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nasa20/100

Sloan Digital Sky Survey I/II Cataclysmic Variables Catalog

The reference paper completed the series of cataclysmic variables (CVs) identified from the Sloan Digital Sky Survey (SDSS) I and II. The coordinates, magnitudes, and SDSS spectra of 33 more CVs were presented. Among the 33 are eight systems known prior to SDSS (CT Ser, DO Leo, HK Leo, IR Com, V849 Her, V405 Peg, PG1230+226, and HS0943+1404), as well as nine objects recently found through various photometric surveys. Among the systems identified since the SDSS are two polar candidates, two intermediate polar candidates, and one candidate for containing a pulsating white dwarf. A complete summary table of the 285 CVs with spectra from SDSS I/II which were listed in the reference paper and the 7 previous papers in the series is contained herein. This table was created by the HEASARC in January 2012 based on an electronic version of Table 6 from the reference paper which was obtained from the AJ web site. This is a service provided by NASA HEASARC .

restrictednotspecifiedApr 2025View details →
nasa20/100

VO1/VO2 MARS VISUAL IMAGING SUBSYSTEM DIGITAL TERRAIN MODEL

This digital image map of Mars is a cartographic extension of a previously released set of CDROM volumes containing individual Viking Orbiter Images (PDS volumes VO_1001, VO_1002, etc.). The data in the latter are pristine, in the sense that they were processed only to the extent required to view them as images. They contain the artifacts and the radiometric, geometric, and photometric characteristics of the raw data transmitted by the spacecraft. This new volume set, on the other hand, contains cartographic compilations made by processing the raw images to reduce radiometric and geometric distortions and to form geodetically controlled Mosaicked Digital Image Models (MDIMs). (Because the photometric processing used in this MDIM was oversimplified, quantitative radiometric analysis on this data is not possible.) It also contains digitized versions of an airbrushed map of Mars as well as a listing of all IAU-approved feature names. In addition, special geodetic and photogrammetric processing has been performed to derive rasters of topographic data, or Digital Terrain Models (DTMs). The latter has a format similar to that of the MDIM, except that elevation values are used in the array instead of image brightness values. The Mars DTM exists in its entirety on Volume 7. Finally, Volume 7 has a listing of SPICE files derived for the Viking images used in the MDIM and the DTM. These files contain updated camera orientation matrices for each of the frames. The matrices are by-products of the photogrammetric processing for the control network required to compile the MDIM and the DTM.

restrictedus-pdMar 2025View details →
nasa20/100

Sloan Digital Sky Survey/XMM-Newton AGN Spectral Properties Catalog

Bright XMM-Newton data are combined with the Chandra Deep Field South observations to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity. The sample consists of 359 sources selected in the hard 2 - 8 keV band, spanning the flux range from 6 x 10<sup>-16</sup> - 3 x 10<sup>-13</sup> erg/cm<sup>2</sup>/s with a high rate of spectroscopic or photometric redshift completeness (100 and 85 percent for the Chandra and XMM-Newton data, respectively). The authors derive the column density values using X-ray spectral fits. They find that the fraction of obscured AGN falls with increasing luminosity in agreement with previous findings. The fraction of obscured AGN shows an apparent increase at high redshifts (z > 2). Simulations show that this effect can most probably be attributed to the fact that at high redshifts the column densities are overestimated. This table contains the subset of 153 brighter hard X-ray sources in the XMM-Newton/Sloan Digital Sky Survey (SDSS) sample which have 2-8 keV fluxes > 3 x 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>, excluding a number of sources with extended optical morphology and blue colors, as well as 4 sources with X-ray to optical fluxes < 0.1 which are fit better with stellar rather than QSO templates. Much more information on the SDSS is available at the project's web site at <a href="http://www.sdss.org/">http://www.sdss.org/</a>. This table was created by the HEASARC in July 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/459/693">CDS Catalog J/A+A/459/693</a> file table2.dat. This is a service provided by NASA HEASARC .

restrictednotspecifiedApr 2025View details →
nasa20/100

USGS Digital Orthophoto Quadrangles

A Digital Orthophoto Quadrangle (DOQ) is a computer-generated image of an aerial photograph in which the image displacement caused by terrain relief and camera tilt has been removed. The DOQ combines the image characteristics of the original photograph with the georeferenced qualities of a map. DOQs are black and white (B/W), natural color, or color-infrared (CIR) images with 1-meter ground resolution. The USGS produces three types of DOQs: 1. 3.75-minute (quarter-quad) DOQs cover an area measuring 3.75-minutes longitude by 3.75-minutes latitude. Most of the U.S. is currently available, and the remaining locations should be complete by 2004. Quarter-quad DOQs are available in both Native and GeoTIFF formats. Native format consists of an ASCII keyword header followed by a series of 8-bit binary image lines for B/W and 24-bit band-interleaved-by-pixel (BIP) for color. DOQs in native format are cast to the Universal Transverse Mercator (UTM) projection and referenced to either the North American Datum (NAD) of 1927 (NAD27) or the NAD of 1983 (NAD83). GeoTIFF format consists of a georeferenced Tagged Image File Format (TIFF), with all geographic referencing information embedded within the .tif file. DOQs in GeoTIFF format are cast to the UTM projection and referenced to NAD83. The average file size of a B/W quarter quad is 40-45 megabytes, and a color file is generally 140-150 megabytes. Quarter-quad DOQs are distributed via File Transfer Protocol (FTP) as uncompressed files. 2. 7.5-minute (full-quad) DOQs cover an area measuring 7.5-minutes longitude by 7.5-minutes latitude. Full-quad DOQs are mostly available for Oregon, Washington, and Alaska. Limited coverage may also be available for other states. Full-quad DOQs are available in both Native and GeoTIFF formats. Native is formatted with an ASCII keyword header followed by a series of 8-bit binary image lines for B/W. DOQs in native format are cast to the UTM projection and referenced to either NAD27 or NAD83. GeoTIFF is a georeferenced Tagged Image File Format with referencing information embedded within the .tif file. DOQs in GeoTIFF format are cast to the UTM projection and referenced to NAD83. The average file size of a B/W full quad is 140-150 megabytes. Full-quad DOQs are distributed via FTP as uncompressed files. 3. Seamless DOQs are available for free download from the Seamless site. DOQs on this site are the most current version and are available for the conterminous U.S. [Summary provided by the USGS.]

restrictednotspecifiedMar 2025View details →
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PSP FIELDS Digital Fields Board (DFB) AC-coupled Searchcoil Magnetometer, SCM, Spectra, Low Frequency, High Gain, u-component, Sensor coordinates, Level 2 (L2), 0.873813 s Data

PSP FIELDS Digital Fields Board, DFB, SCMulflg data:The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].DFB AC spectra data consist of power spectral densities as a function of frequency and time. These spectra are averaged over both frequency and time as described in [3]. The spectra have pseudo-logarithmically spaced frequency bins with the bin central frequencies reported in the metadata. The AC spectra are duty-cycled such that spectral averaging takes place over the first 1/8 of any given NYsecond when the data cadence is equal to one NYsecond. Less data are averaged by a factor of 2^N for data cadences that are faster than one NYsecond by 2^N. For cadences slower than one NYsecond, the first 1/8 of each NYsecond of data included are averaged together to construct the reported data.The Level 2 data products contained in this data file have been calibrated for:* 1) The Hanning window used in the spectral calculation* 2) DFB in-band gain* 3) DFB analog filter gain response* 4) DFB digital filter gain response* 5) The search coil preamplifier response, when applicable* 6) The bandwidth of each spectral binNote that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz.The Level 2 data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer spectral data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field spectral data are in expressed in search coil magnetometer sensor coordinates with components [u,v,w].To rotate from [d,e,f] coordinates into [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.R = [[ 0.46834856, -0.81336422 , 0.34509170] [ -0.66921924, -0.071546954, 0.73961249] [ -0.57688408, -0.57733845 , -0.57782790]]The time resolution of the DFB AC spectral data can vary by multiples of 2^N. During encounter when PSP is within 0.25 AU of the Sun, the DFB AC spectra data cadence is typically NYsecond NYsecond [2]. Timestamps correspond to the center time of each window.References:* 1) Fox, N.J., Velli, M.C., Bale, S.D. et al., Space Sci Rev (2016) 204:7. https://doi.org/10.1007/s1121401502116* 2) Bale, S.D., Goetz, K., Harvey, P.R. et al., Space Sci Rev (2016) 204:49. https://doi.org/10.1007/s1121401602445* 3) Malaspina, D.M., Ergun, R.E., Bolton, M. et al., JGR Space Physics (2016), 121, 5088-5096. https://doi.org/10.1002/2016JA022344

restrictednotspecifiedAug 2025View details →
nasa20/100

IHW COMET HALLEY DIGITIZED PHOTOGRAPHIC SPECTRA V1.0

NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the IHW. The observations belong to one of the following Disciplines: Amateur, Astrometry, Infrared Studies, Large-Scale Phenomena, Meteor Studies, Near-Nucleus Studies, Photometry and Polarimetry, Radio Studies, and Spectroscopy and Spectrophotometry. The data collected by these nine disciplines were augmented by Spacecraft measurements. The data were submitted to IHW, but the evaluation and selection for the Archive has been the primary responsibility of the Discipline Specialist Teams for each network in cooperation with the Lead Center. The Spectroscopy and Spectrophotometry Network collected 352 files that represented the digitized spectra from plate material. In some cases, the non-Halley targets for the spectroscopic observations can be grouped according to 'laboratory' calibration, dark, bias, flatfield, sky, and photometric standards. In the first category, a large number of 'arcs' and 'lamps' were used as follows: HE-NE, TH-AR, NE-AR, CU-AR, CU-NE, Thorium, Tungsten, Quartz, and Rubidium. For the 'sky' observers used the twilight, moonlight, and blank sky. The most common 'photometric' standards were stars, but observers also included other comets (Hartley-Goode), asteroids (Ceres), reflection nebulae (R8), and emission nebulae (NGC1982, NGC7000). A list of these stellar calibration targets follows: HD 140283, HD 184711, HD89688, HD102870, HD120086, HD13974, HD219188, HD 25680, HD 19445, HD18803, HD30455, HD26912, SAO 1280, HZ15, CD-22 7696, GD 190, GC5106, GC2188, GC2192, G19113213, G 99-37, L745-46A, Feige 15, Feige 56, Landolt 98, Landolt 92, Van Beuren, RHO ORION, CHI 1 ORION, 29 PI LEO. For this data, no distinction about 'reduction' is distinguished for this process. The data cover the date range from 1985 October 17 through 1986 December 12.

restrictedus-pdMar 2025View details →
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PSP FIELDS Digital Fields Board (DFB) DC-coupled Searchcoil Magnetometer, SCM, Spectra, Low Frequency, High Gain, d-component, Sensor coordinates, Level 2 (L2), 6.99054 s Data

PSP FIELDS Digital Fields Board, DFB, SCMdlfhg data:The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].DFB DC spectra data consist of power spectral densities as a function of frequency and time. These spectra are averaged over both frequency and time as described in [3]. The spectra have pseudo-logarithmically spaced frequency bins with the bin central frequencies reported in the metadata.The Level 2 data products contained in this data file have been calibrated for:* 1) The Hanning window used in the spectral calculation* 2) DFB in-band gain* 3) DFB analog filter gain response* 4) DFB digital filter gain response* 5) The search coil preamplifier response, when applicable* 6) The bandwidth of each spectral binNote that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz.The Level 2 data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer spectral data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field spectral data are in expressed in search coil magnetometer sensor coordinates with components [u,v,w].To rotate from [d,e,f] coordinates into [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.R = [[ 0.46834856, -0.81336422 , 0.34509170] [ -0.66921924, -0.071546954, 0.73961249] [ -0.57688408, -0.57733845 , -0.57782790]]The time resolution of the DFB DC spectral data can vary by multiples of 2^N. During encounter when PSP is within 0.25 AU of the Sun, the DFB DC spectra data cadence is typically 30 NYseconds NYsecond [2]. Timestamps correspond to the center time of each window.References:* 1) Fox, N.J., Velli, M.C., Bale, S.D. et al., Space Sci Rev (2016) 204:7. https://doi.org/10.1007/s1121401502116* 2) Bale, S.D., Goetz, K., Harvey, P.R. et al., Space Sci Rev (2016) 204:49. https://doi.org/10.1007/s1121401602445* 3) Malaspina, D.M., Ergun, R.E., Bolton, M. et al., JGR Space Physics (2016), 121, 5088-5096. https://doi.org/10.1002/2016JA022344

restrictednotspecifiedAug 2025View details →
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SMAPVEX19-22 Massachusetts Lidar Derived Digital Surface Model V001

These data consist of ground surface elevations derived from source lidar measurements collected in April and August 2022 in the vicinity of Petersham, MA during the SMAPVEX19-22 campaign. This location was chosen due to its forested land cover, as SMAPVEX19-22 aims to validate satellite derived soil moisture estimates in forested areas. The two acquisition periods occurred to characterize differences during "leaf-on" and "leaf-off" conditions.

restrictednotspecifiedApr 2025View details →
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PSP FIELDS Digital Fields Board (DFB) AC-coupled Differential Voltage, V3-V4 Antennae, Dipole Mode, Spectra, High Gain, Sensor coordinates, Level 2 (L2), 0.873813 s Data

PSP FIELDS Digital Fields Board, DFB, dV34hg data:The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].DFB AC spectra data consist of power spectral densities as a function of frequency and time. These spectra are averaged over both frequency and time as described in [3]. The spectra have pseudo-logarithmically spaced frequency bins with the bin central frequencies reported in the metadata. The AC spectra are duty-cycled such that spectral averaging takes place over the first 1/8 of any given NYsecond when the data cadence is equal to one NYsecond. Less data are averaged by a factor of 2^N for data cadences that are faster than one NYsecond by 2^N. For cadences slower than one NYsecond, the first 1/8 of each NYsecond of data included are averaged together to construct the reported data.The Level 2 data products contained in this data file have been calibrated for:* 1) The Hanning window used in the spectral calculation* 2) DFB in-band gain* 3) DFB analog filter gain response* 4) DFB digital filter gain response* 5) The search coil preamplifier response, when applicable* 6) The bandwidth of each spectral binNote that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz.The Level 2 data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer spectral data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field spectral data are in expressed in search coil magnetometer sensor coordinates with components [u,v,w].To rotate from [d,e,f] coordinates into [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.R = [[ 0.46834856, -0.81336422 , 0.34509170] [ -0.66921924, -0.071546954, 0.73961249] [ -0.57688408, -0.57733845 , -0.57782790]]The time resolution of the DFB AC spectral data can vary by multiples of 2^N. During encounter when PSP is within 0.25 AU of the Sun, the DFB AC spectra data cadence is typically NYsecond NYsecond [2]. Timestamps correspond to the center time of each window.References:* 1) Fox, N.J., Velli, M.C., Bale, S.D. et al., Space Sci Rev (2016) 204:7. https://doi.org/10.1007/s1121401502116* 2) Bale, S.D., Goetz, K., Harvey, P.R. et al., Space Sci Rev (2016) 204:49. https://doi.org/10.1007/s1121401602445* 3) Malaspina, D.M., Ergun, R.E., Bolton, M. et al., JGR Space Physics (2016), 121, 5088-5096. https://doi.org/10.1002/2016JA022344

restrictednotspecifiedAug 2025View details →
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Sloan Digital Sky Survey/XMM-Newton Type1 AGN X-Ray and Radio Properties Catalog

X-ray emission from active galactic nuclei (AGN) is dominated by the accretion disk around a supermassive black hole. The radio luminosity, however, has not such a clear origin except in the most powerful sources where jets are evident. The origin (and even the very existence) of the local bi-modal distribution in radio-loudness is also a debated issue. By analyzing X-ray, optical and radio properties of a large sample of type 1 AGN and quasars (QSOs) up to z > 2, where the bulk of this population resides, the authors aim to explore the interplay between radio and X-ray emission in AGN, in order to further our knowledge on the origin of radio emission, and its relation to accretion. They analyze a large (~800 sources) sample of type 1 AGN and QSOs selected from the 2XMMi XMM-Newton X-ray source catalog, cross-correlated with the SDSS DR7 spectroscopic catalog, covering a redshift range from z ~ 0.3 to z ~ 2.3. Supermassive black hole masses are estimated from the Mg II emission line, bolometric luminosities from the X-ray data, and radio emission or upper limits from the FIRST catalog. Most of the sources accrete close to the Eddington limit and the distribution in radio-loudness does not appear to have a bi-modal behavior. This study confirms that radio-loud AGN are also X-ray loud, with an X-ray-to-optical ratio up to twice that of radio-quiet objects, even excluding the most extreme strongly jetted sources. By analyzing complementary radio-selected control samples, the authors find evidence that these conclusions are not an effect of the X-ray selection, but are likely a property of the dominant QSO population. The authors of this catalog conclude that their findings are best interpreted in a context where radio emission in AGN, with the exception of a minority of beamed sources, arises from very close to the accretion disk and is therefore heavily linked to X-ray emission. They also speculate that the radio-loud/radio-quiet dichotomy might either be an evolutionary effect that developed well after the QSO peak epoch, or an effect of incompleteness in small samples. Basic information and derived properties are presented for the sample of X-ray selected type 1 AGN (as well as for the 11 X-ray undetected type 1 AGN in the "control sample"): coordinates, redshift, X-ray and radio fluxes, optical magnitudes, from the SDSS, 2XMMi, and FIRST catalogs; continuum luminosities at 3000 Angstroms and in the X-ray band, black hole masses, bolometric luminosities, Eddington ratios; for the sources falling in the FIRST field, optical fluxes at 2500 and 4400 Angstroms, X-ray-to-optical index, radio classification, and the ratios between the radio and the UV, optical, and X-ray fluxes. This table was created by the HEASARC in October 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/545/A66">CDS Catalog J/A+A/545/A66</a> files table3.dat, table4.dat and table5.dat. This is a service provided by NASA HEASARC .

restrictednotspecifiedApr 2025View details →
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IHW COMET LSPN EDITED DIGITALIZED IMAGE DATA RECORD GZ V1.0

In preparation for the concerted international study of Comet Halley, the IHW conducted a trial run with observations of Comet Crommelin, largely during February and March of 1984.

restrictedus-pdMar 2025View details →
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1:100,000-scale Digital Line Graphs (DLG) from the U.S. Geological Survey

Digital line graph (DLG) data are digital representations of cartographic information. DLG's of map features are converted to digital form from maps and related sources. Intermediate-scale DLG data are derived from USGS 1:100,000-scale 30- by 60-minute quadrangle maps. If these maps are not available, Bureau of Land Management planimetric maps at a scale of 1: 100,000 are used. Intermediate-scale DLG's are sold in five categories: (1) Public Land Survey System; (2) boundaries (3) transportation; (4) hydrography; and (5) hypsography. All DLG data distributed by the USGS are DLG - Level 3 (DLG-3), which means the data contain a full range of attribute codes, have full topological structuring, and have passed certain quality-control checks.

restrictednotspecifiedApr 2025View details →
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IHW COMET HALLEY LSPN NON-DIGITIZED IMAGES V1.0

NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the IHW. The observations belong to one of the following Disciplines: Amateur, Astrometry, Infrared Studies, Large-Scale Phenomena, Meteor Studies, Near-Nucleus Studies, Photometry and Polarimetry, Radio Studies, and Spectroscopy and Spectrophotometry. The data collected by these nine disciplines were augmented by Spacecraft measurements. The data were submitted to IHW, but the evaluation and selection for the Archive has been the primary responsibility of the Discipline Specialist Teams for each network in cooperation with the Lead Center. The data from the Large-Scale Phenomena Network has been organized into a set of digitized images and those left in the original analog state for reasons of quality, time coverage, or submission problems. These latter 1771 pieces of data are held in an archive both at Goddard Space Flight Center and with the Small Bodies Node of the Planetary Data System. (In the latter case, contact specifically the Comet Sub-Node of the PDS at the Laboratory for Atmospheric and Space Physics associated with the University of Colorado Boulder, for more assistance). Some of these analog images are presented in 'The International Halley Watch Atlas of Large-Scale Phenomena' (Brandt, John C., Niedner, Malcolm B. Jr., Rahe, Jurgen, 1992). The data cover a time range from 1984 December 22 through 1987 April 26 through 23 of the IHW Chronological Data Archive Collection

restrictedus-pdMar 2025View details →
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SMAPVEX19-22 Massachusetts Lidar Derived Digital Surface Model V001

These digital surface model (DSM) data consist of surface elevations derived from source lidar measurements collected in August 2022 in the vicinity of Petersham, MA during the SMAPVEX19-22 campaign. The location was selected due to its forested land cover, as SMAPVEX19-22 aims to validate satellite derived soil moisture estimates in forested areas. The August collection period was selected to characterize ‘leaf-on’ conditions. DSM data represents the highest elevation of features on the Earth’s surface, which may include bare-earth, vegetation, and human-made objects.

restrictednotspecifiedMar 2025View details →
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SMAPVEX19-22 Millbrook Lidar Derived Digital Surface Model V001

These data consist of ground surface elevations derived from source lidar measurements collected in April and August 2022 in the vicinity of Millbrook, NY during the SMAPVEX19-22 campaign. This location was chosen due to its forested land cover, as SMAPVEX19-22 aims to validate satellite derived soil moisture estimates in forested areas. The two acquisition periods occurred to characterize differences during "leaf-on" and "leaf-off" conditions.

restrictednotspecifiedMar 2025View details →
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ROSAT All-Sky Survey and Sloan Digital Sky Survey DR7 Galaxy Clusters

The authors use ROSAT All-Sky Survey (RASS) broad-band X-ray images and the optical clusters identified from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) to estimate the X-ray luminosities around ~65,000 candidate galaxy clusters with masses >~10<sup>13</sup> h<sup>-1</sup> M<sub>sun</sub> based on an optical to X-ray (OTX) code that they developed. They obtain a catalog with X-ray luminosities for all 64,646 clusters. A total of 34,522 (~53%) of these clusters have a signal-to-noise ratio S/N > 0 after subtracting the background signal. According to the reference paper (but see HEASARC Caveats section below), this catalog contains 817 clusters (473 at redshift z <= 0.12) with S/N > 3 for their X-ray detections (an additional 12,629 clusters have 3 >= S/N > 1 and 21,076 clusters have 1 >= S/N > 0). The authors find about 65% of these X-ray clusters have their most massive member located near the X-ray flux peak; for the remaining 35%, the most massive galaxy is separated from the X-ray peak, with the separation following a distribution expected from a Navarro-Frenk-White profile. In the reference paper, the authors investigate a number of correlations between the optical and X-ray properties of these X-ray clusters, and find that the cluster X-ray luminosity is correlated with the stellar mass (luminosity) of the clusters, as well as with the stellar mass (luminosity) of the central galaxy and the mass of the halo, although the scatter in these correlations is large. Comparing the properties of X-ray clusters of similar halo masses but having different X-ray luminosities, they find that massive haloes with masses >~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> contain a larger fraction of red satellite galaxies when they are brighter in X-ray. An opposite trend is found in central galaxies in relative low-mass haloes with masses <~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> where X-ray brighter clusters have smaller fraction of red central galaxies. Clusters with masses >~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> that are strong X-ray emitters contain many more low-mass satellite galaxies than weak X-ray emitters. These results are also confirmed by checking X-ray clusters of similar X-ray luminosities but having different characteristic stellar masses. The cluster catalog containing the optical properties of member galaxies and the X-ray luminosity is also available at <a href="http://gax.shao.ac.cn/data/Group.html">http://gax.shao.ac.cn/data/Group.html</a>. The optical data used in this analysis are taken from the SDSS galaxy group catalogs of Yang et al. (2007, ApJ, 671, 153), constructed using the adaptive halo-based group finder of Yang et al. (2005, MNRAS, 356, 1293), here updated to DR7. The parent galaxy catalog is the New York University Value-Added Galaxy Catalog (NYU-VAGC; Blanton et al. 2005, AJ, 129, 2562) based on the SDSS DR7 (Abazajian et al. 2009, ApJS, 182, 543), which contains an independent set of significantly improved reductions. In this study, the authors adopt a Lambda cold dark matter cosmology whose parameters are consistent with the 7-year data release of the WMAP mission: Omega<sub>m</sub> = 0.275, Omega<sub>Lambda</sub> = 0.725, h = H<sub>0</sub>/(100 km s<sup>-1</sup> Mpc<sup>-1</sup>) = 0.702, and sigma<sub>8</sub> = 0.816. This table was created by the HEASARC in June 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/439/611">CDS Catalog J/MNRAS/439/611</a> file catalog.dat. This is a service provided by NASA HEASARC .

restrictednotspecifiedApr 2025View details →
nasa20/100

Nimbus High Resolution Infrared Radiometer Remapped Digital Data Daily L3, GeoTIFF V001

This data set (NmHRIR3G) consists of daily composites constructed from Nimbus 1, Nimbus 2, and Nimbus 3 satellites High Resolution Infrared Radiometer (HRIR) data for the region between 60 N and 60 S. Measurements were obtained during 1964, 1966, and 1969. Data are available as GeoTIFFs and browse images. For the HDF5 formatted version of these data, see the <a href="http://dx.doi.org/10.5067/NIMBUS/NmHRIR3H">Nimbus High Resolution Infrared Radiometer Remapped Digital Data Daily L3, HDF5</a> data set.

restrictednotspecifiedMar 2025View details →
nasa20/100

PSP FIELDS Digital Fields Board (DFB) AC-coupled Searchcoil Magnetometer, SCM, Spectra, Low Frequency, High Gain, f-component, Sensor coordinates, Level 2 (L2), 0.873813 s Data

PSP FIELDS Digital Fields Board, DFB, SCMflfhg data:The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].DFB AC spectra data consist of power spectral densities as a function of frequency and time. These spectra are averaged over both frequency and time as described in [3]. The spectra have pseudo-logarithmically spaced frequency bins with the bin central frequencies reported in the metadata. The AC spectra are duty-cycled such that spectral averaging takes place over the first 1/8 of any given NYsecond when the data cadence is equal to one NYsecond. Less data are averaged by a factor of 2^N for data cadences that are faster than one NYsecond by 2^N. For cadences slower than one NYsecond, the first 1/8 of each NYsecond of data included are averaged together to construct the reported data.The Level 2 data products contained in this data file have been calibrated for:* 1) The Hanning window used in the spectral calculation* 2) DFB in-band gain* 3) DFB analog filter gain response* 4) DFB digital filter gain response* 5) The search coil preamplifier response, when applicable* 6) The bandwidth of each spectral binNote that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz.The Level 2 data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer spectral data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field spectral data are in expressed in search coil magnetometer sensor coordinates with components [u,v,w].To rotate from [d,e,f] coordinates into [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.R = [[ 0.46834856, -0.81336422 , 0.34509170] [ -0.66921924, -0.071546954, 0.73961249] [ -0.57688408, -0.57733845 , -0.57782790]]The time resolution of the DFB AC spectral data can vary by multiples of 2^N. During encounter when PSP is within 0.25 AU of the Sun, the DFB AC spectra data cadence is typically NYsecond NYsecond [2]. Timestamps correspond to the center time of each window.References:* 1) Fox, N.J., Velli, M.C., Bale, S.D. et al., Space Sci Rev (2016) 204:7. https://doi.org/10.1007/s1121401502116* 2) Bale, S.D., Goetz, K., Harvey, P.R. et al., Space Sci Rev (2016) 204:49. https://doi.org/10.1007/s1121401602445* 3) Malaspina, D.M., Ergun, R.E., Bolton, M. et al., JGR Space Physics (2016), 121, 5088-5096. https://doi.org/10.1002/2016JA022344

restrictednotspecifiedAug 2025View details →
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Nimbus Temperature-Humidity Infrared Radiometer 6.7 µm Water Vapor Remapped Digital Data Daily L3, HDF5 V001

This data set (NmTHIR67-3H) consists of daily, global composites of radiative temperatures measured in the 6.7 µm water vapor window (6.5 µm - 7.0 µm) by the Temperature-Humidity Infrared Radiometer (THIR) onboard the Nimbus 4 satellite. The composites were constructed from Nimbus 4 THIR <a href="http://nsidc.org/data/nmthir67-1h/">swath data</a> and show water vapor distribution in the upper troposphere and stratosphere.

restrictednotspecifiedMar 2025View details →
nasa20/100

Sloan Digital Sky Survey/UKIRT DSS Large Area Survey Matched Quasars Catalog

This table contains a catalog of over 130,000 quasar candidates with near-infrared (NIR) photometric properties, with an areal coverage of approximately 1200 deg&lt;sup&gt;2&lt;/sup&gt;. This is achieved by matching the Sloan Digital Sky Survey (SDSS) in the optical ugriz bands to the UKIRT Infrared Digital Sky Survey (UKIDSS) Large Area Survey (LAS) in the NIR YJHK bands. The authors match the ~1 million SDSS DR6 Photometric Quasar catalog to Data Release 3 of the UKIDSS LAS (ULAS) and produce a catalog with 130,827 objects with detections in one or more NIR bands, of which 74,351 objects have optical and K-band detections and 42,133 objects have the full nine-band photometry. The majority (~85%) of the SDSS objects were not matched simply because these were not covered by the ULAS. The positional standard deviation of the SDSS Quasar to ULAS matches is 0.1370 arcseconds in RA and 0.1314 arcseconds in Dec. The authors find an absolute systematic astrometric offset between the SDSS Quasar catalog and the UKIDSS LAS, of |RA offset| = 0.025 arcseconds and |Dec offset| = 0.040 arcseconds; they suggest the nature of this offset to be due to the matching of catalog, rather than image, level data. Their matched catalog has a surface density of ~53 deg&lt;sup&gt;-2&lt;/sup&gt; for K &lt;= 18.27 objects; tests using this matched catalog, along with data from the UKIDSS Deep Extragalactic Survey, imply that its limiting magnitude is i ~ 20.6. Color-redshift diagrams, for the optical and NIR, show a close agreement between this matched catalog and recent quasar color models at redshift z &lt;~ 2.0, while at higher redshifts, the models generally appear to be bluer than the mean observed quasar colors. This table was created by the HEASARC in September 2012 based on &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/141/105"&gt;CDS Catalog J/AJ/141/105&lt;/a&gt; file table4.dat. This is a service provided by NASA HEASARC .

restrictednotspecifiedApr 2025View details →

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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.

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Allen Brain Atlas

Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.

allen-brain-atlas
neuroscienceopenDocumentation, web resources, and API references are available online.
Last verified 2026-04-30Open record

Annotated Behaviour and Observability Dataset (ABODe)

ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.

abode-home-cage
behavioral-neuroscienceopenThe DataShare record exposes download links for annotations, documentation, license text, and the zipped per-snippet data directory.
Last verified 2026-04-30Open record

DANDI Archive for NWB datasets

DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.

dandi-nwb
electrophysiologyopenPublished Dandiset metadata and archive endpoints are available through the production DANDI API.
Last verified 2026-04-30Open record

International Brain Laboratory public data

The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.

ibl
behavioral-neuroscienceopenPublic sessions can be searched and loaded from the IBL public data server through ONE.
Last verified 2026-04-29Open record

OpenNeuro

OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.

openneuro
neuroscienceopenPublished datasets are available on demand over the internet.
Last verified 2026-04-29Open record

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