The NPM2 Catalog is the second part of the Lick Northern Proper Motion (NPM) program to measure absolute proper motions, on an inertial system defined by distant galaxies, for nearly 400,000 stars over a blue apparent magnitude range from 8 to 18. There are 1246 6x6degree fields in the NPM survey (to declination -23 degrees). The NPM2 Catalog covers the 28% of the northern sky lying near the plane of the the Milky Way and contains some 232,000 stars in the 347 NPM fields remaining after the 1993 NPM1 Catalog (149,000 stars in 899 fields away from the Milky Way). Each NPM field was photographed with the 51cm Carnegie Double Astrograph at two epochs between 1947 and 1988. The mean first and second epochs are 1950 and 1977; the average epoch difference is 27 years. The first-epoch plates were taken in the blue only; both blue and yellow plates were taken at the second epoch. For NPM2, the plates were scanned by the Precision Measuring Machine (PMM) at the US Naval Observatory, Flagstaff. From the PMM scans, 120,000 faint (B>14) stars were chosen anonymously for the NPM astrometric reductions and for statistical studies of stellar motions. The NPM2 catalog also contains 92,000 bright (B<14) positional reference stars, mostly from the Tycho-2 Catalogue, and 35,000 stars chosen for astronomical interest from Klemola's "Lick Input Catalog of Special Stars". (These categories overlap). Details of the NPM2 star selection, data reductions, and catalog compilation will be presented in a paper being prepared for the Astronomical Journal. The completed version of the NPM2 Catalog totals 232,062 stars from all 347 NPM2 fields; it supersedes the September 2002 preliminary version (295 fields). Together with the NPM1 Catalog (Cat. I/199, or http://www.ucolick.org/~npm/NPM1/) the NPM2 Catalog completes the Lick Northern Proper Motion program after more than a half-century of work by three generations of Lick Observatory astronomers. The NPM2 catalog gives J2000 positions computed for the catalog epoch 2000, and is ordered in 108 one-degree declination zones from +83 degrees to -23 degrees. Following the convention of the NPM1 catalog, each NPM2 star has an NPM2 "name" (e.g. +83.0001) reflecting the declination zone and a running number in right ascension order within the zone. The NPM2 Catalog is also available as 108 separate files, one for each declination zone from +83 degrees (z+83n) to -23 degrees (z-23n), from http://www.ucolick.org/~npm/NPM2/zones/ Each star's entry includes the absolute proper motion and blue (B) magnitude. For 98.5% of the stars the B-V color is also given. Other data given for each star are: the original mean epoch, a stellar class code, the number of NPM fields on which the star was measured, and discrepancy flags for proper motion, and photometry. Tycho-2 numbers are given for the primary positional reference stars (40% of NPM2); for these stars the Tycho B,V photometry, transformed to Johnson B and B-V, has been averaged with the NPM2 photographic photometry, with appropriate weights. ACRS and Hipparcos numbers are also given for NPM2 stars selected from those catalogs. The RMS precision of the NPM2 individual proper motions is about 0.6"/cent (6mas/yr) in each coordinate, comparable to the NPM1 errors. The NPM2 relative proper motions in each field were reduced to absolute (ICRS system) using an average of 370 Tycho-2 stars per NPM2 field. Magnitude-dependent systematic errors for the brightest (8<B<12) NPM2 stars were removed in the same reductions. The RMS accuracy of the proper motion zero point in each field is about 0.05"/cent (0.5mas/yr) in each coordinate. The RMS position errors at the NPM2 catalog epoch 2000 average about 0.2" (200mas) in each coordinate, due mostly to the accumulated proper motion error from original plate epochs (average 1968) to 2000. The pure positional errors at the original epochs average 0.08" (80mas) in each coordinate. The RMS errors for the NPM photographic photometry average about 0.18mag in B, and 0.20 mag in B-V. We thank the National Science Foundation for its long-term support of the NPM program. The NPM2 phase was supported by NSF grants AST-9530632 and AST-9988105. We thank the Yale Southern Proper Motion group (W. van Altena, I. Platais, and T. Girard) for their help in developing software to process the PMM plate scans.
We present the classification of 197 point sources observed with the Infrared Spectrograph in the SAGE-Spec Legacy programme on the Spitzer Space Telescope. We introduce a decision-tree method of object classification based on infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership and variability information, which is used to classify the SAGE-Spec sample of point sources. The decision tree has a broad application to mid-infrared spectroscopic surveys, where supporting photometry and variability information are available. We use these classifications to make deductions about the stellar populations of the Large Magellanic Cloud and the success of photometric classification methods. We find 90 asymptotic giant branch (AGB) stars, 29 young stellar objects, 23 post-AGB objects, 19 red supergiants, eight stellar photospheres, seven background galaxies, seven planetary nebulae, two HII regions and 12 other objects, seven of which remain unclassified.
This is the second of two papers describing the observations and source catalogues derived from sensitive $3$-GHz images of the Lockman Hole North using the Karl G. Jansky Very Large Array. We describe the reduction and cataloguing process, which yielded an image with 8-arcsec resolution and instrumental noise of {sigma}_n=1.01uJy/beam rms (before primary beam corrections) and a catalogue of 558 sources detected above 5{sigma}_n. We include details of how we estimate source spectral indices across the 2GHz VLA bandwidth, finding a median index of -0.76+/-0.04. Stacking of source spectra reveals a flattening of spectral index with decreasing flux density. We present a source count derived from the catalogue. We show a traditional count estimate compared with a completely independent estimate made via a P(D) confusion analysis, and find very good agreement. Cross-matches of the catalogue with X-ray, optical, infrared, radio, and redshift catalogues are also presented. The X-ray, optical and infrared data, as well as AGN selection criteria allow us to classify 10 per cent as radio-loud AGN, 28 percent as radio-quiet AGN, and 58 per cent as star-forming galaxies, with only 4 per cent unclassified.
A well known property of the {gamma}-ray sources detected by Cos-B in the 1970s, by the Compton Gamma-Ray Observatory in the 1990s, and recently by the Fermi observations is the presence of radio counterparts, particularly for those associated with extragalactic objects. This observational evidence is the basis of the radio-{gamma}-ray connection established for the class of active galactic nuclei known as blazars. In particular, the main spectral property of the radio counterparts associated with {gamma}-ray blazars is that they show a flat spectrum in the GHz frequency range. Our recent analysis dedicated to search blazar-like candidates as potential counterparts for the unidentified {gamma}-ray sources allowed us to extend the radio-{gamma}-ray connection in the MHz regime. We also showed that blazars below 1GHz maintain flat radio spectra. Thus, on the basis of these new results, we assembled a low-frequency radio catalog of flat-spectrum sources built by combining the radio observations of the Westerbork Northern Sky Survey and of the Westerbork in the southern hemisphere catalog with those of the NRAO Very Large Array Sky survey (NVSS). This could be used in the future to search for new, unknown blazar-like counterparts of {gamma}-ray sources. First, we found NVSS counterparts of Westerbork Synthesis Radio Telescope radio sources, and then we selected flat-spectrum radio sources according to a new spectral criterion, specifically defined for radio observations performed below 1GHz. We also described the main properties of the catalog listing 28358 radio sources and their logN-logS distributions. Finally, a comparison with the Green Bank 6cm radio source catalog was performed to investigate the spectral shape of the low-frequency flat-spectrum radio sources at higher frequencies.
We present the results of a search for all embedded protostars with internal luminosities <=1.0L_{sun}_ in the full sample of nearby, low-mass star-forming regions surveyed by the Spitzer Space Telescope Legacy Project "From Molecular Cores to Planet Forming Disks" (c2d). We present a set of selection criteria used to identify candidates from the Spitzer data and examine complementary data to decide whether each candidate is truly an embedded protostar. Between 75% and 85% of cores classified as starless prior to being observed by Spitzer remain starless to our luminosity sensitivity; the remaining 15%-25% harbor low-luminosity, embedded protostars. We compile complete spectral energy distributions for all 50 objects and calculate standard evolutionary signatures (L_bol_, T_bol_, and L_bol_/L_smm_) and argue that these objects are inconsistent with the simplest picture of star formation, wherein mass accretes from the core onto the protostar at a constant rate.
We determine the ages of the young, resolved stellar populations at the locations of 237 optically identified supernova remnants in M83. These age distributions put constraints on the progenitor masses of the supernovae that produced 199 of the remnants. The other 38 show no evidence for having a young progenitor and are therefore good Type Ia SNR candidates. Starting from Hubble Space Telescope broadband imaging, we measured resolved stellar photometry of seven archival WFC3/UVIS fields in F336W, F438W, and F814W. We generate color-magnitude diagrams of the stars within 50pc of each SNR and fit them with stellar evolution models to obtain the population ages. From these ages we infer the progenitor mass that corresponds to the lifetime of the most prominent age within the past 50Myr. In this sample, there are 47 SNRs with best-fit progenitor masses >15M_{sun}_, and 5 of these are >15M_{sun}_ at 84% confidence. This is the largest collection of high-mass progenitors to date, including our highest-mass progenitor inference found so far, with a constraint of <8Myr. Overall, the distribution of progenitor masses has a power-law index of -3.0_-0.7_^+0.2^, steeper than Salpeter initial mass function (-2.35). It remains unclear whether the reason for the low number of high-mass progenitors is due to the difficulty of finding and measuring such objects or because only a fraction of very massive stars produce supernovae.
A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to K_s_=11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10^11^ and 10^15^M_{sun}_. Group masses inferred from K_s_ luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3000 and 10000km/s. The 24044 galaxies in this range are identified with 13607 entities, 3461 of them with two or more members. A group mass function is constructed. The Sheth-Tormen formalism provides a good fit to the shape of the mass function for group masses above 6h^-1^x10^12^M_{sun}_ but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3000 and 10000km/s gives a density of collapsed matter as a fraction of the critical density of {Omega}_collapsed_=0.16.
We aim to provide a list of sources found to be unresolved from direct observations with high angular resolution and dynamic range, which can be used to choose interferometric calibrators. To this purpose, we have used a large number of lunar occultations recorded with the ISAAC instrument at the Very Large Telescope to select sources found to be unresolved and without close companions. An algorithm has been used to determine the limiting angular resolution achieved for each source, taking into account a noise model built from occulted and unocculted portions of the light curves. We have obtained upper limits on the angular sizes of 556 sources, with magnitudes ranging from Ks~4 to 10, with a median of 7.2mag. The upper limits on possible undetected companions (within ~0.5") range from Ks~8 to 13, with a median of 11.5mag. One-third of the sources have angular sizes <=1mas, and two-thirds have sizes <=2mas. This list of unresolved sources matches well the capabilities of current large interferometric facilities. We also provide available cross-identifications, magnitudes, spectral types, and other auxiliary information. A fraction of the sources are found to be potentially variable. The list covers parts of the Galactic Bulge and in particular the vicinity of the Galactic Center, where extinction is very significant and traditional lists of calibrators are often insufficient.
Master Catalogue towards the Magellanic Clouds (MC2)
Short Name:
IV/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Master Catalogue of stars towards the Magellanic Clouds (MC2) is a multi-wavelength reference catalogue. The current paper presents the first results of the MC2 project. We started with a massive cross-identification of the two recently released near-infrared surveys: the DENIS Catalogue towards the Magellanic Clouds (DCMC) with more than 1.3 million sources identified in at least two of the three DENIS filters (I J Ks) and the 2nd Incremental Release of the 2MASS point source catalogue (J H Ks) covering the same region of the sky. Both point source catalogues provide an unprecedented wealth of data on the stellar populations of the Magellanic Clouds (MCs). The cross-matching procedure has been extended to optical wavelength ranges, including the UCAC1 (USNO) and GSC2.2 catalogues. New cross-matching procedures for very large catalogues have been developed and important results on the astrometric and photometric accuracy of the cross-identified catalogues were derived. The cross-matching of large surveys is an essential tool to improve our understanding of their specific contents. This study has been partly supported by the ASTROVIRTEL project that aims at improving access to astronomical archives as virtual telescopes. This work has been supported by ASTROVIRTEL, a project funded by the European Commission under FP5 Contract No. HPRI-CT-1999-00081.
We present the first unbiased source catalog of the Monitor of All-sky X-ray Image (MAXI) mission at high Galactic latitudes (|b|>10{deg}), produced from the first 7-month data (2009 September 1 to 2010 March 31) of the Gas Slit Camera in the 4-10keV band. We have developed an analysis procedure to detect faint sources from the MAXI data, utilizing a maximum likelihood image fitting method, where the image response, background, and detailed observational conditions are taken into account. The catalog consists of 143 X-ray sources above the 7{sigma} significance level with a limiting sensitivity of ~1.5x10^-11^erg/cm^2^/s (1.2mCrab) in the 4-10keV band. Among them, we have identified 38 Galactic/LMC/SMC objects, 48 galaxy clusters, 39 Seyfert galaxies, 12 blazars, and 1 galaxy. Four other sources are confused with multiple objects, and one remains unidentified. The logN-logS relation of extragalactic objects is in good agreement with the HEAO-1 A-2 result, although the list of the brightest AGNs in the entire sky has significantly changed since that produced 30yr ago.
