This table contains a spectroscopic catalog of the 1564 brightest (J < 9^m) M-dwarf candidates in the northern sky, as selected from the SUPERBLINK proper-motion catalog (Lepine and Shara 2005, AJ, 129, 1483). Observations confirm 1408 of the candidates to be late-K and M dwarfs with spectral subtypes K7 - M6. From the low (mu > 40 mas yr^-1) proper motion limit and high level of completeness of the SUPERBLINK catalog in that magnitude range, the authors estimate that their spectroscopic census most likely includes > 90% of all existing, northern-sky M dwarfs with apparent magnitude J < 9^m. Only 682 stars in this sample are listed in the Third Catalog of Nearby Stars (CNS3, Gliese and Jahreiss 1991); most others are relative unknowns and have spectroscopic data presented here for the first time. Spectral subtypes are assigned based on spectral index measurements of CaH and TiO molecular bands; a comparison of spectra from the same stars obtained at different observatories, however, reveals that spectral band index measurements are dependent on spectral resolution, spectrophotometric calibration, and other instrumental factors. As a result, the authors find that a consistent classification scheme requires that spectral indices be calibrated and corrected for each observatory/instrument used. After systematic corrections and a recalibration of the subtype-index relationships for the CaH2, CaH3, TiO5, and TiO6 spectral indices, the authors find that they can consistently and reliably classify all the stars to a half-subtype precision. The use of corrected spectral indices further requires them to recalibrate the zeta parameter, a metallicity indicator based on the ratio of TiO and CaH optical bandheads. However, the authors find that their zeta values are not sensitive enough to diagnose metallicity variations in dwarfs of subtypes M2 and earlier (+/- 0.5 dex accuracy) and are only marginally useful at later M3-M5 subtypes (+/- 0.2 dex accuracy). Fits of their spectra to the Phoenix atmospheric model grid are used to estimate effective temperatures. These suggest the existence of a plateau in the M1-M3 subtype range, in agreement with model fits of infrared spectra but at odds with photometric determinations of T_eff. Existing geometric parallax measurements are extracted from the literature for 624 stars, and are used to determine spectroscopic and photometric distances for all the other stars. Active dwarfs are identified from measurements of H-alpha equivalent widths, and the authors find a strong correlation between H-alpha emission in M dwarfs and detected X-ray emission from ROSAT and/or a large UV excess in the GALEX point source catalog. Proper motion data and photometric distances are combined in order to evaluate the (U, V, W) distribution in velocity space, which is found to correlate tightly with the velocity distribution of G dwarfs in the solar neighborhood. However, active stars show a smaller dispersion in their space velocities, which is consistent with those stars being younger on average. The authors state that this catalog will be very useful for guiding the selection of the best M dwarf targets for exoplanet searches, in particular those using high-precision radial velocity measurements. This online catalog was created by the HEASARC in June 2013 based on a machine-readable version of Tables 1, 3 and 7 from the paper which were obtained from the AJ website (Tables 1 and 3) or from the first author (Table 7). This is a service provided by NASA HEASARC .

This table contains an all-sky catalog of M dwarf stars with apparent infrared magnitude J < 10. The 8889 stars are selected from the ongoing SUPERBLINK survey of stars with proper motion mu > 40 mas yr^-1, supplemented on the bright end with the Tycho-2 catalog. Completeness tests which account for kinematic (proper motion) bias suggest that this catalog represents ~75% of the estimated ~11,900 M dwarfs with J < 10 expected to populate the entire sky. The catalog is, however, significantly more complete for the northern sky (~90%) than it is for the south (~60%). Stars are identified as cool, red M dwarfs from a combination of optical and infrared color cuts, and are distinguished from background M giants and highly reddened stars using either existing parallax measurements or, if such measurements are lacking, using their location in an optical-to-infrared reduced proper motion diagram. These bright M dwarfs are all prime targets for exoplanet surveys using the Doppler radial velocity or transit methods; the combination of low-mass and bright apparent magnitude should make possible the detection of Earth-size planets on short-period orbits using currently available techniques. Parallax measurements, when available, and photometric distance estimates are provided for all stars, and these place most systems within 60 pc of the Sun. Spectral type estimated from V-J color shows that most of the stars range from K7 to M4, with only a few late M dwarfs, all within 20 pc. Proximity to the Sun also makes these stars good targets for high-resolution exoplanet imaging searches, especially if younger objects can be identified on the basis of X-ray or UV excess. For that purpose, we include X-ray flux from ROSAT and FUV/NUV ultraviolet magnitudes from GALEX for all stars for which a counterpart can be identified in those catalogs. Additional photometric data include optical magnitudes from Digitized Sky Survey plates and infrared magnitudes from the Two Micron All Sky Survey. This table was first created by the HEASARC in October 2011 based on electronic versions of Tables 1 and 2 from the reference paper which were obtained from the AJ web site. A slightly revised version based on corrected versions of the input tables received from the author was ingested in December 2011. This is a service provided by NASA HEASARC .

This table contains a new catalog of spectroscopically confirmed white dwarf stars from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) spectroscopic catalog. The authors find 20,407 white dwarf spectra, representing 19,712 stars, and provide atmospheric model fits to 14,120 DA and 1011 DB white dwarf spectra from 12,843 and 923 stars, respectively. These numbers represent more than a factor of two increase in the total number of white dwarf stars from the previous SDSS white dwarf catalogs based on DR4 data. The distribution of subtypes varies from previous catalogs due to the authors' more conservative, manual classifications of each star in our catalog, supplementing their automatic fits. In particular, they find a large number of magnetic white dwarf stars whose small Zeeman splittings mimic increased Stark broadening that would otherwise result in an overestimated log g if fit as a non-magnetic white dwarf. The authors calculate mean DA and DB masses for their clean, non-magnetic sample and find the DB mean mass is statistically larger than that for the DAs. This table lists the 20,407 white dwarf spectra corresponding to 19,712 distinct stars. This table was created by the HEASARC in January 2013 based on the electronic version of Table 2 from the reference paper which was obtained from the ApJS web site. One duplicate entry was removed from the table in June 2019. This is a service provided by NASA HEASARC .

Planets orbiting within the close-in habitable zones of M dwarf stars will be exposed to elevated high-energy radiation driven by strong magnetohydrodynamic dynamos during stellar youth. Near-ultraviolet (NUV) irradiation can erode and alter the chemistry of planetary atmospheres, and a quantitative description of the evolution of NUV emission from M dwarfs is needed when modeling these effects. The authors investigated the NUV luminosity evolution of early M-type dwarfs by cross-correlating the Lepine & Gaidos (LG11: 2011, AJ, 142, 138) catalog of bright M dwarfs (available at the HEASARC as the MDWARFASC table) with the Galaxy Evolution Explorer (GALEX) catalog of NUV (1771-2831 Angstrom) sources. Of the 4,805 sources with GALEX counterparts, 797 have NUV emission significantly (> 2.5 sigma) in excess of an empirical basal level. The authors inspected these candidate active stars using visible-wavelength spectra, high-resolution adaptive optics imaging, time-series photometry, and literature searches to identify cases where the elevated NUV emission is due to unresolved background sources or stellar companions; they estimated the overall occurrence of these "false positives" (FPs) as ~ 16%. The authors constructed an NUV luminosity function that accounted for FPs, detection biases of the source catalogs, and GALEX upper limits. They found the NUV luminosity function to be inconsistent with predictions from a constant star-formation rate and simplified age-activity relation defined by a two-parameter power law. This table was created by the HEASARC in March 2015 based on an electronic versions of Table 4 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .

This table contains a source catalog based om XMM-Newton observations of the nearby galaxy M 33. In an XMM-Newton raster observation of this bright Local Group spiral galaxy, the authors studied the population of X-ray sources (X-ray binaries, supernova remnants) down to a 0.2-4.5 keV luminosity limit of 10³⁵ erg/s, more than a factor of 10 deeper than earlier ROSAT observations. European Photon Imaging Camera (EPIC) hardness ratios and optical and radio information are used to distinguish between different source classes. The survey detects 408 sources in an area of 0.80 square degree. The authors correlated these newly detected X-ray sources with earlier M 33 X-ray catalogs and information from optical, infra-red and radio wavelengths. As M 33 sources, theydetect 21 supernova remnants (SNR) and 23 SNR candidates, 5 super-soft sources and 2 X-ray binaries (XRBs). There are 267 sources classified as hard, which may either be XRBs or Crab-like SNRs in M 33 or background AGN. The 44 confirmed and candidate SNRs more than double the number of X-ray detected SNRs in M 33. 16 of these are proposed as SNR candidates from the X-ray data for the first time. On the other hand, there are several sources not connected to M 33: five foreground stars, 30 foreground star candidates, 12 active galactic nucleus candidates, one background galaxy and one background galaxy candidate. Extrapolating from deep field observations, 175 to 210 background sources are expected in this field. This indicates that about half of the sources which were detected are actually within M 33. This table was created by the HEASARC in October 2004 based on CDS table J/A+A/426/11/table3.dat This is a service provided by NASA HEASARC .

The authors have obtained a deep 8-field XMM-Newton mosaic of M33 covering the galaxy out to the D₂₅ isophote and beyond to a limiting 0.2-4.5 keV unabsorbed flux of 5 x 10^-16 erg cm^-2 s^-1 (L > 4 x 10³⁴ erg s^-1 at the 817 kpc distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). In the reference paper, the authors describe the methods they used to identify and characterize 1296 point sources in the 8 fields. They compare their resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ~15% of the 391 bright sources with L > 3.6 x 10³⁵ erg s^-1 are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)-log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, the authors note the discovery of an interesting new transient X-ray source, which they are unable to classify. The list of XMM-Newton observations used for this survey is given in Table 1 of the reference paper. The data reduction and source detection techniques are described in Section 3 of this same reference. The unabsorbed energy conversion factors (ECF) values for different energy bands and instruments that were used in this paper are as follows (the units are 10¹¹ counts cm² erg^-1):

 HEASARC Energy Band MOS1 MOS2 PN band prefix (keV) Med Filter Med Filter Thin Filter sb0_ 0.2-0.5 0.5009 0.4974 2.7709 sb1_ 0.5-1.0 1.2736 1.2808 6.006 mb_ 1.0-2.0 1.8664 1.8681 5.4819 hb_ 2.0-4.5 0.7266 0.7307 1.9276 fb_ 0.2-4.5 

This table was created by the HEASARC in July 2015 based on an electronic version of Table 3 of the reference paper, the list of XMM-Newton X-ray point sources detected in a deep 8-field mosaic of M33, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .