BVRI photometry of possible standard stars in NGC 188

CCD photometry of possible standard stars, in Cousins B, V, R and I, in a field in the region of NGC 188 is presented.     

Fast variability of BL Lacertae at 1 μm

We present the results of photometric observations of BL Lacertae at 1 μm performed during the strong outburst that occurred in the summer of 1997. Measurements were carried out using the F99 filter of the Arizona system. Simultaneous observations in the B V bands were made with other telescopes. Large and fast variations were observed on the night of August 2 when the brightness of BL Lacertae changed by ∼ 0.5 mag in about 2 h: the variation amplitude is greater at higher frequency. Some implications of these results for the origin of the fast variations are discussed. We also report the first F99 calibration for three reference stars in the BL Lac field.     

三溴偶氮胂分光光度法测定稀土元素的研究

在1.0 mol/L盐酸介质中,显色剂三溴偶氮胂与稀土元素能发生高灵敏度显色反应,形成稳定的蓝紫色络合物,表观摩尔吸光系数ε_La为1.69×10⁵ L·mol^-1·cm^-1.试剂和络合物的最大吸收波长分别位于525 nm和625 nm.确定了络合物的组成为1:3.在25 mL溶液中,稀土元素在0~17 μg范围内符合比尔定律.本方法受酸度及共存离子影响小,并且有准确、快速、简单的特点.对两个标样做了分析,精密度RSD分别为2.82%和2.57%,准确度RE分别为-2.34%和-5.82%.本方法可不经分离富集,直接用于稀土矿样分析,结果令人满意.     

Observation and Research of the Transits of Extrasolar Planets

In order to make more accurate estimates of the physical parameters of extrasolar planets, the observation and research on the phenomena of transits of the 7 known stars with the planetary systems TrES-1, TrES-3, XO-2, WASP-1, WASP-2, WASP-3 and HAT-P-7 are carried out with the 1-m reflecting telescope at Shandong University Weihai Astronomical Observatory/Weihai Municipal Astronomical Observatory. The fundamental conditions of the observation and data processing are introduced, and the transit light curves as well as the parameters of some planets derived from them are given. At the same time, when the results are summarized and analyzed, the prospects for the more in-depth and detailed researches which will be further carried out are also described.     

用于震害研究的遥感资料航摄与影像图制作技术

本文从对震害进行分析和研究的目的出发,讨论了航空遥感飞行与影像图制作的有关技术和实施问题,主要包括在震害研究和调查中,航摄与制图比例尺的选择、航空遥感飞行的方案设计、利用影像图进行震害研究分析的优越性及系列震害专题影像图的确定与制作特点等内容。     

Star formation properties of Universidad Complutense de Madrid survey galaxies

We present new near-infrared J and K imaging data for 67 galaxies from the Universidad Complutense de Madrid (UCM) survey used in the determination of the SFR density of the local Universe by Gallego et al. This is a sample of local star-forming galaxies with redshift lower than 0.045, and they constitute a representative subsample of the galaxies in the complete UCM survey. From the new data, complemented with our own Gunn- r images and long-slit optical spectroscopy, we have measured integrated K -band luminosities, r − J and J − K colours, and H α luminosities and equivalent widths. Using a maximum likelihood estimator and a complete set of evolutionary synthesis models, these observations allow us to estimate the strength of the current (or most recent) burst of star formation, its age, the star formation rate and the total stellar mass of the galaxies. An average galaxy in the sample has a stellar mass of 5×10¹⁰ M_⊙ and is undergoing (or has recently completed) a burst of star formation involving about 2 per cent of its total stellar mass. We identify two separate classes of star-forming galaxies in the UCM sample: low-luminosity, high-excitation galaxies (H  ii like ) and relatively luminous spiral galaxies (starburst disc- like ). The former show higher specific star formation rates (SFRs per unit mass) and burst strengths, and lower stellar masses than the latter. With regard to their specific star formation rates, the UCM galaxies are intermediate objects between normal quiescent spirals and the most extreme H  ii galaxies.     

Imaging of the merging galaxy NGC 3597 and its population of protoglobular clusters

We present wide field-of-view near-infrared imaging from the NTT and very deep optical imaging from the HST of the young merging galaxy NGC 3597. The morphology of the galaxy and the properties of the newly formed protoglobular clusters (PGCs) are examined. Our K -band data reveal the presence of a second nucleus, which provides further evidence that NGC 3597 is the result of a recent merger. Combining new K -band photometry with optical photometry, we are able for the first time to derive a unique age for the newly formed PGCs of a few Myr. This is consistent with the galaxy starburst age of ≤10 Myr. From deep HST imaging, we are able to probe the luminosity function ∼8 magnitudes fainter than normal, old globular clusters, and confirm that the PGCs have a power-law distribution with a slope of ∼−2.     

Infrared photometry of z ∼ 1 3C quasars

We present JHKL ' photometry of a complete sample of steep-spectrum radio-loud quasars from the revised 3CR catalogue in the redshift range 0.65 z <1.20. After correcting for contributions from emission lines and the host galaxies, we investigate their spectral energy distributions (SEDs) around 1 μm. About 75 per cent of the quasars are tightly grouped in the plane of optical spectral index, α _opt, versus near-infrared spectral index, α _IR, with the median value of α _opt close to the canonical value, and the median α _IR slightly flatter. We conclude that the fraction of moderately obscured, red quasars decreases with increasing radio power, in accordance with the 'receding torus' model which can also explain the relatively flat median near-infrared spectra of the 3CR quasars. Two of the red quasars have inverted infrared spectral indices, and we suggest that their unusual SEDs might result from a combination of dust-scattered and transmitted quasar light.     

The LBDS Hercules sample of mJy radio sources at 1.4 GHz – I. Multicolour photometry

The results are presented of an extensive programme of optical and infrared imaging of radio sources in a complete subsample of the Leiden–Berkeley Deep Survey. The LBDS Hercules sample consists of 72 sources observed at 1.4 GHz, with flux densities S _1.41.0 mJy, in a 1.2 deg² region of Hercules. This sample is almost completely identified in the g , r , i and K bands, with some additional data available at J and H . The magnitude distributions peak at r ≃22 mag, K ≃16 mag and extend down to r ≃26 mag, K ≃21 mag. The K -band magnitude distributions for the radio galaxies and quasars are compared with those of other radio surveys. At S _1.4 GHz≲1 Jy, the K -band distribution does not change significantly with radio flux density. The sources span a broad range of colours, with several being extremely red ( r − K ≳6). Though small, this is the most optically complete sample of mJy radio sources available at 1.4 GHz, and is ideally suited for studying the evolution of the radio luminosity function out to high redshifts.