Spectroscopy of Galaxies in Selected Fields of the Second Byurakan Survey

Spectroscopic data are presented for 35 galaxies from selected fields of the Second Byurakan Survey (SBS). The observations were made on the 2.6 m telescope at the BAO using the SCORPIO spectral camera. A majority of the objects were observed for the purpose of improving the classification of types in accordance with an adapted scheme presented in this paper.     

A hard X-ray sky survey with the SIGMA telescope of the GRANAT observatory

The SIGMA X-ray telescope accumulated the images of more than a quarter of the sky during the in-orbit operation of the GRANAT observatory. The longest exposure time (～9 million s) was spent on the observations of the Galactic center region. We give an overview of the SIGMA X-ray observations and report the sensitivities achieved in various regions of the sky.     

Spin Temperature of Ammonia Determined from NH2 in Comet C/2001 A2 (LINEAR)

The ortho-to-para ratio (OPR) of a cometary molecule is one of primordial character in comets. The OPR which is characterized by a spin temperature, is thought to reflect the formation conditions of the molecule. In this paper we show the high-dispersion spectrum of cometary NH₂ in Comet C/2001 A2 (LINEAR), from which the OPR of NH₂ is determined based on the fluorescence excitation model. Since the NH₂ is a photodissociation product of cometary ammonia, we applied the permutation group theory to the whole reaction system (i.e. the photodissociation reaction of ammonia to NH₂ and H) in order to derive the OPR of ammonia from that of NH₂. The derived OPR of ammonia is 1.12 ± 0.03 in Comet C/2001 A2 (LINEAR). This value corresponds to a spin temperature of 30⁺³ _-2 K. If this reflects the temperature where the comet formed in the protosolar nebula, our result indicates that thiscomet was formed in the region of the giant planets between Jupiter and Neptune.     

Observations of the X-ray binaries 4U 1700-37 and GRO J1655-40 during the Grif experiment onboard the mir orbiting station

Various areas of the sky, including the Galactic-center region and the region with the X-ray binaries 4U 1700-37 and GRO J1655-40, were observed in the hard (10–300 keV) energy range during the Grif experiment onboard the Mir orbiting station. An epoch-folding analysis of the data has revealed periodicities with periods of 82 and 62 h, which are equal to the orbital periods of 4U 1700-37 and GRO J1655-40. Previously, these periodicities were observed during the Prognoz-9 X-ray experiment. Periodicities with periods in the range of days, 98 and 152 h, which were also observed during the Prognoz-9 experiment, were not revealed by the Grif data. We obtained upper limits on the intensities of these periodicities in various energy ranges. For the 62-h periodicity, we constructed an average 25–50-keV light curve and estimated the spectral flux density, which characterizes the intensity of the periodic component at different energies in different observing intervals during 1995–1997. The Prognoz-9 and Grif observations of GRO J1655-40 are compared with its CGRO, RXTE, and BeppoSax observations. The orbital periodicity is shown to manifest itself in the hard emission from the extremely bright X-ray transient GRO J1655-40, a likely black-hole candidate, even at the epochs between its X-ray outbursts.     

低频天波信号异常与太阳软X射线爆发的关系的分析

对 2 0 0 3年 1 0月下旬至 1 1月上旬太阳剧烈活动期间在中国陕西临潼接收的低频一跳天波信号的突然相位异常 (SPA)和突然幅度异常 (SFA)事件与美国空间环境中心 (SpaceEnvironmentCenter)提供的由GOSE1 2卫星探测得到的太阳 1 -8 A软X射线耀斑爆之间的关系进行了分析研究。同时还对SPA及SFA与太阳射电爆发之间的关系进行了分析     

纳米珍珠层粉的制备

以海水珍珠层粉为原料 ,用行星式球磨机制备纳米珍珠层粉 ,对所得珍珠层粉采用扫描电镜法进行检测和X射线衍射分析。结果表明 ,所得珍珠层粉实现了纳米化 ,其颗粒大小为 4 5～ 6 5nm。     

Star formation histories across hubble types

Using population fitting and galactic chemical evolution (GCE) models we unravel the information present in spectral line-strengths, for a sample of 32 galaxies including ellipticals, S0s and spiral bulges. This revised version was published online in August 2006 with corrections to the Cover Date.     

Black Hole Systems Seen at High Spectral Resolution: Inflow and Outflow

High-resolution Chandra and XMM-Newton X-ray spectroscopic studies of stellar and supermassive black holes have revealed that these phenomenologically different systems share many common physical characteristics. The observed outflows in the micro-quasar GRS 1915+105, the Seyfert 1 galaxy MCG–6-30-15 and the Seyfert 2 galaxy IRAS 18325-5926 are the focus of this proceeding.     

The X-ray pulse profile of BG CMi

We present an analysis of the X-ray data of a magnetic cataclysmic variable, BG CMi, obtained with ROSAT in March 1992 and with ASCA in April 1996. We show that four peaks clearly exist in the X-ray pulse profile, unlike a single peak found in the optical profile. The fluxes of two major pulses are 2–5 times larger than those of two minor pulses. The fraction of the total pulsed flux increases from 51% to 85% with increasing energy in 0.1–2.0 keV, whereas it decreases from 96% to 22% in 0.8–10 keV. We discuss the implications of our findings for the origin of the pulse profile and its energy dependence.