ABSTRACT In molecular cloud cores, the cosmic ray (CR) induced sputtering via CR ion-icy grain collision is one of the desorption processes for ice molecules from mantles around dust grains. The efficiency of this process depends on the incident CR ion properties as well as the physicochemical character of the ice mantle. Our main objective is the examination of the sputtering efficiency for H2O and CO ices found in molecular cloud cores. In the calculation routine, we consider a multidimensional parameter space that consists of 30 CR ion types, 5 different CR ion energy flux distributions, 2 separate ice mantle components (pure H2O and CO), 3 ice formation states, and 2 sputtering regimes (linear and quadratic). We find that the sputtering behaviour of H2O and CO ices is dominated by the quadratic regime rather than the linear regime, especially for CO sputtering. The sputtering rate coefficients for H2O and CO ices show distinct variations with respect to the adopted CR ion energy flux as well as the grain-size-dependent mantle depth. The maximum radius of the cylindrical latent region is quite sensitive to the effective electronic stopping power. The track radii for CO ice are much bigger than H2O ice values. In contrast to the H2O mantle, even relatively light CR ions (Z ≥ 4) may lead to a track formation within the CO mantle, depending on Se,eff. We suggest that the latent track formation threshold can be assumed as a separator between the linear and the quadratic regimes for sputtering.

Be55, Ki02 ve NGC457 acik yildiz kumeleri Galaksimizin birinci ve ikinci ceyreginde bulunan, F-G tayf turunden yildizlar icerdigi bilinen kumeler icerisinden secilmistir. Secilen bu kumelere ait $CCD$ $UBV(RI)_{C}$ gozlemleri Sierra San Pedro Martir (SPM) gozlemevinden ayni teleskop ($0.84$ cm), CCD ve filtreler ile alinmistir. Kumelerin goruntuleri, Aciklik (Aperture) ve PSF teknigi ile IRAF'da indirgenmistir. Acik yildiz kumelerinin temel parametreleri belirlenirken hem $CCD$ $UBV(RI)_{C}$ hem de $2MASS$ (The Two Micron All Sky Survey) $JHK_{S}$ fotometrisi kullanilarak oldukca genis bir filtre araliginda calisilmistir. Kume analizlerinde $\delta(U-B)$ morotesi artigi teknigi kullanilarak kumelerin fotometrik metal bolluklari ilk kez tespit edilmistir.

Teknolojinin gelismesi, astronomik alanda buyuk teleskoplarin uretimini hizlandirmistir. Uretilen teleskoplardan maksimum verimin alinabilmesi icin yerleskenin en uygun kosullara sahip olmasi gerekmektedir. Dunya uzerinde astronomik acidan uygun yerlerin belirlenebilmesi icin etkin faktorlerin (yukseklik, bulutluluk, isik kirliligi, su buhari miktari, Atmosferde bulunan Aerosol miktari vb.) niceliksel ve konumsal olarak analizi ile uzun donemli meteorolojik yer verileri gerekmektedir. Bu faktorleri temsil eden sayisal verilerin temin edilmesi, duzenlenmesi, standardizasyonu, entegrasyonu ve analizlerinin ise geleneksel yontemlerden ziyade Uzaktan Algilama ve Cografi Bilgi Sistemleri (CBS) yardimiyla cok daha hizli, ekonomik ve etkin bir sekilde gerceklestirilebilmektedir. \cite{Aksaker} tarafindan Turkiye icin gerceklestirilen ve etkin ciktilar ureterek tecrube kazanimi saglanan boyle bir yaklasimin, bu calisma ile global olcegi hedeflenmistir. Bu calismada; Dunya uzerinde Optik/Kizilote bolgede calisabilecek teleskoplar icin en uygun yerler belirlenmesi, var olan gozlemevlerinin durumu karsilastirmali olarak ortaya cikarilmasi ve yeni bir gozlemevi kurmak isteyen ulkeler, arastirma merkezleri ve universiteler icin guncel veriler CBS-CKKA (Cografi Bilgi Sistemi-Cok Kriterli Karar Analizi) ile yapilmistir. Sonucta dusuk cozunurluk ve 1 yillik arsiv verileri kullanilarak Dunyada gozlemevleri icin uygun yerler belirlenmistir. Buna gore Antarktika, Amerikanin bati kiyilari, Gronland, Afrikanin dogusunda bir kac bolge ve Hindistan-Cin arasindaki daglik bolgeler uygun yerlerdir.

Bu cagrili bildiride son doktora ogrencisi olmakla onur duydugum degerli hocam rahmetli Prof.Dr. Dilhan Eryurt Ezer'in bilim yasami ve bilime katkilarindan bahsedilmektedir. Benim gayretim, aktif calisma hayatimdan ayrildigim zaman, yildizlarin yapilari ve evrimleriyle ilgili calismalara devam edecek elemanlar yetistirmekti diyen, ogrencilerini yetistirirken en onem verdigi hususun, onlarin olabildigince bagimsiz calisabilecek nitelikte yetismeleri olan Prof.Dr. Dilhan Eryurt Ezer'in bize biraktiklari anlatilmistir.

Ulkemiz astronomi camiasi olarak gorsel dalgaboylarinda uzun bir gecmise sahibiz. Kurulmakta olan ve ilk isigi 2018 yilinda almasi planlanan Dogu Anadolu Gozlemevi (DAG) sayesinde ise kizilote bolgede evreni inceleme firsati bulacagiz. Yakin evrende gorsel dalgaboylarinda gorulemeyen bircok fiziksel olguyu arastirabilmek ve evrenin daha derinlerini gozleyebilmek icin ulke olarak siradaki hedefimiz mm/mm-alti ve radyo bolgelere duyarli teleskoplar insa etmek olmalidir. Bu sayede Turk astronomisi evreni coklu-dalgaboyu penceresinden inceleme firsati bulacaktir. Bu bildiride, mm/mm-alti/radyo astronominin Dunya'daki onemi ve Turkiye Ulusal Radyo Astronomi Gozlemevi (TURAG) projemizin gerekliligi ve geldigi nokta ile birlikte gelecekteki planlar ozetlenecektir.

Bu calismada Turkiye'de potansiyel gozlemevleri icin yer secimi calismalari Cok Kriterli Karar Analizi {\itshape (CKKA)} ve Cografi Bilgi Sistemleri {\itshape (CBS)} icerisinde uydu goruntuleri kullanilarak yapilmistir. Bulutluluk, Sayisal Yukseklik Modeli, Yapay Isiklilik, Yogusabilir Su Buhari miktari, Aerosol Optik kalinligi ve ruzgar hizi katmanlari CBS icerisinde calisildi. CKKA'nin sonucu olarak Turkiyedeki en uygun yerlerin guney batidan kuzey doguya cizilen bir dogrunun dogu kisminda oldugu belirlendi. Bu bolgeler ileride yapilacak ayrintili calismalarda birincil adaylardir. Buna ek olarak buyuk gozlemevlerimizde calisilmistir. Potansiyel gozlemevi adaylarindaki test calisalarinda kullanilacak bir prototip uretilmek uzere bir TUBITAK projesi devam etmektedir.

Bu calismada Meksika San Pedro Martir (SPM) Ulusal Astronomi Gozlemevi’nde 0.84m teleskop ile gozlenmis Feibelman 1 ve NGC 436 Acik Yildiz Kumeleri’nin CCD UBVRI verileriyle birlikte 2MASS veri katalogundaki JHK verileri kullanilarak bu kumelere ait temel ve yapisal parametreler (renk artigi, uzaklik, uzaklik modulu, yas, metal bollugu, kume limityaricapi) belirlenmistir. Kume uyelikleri belirlenirken ise PPMXL veri katalogundaki oz hareket verileri kullanilmistir.

Bu calismada, ERU UZAYBIMER UYG-AR Merkezinde bulunan ERT-5 tek canak radyo teleskopu icin aki kalibrasyonu calismasi yapilmistir. Bu calismanin yapilabilmesi icin radyo teleskop sisteminde kullanilmak uzere radyo teleskop kontrol kumandasi ve radyometre alici cihazlari tasarlanmis ve prototip olarak uretilmistir.

Bu calismada gozlemevi yerleskelerinde gokyuzu kalitesini olcmek icin uretilen prototip olcerin bir ozeti sunulmustur. GOKSIS olarak adlandirilan bu prototip bes farkli sistemden olusmaktadir: Meteoroloji sistemi, tum gokyuzu kamerasi, astronomik gorus izleme, bulutluluk olcumu ve gokyuzu parlakligi olcumu. Tum sistem LabView ortaminda otomatik olarak kontrol edilebilmektedir. Sistem test amacli olarak 14 Haziran 2017’de TUBITAK Ulusal Gozlemevine (TUG) kurulmus ve olcumlere baslamistir. Su anda TUG meteorolojik olcum sistemine entegre edilerek sitede surekli gorus (seeing) olcumleri elde edilir hale getirilmistir. TUG’da kurulan bu prototip, aldigi veri ve gosterdigi sonuclar nedeniyle basariyla veri topluyor olsa da prototip mekanik acidan guncellemeye ihtiyac duymaktadir.

Yildizlar arasindaki ortamdaki (YAO) materyalin kimyasal ozellikleri molekuler hidrojen, karbon monoksit, cesitli radikaller ve karmasik molekuler baglarla bir araya gelmis poliaromatik hidrokarbonlar ve yasamin temelini olusturan bazi aminoasit yapilarini da iceren kompleks organik molekuller gibi yildizlardaki termonukleer yanma surecleri sonucunda olusmalari mumkun olmayan molekuller yapilarin olusma ve yok olma etkinliklerine baglidir. YAO daki molekul olusum surecleri, gaz evresinde gerceklesen ve toz parcaciklarinin uzerinde meydana gelen reaksiyonlar olmak uzere temel olarak iki ana alt sinifa ayrilir. YAO kosullari goz onune alindiginda gaz-evresinde meydana gelme olasiligi oldukca dusuk olan bazi yuksek aktivasyon enerjili reaksiyonlar, toz paraciklarinin yuzey bolgelerinde sogurulan gaz-evresi reaktantlari tarafindan gerceklestirildiginden, toz parcaliklari uzerlerinde gerceklesen fizikokimysal sureclerin etkileri kimyasal modellerinde mutlaka goz onune alinmadir. Bildiri kapsaminda sunacagimiz calismamizin birinci amaci, farkli fiziksel ozelliklere sahip YAO bolgelerindeki belirli molekul olusum ve yok olma sureclerinin analitik olarak tanimlayan astrokimyasal modeller icin toz parcaciklarinin kimyasal kompozisyon, boyut ve yuzey sicakligi gibi yapisal ozelliklerinin onemlerini ortaya cikaran literaturdeki guncel bazi teorik ve deneysel sonuclarin paylasilmasidir. Calismamizin ikinci ve en onemli amaci ise, acik kaynakli bir kod olan ASTROCHEM kimyasal modelleme kodunda yapacagimiz modifikasyonlar sonunca ulasmayi planladigimiz bilimsel hedeflerimizdir.

In this paper we inform about the last stage of start and adjustment procedures of Turkish radio telescope ERT5. Here we report on the methods of observational data reduction and receiver calibration, more detailed estimation of the shape of antenna power pattern and the process of deconvolution of observational data. We also describe two (ground based and satellite) methods of antenna pattern measurements of ERT5 and their results. Beam estimations of ERT5 have been made for two frequencies (1.4 and 10 GHz) and the results are in good agreement with the theoretical estimations. We found that at the frequencies of 11 GHz ERT5 power pattern has the elliptic shape with the HPBW about 23′.5 and 45′.7. At the 1.4 GHz these values are correspondingly 160′ and 225′. Estimated beam efficiency of ERT5 is nearly 0.5. After precise beam estimations we performed 2D restoration of observed data with some methods of deconvolution (simple FFT, Lucy-Rychardson and maximum entropy (MEM)). Obtained results are in good agreement with each other and with other observations.

Applying external field to vircator has been performed to reach various aims which are phase locking, microwave signal amplification, frequency control and enhancing vircator performance [1]–[3]. In this study, double gap vircator with feedback structure in Ref [4] is investigated in MAGIC simulation environment by considering start time, frequency control and efficiency under the application of external signal. External signal is applied by injecting desired mode to modulating cavity from the location of plunger by removing the plunger. Modulating cavity is coupled to output waveguide via coupling window which yields feedback from output waveguide to modulating cavity in vircator [5]. Double gap vircator gives 162MW output power in a single main frequency in S band with power efficiency of 5.36% when 450kV gap voltage is applied. Cross sections are rectangular and generated mode is TE10. Coupling field strengths in modulating cavity for vircator without field injection is found and strength of the inj ected electric field signal is chosen as not to exceed that value. Firstly, signal with same frequency in initial case is inj ected. During the various levels of field injection, open and close cases for coupling window are examined separately. Oscillations start ~4ns earlier for signal injection cases and 209MW output power with efficiency of 6.51 %, includes injected field power, is observed as highest value. Then magnitude of external signal is fixed, S band is almost covered in the vircator output by inj ecting various frequency of external signals. Power drops in this coverage is observed as due to cavity field distribution on the beam center. After the observations on this vircator structure, frequency tuning procedure including AK gap, positions of plunger and length of the coupling window is developed and verified for two different frequency of operation.

This paper presents design and simulation results of the cylindrical axial virtual cathode oscillator which is frequently used to damage electronic equipment by generating High Power Microwaves (HPM). Simulations are performed in MAGIC Tool Suite which uses FDTD-PIC algorithm to solve particle beam and field interactions. During the design procedure, AK Gap is changed from 5 mm to 12 mm and the scaling law is verified by simulation results. 9 mm AK gap values are selected as the most suitable one when output power and frequency of radiated field are taken into consideration. Further investigations are made by using 9 mm AK value in simulation environment. Formation of the virtual cathode is confirmed by Pz vs. z phase space diagram. The mean of applied input voltage value and input power value are found as 87.76 kV and 246 MW, respectively. The peak power and the average power for the generated microwave at the output are also 6.3 MW and 1.8 MW. Thus, power conversion efficiency for both peak and average output power are obtained as 2.56% and 0.73%, respectively. Frequency of the radial and longitudinal components of the produced electric field at the output is 2.92 GHz. Waveguide mode at 2.92 GHz is inferred from radial field distributions of fields and the propagating mode is found as TM01 at 2.92 GHz, which verifies our prediction.

12.9 metrelik NATO askeri radari, Radyo Teleskop haline donusturulmustur. Ilk olarak teleskop uzerinde bulunan elektronik ve mekanik sistemlere gore yazilim gelistirilmesi yapilmistir. Tasarlanan mekatronik sistem ve gelistirilen yazilim ile hangi radyo kaynaklarin gozlenebilecegi hakkinda bilgiler verilecektir.

A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBIMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.

A site selection of potential observatory locations in Turkey have been carried out by using Multi-Criteria Decision Analysis (MCDA) coupled with Geographical Information Systems (GIS) and satellite imagery which in turn reduced cost and time and increased the accuracy of the final outcome. The layers of cloud cover, digital elevation model, artificial lights, precipitable water vapor, aerosol optical thickness and wind speed were studied in the GIS system. In conclusion of MCDA, the most suitable regions were found to be located in a strip crossing from southwest to northeast including also a diverted region in southeast of Turkey. These regions are thus our prime candidate locations for future on-site testing. In addition to this major outcome, this study has also been applied to locations of major observatories sites. Since no goal is set for the best, the results of this study is limited with a list of positions. Therefore, the list has to be further confirmed with on-site tests. A national funding has been awarded to produce a prototype of an on-site test unit (to measure both astronomical and meteorological parameters) which might be used in this list of locations.

We describe our program to search for variable stars in four open clusters. Future efforts to solve the light curves of eclipsing systems and derive parameters of these variable stars will be used to understand the evolution and environment of the host clusters.

Astrophysical parameters (age, reddening, distance, radius, luminosity function, mass function, total mass, relaxation time and mass segregation) have been estimated for open clusters NGC 2571, NGC 6802, Koposov 53 and Be 89 by using the Two Micron All Sky Survey (2MASS) photometry. We analyse the color-magnitude diagrams and stellar radial density profiles. We have found that NGC 2571 is the youngest one having young main sequence stars while Be 89 is the oldest cluster.