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The US Geological Survey operates an automated observatory dedicated to the radiometry of the Moon with the objective of developing a multispectral, spatially resolved photometric model of the Moon to be used in the calibration of Earth‐orbiting spacecraft. Interference filters are used with two imaging instruments to observe the Moon in 32 passbands from 350–2500 nm. Three computers control the telescope mount and instruments with a fourth computer acting as a master system to control all observation activities. Real‐time control software has been written to operate the instrumentation and to automate the observing process. The observing software algorithms use information including the positions of objects in the sky, the phase of the Moon, and the times of evening and morning twilight to decide how to observe program objects. The observatory has been operating in a routine mode since late 1995 and is expected to continue through at least 2002 without significant modifications.

We present an analysis of the photometric data on V529 CrA. The data include published photographic data as well as our own UBV(RI)_C measurements. Two dominant modulations with periods of 23.571 and 761.5 days are present in the light curve. The double of the 23.571 day period (47.142 days) shows the alternating deep/shallow minima behavior of the RV Tauri class of variables, while the presence of a longer modulation indicates a classification in the photometric subclass RVb. Medium‐resolution optical spectroscopy is also presented.

The intriguing nearly face-on southern ringed spiral galaxy NGC 4622, the first galaxy definitively shown to have leading spiral structure, is revisited in this paper with new images from the Hubble Space Telescope's (HST) WFPC2, together with ground-based optical and near-IR imaging, and a Fabry-Perot Hα velocity field. The data provide new information on the disk/bulge/halo mix, rotation curve, star formation in the galaxy, and the sense of winding of its prominent spiral arms. Previously, we suggested that the weaker, inner single arm most likely has the leading sense, based on a numerical simulation. Now, taking advantage of HST resolution and using de Vaucouleurs' standard extinction and reddening technique to determine the near side of the galaxy's slightly tilted disk, we come to the more surprising conclusion that the two strong outer arms have the leading sense. We suggest that this highly unusual configuration may be the result of a past minor merger or mild tidal encounter. Possible evidence for a minor merger is found in a short, central dust lane, although this is purely circumstantial and an unrelated interaction with a different companion could also be relevant. The leading arms may be allowed to persist because NGC 4622 is dark halo dominated (i.e., not "maximum disk" in the inner regions) and displays a significantly rising rotation curve. The new HST observations also reveal a rich globular cluster system in the galaxy. The mean color of these clusters is (V-I)₀ = 1.04, and the specific frequency is 3.4 ± 0.6. The luminosity function of these clusters confirms the membership of NGC 4622 in the Centaurus Cluster.

Forty molecular cloud cores in the southern hemisphere from the initial Spitzer Space Telescope Cores-to-Disks (c2d) Legacy program source list have been surveyed in ¹³CO(2→1), ¹²CO(4→3), and ¹²CO(7→6) with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO). The cores, 10 of which contain embedded sources, are located mostly in the Vela, Ophiuchus, Lupus, Chamaeleon, Musca, and Scorpius complexes. ¹²CO(7→6) emission was undetected in all 40 clouds. We present data of 40 sources in ¹³CO(2→1) and ¹²CO(4→3), significant upper limits of ¹²CO(7→6), as well as a statistical analysis of the observed properties of the clouds. We find the typical ¹³CO(2→1) line width to be 2.0 km s^-1 for cores with embedded stars and 1.8 km s^-1 for all others. The typical ¹²CO(4→3) line width is 2.6-3.7 km s^-1 for cores with known embedded sources, and 1.6-2.3 km s^-1 for all others. The average ¹³CO column density derived from the line intensities was found to be 1.9 × 10¹⁵ cm^-2 for cores with embedded stars and 1.5 × 10¹⁵ cm^-2 for all others. The average kinetic temperature in the molecular cores, determined through a large velocity gradient analysis of a set of nine cores, has an average lower limit of 16 K and an average upper limit of 26 K. The average molecular hydrogen density has an average lower limit of 10 ^2.9 cm^-3 and an average upper limit of 10^3.3 cm^-3 for all cores. For a different subset of nine cores, we have derived masses. They range from 4 to 255 M_☉. Overall, our c2d sample of southern molecular cores has a range of properties (line width, column density, size, mass, embedded stars) similar to those of past studies.

Optical images of SN 1987A show a triple-ring structure. The inner (dust) ring has recently increased in brightness and in the number of hot spots, suggesting that the supernova shock wave has collided with the dense preexisting circumstellar medium, a scenario supported by radio and X-ray observations. Such a shocked environment is widely expected to result in the acceleration of charged particles and the accompanying emission of very high energy gamma-rays. Here we report the results of observations made in 2004 and 2006, yielding upper limits on the TeV gamma-ray flux, which are compared with a theoretical prediction. In addition, we set upper limits on the TeV flux for four high-energy objects which are located within the same field of view of the observation: the superbubble 30 Dor C, the Crab-like pulsar PSR B0540–69, the X-ray binary LMC X-1, and the supernova remnant N157B.

The AKARI All-Sky Catalogues are an important infrared astronomical database for next-generation astronomy that take over the IRAS catalog. We have developed an online service, AKARI Catalogue Archive Server (AKARI-CAS), for astronomers. The service includes useful and attractive search tools and visual tools. One of the new features of AKARI-CAS is cached SIMBAD/NED entries, which can match AKARI catalogs with other catalogs stored in SIMBAD or NED. To allow advanced queries to the databases, direct input of SQL is also supported. In those queries, fast dynamic cross-identification between registered catalogs is a remarkable feature. In addition, multiwavelength quick-look images are displayed in the visualization tools, which will increase the value of the service. In the construction of our service, we considered a wide variety of astronomers' requirements. As a result of our discussion, we concluded that supporting users' SQL submissions is the best solution for the requirements. Therefore, we implemented an RDBMS layer so that it covered important facilities, including the whole processing of tables. We found that PostgreSQL is the best open-source RDBMS products for such purpose, and we wrote codes for both simple and advanced searches into the SQL stored functions. To implement such stored functions for fast radial search and cross-identification with minimum cost, we applied a simple technique that is not based on HTM or HEALPix. In contrast, the online application layer became compact and was written in simple procedural PHP codes. In total, our system realizes cost-effective maintenance and enhancements.

This investigation presents a photometric study of the Galactic structure toward the Carina arm tangent. The field is located between 280° and 286° Galactic longitude and -4° to 4° Galactic latitude. All currently available uvbyβ data are used to obtain homogeneous color excesses and distances for more than 260 stars of spectral types O to G. We present revised distances and average extinction for the open clusters and cluster candidates NGC 3293, NGC 3114, Lodén 46, and Lodén 112. The cluster candidate Lodén 112 appears to be a very compact group at a true distance modulus of 11.06 ± 0.11(s.e.) (), which is significantly closer than previous estimates. We found other OB stars at that same distance and, based on their proper motions, suggest a new OB association at coordinates 282° < l < 285° and -2° < b < 2°. Utilizing BV photometry and spectral classification of the known O-type stars in the very young open cluster Wd 2, we provide a new distance estimate of 14.13 ± 0.16 (s.e.) (), in excellent agreement with recent distance determinations to the giant molecular structures in this direction. We also discuss a possible connection between the H ii region RCW 45 and the highly reddened B+ star CPD -553036 and provide a revised distance for the luminous blue variable HR Car.

We present a second catalog of H i sources detected in the Arecibo Legacy Fast ALFA Survey. We report 488 detections over 135 deg², within the region of the sky having 22 h < α < 03 h and +26° < δ < +28°. We present here the detections that have either (a) S/N>6.5, where the reliability of the catalog is better than 95% or (b) 5.0 < S/N < 6.5 and a previously measured redshift that corroborates our detection. Of the 488 objects presented here, 49 are high-velocity clouds or clumps thereof with negative heliocentric recession velocities. These clouds are mostly very compact and isolated, while some of them are associated with large features such as Wright's Cloud or the northern extension of the Magellanic Stream. The remaining 439 candidate detections are identified as extragalactic objects and have all been matched with optical counterparts. Five of the six galaxies detected with $M_{{\rm H}\,{\mathsc{i}}}<10^{7.5}$ M_☉ are satellites of either the NGC672/IC1727 nearby galaxy pair or their neighboring dwarf irregular galaxy NGC784. The data of this catalog release include a slice through the Pisces–Perseus foreground void, a large nearby underdensity of galaxies. We report no detections within the void, where our catalog is complete for systems with ${\rm H}\,\mathsc{i}$ masses of 10⁸ M_☉. Gas-rich, optically-dark galaxies do not seem to constitute an important void population, and therefore do not suffice for producing a viable solution to the void phenomenon.

We have developed a method for recovering polarization structures from the NRAO Very Large Array Sky Survey (NVSS) on larger angular scales than the nominal 15 arcmin survey limit. The technique depends on the existence of smaller-scale fluctuations in the polarization angle, to which the interferometer is sensitive, while the undetected total intensity of the structures can be arbitrarily large. We recover the large-scale structure of the polarized Milky Way, as seen in single-dish surveys, as well as a wide variety of smaller-scale Galactic and extragalactic features. We present a brief discussion of the uncertainties and limitations of the reprocessed NVSS polarization survey, a comparison of single-dish and NVSS results, and a sampling of the new polarization structures. We show a companion feature 1.8 Mpc outside of Abell cluster 3744, apparent Mpc-scale extensions to the tailed radio galaxy 3C31, a possible new giant Galactic loop, and a new bright polarized patch in supernova remnant CTA1. We note that there is little quantitative information from these detections, and follow-up investigations would be necessary to measure reliable polarized fluxes and position angles. Some of the new features discovered in this NVSS reanalysis could provide a foreground for cosmic microwave background polarization studies, but the internal foreground modeling for the next generation of experiments should have no difficulty accounting for them.

We present a study of the spectral, polarimetric, morphological, and environmental properties of the diffuse radio source 0809+39 using observations taken with the Westerbork Synthesis Radio Telescope, the Very Large Array, and archival optical and X-ray data. The source has two distinct diffuse, steep-spectrum components, one in the north that is highly polarized, and a linear southern component undetected in polarization. We discuss several plausible origins for each component, and conclude that the northern bright polarized component is most likely a radio relic associated with a poor z ∼ 0.2 cluster of galaxies, with a radio/X-ray luminosity ratio two orders of magnitude above typical values. The southern component is aligned with a more extended filament of galaxies ∼5 Mpc long at z ∼ 0.04. Deep optical and X-ray follow-ups are still needed in order to confirm and understand the physical origins of the synchrotron emission. Whatever the details of these origins, 0809+39 highlights the utility of synchrotron radiation for illuminating the diffuse components of low density environments unrelated to rich clusters.