Timeline analysis and wavelet multiscale analysis of the AKARI All-Sky Survey at 90 μm

We present a careful analysis of the point-source detection limit of the AKARI All-Sky Survey in the WIDE-S 90-μm band near the North Ecliptic Pole (NEP). Timeline analysis is used to detect IRAS ( Infrared Astronomy Satellite ) sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90-μm flux of a source. Combined with a robust noise measurement, the point-source flux detection limit at signal-to-noise ratio  (S/N) > 5  for a single detector row is  1.1 ± 0.1 Jy  which corresponds to a point-source detection limit of the survey of ∼0.4 Jy.
Wavelet transform offers a multiscale representation of the Time Series Data ( tsd ). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4σ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non- IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non- IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.     

VLT‐CRIRES: “Good Vibrations” Rotational‐vibrational molecular spectroscopy in astronomy

Near‐Infrared high spectral and spatial resolution spectroscopy offers new and innovative observing opportunities for astronomy. The “traditional” benefits of IR‐astronomy – strongly reduced extinction and availability of adaptive optics – more than offset for many applications the compared to CCD‐based astronomy strongly reduced sensitivity. Especially in high resolution spectroscopy interferences by telluric lines can be minimized. Moreover for abundance studies many important atomic lines can be accessed in the NIR. A novel spectral feature available for quantitative spectroscopy are the molecular rotational‐vibrational transitions which allow for fundamentally new studies of condensed objects and atmospheres. This is also an important complement to radio‐astronomy, especially with ALMA, where molecules are generally only observed in the vibrational ground state. Rot‐vib transitions also allow high precision abundance measurements – including isotopic ratios – fundamental to understand the thermo‐nuclear processes in stars beyond the main sequence. Quantitative modeling of atmospheres has progressed such that the unambiguous interpretation of IR‐spectra is now well established. In combination with adaptive optics spectro‐astrometry is even more powerful and with VLT‐CRIRES a spatial resolution of better than one milli‐arcsecond has been demonstrated. Some highlights and recent results will be presented: our solar system, extrasolar planets, star‐ and planet formation, stellar evolution and the formation of galactic bulges (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Optical Design of Multilayer Achromatic Waveplate by Simulated Annealing Algorithm

We applied a Monte Carlo method-simulated annealing algorithm-to carry out the design of multilayer achromatic waveplate. We present solutions for three-, six-and ten-layer achromatic waveplates. The optimized retardance settings are found to be 89°51'39"±0°33'37" and 89°54'46"±0°22'4" for the six-and ten-layer waveplates, respectively, for a wavelength range from 1000nm to 1800nm. The polarimetric properties of multilayer waveplates are investigated based on several numerical experiments. In contrast to previously proposed three-layer achromatic waveplate, the fast axes of the new six-and ten-layer achromatic waveplate remain at fixed angles, independent of the wavelength. Two applications of multilayer achromatic waveplate are discussed, the general-purpose phase shifter and the birefringent filter in the Infrared Imaging Magnetograph (IRIM) system of the Big Bear Solar Observatory (BBSO). We also checked an experimental method to measure the retardance of waveplates.     

Infrared spectral evolution of carbon stars

We collected almost all Highly Processed Data Products(HPDP)of ISO SWS01 spectra for the Galactic visual carbon stars,infrared carbon stars,extreme carbon stars and carbon-rich proto-planetary nebulae(PPNs).Those infrared spectra are primarily analyzed and discussed.It is shown that either spectral shapes/peaks,or main molecular/dust features are evidenced to change in the sequence of visual carbon stars,infrared carbon stars,extreme carbon stars and carbon-rich PPNs.Statistically,in this sequence,continua are gradually changed from blue to red and locations of spectral peaks of continua are also gradually changed from short wavelengths to long wavelengths.In addition,in this sequence,intensifies of main molecular/dust features are also gradually changed from prominent in the short wavelengths to prominent in the long wavelengths.Furthermore,from 2MASS and IRAS photometric data,the sequence is also proved.Results in this paper strongly support the previous suggestion for the evolution sequence of carbon-rich objects in our Galaxy,that is the sequence of visual carbon stars→infrared carbon stars→extreme carbon stars→carbon-rich PPNs.     

年轻星天体喷流的近红外成像观测进展

分子氢的红外振动发射线是显现年轻星质量外流的重要谱线之一。自Gautier等人1976年在猎户座发现年轻星质量外流的分子氢发射开始,人们在银河系内几乎所有的恒星形成区都发现了这种线发射。研究表明,分子氢发射与年轻星周围的其它活动现象（如分子外流和光学喷流）之间有着非常密切的联系。红外和光学喷流代表了年轻星剧烈活动的两个侧面,是喷流与周围介质相互作用强弱不同的表现,这种作用还拖带周围介质,产生分子外流,光学、红外喷流和分子外流组成了恒星形成区壮观的景象,它们是恒星形成活动的重要标志。随着红外探测技术的飞速发展,对年轻星外流活动现象的观测越来越丰富的详细,使人们对这种现象的本质越来越了解。在20世纪90年代NICMOS等大阵列红外探测器投入使用后,红外成像观测有了长足的进步。目前已在70个左右的区域里发现了H2发射,这一数字还在迅速增加,今后的研究主要可能向两个方向发展。其一是高分辨观测,进一步了解H2发射的结构以及与光学喷流和分子外流之间的关系;其二是天观测,了解银河系内的恒星形成H2区发射的大尺度结构和恒星形成的统计分布规律。     

Evolutionary constraints from infrared source counts

The backward evolution approach to modelling galaxy source counts is re-visited in the wake of the numerous results and revelations from the Infrared Space Observatory ( ISO ), the Submillimetre Common User Bolometer Array (SCUBA) and the detections and measurements of the cosmic extragalactic background light. Using the framework of the Pearson & Rowan-Robinson galaxy evolution model, the observed source counts and background measurements are used to constrain the evolution in the galaxy population. It is found that a strong evolution in both density and luminosity of the high-luminosity tail of the infrared (IR) luminosity function, interpreted as the ultraluminous galaxies discovered first by IRAS and later elevated in status by SCUBA and ISO , can account for the source counts from 15 μm (where it matches the undulations in the integral counts and the hump in the differential counts extremely well) to the submillimetre region, as well as explain the peak in the cosmic infrared background at ∼140 μm. The submillimetre counts are interpreted as the superposition of two separate populations comprising ultraluminous infrared galaxies (ULIGs) at the brighter submillimetre fluxes and starburst galaxies at fluxes fainter than ∼2 mJy. In this scenario the high-redshift ULIGs are tenuously interpreted as the progenitors of today's giant elliptical (gE) galaxies.
All the source count models can be accessed via the world wide web at the URL http://www.ir.isas.ac.jp/~cpp/counts/     

天文用近红外焦平面阵列

总结了天文用红外焦平面阵列（IRFPA）的发展历程,阐述了IRFPA的结构,重点介绍了InSb、HgCdTe和Ptsi三种近红外探测器阵列,结合目前正在筹建的红外太阳塔计划,对其各项性能指标作了详细比较．     

Visible and Near-Infrared Contrast of Faculae in Active Region NOAA 8518

We compare the contrast of faculae, in visible light and in the near infrared (NIR), that were associated with the active region NOAA 8518 which crossed the solar disk from April 19 to 27, 1999. We obtained NIR continuum images at 1.6 μm at the Big Bear Solar Observatory (BBSO) with an Indium Gallium Arsenide (In Ga As) NIR digital camera. We also obtained high-resolution longitudinal magnetograms and visible light filtergrams at 610.3 nm with the newly developed Digital Vector Magnetograph (DVMG). Our data show that the contrast of faculae has the same sign in both the visible and the NIR. We did not find any so-called “dark faculae”, faculae that are bright in the visible and simultaneously dark in the NIR.We determined a threshold magnetic flux density that separates pores from faculae.     

The European Large Area ISO Survey – I. Goals, definition and observations

We describe the European Large Area ISO Survey (ELAIS). ELAIS was the largest single Open Time project conducted by ISO , mapping an area of 12 deg² at 15 μm with ISOCAM and at 90 μm with ISOPHOT. Secondary surveys in other ISO bands were undertaken by the ELAIS team within the fields of the primary survey, with 6 deg² being covered at 6.7 μm and 1 deg² at 175 μm.
This paper discusses the goals of the project and the techniques employed in its construction, as well as presenting details of the observations carried out, the data from which are now in the public domain. We outline the ELAIS 'preliminary analysis' which led to the detection of over 1000 sources from the 15 and 90-μm surveys (the majority selected at 15 μm with a flux limit of ∼3 mJy), to be fed into a ground-based follow-up campaign, as well as a programme of photometric observations of detected sources using both ISOCAM and ISOPHOT.
We detail how the ELAIS survey complements other ISO surveys in terms of depth and areal coverage, and show that the extensive multi-wavelength coverage of the ELAIS fields resulting from our concerted and on-going follow-up programme has made these regions amongst the best studied areas of their size in the entire sky, and, therefore, natural targets for future surveys. This paper accompanies the release of extremely reliable subsets of the 'preliminary analysis' products. Subsequent papers in this series will give further details of our data reduction techniques, reliability and completeness estimates and present the 15‐ and 90-μm number counts from the 'preliminary analysis', while a further series of papers will discuss in detail the results from the ELAIS 'final analysis', as well as from the follow-up programme.     

Boxy/peanut 'bulges': comparing the structure of galaxies with the underlying families of periodic orbits

The vertical profiles of disc galaxies are built by the material trapped around stable periodic orbits, which form their 'skeletons'. Therefore, knowledge of the stability of the main families of periodic orbits in appropriate 3D models enables one to predict possible morphologies for edge-on disc galaxies. In a pilot survey we compare the orbital structures that lead to the appearance of 'peanut'- and 'X'-like features with the edge-on profiles of three disc galaxies (IC 2531, NGC 4013 and UGC 2048). The subtraction from the images of a model representing the axisymmetric component of the galaxies reveals the contribution of the non-axisymmetric terms. We find a direct correspondence between the orbital profiles of 3D bars in models and the observed main morphological features of the residuals. We also apply a simple unsharp masking technique in order to study the sharpest features of the images. Our basic conclusion is that the morphology of the boxy 'bulges' of these galaxies can be explained by considering disc material trapped around stable 3D periodic orbits. In most models, these building-block periodic orbits are bifurcated from the planar central family of a non-axisymmetric component, usually a bar, at low-order vertical resonances. In such a case, the boxy 'bulges' are parts of bars seen edge-on. For the three galaxies we study, the families associated with the 'peanut' or 'X'-shape morphology are probably bifurcations at the vertical 2/1 or 4/1 resonance.     

On the Carbon—Star Status of Five Stars in a New Carbon Star Catalog

We find that five sources listed in the new carbon star catalog are not really carbon-rich objects but oxygen-rich stars, because they all have the prominent 10μm silicate features in absorption and the 1612MHz OH maser emission or/and the SiO molecular features. These objects were considered as carbon stars in the catalog based only on their locations in the infrared two-color diagram. Therefore to use the infrared two-color diagram to distinguish carbon-rich stars from oxygenrich stars must be done with caution, because, in general, it has only a statistical meaning.     

Sh2-205 – II. Quiescent star-formation activity

We present a study of active star-forming regions in the environs of the H  ii region Sh2-205. The analysis is based on data obtained from point source catalogues and images extracted from the Two-Micron All-Sky Survey (2MASS), Midcourse Space Experiment ( MSX ) and IRAS surveys. Complementary data are taken from a CO survey. The identification of primary candidates for star-formation activity is made following colour criteria and a correlation with molecular gas emission.
A number of star-formation tracer candidates are projected on to two substructures of the H  ii region: SH 148.83–0.67 and SH 149.25–0.00. However, the lack of molecular gas related to these structures casts doubt on the nature of the sources. Additional infrared sources may be associated with the H  i shell centred at  ( l , b ) = (149°0', −1°30')  .
The most striking active area was found in connection with the H  ii region LBN 148.11–0.45, where star-formation candidates are projected on to molecular gas. The analytical model of the 'collect and collapse' process shows that star-formation activity could have been triggered by the expansion of this H  ii region.     

AGB星的ISO观测

概述了ＩＲＡＳ升空以来在ＡＧＢ星研究方面的进展和发现的问题,比较详细地报告了６０ｃｍ空间红外望远镜ＩＳＯ携带的探测器及其性能,以及它的成像和光谱观测对研究ＡＧＢ星的演化的影响,尤其是对ＡＧＢ星星周包层的化学环境的研究的重要作用。