G\u00f6kbilimciler, 2017 y\u0131l\u0131n\u0131n Ekim ay\u0131nda, o y\u0131l\u0131n ba\u015flar\u0131nda iki n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n birle\u015fmesinden ortaya \u00e7\u0131kan yer\u00e7ekimi dalgalar\u0131na ili\u015fkin ilk tespitlerini duyurdular. 70\u2019ten fazla teleskobun meydana gelen olay sonucu yay\u0131lan optik \u0131\u015f\u0131klar, X-\u0131\u015f\u0131nlar\u0131, gama \u0131\u015f\u0131nlar\u0131 ve sonras\u0131nda meydana gelen a\u015f\u0131r\u0131 parlamalar\u0131 g\u00f6zlemlemesinin ard\u0131ndan, bu ara\u015ft\u0131rma arac\u0131l\u0131\u011f\u0131yla \u201c\u00e7oklu kaynak astronomisi\u201d** \u00e7a\u011f\u0131na da girilmi\u015f oldu. Sonu\u00e7 olarak, bir galaksiden 6.6 milyar \u0131\u015f\u0131k y\u0131l\u0131 uzakta g\u00f6zlemlenen ve \u201cXT2\u201d diye adland\u0131r\u0131lan bir X-\u0131\u015f\u0131n\u0131 sinyali, inan\u0131lmaz d\u00fczeyde g\u00fc\u00e7l\u00fc bir manyetik alana sahip tek ve daha a\u011f\u0131r bir n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n geride b\u0131rakt\u0131\u011f\u0131 ba\u015fka bir n\u00f6tron y\u0131ld\u0131z\u0131 birle\u015fimini a\u00e7\u0131\u011fa \u00e7\u0131kard\u0131: Bu, bir magnetard\u0131.<\/p>\n
\u00c7in Bilim ve Teknoloji \u00dcniversitesi\u2019nde g\u00f6revli Yongquan Xue d\u00fczenledi\u011fi bas\u0131n a\u00e7\u0131klamas\u0131nda, \u201cBir n\u00f6tron y\u0131ld\u0131z\u0131 birle\u015fimini saptayabilmek amac\u0131yla tam anlam\u0131yla yeni bir y\u00f6ntem geli\u015ftirdik,\u201d diyor. Xue, 11 Nisan\u2019da Nature dergisinde yay\u0131nlanan ve bulgular\u0131 aktaran makalenin de ba\u015fyazar\u0131. Xue, \u201cBu X-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131nda g\u00f6zlemlenen davran\u0131\u015f, ara\u015ft\u0131rma grubu \u00fcyelerimizden birinin bu olaylar hakk\u0131nda \u00f6ng\u00f6rd\u00fckleriyle e\u015fle\u015fiyor,\u201d diyor.<\/p>\n
N\u00f6tron y\u0131ld\u0131zlar\u0131 birlikte sarmalla\u015farak birle\u015fti\u011fi zaman, ger\u00e7ekle\u015fen olay elektromanyetik yelpazenin yan\u0131 s\u0131ra yer\u00e7ekimi dalgalar\u0131 boyunca sinyaller g\u00f6nderir. Birle\u015fmenin D\u00fcnya\u2019ya g\u00f6re nas\u0131l konumland\u0131\u011f\u0131na ba\u011fl\u0131 olarak, parlama sonras\u0131, gama \u0131\u015f\u0131nlar\u0131 ya da X-\u0131\u015f\u0131nlar\u0131 gibi farkl\u0131 \u0131\u015f\u0131k t\u00fcrlerini g\u00f6zlemleyebiliriz. Dolay\u0131s\u0131yla, aramam\u0131z gereken i\u015faretleri bilmemiz, di\u011fer i\u015faretlerin yoklu\u011funda ve yer\u00e7ekimi dalgalar\u0131 alg\u0131lanamad\u0131\u011f\u0131nda dahi, g\u00f6kbilimcilerin birle\u015fmeleri saptamalar\u0131na yard\u0131mc\u0131 olabiliyor.<\/p>\n
XT2 olay\u0131nda, Chandra X-\u0131\u015f\u0131n\u0131 G\u00f6zlemevi, 22 Mart 2015 tarihinde yakla\u015f\u0131k yedi saat boyunca parlayan ve ard\u0131ndan s\u00f6n\u00fcmlenen bir X-\u0131\u015f\u0131n\u0131 dalgas\u0131 tespit etti. Bu sinyal g\u00f6zlemlendi\u011fi zaman tan\u0131mlanamasa da, Chandra Derin Alan-G\u00fcney g\u00f6zlemcisi taraf\u0131ndan bug\u00fcne kadar taranan g\u00f6ky\u00fcz\u00fcn\u00fcn bir k\u0131sm\u0131nda elde edilen veriler sayesinde ke\u015ffedildi; sonu\u00e7, \u015fimdiye dek elde edilen en derin X-\u0131\u015f\u0131n\u0131 g\u00f6r\u00fcnt\u00fcs\u00fcyd\u00fc.<\/p>\n
2013 y\u0131l\u0131nda XT2 sinyalinin ortaya koydu\u011fu parlakl\u0131k ve g\u00f6sterdi\u011fi davran\u0131\u015f, iki n\u00f6tron y\u0131ld\u0131z\u0131 birle\u015fti\u011finde ve bir magnetar do\u011fdu\u011funda ortaya \u00e7\u0131kmas\u0131 ve serbest kalmas\u0131 gereken X-\u0131\u015f\u0131nlar\u0131 hakk\u0131nda Nevada \u00dcniversitesi\u2019nde g\u00f6revli \u00e7al\u0131\u015fma yazar\u0131 Bing Zhang taraf\u0131ndan ifade edilen \u00f6ng\u00f6r\u00fclerle uyu\u015fuyordu. G\u00f6zlemlenen X-\u0131\u015f\u0131n\u0131 verilerine dayanarak, ara\u015ft\u0131rma grubu, birle\u015fmeden sonra yeni olu\u015fan ve h\u0131zla d\u00f6nen magnetar\u0131n k\u0131sa bir s\u00fcre i\u00e7in a\u015f\u0131r\u0131 \u0131s\u0131nd\u0131\u011f\u0131na ve yakla\u015f\u0131k 30 dakika s\u00fcresince devaml\u0131 olarak X-\u0131\u015f\u0131n\u0131 dalga boyunda parlad\u0131\u011f\u0131na inan\u0131yor. Ne var ki k\u0131sa bir s\u00fcre sonra magnetar bir par\u00e7ac\u0131k r\u00fczg\u00e2r\u0131 yayarak d\u00f6n\u00fc\u015f enerjisini yitirmeye ba\u015flad\u0131. Sonraki 6,5 saatte, magnetar\u2019\u0131n yayd\u0131\u011f\u0131 X-\u0131\u015f\u0131n\u0131 sinyali 300 kattan fazla azald\u0131 ve netice olarak Chandra\u2019n\u0131n objektifinde kayboldu.<\/p>\n
N\u00f6tron y\u0131ld\u0131zlar\u0131, baz\u0131 b\u00fcy\u00fck y\u0131ld\u0131zlar\u0131n yok olu\u015fu sonucunda ortaya \u00e7\u0131kar; y\u0131ld\u0131z\u0131n \u00e7ekirde\u011fi, bir s\u00fcpernova olu\u015fturmas\u0131n\u0131n ard\u0131ndan, yakla\u015f\u0131k 20 kilometre \u00e7ap\u0131nda yo\u011fun ve s\u0131cak bir n\u00f6tron topu haline gelir ve bu top h\u0131zl\u0131 bi\u00e7imde d\u00f6nerek D\u00fcnya\u2019n\u0131nkinden daha g\u00fc\u00e7l\u00fc bir manyetik alan meydana getirir. \u015eu ana dek yaln\u0131zca 30 defa tespit edilen magnetarlar\u0131n sahip oldu\u011fu manyetik alanlar n\u00f6tron y\u0131ld\u0131zlar\u0131ndan bile binlerce kat daha g\u00fc\u00e7l\u00fcd\u00fcr; k\u0131sacas\u0131, D\u00fcnya\u2019n\u0131n manyetik alan g\u00fcc\u00fcnden katrilyon kez daha g\u00fc\u00e7l\u00fc manyetik alanlara sahiptir. G\u00f6kbilimciler hen\u00fcz bu manyetik enerji santralleriyle ilgili \u00e7ok \u015fey bilmiyorlarsa da gizemli \u2018h\u0131zl\u0131 radyo patlamalar\u0131n\u0131\u2019 yaratan kaynaklar olduklar\u0131n\u0131 \u00f6ne s\u00fcr\u00fcyorlar.<\/p>\n
Magnetarlar, laboratuvarlarda taklit edilemeyen, inan\u0131lmaz \u00f6l\u00e7\u00fcde egzotik nesnelerdir; bu sebeple onlar ve sahip olduklar\u0131 \u00f6zelliklerle ilgili daha fazla ayr\u0131nt\u0131ya ula\u015fma ihtimali \u00e7ok de\u011ferli. Zhang \u201cNe olduklar\u0131n\u0131 g\u00f6rebilmek amac\u0131yla bir laboratuvarda n\u00f6tron y\u0131ld\u0131zlar\u0131n\u0131 bir araya getiremeyiz. Dolay\u0131s\u0131yla, evren bizim i\u00e7in bunu yapana dek beklememiz gerekiyor,\u201d diyor. \u201cBu birle\u015fme hem genel ba\u011flamda n\u00f6tron y\u0131ld\u0131zlar\u0131 hem de magnetarlarla ilgili \u00f6nemli bilgiler ortaya koyuyor. \u015eayet iki n\u00f6tron y\u0131ld\u0131z\u0131 \u00e7arp\u0131\u015f\u0131r ve geride a\u011f\u0131r bir n\u00f6tron y\u0131ld\u0131z\u0131 kal\u0131rsa, bu bizim i\u00e7in, yap\u0131lar\u0131n\u0131n g\u00f6rece sert ve esnek oldu\u011fu anlam\u0131na gelir,\u201d diye ekliyor.<\/p>\n
Ancak X-\u0131\u015f\u0131nlar\u0131 yaratman\u0131n bir\u00e7ok yolu var ve magnetarlar s\u00f6z konusu oldu\u011funda birden fazla olu\u015fum senaryosu mevcut. Mesela, bir s\u00fcpernovadaki tek ve b\u00fcy\u00fck bir y\u0131ld\u0131z \u00e7\u00f6kerek magnetar olu\u015fturursa ne olur?<\/p>\n
Ara\u015ft\u0131rma grubu, XT2\u2019nin, birka\u00e7 nedenden \u00f6t\u00fcr\u00fc bir \u00e7ift n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n birle\u015fiminden meydana geldi\u011finden emin. Sinyal, n\u00f6tron y\u0131ld\u0131zlar\u0131n\u0131n bulunabilece\u011fi ev sahibi galaksinin \u00e7eperinden yay\u0131ld\u0131. Bunun sebebi, n\u00f6tron y\u0131ld\u0131zlar\u0131n\u0131n bir s\u00fcpernovadan do\u011fup n\u00f6tron y\u0131ld\u0131z\u0131na bir darbe vurarak onlar\u0131 as\u0131l konumlar\u0131ndan galaksinin d\u0131\u015f b\u00f6lgelerine do\u011fru f\u0131rlatmas\u0131. Buna ek olarak, ev sahibi galaksinin kendisi de bir ana n\u00f6tron y\u0131ld\u0131z fabrikas\u0131 gibi g\u00f6r\u00fcn\u00fcyor. \u00c7ok say\u0131da yeni y\u0131ld\u0131z yaratm\u0131yor ve bu durum, sinyalin iki eski n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n birle\u015fmesinden gelme ihtimalinin \u00e7ok fazla olmad\u0131\u011f\u0131 ve tek bir gen\u00e7 ve devasa y\u0131ld\u0131zdan yay\u0131lmas\u0131n\u0131n daha b\u00fcy\u00fck bir ihtimal oldu\u011fu anlam\u0131na geliyor.<\/p>\n
Peki, o halde XT2 neden yer\u00e7ekimsel dalgalar \u00fcretmedi? Asl\u0131nda, g\u00f6kbilimciler b\u00f6yle oldu\u011funa inan\u0131yordu; ancak olay (2017 tarihli birle\u015fmeyi tespit eden) \u2018Advanced LIGO\u2019 adl\u0131 g\u00f6zlem arac\u0131n\u0131n kullan\u0131lmaya ba\u015flamas\u0131ndan \u00f6nce ger\u00e7ekle\u015fti ve ayn\u0131 zamanda tespit etmek i\u00e7in \u00e7ok uzakt\u0131. N\u00f6tron y\u0131ld\u0131z birle\u015fmelerini tespit etmek i\u00e7in (Chandra taraf\u0131ndan XT2\u2019de g\u00f6zlemlenen X-\u0131\u015f\u0131n\u0131 sal\u0131mlar\u0131nda oldu\u011fu gibi) yer\u00e7ekimi dalgalar\u0131 yerine di\u011fer sinyalleri kullanman\u0131n de\u011ferinin alt\u0131n\u0131 \u00e7izen de yine bu durum. Bir birle\u015fme esnas\u0131nda yer\u00e7ekimsel dalgalar\u0131n ve kimi di\u011fer \u0131\u015f\u0131k t\u00fcrlerinin g\u00f6r\u00fclememesinin bir\u00e7ok sebebi mevcut; h\u00e2l b\u00f6yleyken, bu t\u00fcrden olaylar\u0131 di\u011fer sinyaller arac\u0131l\u0131\u011f\u0131yla tan\u0131mlamak, astronomlar\u0131n bu olaylar\u0131 ve sonu\u00e7lar\u0131n\u0131 incelemek i\u00e7in daha fazla birle\u015fim tespit etmelerini ve bunun meydana getirdi\u011fi n\u00f6tron y\u0131ld\u0131zlar\u0131n\u0131 ve geride b\u0131rakt\u0131klar\u0131 nesneleri bulmalar\u0131n\u0131 sa\u011fl\u0131yor.<\/p>\n
Bu d\u00fc\u015f\u00fcnceyi akl\u0131nda tutan ara\u015ft\u0131rma grubu, \u015fimdi ek sinyaller bulabilmek umuduyla di\u011fer Chandra bulgular\u0131n\u0131 inceliyor. \u0130ki n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n birle\u015fimi, ara\u015ft\u0131r\u0131lacak iki kat veri demek; l\u00e2kin g\u00f6kbilimcilerin ger\u00e7ekten de bu \u00f6nemli olaylar hakk\u0131nda kesin cevaplar bulabilmesi i\u00e7in bu b\u00fcy\u00fck birle\u015fim k\u00fcmesi hakk\u0131nda kat etmesi gereken h\u00e2l\u00e2 \u00e7ok uzak bir yol var.<\/p>\n","protected":false},"excerpt":{"rendered":"
G\u00f6kbilimciler, 2017 y\u0131l\u0131n\u0131n Ekim ay\u0131nda, o y\u0131l\u0131n ba\u015flar\u0131nda iki n\u00f6tron y\u0131ld\u0131z\u0131n\u0131n birle\u015fmesinden ortaya \u00e7\u0131kan yer\u00e7ekimi dalgalar\u0131na ili\u015fkin ilk tespitlerini duyurdular. 70\u2019ten fazla teleskobun meydana gelen olay sonucu yay\u0131lan optik \u0131\u015f\u0131klar, X-\u0131\u015f\u0131nlar\u0131, gama \u0131\u015f\u0131nlar\u0131 ve sonras\u0131nda meydana gelen a\u015f\u0131r\u0131 parlamalar\u0131 g\u00f6zlemlemesinin ard\u0131ndan, bu ara\u015ft\u0131rma arac\u0131l\u0131\u011f\u0131yla \u201c\u00e7oklu kaynak astronomisi\u201d** \u00e7a\u011f\u0131na da girilmi\u015f oldu. Sonu\u00e7 olarak, bir galaksiden […]<\/p>\n","protected":false},"author":23,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[506],"tags":[],"class_list":["post-88956","post","type-post","status-publish","format-standard","hentry","category-astronomi"],"acf":[],"yoast_head":"\n