Collections of stellar spectra, often called stellar libraries, are useful in a variety of applications in the field of stellar populations. This is an attempt to improve the much-used Lick library of stellar spectra by removing jitter from the wavelength scale via cross-correlation, and calling the result the LickX library.
The LIFE Target Star Database contains information useful
for the planned `LIFE mission`_ (mid-ir, nulling
interferometer in space). It characterizes possible
target systems including information about stellar,
planetary and disk properties. The data itself is mainly
a collection from different other catalogs.
Note that LIFE's target database is living
data. The content – and to some extent even structure – of these
tables may change at any time without prior warning.
.. _LIFE mission: https://life-space-mission.com/
The X-ray luminosity-temperature relation for nearby T ~= 3.5-10 keV clusters is rederived using new ASCA temperatures and ROSAT luminosities. Both quantities are derived by directly excluding the cooling flow regions. This correction results in a greatly reduced scatter in the L_X_-T relation; cooling flow clusters are similar to others outside the small cooling flow regions. For a fit of the form L_bol_ {prop.to} T^{alpha}^, we obtain {alpha} = 2.64 +/- 0.27 (90%) and a residual rms scatter in log L_bol_ of 0.10. The derived relation can be directly compared to theoretical predictions that do not include radiative cooling. It also provides an accurate reference point for future evolution searches and comparison to cooler clusters. The new temperatures and L_X_-T relation together with a newly selected cluster sample are used to update the temperature function at z ~ 0.05. The resulting function is generally higher and flatter than, although within the errors of, the previous estimates by Edge and coworkers and Henry and Arnaud (as rederived by Eke and coworkers). For a qualitative estimate of constraints that the new data place on the density fluctuation spectrum, we apply the Press-Schechter formalism for {Omega}_0_ = 1 and 0.3. For {Omega}_0_ = 1, assuming cluster isothermality, the temperature function implies {sigma}_8_ = 0.55 +/- 0.03, while taking into account the observed cluster temperature profiles, {sigma}_8_ = 0.51 +/- 0.03, consistent with the previously derived range. The dependence of {sigma}_8_ on {Omega}_0_ is different from the earlier results because of our treatment of the slope of the fluctuation spectrum, n, as a free parameter. For the considered values of {Omega}_0_, n = -(2.0-2.3) +/- 0.3, somewhat steeper than that derived from the earlier temperature function data, in agreement with the local slope of the galaxy fluctuation spectrum from the Automatic Plate Measuring Facility (APM) survey, and significantly steeper than the standard cold dark matter prediction.
The Magellanic system comprises the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the less frequently observed Magellanic Bridge and Magellanic Stream. The Bridge is traced by neutral gas and has an observed stellar component, while the Stream consists of gas only, with no observed stellar counterpart to date. This study uses catalogues created in the direction of the Bridge from 2MASS and WISE to investigate the stellar content of the Magellanic Bridge.
The Magellanic Catalogue of Stars (MACS) is based on scans of ESO Schmidt plates and contains about 244,000 stars covering large areas around the LMC and the SMC. The limiting magnitude is B<16.5m and the positional accuracy is better than 0.5" for 99% of the stars. The stars of this catalogue were screened interactively to ascertain that they are undisturbed by close neighbours.
The magnetic field (B-field) of the starless dark cloud L1544 has been studied using near-infrared (NIR) background starlight polarimetry (BSP) and archival data in order to characterize the properties of the plane-of-sky B-field. NIR linear polarization measurements of over 1700 stars were obtained in the H band and 201 of these were also measured in the K band. The NIR BSP properties are correlated with reddening, as traced using the Rayleigh-Jeans color excess (H-M) method, and with thermal dust emission from the L1544 cloud and envelope seen in Herschel maps. The NIR polarization position angles change at the location of the cloud and exhibit their lowest dispersion there, offering strong evidence that NIR polarization traces the plane-of-sky B-field of L1544. In this paper, the uniformity of the plane-of-sky B-field in the envelope region of L1544 is quantitatively assessed. This allows evaluation of the approach of assuming uniform field geometry when measuring relative mass-to-flux ratios in the cloud envelope and core based on averaging of the radio Zeeman observations in the envelope, as done by Crutcher et al. (2009ApJ...692..844C). In L1544, the NIR BSP shows the envelope B-field to be significantly non-uniform and likely not suitable for averaging Zeeman properties without treating intrinsic variations. Deeper analyses of the NIR BSP and related data sets, including estimates of the B-field strength and testing how it varies with position and gas density, are the subjects of later papers in this series.
The WATTS' charts provide the elevation of the limb of the moon using 1800 contour maps (step of 0.2deg) that cover all libration ranges of the moon. The contours of the maps were digitised by H.M. Nautical Almanac Office in the late 1960's, and then converted to a grid format by US Naval Observatory in the early 1970's. These charts are present in 2 forms: as an ascii file watts.dat (without carriage-return or line-feed!), or as a 3-D FITS file watts.fit (transformed from the ascii files with the program "make_fit.c"). More details, especially about the transformations between the original charts and the files stored here, and the special processing of the 36.0{deg} map (map#181), can be found in the "doc.txt" file.
Mark-I is a solar spectrophotometer located and operated at Observatorio del Teide (Tenerife, Canary Islands, Spain) that provides precise radial velocity observations of the Sun-as-a-star at the Potassium KI 7699A absorption solar line. Observations extend from 1976 to 2012 with only summer campaigns from 1976 to 1983.
We present data from a moderately deep spectroscopic Schmidt survey (B_lim_=17.5) of "active galaxies" selected by the presence of emission lines in their spectra and/or their UV excess. 92 emission line objects have been found in two adjacent fields (approximately 50deg^2^) in the direction of the southern extension of the Virgo cluster. We give a catalog containing positions, photographic R and B magnitudes, U-R colors, effective diameters, redshifts, equivalent widths and intensity ratios of the [OIII]{lambda}{lambda}4959,5007, H{beta} and [OII]{lambda}3727 emission lines. On these fields, we evaluate the completeness limit of the survey at a pseudo B magnitude values of 15.7. A more elaborate astrophysical analysis will appear in a forthcoming paper.
Sternberg Astronomical Institute Virtual Observatory Project
Description:
The Two Micron All Sky Survey (2MASS) project is designed to close the
gap between our current technical capability and our knowledge of the
near-infrared sky. In addition to providing a context for the
interpretation of results obtained at infrared and other wavelengths,
2MASS will provide direct answers to immediate questions on the
large-scale structure of the Milky Way and the Local Universe.
To achieve these goals, 2MASS is uniformly scanning the entire sky in
three near-infrared bands to detect and characterize point sources
brighter than about 1 mJy in each band, with signal-to-noise ratio
(SNR) greater than 10, using a pixel size of 2.0". This will achieve
an 80,000-fold improvement in sensitivity relative to earlier surveys.
2MASS uses two new, highly-automated 1.3-m telescopes, one at Mt.
Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a
three-channel camera, each channel consisting of a 256x256 array of
HgCdTe detectors, capable of observing the sky simultaneously at J
(1.25 {mu}m), H (1.65 {mu}m), and Ks (2.17 {mu}m), to a 3{sigma}
limiting sensitivity of 17.1, 16.4 and 15.3mag in the three bands.
The 2MASS arrays image the sky while the telescopes scan smoothly in
declination at a rate of ~1' per second. The 2MASS data "tiles" are 6
deg. long in the declination direction and one camera frame (8.5')
wide. The camera field-of-view shifts by ~1/6 of a frame in
declination from frame-to-frame. The camera images each point on the
sky six times for a total integration time of 7.8 s, with sub-pixel
"dithering", which improves the ultimate spatial resolution of the
final Atlas Images.
The University of Massachusetts (UMass) is responsible for the overall
management of the project, and for developing the infrared cameras and
on-site computing systems at both facilities. The Infrared Processing
and Analysis Center (IPAC) is responsible for all data processing
through the Production Pipeline, and construction and distribution of
the data products. The 2MASS project involves the participation of
members of the Science Team from several different institutions. The
2MASS project is funding by the National Aeronautics and Space
Administration (NASA) and the National Science Foundation (NSF).
Acknowledging 2MASS in publications:
Please include the following in any published material that makes use
of the 2MASS data products:
"This publication makes use of data products from the Two Micron All
Sky Survey, which is a joint project of the University of Massachusetts
and the Infrared Processing and Analysis Center/California Institute of
Technology, funded by the National Aeronautics and Space Administration
and the National Science Foundation."
