Exterior orientation of CBERS-2B imagery using multi-feature control and orbital data

The major contribution of this paper relates to the practical advantages of combining Ground Control Points (GCPs), Ground Control Lines (GCLs) and orbital data to estimate the exterior orientation parameters of images collected by CBERS-2B (China–Brazil Earth Resources Satellite) HRC (High-resolution Camera) and CCD (High-resolution CCD Camera) sensors. Although the CBERS-2B is no longer operational, its images are still being used in Brazil, and the next generations of the CBERS satellite will have sensors with similar technical features, which motivates the study presented in this paper. The mathematical models that relate the object and image spaces are based on collinearity (for points) and coplanarity (for lines) conditions. These models were created in an in-house developed software package called TMS (Triangulation with Multiple Sensors) with multi-feature control (GCPs and GCLs). Experiments on a block of four CBERS-2B HRC images and on one CBERS-2B CCD image were performed using both models. It was observed that the combination of GCPs and GCLs provided better bundle block adjustment results than conventional bundle adjustment using only GCPs. The results also demonstrate the advantages of using primarily orbital data when the number of control entities is reduced.     

NOIRCAT – the Northern HIPASS Optical/IR Catalogue

We present the Northern HIPASS (H  i Parkes All-Sky Survey) Optical/Infrared Catalogue (NOIRCAT), an optical/near-infrared (NIR) counterpart to the Northern HIPASS Catalogue (NHICAT). Of the 1002 sources in NHICAT, 655 (66 per cent) have optical counterparts with matching optical velocities. A further 85 (8 per cent) sources have optical counterparts with matching velocities from previous radio emission-line surveys. We find a correlation between the gas and stellar content of the NOIRCAT sources. Our H  i -selected sample of isolated galaxies also presents a wider range in NIR colours than previous optically selected studies of regular, isolated galaxies. All H  i detections in optically unobscured fields could be matched with either a NASA/IPAC Extragalactic Database optical counterpart, or a galaxy visible in Second Palomar Observatory Sky Survey or Digitized Sky Survey images. However, as over 200 of these matched galaxies have no velocity information, further follow-up observations are needed to confirm the matches, and hence confirm or deny the existence of dark galaxies in this data set.     

����LIDAR������ȡɽ�����������ߵ��㷨�о�

????????????LIDAR??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????С?????????????и????ü????????????????????????????????????С?     

南海区域商船典型空间分布及贸易流向研究

随着中国对外开放的深入以及“一带一路”倡议的推进,南海战略地位更加显著。如何科学监管南海船舶,维护国家权益,促进地区之间贸易也成为摆在政府部门面前的难题。在本文中利用南海区域2015年的卫星AIS数据与船舶数据档案资料,通过计算南海水域船舶交通密度分析主要航路,与关键门线船舶流量计算相结合,明确船舶典型空间分布;同时基于4种类型船舶的主要航路的选择,明确南海货物贸易主要流向。研究成果表明：① 船舶空间分布在《世界大洋航路》的推荐航线上,南海的建设开发并未影响船舶的贸易运输;② 贸易运输以跨越南海的长距离运输为主,珠三角作为主要航路的重要端点表明中国在南海贸易的优势地位。     

Probing the feeding and feedback of activity near and far

High-resolution CO maps are an essential tool to search for observational evidence of AGN fueling in galaxy nuclei. While their capabilities will be surpassed by ALMA, current mm-interferometers can already provide relevant information on scales which are critical for the process of angular momentum transfer in fueling the AGN. In this context we present the latest results issued from the NUclei of GAlaxies (NUGA) project, a high-resolution (0.5^′′–1^′′) CO survey of low luminosity AGNs conducted with the IRAM Plateau de Bure interferometer (PdBI). The use of more specific molecular tracers of dense gas can probe the feedback influence of activity on the chemistry and energy balance in the interstellar medium of nearby galaxies, a prerequisite to understanding how feedback operate at higher redshift galaxies. We discuss the results obtained in an ongoing study devoted to probe the feedback of activity from nearby Seyferts to high-redshift QSO.     

Relation between the ＂Double-Hump＂ Behavior in the Radio Band and the Broad-Line Luminosity for Blazars

The physics behind the spectral energy distribution (SED) of blazars remains open.We assembled 36 blazars to tackle the factors that control their SED. Now, many blazar spectra have the "double hump" feature in the radio and far-IR frequencies. For these a parameter,△, is created to characterize the behavior of the SED. We found a significant correlation between the broad-line luminosity (LBLR) and △. Because LBLR is an indicator of the accreting power of the source in blazars, we derived a linear correlation,△∝ (M)1/3. 18, which suggests that the SED of blazars may depend on the accretion rate, like that of BL Lac objects. We also found a significant correlation between (m) and△ for a sample of 11 blazars (out of one of 36)with available black hole masses. This implies the Eddington accretion ratio may influence the shape of the SED of blazars.     

H i content in galaxies in loose groups

Gas deficiency in cluster spirals is well known and ram-pressure stripping is considered the main gas removal mechanism. In some compact groups too gas deficiency is reported. However, gas deficiency in loose groups is not yet well established. Lower dispersion of the member velocities and the lower density of the intragroup medium in small loose groups favour tidal stripping as the main gas removal process in them. Recent releases of data from the H  i Parkes All-Sky Survey (HIPASS) and catalogues of nearby loose groups with associated diffuse X-ray emission have allowed us to test this notion. In this paper, we address the following questions: (i) do galaxies in groups with diffuse X-ray emission statistically have lower gas content compared to the ones in groups without diffuse X-ray emission? (ii) does H  i deficiency vary with the X-ray luminosity, L _X, of the loose group in a systematic way? We find that (i) galaxies in groups with diffuse X-ray emission, on average, are H  i deficient, and have lost more gas compared to those in groups without X-ray emission; the latter are found not to have significant H  i deficiency; (ii) no systematic dependence of the H  i deficiency with L _X is found. Ram-pressure-assisted tidal stripping and evaporation by thermal conduction are the two possible mechanisms to account for this excess gas loss.     

Very Long Baseline Array imaging of a periodic 12.2-GHz methanol maser flare in G9.62+0.20E

The class II methanol maser source G9.62+0.20E undergoes periodic flares at both 6.7 and 12.2 GHz. The flare starting in 2001 October was observed at seven epochs over three months using the Very Long Baseline Array (VLBA) at 12.2 GHz. High angular resolution images (beam size  ∼1.7 × 0.6 mas  ) were obtained, enabling us to observe changes in 16 individual maser components. It was found that while existing maser spots increased in flux density, no new spots developed and no changes in morphology were observed. This rules out any mechanism which disturbs the masing region itself, implying that the flares are caused by a change in either the seed or pump photon levels. A time delay of one to two weeks was observed between groups of maser features. These delays can be explained by light travel time between maser groups. The regularity of the flares can possibly be explained by a binary system.