observations eds V Avila-Reese, C Firmani, C Frenk & C Allen Rev Mex AA 10pp, 8.ps and 4 .jpg figures "Zvezdnye populyacii - okamenevshaya zapis' evolyucii Galaktiki". Stat'ya predstavlyaet soboi dovol'no prostoi i neglubokii obzor voprosov formirovaniya nashei Galaktiki i Mestnoi gruppy. Naibol'shee vnimanie avtory udelyayut samym starym podsistemam Mlechnogo puti - baldzhu, tolstomu disku i galo. Izuchenie etih processov pozvolit pravil'no ponyat' to, chto my vidim v galaktikah na bol'shih z.
Authors: Roberto Soria (MSSL/UCL) Commets: to appear in the Proceedings of "High Energy Processes and Phenomena in Astrophysics", IAU Symposium No.214, Suzhou (China), 5-10 August 2002; eds.: Xiang-dong Li, Zhen-ru Wang, Virginia Trimble. Higher resolution figures available at http://www.mssl.ucl.ac.uk/~rs1/iau214 Rentgenovskie issledovaniya blizkih galaktik s moshnym zvezdoobrazovaniem pozvolyayut issledovat' temperaturu i prostranstvennoe raspredelenie goryachego gaza, opredelit' chislo diskretnyh istochnikov raznyh tipov (massivnye i malo-massivnye dvoinye, ostatki sverhnovyh, sverhmyagkie i sverhyarkie istochniki). Vse eti vozmozhnosti pokazany na primere galaktiki M83. Vtoraya polovina stat'i posvyashena ul'trayarkim istochnikam. V nashei Galaktike takih istochnikov net, no v sosednih oni obnaruzheny. Priroda etih ob'ektov do konca ne izvestna, skoree vsego eto mozhet byt' chernaya dyra promezhutochnoi massy (~100Mo) v tesnoi dvoinoi sisteme,
Authors: F. Quevedo Commets: 75 pages, 29 figures, lectures delivered in January 2002 at the third RTN school on ``The Quantum Structure of Spacetime and the Geometric Nature of Fundamental Interactions'', Utrecht Report-no: DAMTP-2002-128 Polnocennyi kurs lekcii (75 stranic) otrazhayushii sovremennoe sostoyanie strunnoi/brannoi kosmologii. Sudya po prostym formulam eto dostatochno populyarnyi vvodnyi kurs. No voprosy, svyazannye s inflyaciei, s D-branami i okolo 10 razlichnyh scenariev v nem rassmotreny.
Authors: A. Lazarian, Jungyeon Cho, Huirong Yan Commets: 27 pages, 7 figures, to be published in "Recent Reaserch Developments in Astrophyics" (Research Signpost) Po mneniyu avtorov v poslednie godu byl dostignut znachitel'nyi progress v ponimanii svoistv MGD turbulentnosti. Avtory dayut obzor etih dostizhenii i obsuzhdayut nekotorye astrofizicheskie prilozheniya.
Authors: J.V. Narlikar et al. Comments: 27 pages, including 5 figures; to appear in Astrophys. J Neodnorodnosti reliktovogo fona obsuzhdayutsya v ramkah staroi dobroi modeli kvazistacionarnoi Vselennoi Hoila-Berbidzha-Narlikara. Tochnee eto model' 90-h godov, no na baze staroi 48 goda (dlya oznakomleniya rekomenduyu posmotret' dostupnuyu on-lain stat'yu 1994 g., posvyashennuyu kvazistacionarnoi modeli). Otmechu, chto taki model' eta nezhiznesposobna, no, kak izvestno, idei umirayut vmeste s .... V svyazi s etim nel'zya ne upomyanut' i svezhuyu stat'yu Berbidzhei s Arpom. Otmetim takzhe drugoi (bolee realistichnyi) podhod v kritike standartnoi kosmologicheskoi modeli.
Authors: Eric D. Feigelson et al. Comments: 51 pages, 8 figures. To appear in the Astrophysical Journal Maloizvestnyi fakt: molodye (v tom chisle obrazuyushiesya) zvezdy yavlyayutsya istochnikami rentgenovskih luchei. V stat'e na bol'shom nablyudatel'nom materiale (bolee 1000 istochnikov) razbiraetsya kak takoe izluchenie obrazuetsya, i kakie ogranicheniya na modeli my mozhem sdelat'.
Authors: Sara Lucatello et al. Comments: 55 pages, 17 color figures included; Accepted for publication in the February 2003 issue of the Astronomical Journal
"Navstrechu obsuzhdeniyu himsostava zvezd na forume Scientific.Ru" Ochen' poleznym mozhet v etoi svyazi mozhet okazat'sya sovsem svezhii obzor po obiliyu elementov v raznyh blizkih galaktikah.
Authors: N. Andersson Commets: invited review article for Class Quantum Grav., 47 pages, 16 ps figures V obzore rech' idet o neustoichivostyah v neitronnyh zvezdah (v pervuyu ochererd' v molodyh), privodyashih k izlucheniyu gravitacionnyh voln. V principe takie volny (esli povezet) mozhno zaregistrirovat' s pomosh'yu stroyashihsya interferometrov.
Authors: A. Heger et al. Commets: 10 pages, 5 figues, to appear in Proc. "From Twilight to Highlight - The Physics of Supernovae" ESO/MPA/MPE Workshop Garching July 29 - 31, 2002 Opisyvaetsya evolyuciya massivnyh zvezd na raznyh stadiyah zhizni Vselennoi. V tom chisle t.n. zvezdy populyacii III (Pop III). Eto samye pervye zvezdy, sostoyashie iz vodoroda i geliya (pervichnyi himsostav). Obsuzhdayutsya vzryvy razlichnyh massivnyh zvezd i ostatki etih vzryvov dlya razlichnyh metallichnostei.
Authors: S. E. Woosley et al. Commets: 10 pages, 2 figures, to appear in Proc. "From Twilight to Highlight - The Physics of Supernovae" ESO/MPA/MPE Workshop, Garching July 29 - 31 Daetsya obzor sovremennogo sostoyaniya del v izuchenii svyazi gamma-vspleskov so sverhnovymi zvezdami, a takzhe rol' dzhetov (strui) v etih processah. Rassmatrivayutsya samye raznye modeli, gde glavnuyu rol' igraet vrashenie, akkerciya na chernuyu dyru ili sverhsil'noe magnitnoe pole. Po mneniyu avtorov 99% sverhnovyh s gamma-vspleskami nikak ne svyazany, t.k. dlya gamma-vspleskov neobhodimy dovol'no ekzoticheskie usloviya.
Authors: Roger W. Romani Commets: 7 pages, 3 figures, to appear in proceedings of the conference "Radio Pulsars" held in Chania, Crete, Sept 2002 V zametke rech' v pervuyu ochered' idet ne o teplovom, a o magnitosfernom izluchenii molodyh pul'sarov. Eto pul'siruyushee, t.e. napravlennoe izluchenie - sushestvuet puchok. Avtor pytaetsya skonstruirovat' nekuyu "edinuyu" model' (podobno opisaniyu aktivnyh yader galaktik), gde v zavisimosti ot orientacii osei pul'sara otnositel'no lucha zreniya poluchalis' by raznye spektry i krivye bleska.
Authors: B.K. Lubsandorzhiev, P.G. Pokhil, R.V. Vasiliev, Y.E. Vyatchin Commets: 4 pages, 5 figures, talk presented at RICH2002, to be published in NIMA Kakih tol'ko pobochnyh rezul'tatov ne mogut dat' fundamental'nye issledovaniya. V ozere Baikal provoditsya eksperiment po registracii neitrino sverhvysokih energii. Neitrino vybivaet iz molekul vody elektron. On dvizhetsya s relyativistskoi skorost'yu, kotoraya, v svoyu ochered', vyshe skorosti rasprostraneniya sveta v vode. V rezul'tate chego elektron, kak zaryazhennaya chastica, ispuskaet cherenkovskoe izluchenie. Eto sinii svet, kotory v vode ispuskaetsya v osnovnom pod uglom ~42o k napravleniyu dvizheniya elektronov. Takaya vspyshka sveta fiksiruetsya neskol'kimi fotoumnozhitelyami (special'noi konstrukcii, ved' oni raspolozheny gluboko pod vodoi), chto pozvolyaet opredelit' energiyu i napravlenie dvizheniya porodivshego ee neitrino. V svoe vremya eksperimentatoram udalos' izuchit' sezonnye izmereniya prozrachnosti vody (eto parametr kriticheski vazhnyi dlya cherenkovskih detektorov) s tochnost'yu nikogda ranee ne dostigavsheisya ni biologami, ni geofizikami. Teper' udalos' izmerit' skorost' sveta v vode, prichem srazu na neskol'kih dlinah voln: na 370 nm c=2.148.108 m/s, na 470 nm c=2.193.108 m/s, na 520 nm c=2.206.108 m/s (izmereniya velis' na glubine 1100 m ot poverhnosti ozera). Chto eshe dast nam etot eksperiment?
Authors: R. Della Ceca Commets: On the behalf of the XMM-Newton Survey Science Centre (SSC) CONSORTIUM, 4 pages, 1 figure, Presented at AGN05: Inflows, Outflows and Reprocessing around black holes, Como (Italy), 11-14 June 2002. To appear in the Proceedings Segodnya v spiske yarkih sluchainyh (ne povtoryayushihsya) istochnikov rentgenovskoi observatorii XMM-N'yuton nemnogim bolee 1000 istochnikov s potokami vyshe Fx>10-13erg/sm2/c na vysokih (|b|>20o) galakticheskih shirotah. Iz nih otozhdestvleny tol'ko chut' bolee 200 ob'ektov. Vse oni v optike imeyut velichinu R~21 i slabee. Sredi etih ob'ektov vstrechayutsya galaktiki s aktivnymi yadrami, skopleniya galaktik, normal'nye galaktiki, lacertidy i zvezdy.
Authors: I.F. Mirabel Commets: 10 pages, 2 figures. Invited review at the IAU Symposium No.214: High Energy Processes and Phenomena in Astrophysics Mikrokvazary - eto tesnye dvoinye sistemy s akkreciruyushimi kompaktnymi ob'ektami (po vsei vidimosti s chernymi dyrami), gde krome obychnoi v takih sluchayah aktivnosti takzhe nablyudayutsya struinye vybrosy (dzhety). Avtor (kstati, termin "mikrokvazar" prinadlezhit emu) posledovatel'no provodit analogii mezhdu mikrokvazarami i razlichnymi istochnikami vysokoenergichnogo izlucheniya. Obzor ochen' dostupen (ni odnoi formuly), i ego vsyacheski mozhno rekomendovat' vsem, vladeyushim angliiskim yazykom i interesuyushimsya sovremennoi astronomiei.
Authors: D.G. Yakovlev, K.P. Levenfish Comments: 12 pages, 1 figure, uses sc3conf.sty, to appear in Proc. Third Sakharov Conference on Physics, A.Semikhatov et al. (eds.), Scientific World, Moscow (2003) V otlichii ot termoyadernogo goreniya (nevysokaya plotnost', vysokie temperatury) piknoyadernoe gorenie proishodit pri vysokoi plotnosti i otnositel'no nizkih temperaturah (t.e. v ramkah dannoi zadachi temperaturu mozhno polozhit' ravnoi 0, no eto ne znachit, chto my imeem delo s absolyutnym nulem, napomnim, chto v nekotoryh zadachah vnutrennie chasti neitronnyh zvezd mozhno schitat' nahodyashimisya pri nulevoi temperature, naprimer, yadro neitronnoi zvezdy mozhet byt' sverhtekuchim, no real'naya temperatura tam. po zemnym merkam, ochen' vysokaya). Takie usloviya realizuyutsya, naprimer, v kore akkreciruyushei neitronnoi zvezdy. Veshestvo opuskaetsya v oblast' bolee vysokoi plotnosti pod davleniem svezhevypavshego veshestva. Rezhim piknoyadernogo goreniya mozhet byt' vazhen dlya zvezd, akkreciya na kotorye nepostoyanna. Togda vo vremya nulevoi akkrecii zvezda budet prodolzhat' svetit' za schet piknoyadernyh reakcii. Seichas eto vpolne nablyudaemaya vesh'.
Authors: Penny D. Sackett et al. Comments: 5 pages, 3 figures. (To appear in) Bioastronomy 2002: Life Among the Stars, IAU Symposium 213, eds. R. Norris, C. Oliver and F. Stootman, ASP, 2003 Mnogie ekzoplanety otkryty po doplerovskomu smesheniyu linii v spektre zvezd, vokrug kotoryh planety i vrashayutsya. Odnako, ne vse planety mozhno otkryt' takim sposobom. K schast'yu, sushestvuyut i drugie. Naprimer, eto mikrolinzirovanie, a takzhe fotometricheskaya registraciya prohozhdeniya planety po disku zvezdy. V korotkoi zametke avtory rasskazyvayut o pervyh rezul'tatah i dal'neishih planah bol'shogo proekta, kotoryi ekspluatiruet eti dva metoda. Poka iz rezul'tatov est' tol'ko ogranicheniya na kolichestvo gazovyh gigantov na orbitah s poluos'yu 1-7 a.e.
Authors: Jose A. Font, Frederic Daigne Comments: 12 pages, 3 figures, accepted for publication in ApJL Issleduetsya ustoichivost' diskov dlya parametrov, primenyaemyh pri modelirovanii kosmicheskih gamma-vspleskov. T.e. eto ne tesnaya dvoinaya sistema, a bystrovrashayushayasya chernaya dyra s tolstym torom vokrug. Uchteny effekty OTO. Avtory nahodyat neustoichivost' na dinamicheskom masshtabe vremeni.
Authors: Elena Pian Commets: 10 pages, 8 Postscript figures, Invited Talk at the International Workshop "High Energy Blazar Astronomy" Blazary - eto vid aktivnyh galakticheskih yader. Oni ochen' aktivny v zhestkih diapazonah (rentgen, gamma). Vremennaya i spektral'naya chuvstvitel'nost' sputnikov novogo pokoleniya ochen' vysoka, chto pozvolilo poluchit' mnogo interesnyh rezul'tatov po blazaram, o chem i idet rech' v dannom obzore.
Authors: Jong-Hak Woo, C. Megan Urry Comments: 5 pages with 1 figure, accepted for publication in ApJL
Ne chernoi dyroi edinoi!
Authors: Vasily Belokurov, N. Wyn Evans, Yann Le Du Comments: 14 pages, 8 figures, submitted to MNRAS Interesnaya rabota. Avtory pytayutsya primenit' prostye neironnye seti dlya analiza mnozhestva krivyh bleska, poluchaemyh v bol'shih obzorah (naprimer, obzorah po poisku mikrolinzirovaniya).
Authors: J. Cottam et al. Comments: Published in Nature (Nov 7, 2002) My ne znaem tochnoe uravnenie sostoyaniya veshestva v neitronnyh zvezdah. Zdes' osobenno zametno skazyvaetsya "nelaboratornost'" astronomicheskih ob'ektov. Dlya neitronnyh zvezd my ne imeem ni odnogo tochnogo odnovremennogo izmereniya massy i radiusa (est' tochnye izmereniya mass, no v etih sluchayah radius neizvesten). Horoshii sposob poluchit' takie dannye - nablyudenie krasnogo gravitacionnogo smesheniya spektral'nyh linii. I ne zrya takoi rezul'tat popal v Nature. Konechno, pryamo iz dannyh po krasnomu smesheniyu nel'zya odnovremenno izvlech' radius i massu. No drugie dannye v itoge pomogayut eto sdelat'. Avtory nablyudali istochnik EXO 0748-676. Eto tesnaya dvoinaya s akkreciruyushei neitronnoi zvezdoi. Periodicheski proishodyat rentgenovskie vspyshki. Udalos' uvidet' neskol'ko smeshennyh linii v rentgenovskom spektre. z=0.35. Rezul'tat sootvetstvuet noramal'noi neitronnoi zvezde (nikakoi kvarkovoi ekzotiiki i t.p.).
Authors: S.S. Komissarov Comments: To appear in The Proceedings of The Third Sakharov Conference on Physics, Moscow, 2002 Avtor detal'no rassmatrivaet mehanizm B-Z. Eto ochen' vazhnyi process dlya fiziki aktivnyh yader galaktik (a takzhe, vozmozhno, gamma-vspleskov i mikrokvazarov).
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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