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1561. ROSAT HRI Pointed Observations (1RXH)
ID:
ivo://CDS.VizieR/IX/28A
Title:
ROSAT HRI Pointed Observations (1RXH)
Short Name:
IX/28A
Date:
21 Oct 2021
Publisher:
CDS
Description:
The hricat.dat table contains a list of sources detected by the Standard Analysis Software System (SASS) in reprocessed, public High Resolution Imager (HRI) datasets. In addition to the parameters returned by SASS (like position, count rate, signal-to-noise, etc.) each source in the table has associated with it a set of source and sequence "flags". These flags are provided by the ROSAT data centers in the US, Germany and the UK to help the user of the ROSHRI database judge the reliability of a given source. These data have been screened by ROSAT data centers in the US, Germany, and the UK as a step in the production of the Rosat Results Archive (RRA). The RRA contains extracted source and associated products with an indication of reliability for the primary parameters.
1562. ROSAT medium-sensitivity Galactic plane survey
ID:
ivo://CDS.VizieR/J/MNRAS/326/1161
Title:
ROSAT medium-sensitivity Galactic plane survey
Short Name:
J/MNRAS/326/1161
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have performed a moderately deep soft X-ray (0.1-2keV) survey of the Galactic plane using pointed observations with the ROSAT Position Sensitive Proportional Counter (PSPC). The survey is more than an order of magnitude more sensitive than previous X-ray surveys near the Galactic plane. The data consist of nine fields each of ~10ks exposure, pointed at positions on or very close to the Galactic plane (|b|<0.3{deg}) in the longitude range 180{deg}<~l<~280{deg}. This region has relatively low X-ray absorbing material out to distances of several hundred pc and presents fewer source-confusion problems than at other longitudes. The total sky area surveyed was 2.5deg^2^ this yielded 93 sources, 89 of which were detected in the hard (0.4-2.0keV) band. Nine sources were detected in both soft (0.1-0.4keV) and hard bands. In the hard band, the survey coverage is 90 per cent for sources brighter than 0.002count/s (~2x10^-14^erg/cm^2^/s), but falls steeply below this value, with the weakest sources being ~0.001count/s. The median limiting flux is <~0.0013count/s (~1.3x10^14^erg/cm^2^/s). There are 64 sources with hard-band count rates >0.002count/s. We present the catalogue of X-ray sources and the number-flux relations (logN-logS). Eighteen sources have possible identifications from the SIMBAD data base. We have searched the Tycho-2 (Cat. <I/259>) and USNO-A2.0 (Cat. <I/252>) catalogues to find all possible optical counterparts brighter than 19th magnitude, and attempt to classify these on the basis of log(FX/Fopt) versus optical colour diagrams and near-infrared photometry from the 2MASS Second Incremental Data Release (Cat. <B/2mass>). Hence, we have found the majority of these sources to be consistent with being late-type main-sequence stars, as previous studies have proposed from incompletely identified surveys. Comparison of the measured number-flux relations with predictions of Galactic (stellar) and extragalactic populations supports the view that the population of young stars in the plane is denser than previously thought.
1563. ROSAT NEP X-ray source catalog
ID:
ivo://CDS.VizieR/J/ApJS/162/304
Title:
ROSAT NEP X-ray source catalog
Short Name:
J/ApJS/162/304
Date:
21 Oct 2021
Publisher:
CDS
Description:
The sky around the North Ecliptic Pole (NEP), at 18:00:00+66:33:39, has the deepest exposure of the entire ROSAT All-Sky Survey (RASS, Cat. <IX/10>). The NEP is an undistinguished region of moderate Galactic latitude, b=29.8{deg}, and hence suitable for compiling statistical samples of both Galactic and extragalactic objects. We have made such a compilation in the 80.6{deg}^2^ region surrounding the NEP. Our sample fully exploits the properties of the RASS, since the only criteria for inclusion are source position and significance, and it yields the deepest large solid angle contiguous sample of X-ray sources to date. We find 442 unique sources above a flux limit ~2x10^-14^ergs/cm^2^/s in the 0.5-2.0keV band. In this paper we present the X-ray properties of these sources as determined from the RASS. These include positions, fluxes, spectral information in the form of hardness ratios, and angular sizes. Since we have performed a comprehensive optical identification program we also present the average X-ray properties of classes of objects typical of the X-ray sky at these flux levels. We discuss the use of the RASS to find clusters of galaxies based on their X-ray properties alone.
1564. ROSAT North Ecliptic Pole Survey
ID:
ivo://CDS.VizieR/J/ApJS/149/29
Title:
ROSAT North Ecliptic Pole Survey
Short Name:
J/ApJS/149/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
The X-ray data around the North Ecliptic Pole (NEP) of the ROSAT All Sky Survey have been used to construct a contiguous area survey consisting of a sample of 445 individual X-ray sources above a flux of ~2x10^-14^erg/cm^2^/s in the 0.5-2.0keV energy band. The NEP survey is centered at RA=18:00 (2000) DE=+66:33 and covers a region of 80.7deg^2^ at a moderate Galactic latitude of b=29.8{deg}. Hence, the NEP survey is as deep and covers a comparable solid angle to the ROSAT serendipitous surveys but is also contiguous. We have identified 99.6% of the sources and determined redshifts for the extragalactic objects. In this paper we present the optical identifications of the NEP catalog of X-ray sources including basic X-ray data and properties of the sources. We also describe with some detail the optical identification procedure. The classification of the optical counterparts to the NEP sources is very similar to that of previous surveys, in particular the Einstein Extended Medium Sensitivity Survey (EMSS). The main constituents of the catalog are active galactic nuclei (AGNs) (~49%), either type 1 or type 2 according to the broadness of their permitted emission lines. Stellar counterparts are the second most common identification class (~34%). Clusters and groups of galaxies comprise 14%, and BL Lacertae objects 2%. One non-AGN galaxy and one planetary nebula have also been found. The NEP catalog of X-ray sources is a homogeneous sample of astronomical objects featuring complete optical identification.
1565. Rosat North Ecliptic survey stellar population
ID:
ivo://CDS.VizieR/J/A+A/461/977
Title:
Rosat North Ecliptic survey stellar population
Short Name:
J/A+A/461/977
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray surveys are a very efficient mean of detecting young stars and therefore allow us to study the young stellar population in the solar neighborhood and the local star formation history in the last billion of years. We want to study the young stellar population in the solar neighborhood, to constrain its spatial density and scale height as well as the recent local star formation history. We analyze the stellar content of the ROSAT North Ecliptic Pole survey, and compare the observations with the predictions derived from stellar galactic model. Since the ROSAT NEP survey is sensitive at intermediate fluxes is able to sample both the youngest stars and the intermediate age stars (younger than 10^9^years), linking the shallow and deep flux surveys already published in the literature. We confirm the existence of an excess of yellow stars in our neighborhood previously seen in shallow survey, which is likely due to a young star population not accounted for in the model. However the excellent agreement between observations and predictions of dM stars casts some doubt on the real nature of this active population.
1566. ROSAT Survey and Pointed Images
ID:
ivo://org.gavo.dc/rosat/q/im
Title:
ROSAT Survey and Pointed Images
Short Name:
ROSAT images
Date:
27 Dec 2024 08:31:12
Publisher:
The GAVO DC team
Description:
Images taken by the ROSAT x-ray observatory. This comprises both pointed observations and images taken within the all-sky survey.
1567. ROSAT survey of bright galaxies clusters
ID:
ivo://CDS.VizieR/J/ApJ/514/148
Title:
ROSAT survey of bright galaxies clusters
Short Name:
J/ApJ/514/148
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the selection of an X-ray flux-limited sample of bright clusters of galaxies in the southern hemisphere, based on the first analysis of the ROSAT All-Sky Survey data (RASS1). The sample is constructed starting from an identification of candidate clusters in RASS1, after which their X-ray fluxes are remeasured using the steepness-ratio technique. This method is better suited than the RASS1 standard algorithm to measuring flux from extended sources. The final sample is count-rate-limited in the ROSAT hard band (0.5-2.0 keV), so that as a result of the distribution of N_H_, its effective flux limit varies between {~}3 and 4x10^-12^ ergs cm^-2^ s^-1^ over the selected area. This covers the {delta} < 2.5{deg} part of the south Galactic cap region (b < -20{deg}), excluding patches of low RASS1 exposure time and of the Magellanic Clouds area, for a total of 8235 deg^2^. One hundred and thirty candidate sources fulfill our selection criteria for bona fide clusters of galaxies in this area. Of these, 101 are Abell/ACO clusters, while 29 do not have a counterpart in these catalogs. Of these clusters, 126 (97%) have a redshift, and for these we compute an X-ray luminosity. 20% of the cluster redshifts come from new observations, as part of the ESO Key Program survey of RASS clusters that is currently under completion. Considering the intrinsic biases and incompletenesses introduced by the flux selection and source identification processes, we estimate the overall completeness to be better than 90%. The observed number count distribution, log Nlog S, is well fitted by a power law with slope {alpha} =1.34{+/-}0.15 and normalization A=11.87{+/-}1.04 sr^-1^ (10^-11^ ergs cm^-2^ s^-1^)^{alpha}^, in good agreement with other measurements.
1568. ROSAT Ultra Deep Survey
ID:
ivo://CDS.VizieR/J/A+A/371/833
Title:
ROSAT Ultra Deep Survey
Short Name:
J/A+A/371/833
Date:
21 Oct 2021
Publisher:
CDS
Description:
The ROSAT Ultra Deep Survey in the Lockman Hole consists of a sample of 94 X-ray sources reaching a limiting flux of 1.2x10-15erg/s/cm^2^ in the 0.5-2.0keV energy band. About 90% of the X-ray sources have been spectroscopically identified using low-resolution Keck spectra.
1569. ROSAT Wide Field Camera: F1
ID:
ivo://nasa.heasarc/skyview/wfcf
Title:
ROSAT Wide Field Camera: F1
Short Name:
WFCF
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This survey is a mosaic of images taken by the ROSAT Wide Field Camera and comprises of 12,743 seperates fields in each of two filters. Each field covers a region 2.6&amp;#176;; x 2.6&amp;#176;; with a 0.3&amp;#176;; overlap. Currently, this data is not a complete coverage of the sky; regions near the northern ecliptic pole are currently not included. Provenance: University of Leicester. This is a service of NASA HEASARC.
1570. ROSAT X-ray sources in LMC. II.
ID:
ivo://CDS.VizieR/J/A+A/388/100
Title:
ROSAT X-ray sources in LMC. II.
Short Name:
J/A+A/388/100
Date:
21 Oct 2021
Publisher:
CDS
Description:
About 200 X-ray sources from a sample of spectrally hard ROSAT PSPC sources, given in the catalog of Haberl & Pietsch (1999, Cat. <J/A+AS/139/277>), and observed in a ~60 square degree field of the LMC during several archival pointed observations with a wide range of exposure times have been reanalyzed. For these sources accurate count rates and hardness ratios have been recalculated. In comparison to Haberl & Pietsch (1999, Cat. <J/A+AS/139/277>) we used merged data from all available observations and we derived average source parameters by investigating each source individually. From a simulation power-law spectral tracks have been derived in the HR1-HR2 plane and ~170 sources have been classified as background X-ray sources or as LMC X-ray binaries. 80% of the spectrally hard X-ray sources with more than 50 observed counts have been found to be consistent with background X-ray sources and 20% with LMC X-ray binaries (53 sources with AGN and 15 with X-ray binaries).

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