This is a catalog of galaxy clusters detected in a new ROSAT PSPC survey. The survey is optimized to sample, at high redshifts, the mass range corresponding to T > 5 keV clusters at z = 0. Technically, our survey is the extension of the 160 square degree survey (160d, the HEASARC Browse table called ROSGALCLUS). The authors use the same detection algorithm, thus preserving the high quality of the resulting sample; the main difference is a significant increase in sky coverage. The new survey covers 397 square degrees and is based on 1610 high Galactic latitude ROSAT PSPC pointings, virtually all of the pointed ROSAT data that were suitable for the detection of distant clusters. The search volume for X-ray luminous clusters within z < 1 exceeds that of the entire local universe (z < 0.1). The authors detected 287 extended X-ray sources with fluxes f_x > 1.4 x 10^-13 erg s^-1 cm^-2 in the 0.5 - 2 keV energy band, of which 266 (93%) are optically confirmed as galaxy clusters, groups or individual elliptical galaxies. The paper from which this table is extracted provides a description of the input data, the statistical calibration of the survey via Monte Carlo simulations, and the catalog of detected clusters. The authors also therein compare the basic results with those from previous, smaller area surveys and find good agreement for the logN - log S distribution and the local X-ray luminosity function. This sample clearly shows a decrease in the number density for the most luminous clusters at z > 0.3. The comparison of these ROSAT-derived fluxes with the accurate Chandra measurements for a subset of high-redshift clusters demonstrates the validity of the 400 square degree survey's statistical calibration. This Browse table contains the main cluster catalog (Table 4 of the reference paper) which comprises 242 serendipitously detected clusters of galaxies. It does not include 24 clusters within a redshift of 0.01 of the redshift of the target of the ROSAT observation (given in Table 5 of the reference paper), as these latter are not entirely serendipitous, 5 noncluster extended sources (given in Table 6 of the reference paper), nor 16 likely false X-ray detections (given in Table 7 of the reference paper). This table was created by the HEASARC in December 2007 based on the machine-readable version of Table 4 (the 'Cluster Catalog') obtained from the electronic ApJ website. This is a service provided by NASA HEASARC .

The CMa R1 star-forming region contains several compact clusters as well as many young early-B stars. It is associated with a well-known bright rimmed nebula, the nature of which is unclear (fossil HII region or supernova remnant). To help elucidate the nature of the nebula, the authors' goal was to reconstruct the star-formation history of the CMa R1 region, including the previously unknown older, fainter low-mass stellar population, using X-rays. The authors analyzed images obtained with the ROSAT satellite, covering ~5 square degrees. Complementary VRI photometry was performed with the Gemini South telescope. Color-magnitude and color-color diagrams were used in conjunction with pre-main sequence evolutionary tracks to derive the masses and ages of the X-ray sources. The ROSAT images show two distinct clusters. One is associated with the known optical clusters near Z CMa, to which ~ 40 members are added. The other, which the authors name the "GU CMa" cluster, is new, and contains ~ 60 members. The ROSAT sources are young stars with masses down to M_star ~ 0.5 M_sun, and ages up to 10 Myr. The mass functions of the two clusters are similar, but the GU CMa cluster is older than the cluster around Z CMa by at least a few Myr. Also, the GU CMa cluster is away from any molecular cloud, implying that star formation must have ceased; on the contrary (as already known), star formation is very active in the Z CMa region. The two ROSAT observations that the authors analyzed are the following. By order of increasing RA, the first Field ('Field 1' hereafter), HEASARC ID RP201011 pointing axis RA(J2000} = 7^h 00^m, Dec(J2000) = -11^o 30', has an exposure of 19.7 ks. 'Field 2', HEASARC ID RP201277, pointing axis RA(J2000) = 7^h 04^m, Dec(J2000) = -11^o 33', has a much shorter exposure of 4.6 ks. This table contains the complete list of sources detected in CMa R1 by ROSAT. This online catalog was created by the HEASARC in April 2010 based on machine-readable tables obtained from the CDS (their catalog J/A+A/506/711, file tablea1.dat). This is a service provided by NASA HEASARC .

The authors have obtained high spatial resolution Chandra X-ray images of the NGC 2237 young stellar cluster on the periphery of the Rosette Nebula. They detect 168 X-ray sources, 80% of which have stellar counterparts in USNO, Two Micron All Sky Survey, and deep FLAMINGOS images. These constitute the first census of the cluster members with 0.2 <~ M <~ 2 M_sun. Star locations in near-infrared color-magnitude diagrams indicate a cluster age of around 2 Myr with a visual extinction of 1 <~ AV <~ 3 at 1.4 kpc, the distance of the Rosette Nebula's main cluster NGC 2244. The authors derive the K-band luminosity function and the X-ray luminosity function of the cluster, which indicate a population of ~ 400-600 stars. The X-ray-selected sample shows a K-excess disk frequency of 13%. The young Class II counterparts are aligned in an arc ~3 pc long suggestive of a triggered formation process induced by the O stars in NGC 2244. The diskless Class III sources are more dispersed. Several X-ray emitting stars are located inside the molecular cloud and around gaseous pillars projecting from the cloud. These stars, together with a previously unreported optical outflow originating inside the cloud, indicate that star formation is continuing at a low level and the cluster is still growing. This X-ray view of young stars on the western side of the Rosette Nebula complements the authors' earlier studies of the central cluster NGC 2244 and the embedded clusters on the eastern side of the Nebula. The large-scale distribution of the clusters and molecular material is consistent with a scenario in which the rich central NGC 2244 cluster formed first, and its expanding H II region triggered the formation of the now-unobscured satellite clusters Rosette Molecular Cloud (RMC) XA and NGC 2237. A large swept-up shell of material around the H II region is now in a second phase of collect-and-collapse fragmentation, leading to the recent formation of subclusters. Other clusters deeper in the molecular cloud appear unaffected by the Rosette Nebula expansion. Some sources which have information from published catalogs are listed by their source_number value below, where for convenience, [OI81] = Ogura & Ishida (1981, PASJ, 33, 149), [MJD95] = Massey, Johnson, & Degioia-Eastwood (1995, ApJ, 454, 151) and [BC02] = Berghofer & Christian (2002, A&A, 384, 890):

 53 = [OI81] 14 = [MJD95] 104; spectral type B1V; pmRA=11.0 mas/yr, pmDE=-2.8 mas/yr; 54 = [OI81] 10 = [MJD95] 108; spectral type B2V; pmRA=-2.3 mas/yr, pmDE=-11.9 mas/yr; 61 = V539 Mon [OI81] 13 = [MJD95] 110; MSX6C G206.1821-02.3456; pmRA=2.8 mas/yr, pmDE=0.4 mas/yr; 71 = [OI81] 12 = [MJD95] 102; pmRA=6.8 mas/yr, pmDE=0.6 mas/yr; 128 = [OI81] 35 = [MJD95] 471; spectral type A2:; pmRA=-0.8 mas/yr, pmDE=3.6 mas/yr; 138 = [OI81] 36 = [MJD95] 497; spectral type B5; pmRA=6.5 mas/yr, pmDE=2.1 mas/yr; 141 = [MJD95] 498; pmRA=-3.0 mas/yr, pmDE=1.9 mas/yr; 149 = [BC02] 11; known X-ray source; log(Lx(ROSAT/PSPC))=31.01 erg/s; pmRA=0.6 mas/yr, pmDE=-12.6 mas/yr; 161 = [MJD95] 653; pmRA=-1.0 mas/yr, pmDE=-5.4 mas/yr 

This table was created by the HEASARC in July 2010 based on electronic versions of Tables 1, 2, 3 and 4 of the reference paper which were obtained from the electronic ApJ web site. To distinguish between the 130 X-ray sources in the primary sample (Table 1 of the reference paper) and the 38 X-ray sources in the tentative sample (Table 2 of the reference paper), the HEASARC has created a parameter called source_sample which is set to 'P' for the primary sources and to 'T' for the tentative sources. This is a service provided by NASA HEASARC .

This catalog presents some of the results from 3 deep ROSAT High Resolution Imager (HRI) observations of the Orion Nebula star-forming region. The fields covered by the X-ray images contain over 1500 catalogued stars in a roughly 0.8 square degree region centered on the Trapezium. In all, 389 distinct X-ray sources were detected, at least two-thirds of which were associated with a single proper-motion cluster member. X-ray emission was detected from stars of all spectral types, from the massive O- and B-type components of the Trapezium to the coolest, low-mass pre-main-sequence (PMS) stars. In the research paper in which these data were presented (Gagne et al. 1995), the authors focussed primarily on X-ray emission from the late-type PMS stars. Of the ~100 late-type cluster members with measured spectral types, approximately three-fourths were detected; the authors derived X-ray luminosity upper limits for the remaining stars. They found that coronal X-ray emission appeared to turn on at around a spectral type of F6, with the upper envelope of activity increasing with decreasing effective temperature. The current database is a representation of Table 6 from Gagne et al. (1995) (notice that the data given in Tables 2 and 3 of this reference is included in the HEASARC database ORIONXRAY, q.v.) which lists X-ray and other data for 175 Orion stars for which spectral types, spectroscopic rotational velocities, and/or spot-modulated photometric rotational periods are available. The X-ray data (either detections or upper limits) are given in the form of X-ray luminosities log Lx and X-ray to bolometric luminosity ratios (log Lx/Lbol). The conversion factor from HRI counts to log Lx was derived for each star based on (i) an assumed 1 keV Raymond and Smith thermal spectrum, (ii) a distance of 440 pc, and (iii) a column density of 2 x 10²¹ cm^-2 per magnitude of visual extinction A(V), where accurate A(V) values are used when available, or otherwise a moderate absorption of 0.25 magnitudes is assumed. Notice that, for stars not identified as candidate optical counterparts in Tables 2 and 3 of Gagne et al. (the HEASARC database ORIONXRAY), the derived upper limit to the X-ray luminosity usually corresponds to the 3 sigma upper limit to the observed count rate. For a handful of stars in the Trapezium region where a star was eliminated as a candidate optical counterpart, despite being within the source search circle, because a more likely counterpart had a smaller position offset, the upper limit corresponds to either half the observed X-ray source count rate or to 3 sigma, whichever is the highest. Such cases are indicated in this database by the presence of the string "NN" in the parameter 'Note'. This is a service provided by NASA HEASARC .

This catalog presents some of the results from 3 deep ROSAT High Resolution Imager (HRI) observations of the Orion Nebula star-forming region. The fields covered by the X-ray images contain over 1500 catalogued stars in a roughly 0.8 square degree region centered on the Trapezium. In all, 389 distinct X-ray sources were detected, at least two-thirds of which were associated with a single proper-motion cluster member. X-ray emission was detected from stars of all spectral types, from the massive O- and B-type components of the Trapezium to the coolest, low-mass pre-main-sequence (PMS) stars. In the research paper in which these data were presented (Gagne et al. 1995), the authors focussed primarily on X-ray emission from the late-type PMS stars. Of the ~100 late-type cluster members with measured spectral types, approximately three-fourths were detected; the authors derived X-ray luminosity upper limits for the remaining stars. They found that coronal X-ray emission appeared to turn on at around a spectral type of F6, with the upper envelope of activity increasing with decreasing effective temperature. The current database is a concatenation of Tables 2 and 3 from Gagne et al. (1995) which list the 389 distinct X-ray sources and their candidate optical counterparts. A detection criterion of 3 sigma was used, i.e., a sigal-to-noise ratio criterion of 3. 324 of the X-ray sources have a single candidate optical counterpart, 50 of the X-ray sources (listed in Table 3 of the original paper) have multiple candidates for the optical counterparts, and the remainder have no optical counterparts. Notice that Table 6 of Gagne et al. (1995) which presents a compilation of optical and X-ray data for a sub-group of the Orion stars for which data on the spectral types and the spectroscopic rotational velocities or the photometric rotational periods are available is not part of this database. This database was created at the HEASARC in December 1997 based on a computer-readable version of Tables 2 and 3 of Gagne et al. (1995) that was obtained from the CDS (their catalog J/ApJ/445/280). This is a service provided by NASA HEASARC .