- ID:
- ivo://nasa.heasarc/nltt
- Title:
- NLTTCatalog&FirstSupplement
- Short Name:
- NLTT
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog (Luyten 1979, 1980) is a collection of stars on more than 800 Palomar Proper Motion Survey plates found to have relative annual proper motions exceeding 0.18 arcsec. The motions have been determined by Luyten and his coworkers by either hand blinking and measuring or with the automated- computerized scanner and measuring machine built by Control Data Corporation and located at the University of Minnesota. The new catalog replaces the LTT Catalogues (Luyten 1957, 1961, 1962), wherein stars in the Bruce Proper Motion Survey discovered to have motions exceeding 0.2 arcsec had been compiled. For further information on the NLTT Catalogue itself, including discussions of positional errors, estimation of magnitudes, star designations used in the catalog, completeness, and accuracy of the measured motions, the introduction to the published NLTT (see Volume I) should be consulted. The First Supplement to the NLTT Catalogue (Luyten and Hughes 1980) is the result of continued plate analysis and measurements during printing of the NLTT. The Supplement contains data for 398 stars having motions larger than 0.179 arcsec annually. Duplicate entries were removed from the HEASARC implementation of this catalog in June 2019. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/narcscat
- Title:
- NormaArmRegionChandraSurveyPoint&ExtendedSourceCatalog
- Short Name:
- NARCSCAT
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the catalog of 1,415 X-ray sources identified in the Norma Arm Region Chandra Survey (NARCS), which covers a 2 degree x 0.8 degree region in the direction of the Norma spiral arm to a depth of ~ 20 ks. Of these sources, 1,130 are point-like sources detected with >= 3-sigma confidence in at least one of three energy bands (0.5 - 10, 0.5 - 2, and 2 - 10 keV), five have extended emission, and the remainder are detected at low significance. Since most sources have too few counts to permit individual classification, they are divided into five spectral groups defined by their quantile properties. The authors analyze stacked spectra of X-ray sources within each group, in conjunction with their fluxes, variability, and infrared counterparts, to identify the dominant populations in this survey. They find that ~ 50% of their sources are foreground sources located within 1 - 2 kpc, which is consistent with expectations from previous surveys. Approximately 20% of sources are likely located in the proximity of the Scutum-Crux and near Norma arm, while 30% are more distant, in the proximity of the far Norma arm or beyond. The authors argue that a mixture of magnetic and non-magnetic cataclysmic variables dominates the Scutum-Crux and near Norma arms, while intermediate polars and high-mass stars (isolated or in binaries) dominate the far Norma arm. In the paper, they also present the cumulative number count distribution for sources in this survey that are detected in the hard energy band. A population of very hard sources in the vicinity of the far Norma arm and active galactic nuclei dominate the hard X-ray emission down to f<sub>X</sub> ~ 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>, but the distribution curve flattens at fainter fluxes. The authors find good agreement between the observed distribution and predictions based on other surveys. Chandra ACIS-I observations were performed in faint mode of a 2 degree by 0.8 degree region of the Norma spiral arm in 2011 June. This field was subdivided into 27 pointings; Table 1 in the reference paper reports their coordinates and exposure times and Figure 1 (op. cit.) is a mosaic image of the survey. The observing strategy was to cover a wide area with relatively uniform flux sensitivity and good spatial resolution; therefore, the authors chose field centers spaced by 12 arcminutes, which provided roughly 70 arcminute<sup>2</sup> of overlap on the outskirts of adjacent observations such that the additional exposure time in these overlapping regions partly made up for the worsening point-spread function (PSF) at large off-axis angles. This table was created by the HEASARC in March 2015 based on electronic versions of Tables 3, 4 and 5 from the reference paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/napexmmcxo
- Title:
- NorthAmerica(NGC7000)&Pelican(IC5070)NebulaeX-RaySourceCatalog
- Short Name:
- NAPEXMMCXO
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from the first extensive X-ray study of the North-America and Pelican star-forming region (NGC 7000/IC 5070), with the aim of finding and characterizing the young population of this cloud. X-ray data from Chandra (four pointings) and XMM-Newton (seven pointings) were reduced and source detection algorithm applied to each image. The authors complement the X-ray data with optical and near-IR data from the IPHAS, UKIDSS, and 2MASS catalogs, and with other published optical and Spitzer IR data. More than 700 X-ray sources are detected, the majority of which have an optical or NIR counterpart. This allowed the authors to identify young stars in different stages of formation. Less than 30% of the X-ray sources are identified with a previously known young star. the authors argue that most X-ray sources with an optical or NIR counterpart, except perhaps for a few tens at near-zero reddening, are likely candidate members of the star-forming region, on the basis of both their optical and NIR magnitudes and colors, and of their X-ray properties such as spectral hardness or flux variations. They are characterized by a wide range of extinction, and sometimes near-IR excesses, both of which prevent derivation of accurate stellar parameters. The optical color-magnitude diagram suggests ages between 1-10 Myr. The X-ray members have a very complex spatial distribution with some degree of subclustering, qualitatively similar to that of previously known members. The detailed distribution of X-ray sources relative to the objects with IR excesses identified with Spitzer is sometimes suggestive of sequential star formation, especially near the 'Gulf of Mexico' region, probably triggered by the O5 star which illuminates the whole region. The authors confirm that around the O5 star no enhancement in the young star density is found, in agreement with previous results. Thanks to the precision and depth of the IPHAS and UKIDSS data used, the authors also determine the local optical-IR reddening law, and compute an updated reddening map of the entire region. This table contains the catalog of X-ray sources, with their optical and near-IR identifications, in the NGC 7000/IC 5070 (North America/Pelican) star formation complex. The final X-ray source list comprises 721 objects, of which there are 378 ACIS detections (of which 34 have an XMM-Newton counterpart), and 343 XMM-Newton-only detection. The chosen detection threshold, corresponding to approximately one spurious detection per field, ensures that no more than approximately ten of the 721 detections are spurious. The 11 XMM-Newton and Chandra fields analyzed in this study are listed in Tables 1 and 2, respectively, of the reference paper. This table was created by the HEASARC in July 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A115">CDS Catalog J/A+A/602/A115</a> file table3.dat, the list of detected X-ray sources in the North America (NGC 7000) & Pelican Nebulae (IC 5070), and file table4.dat, the list of optical and near-IR photometric information for the counterparts of these X-ray sources. It does not contain table5.dat, the list of X-ray undetected stars that have IR or H-alpha excesses. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ncp21cma
- Title:
- North Celestial Pole Region Radio Sources Detected by the 21cm Array
- Short Name:
- NCP21CMA
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the catalog of 624 radio sources detected around the North Celestial Pole (NCP) with the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of the epoch of reionization (EoR). The data are taken from a 12-hr observation made on 2013 April 13, with a frequency coverage from 75 to 175 MHz and an angular resolution of ~4 arcminutes. The catalog includes flux densities at eight sub-bands across the 21CMA bandwidth and provides the in-band spectral indices for the detected sources. To reduce the complexity of interferometric imaging from the so-called "w" term and ionospheric effects, the present analysis is restricted to the east-west baselines within 1500 m only. 624 radio sources are found within 5 degrees around the NCP down to ~0.1 Jy (100 mJy). These source counts are compared, and also exhibit a good agreement, with deep low-frequency observations made recently with the GMRT and MWA. In particular, for fainter radio sources below ~1 Jy, the authors find a flattening trend of source counts toward lower frequencies. While the thermal noise (~0.4 mJy) is well controlled to below the confusion limit, the dynamical range (~10<sup>4</sup>) and sensitivity of current 21CMA imaging are largely limited by calibration and deconvolution errors, especially the grating lobes of very bright sources, such as 3C061.1, in the NCP field, which result from the regular spacings of the 21CMA. The authors note that particular attention should be paid to the extended sources, and their modeling and removal may constitute a large technical challenge for current EoR experiments. Their analysis may serve as a useful guide to the design of next generation low-frequency interferometers like the Square Kilometre Array (SKA). The 21CMA is a ground-based radio interferometer dedicated to the detection of the EoR. The array, sited in the Ulastai valley of western China, consists of 81 pods or stations, and a total of 10,287 log-periodic antennas are deployed in two perpendicular arms along the east-west (6.1 km) (see Figure 1 in the reference paper) and north-south (4 km) directions, respectively. The spacing of these 81 pods is chosen such that a sufficiently large number of redundant baselines and a good uniform UV coverage can both be guaranteed. Each antenna element has 16 pairs of dipoles with lengths varying from 0.242 to 0.829 m, optimized to cover a frequency range of 50-200 MHz, which gives rise to an angular resolution of 3 arcminutes at 200 MHz. All of the antennas are fixed on the ground and point at the NCP for the sake of simplicity and economy. In the current work, the radio point sources observed with the 40 pods of the 21 Centimeter Array (21CMA) E-W baselines in an integration of 12 hours made on 2013 April 13 centered on the North Celestial Pole (NCP) are presented. An extra deep sample with a higher sensitivity from a longer integration time of up to years will be published later. The authors have detected a total of 624 radio sources over the central field within 3 degrees in a frequency range of 75-175 MHz band and in the outer annulus from 3-5 degrees in the 75-125 MHz band. By performing a Monte-Carlo simulation, the authors estimate a completeness of 50% at a flux density of ~0.2 Jy. This table was created by the HEASARC in May 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/832/190">CDS Catalog J/ApJ/832/190</a> file table3.dat. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/noras
- Title:
- Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey Catalog
- Short Name:
- NORASGalClus
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In the construction of an X-ray-selected sample of galaxy clusters for cosmological studies, the authors have assembled a sample of 495 X-ray sources which were found to show extended X-ray emission in the first processing of the ROSAT All-Sky Survey (RASS I), the Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey Catalog. The sample covers the celestial region with declination >=0 degrees and Galactic latitude |b| >= 20 degrees, and comprises sources with a Position Sensitive Proportional Counter (PSPC) count rate >= 0.06 counts/s and a source extent likelihood of L >= 7. In an optical follow-up identification program, the authors found 378 (76%) of these sources to be clusters of galaxies. It was necessary to reanalyze the sources in this sample with a new X-ray source characterization technique to provide more precise values for the X-ray flux and source extent than obtained from the standard processing. This new method, termed growth curve analysis (GCA), has the advantage over previous methods in its ability to be robust, to be easy to model and to integrate into simulations, to provide diagnostic plots for visual inspection, and to make extensive use of the X-ray data. The source parameters obtained assist the source identification and provide more precise X-ray fluxes. This reanalysis is based on data from the more recent second processing of the ROSAT Survey, RASS II. The authors present a catalog of the cluster sources with the X-ray properties obtained as well as a list of the previously flagged extended sources that are found to have a non-cluster counterpart. In their paper, they discuss the process of source identification from the combination of optical and X-ray data. To investigate the overall completeness of the cluster sample as a function of the X-ray flux limit, they extended the search for X-ray cluster sources to the RASS II data for the northern sky region between 9 and 14 hours in right ascension. They included the search for X-ray emission from known galaxy clusters as well as a new investigation of extended X-ray sources. In the course of this search, they found X-ray emission from 85 additional Abell clusters and 56 very probable cluster candidates among the newly found extended sources. A comparison of the X-ray cluster number counts of the NORAS sample with the ROSAT-ESO Flux-limited X-ray (REFLEX) Cluster Survey results leads to an estimate of the completeness of the NORAS sample of ROSAT All-Sky Survey (RASS) I extended clusters of about 50% at an X-ray flux of FX(0.1-2.4 keV) = 3 x 10-12 ergs s<sup>-1</sup> cm<sup>-2</sup>. The estimated completeness achieved by adding the supplementary sample in the study area amounts to about 82% in comparison to REFLEX. The low completeness introduces an uncertainty in the use of the sample for cosmological statistical studies that will be cured with the completion of the continuing Northern ROSAT All-Sky (NORAS) Cluster Survey project. This table was created by the HEASARC in June 2005 based on CDS table J/ApJS/129/435, table1.dat through table9.dat inclusive. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/nvss
- Title:
- NRAO VLA Sky Survey Catalog
- Short Name:
- NVSS
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) Sky Survey, the so-called NVSS Catalog. The NVSS Catalog covers the sky north of the J2000.0 Declination of -40 degrees (82% of the celestial sphere) at 1.4 GHz. The principal data products of the NVSS were (1) a set of 2326 4 degree by 4 degree continuum "cubes" with three planes containing Stokes I, Q, and U images, plus (2) a catalog of almost 2 million discrete sources stronger than a flux density S of about 2.5 mJy. The images all have 45 arcsecond FWHM angular resolution and nearly uniform sensitivity. Their rms brightness fluctuations are approximately 0.45 mJy/beam = 0.14 K (Stokes I) and approximately 0.29 mJy/beam = 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from <= ~1 arcsecond for the 400,000 sources stronger than 15 mJy to 7 arcseconds at the survey limit. The NVSS was made as a service to the astronomical community. All data products, user software, and updates were released via the World-Wide Web as soon as they were produced and verified. For more complete information on the NVSS, please refer to the NVSS website at <a href="http://www.cv.nrao.edu/nvss/">http://www.cv.nrao.edu/nvss/</a> This table was created by the HEASARC in October 2002 based on the file <a href="ftp://ftp.cv.nrao.edu/nvss/CATALOG/NVSSCatalog.text.gz">ftp://ftp.cv.nrao.edu/nvss/CATALOG/NVSSCatalog.text.gz</a> provided by the NVSS Catalog's authors. It was updated by the HEASARC in June 2009 to fix a problem with the original ingest in which the leading digit of some flux fields was lost. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/nuaftl
- Title:
- NuSTAR As-Flown Timeline
- Short Name:
- NUAFTL
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The NUAFTL database table records the As-Flown Timeline for the Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observatory. NuSTAR observes the sky in the high energy X-ray (3 - 79 keV) region of the electromagnetic spectrum using focusing optics. The as-flown timeline provides a summary of what NuSTAR has observed and is updated automatically when each observation is completed. This HEASARC database table is updated automatically within a day or so of updates to the referenced URL. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/nucosmosfc
- Title:
- NuSTAR COSMOS Field X-Ray Source Catalog
- Short Name:
- NUCOSMOSFC
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- To provide the census of the sources contributing to the X-ray background peak above 10 keV, the Nuclear Spectroscopic Telescope Array (NuSTAR) is performing extragalactic surveys using a three-tier "wedding cake" approach. In their paper, the authors present the NuSTAR survey of the COSMOS field, the medium sensitivity, and medium area "tier",covering 1.7 deg<sup>2</sup> and overlapping with both Chandra and XMM-Newton data. This survey consists of 121 NuSTAR observations for a total exposure of ~3 Ms. To fully exploit these data, the authors developed a new detection strategy, carefully tested through extensive simulations. The survey sensitivity at 20% completeness is 5.9, 2.9, and 6.4 x 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup> in the 3-24, 3-8 and 8-24 keV bands, respectively. By combining detections in 3 bands, the survey consists of a sample of 91 NuSTAR sources with luminosities ~ 10<sup>42</sup> - 10<sup>45.5</sup> erg s<sup>-1</sup>and redshifts z ~ 0.04-2.5. Thirty-two sources are detected in the 8-24 keV band with fluxes ~100 times fainter than sources detected by Swift-BAT. Of the 91 detections, all but 4 are associated with a Chandra and/or XMM-Newton point-like counterpart. One source is associated with an extended lower energy X-ray source. The authors present the X-ray (hardness ratio and luminosity)and optical-to-X-ray properties. The observed fraction of candidate Compton-thick active galactic nuclei measured from the hardness ratio is between 13% - 20%. In their paper, the authors discuss the spectral properties of the source named NuSTAR J100259+0220.5 (source number 330) at a redshift z = 0.044, which has the highest hardness ratio in the entire sample. The measured column density exceeds 10<sup>24</sup> cm<sup>-2</sup>, implying the source is Compton-thick. This source was not previously recognized as such without the data at energies >10 keV. This table was created by the HEASARC in August 2015 based on the the machine-readable versions of Table 5 (the COSMOS Field NuSTAR source catalog) that was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/nugalcen
- Title:
- NuSTAR Hard X-Ray Survey of the Galactic Center
- Short Name:
- NUGALCEN
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the the first survey results of hard X-ray point sources in the Galactic Center (GC) region obtained by NuSTAR. The authors have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg<sup>2</sup> region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. They identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x 10<sup>32</sup> and ~8 x 10<sup>32</sup> erg/s at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40% - 60%). Both spectral analysis and logN - logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single-temperature thermal plasma model or an average photon index of Gamma = 1.5 - 2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population. The observations of the GC region with NuSTAR began in 2012 July, shortly after its launch. The original survey strategy for the GC region was to match the central 2 degree x 0.7 degree region covered by the Chandra X-ray Observatory (Wang et al. 2002, Nature, 415, 148; Muno et al. 2009, ApJS, 181, 110). The field of views (FOVs) of neighboring NuSTAR observations in the survey were designed to overlap with each other by ~40%. Multiple observations of the same region with relatively large FOV offsets tend to average out the vignetting effects of each observation, enabling a more uniform coverage of the region. Multiple observations are also suitable for monitoring long term X-ray variability of sources in the region. Even when observing a single target, the NuSTAR observation is often broken up into two or more segments with relatively large pointing offsets to allow an efficient subtraction of a detector coordinate-dependent background component (e.g., Mori et al. 2013, ApJ, 770, L23). This table was created by the HEASARC in March 2018, based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/825/132">CDS Catalog J/ApJ/825/132</a> files table2.dat, table3.dat, table4.dat and table5.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/numaster
- Title:
- NuSTAR Master Catalog
- Short Name:
- NUMASTER
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing instruments far beyond the ~10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. The observatory was placed into a 600-km altitude, 6 degree inclination circular orbit, and consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. NuSTAR has completed its two-year primary science mission, and, with an expected orbit lifetime of more than 10 years, the opportunity for proposing observations as part of the General Observer (GO) program is now available, with observations beginning in 2015. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR offers opportunities for a broad range of science investigations, ranging from probing cosmic ray origins to studying the extreme physics around compact objects to mapping micro-flares on the surface of the Sun. NuSTAR also responds to targets of opportunity including supernovae and gamma-ray bursts. This table contains a list of (a) unobserved targets that are planned or have been accepted for observation by NuSTAR in the future and (b) NuSTAR observations which have been processed and successfully validated by the NuSTAR Science Operation Center. The data from these observations may or may not be public and the user should check the value of the public_date parameter to determine the status of a specified data set. Only those ObsIDs which have a public_date in the past will have data publicly available. Observations with a public_date parameter value which is either blank or a date in the future have been ingested into the HEASARC archive but will remain encrypted until their public date. Entries with the status field set to 'accepted' are targets approved for scheduling, and the planned exposure time given in the exposure_a (and exposure_b) parameter will have a negative value for those targets. This database table is based on information supplied by the NuSTAR Project at Caltech. It is automatically updated on a regular basis. This is a service provided by NASA HEASARC .
