- ID:
- ivo://CDS.VizieR/J/A+AS/122/235
- Title:
- ROSAT active galaxies identifications
- Short Name:
- J/A+AS/122/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 2 gives the 5 GHz high resolution radio source properties for the 1861 Rosat-GreenBank (RGB) sources for which subarcsecond positions and core radio flux densities were obtained. After submission of this paper, we discovered a possible systematic position error in a very small subset of sources. In particular, the sources RGB J0131+005, RGB J0139+178, RGB J0143+129, RGB J0157+235A, RGB J0232+202, RGB J0233+024A, RGB J0243+171, RGB J0256+035, RGB J0303+059, RGB J0308+104, RGB J0312+243A, RGB J0312+242C, and RGB J0314+063 were all observed in our "c" epoch VLA runs and show large systematic offsets with respect to sources found in the NVSS survey. We re-examined these sources and found the position reported in the tables is accurate given our data, but that the noise on these fields before any CLEANing is abnormally high. We thank Dr. Alastair Edge for pointing out this discrepancy. Table 3 gives the 5 GHz radio source properties for the 436 Rosat-Green Bank (RGB) sources for which only low resolution data were obtained. Table 4 gives the 83 Rosat-Green Bank (RGB) sources for which no radio source greater than 5 sigma was observed in the follow-up VLA observations. These catalogs consist of radio- and X-ray-loud AGN selected from a correlation of the 1987 Green Bank radio catalog and the Rosat All-Sky Survey.
Number of results to display per page
Search Results
1472. ROSAT AGN content
- ID:
- ivo://CDS.VizieR/J/A+AS/109/147
- Title:
- ROSAT AGN content
- Short Name:
- J/A+AS/109/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cross-correlation of the source list from the ROSAT All-Sky Survey with the 5 GHz Green Bank survey yields a list of 2127 objects. About two thirds of them are optically unidentified. The majority of the objects with known optical counterparts are quasars and radio galaxies, most of them detected in X-rays for the first time. In this paper we present a list of the previously optically identified objects with their main characteristics and discuss their general (bulk) properties. We find strong correlations between luminosities in the radio, optical, and X-ray bands which differ for quasars and radio galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/356/445
- Title:
- ROSAT-FIRST AGN correlation
- Short Name:
- J/A+A/356/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a correlation of the ROSAT All-Sky Survey with the April 1997 release of the VLA 20cm FIRST (Cat. <VIII/59>) catalogue. We focus our analysis on the 843 X-ray sources which have unique radio counterparts. The majority of these objects (84%) have optical counterparts on the POSS 1 plates. Approximately 30% have been previously classified and we obtain new spectroscopic classifications for 85 sources by comparison with the ongoing FIRST Bright Quasar Survey and 106 additional sources from our own new spectroscopic data. Approximately 51% of the sources are presently classified, and the majority of the unclassified objects are optically faint. The newly classified sources are generally radio weak, exhibiting properties intermediate with previous samples of radio- and X-ray-selected AGN. This also holds for the subsample of 71 BL Lacs which includes many intermediate objects. The 146 quasars show no evidence for a bimodal distribution in their radio-loudness parameter, indicating that the supposed division between radio-quiet and radio-loud AGN may not be real. The X-ray and radio luminosities are correlated over two decades in radio luminosity, spanning the radio-loud and radio-quiet regimes, with radio-quiet quasars showing a linear correlation between the two luminosities. Many of the sources show peculiar or unusual properties which call for more detailed follow-up observations. We also give the X-ray and radio data for the 518 X-ray sources for which more than one radio object is found. Because of the difficulties inherent in identifying optical counterparts to these complex sources, we do not consider these data in the current analysis.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/201
- Title:
- ROSAT Galactic Plane Survey observations
- Short Name:
- J/A+AS/122/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The analysis of the part of the ROSAT all-sky survey covering the galactic plane is the scope of a dedicated project called the ROSAT Galactic Plane Survey. In order to statistically understand the nature of the =~14000 sources discovered by ROSAT at |b|<=20{deg}, a number of sample areas have been chosen for follow-up optical identification. In this paper we present the X-ray and optical material gathered in a region located in the Cygnus constellation, centered at l=90{deg}, b=0{deg} and covering an area of 64.5deg^2^. A total of 95 and 128 sources are detected with a maximum likelihood larger than 10 and 8 respectively. With a typical survey exposure time of the order of 700 to 900 s the flux completeness level is =~0.02cts/s corresponding to =~2x10^-13^erg/cm^2^/s. The position of the sample area allows to investigate the soft X-ray content of a rather typical region of the galactic plane. In this paper we describe the details of the observational procedures and data reduction. For each ROSAT source we list the main X-ray characteristics together with those of the proposed optical identification. When appropriate, we also show optical spectra and finding charts. The full analysis and discussion of these data are presented in a companion paper (Motch et al. 1997, Cat. <J/A+A/318/111>).
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/554/202
- Title:
- ROSAT X-ray observations of M81
- Short Name:
- J/ApJ/554/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the analysis of deep ROSAT HRI and PSPC observations of the spiral galaxy M81. The inferred total (0.5-2keV band) luminosity of M81 is ~3x10^40^ergs/s, excluding the contribution from identified interlopers found within the D_25_ ellipse. The nucleus of the galaxy alone accounts for about 65% of this luminosity. The rest is due to 26 other X-ray sources (contributing ~10%) and to apparently diffuse emission, which is seen across much of the galactic disk and is particularly bright in the bulge region around the nucleus. Spectral analysis further gives evidence for a soft component, which can be characterized by a two-temperature optically thin plasma with temperature at ~0.15 and 0.60keV and an absorption of the galactic foreground only. These components, accounting for ~13% of the X-ray emission from the region, apparently arise in a combination of hot gas and faint discrete sources. We find interesting spatial coincidences of luminous (10^37^-10^40^ergs/s) and variable X-ray sources with shock-heated optical nebulae. Three of them are previously classified as supernova remnant candidates. The other one is far off the main body of M81 but is apparently associated with a dense H I concentration produced most likely by the tidal interactions of the galaxy with its companions. These associations suggest that such optical nebulae may be powered by outflows from luminous X-ray binaries, which are comparable to, or more luminous than, Galactic "microquasars."
1478. Rosette Nebula globules
- ID:
- ivo://CDS.VizieR/J/A+A/605/A82
- Title:
- Rosette Nebula globules
- Short Name:
- J/A+A/605/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Rosette nebula is an HII region ionized mainly by the stellar cluster NGC 2244. Elephant trunks, globules, and globulettes are seen at the interface where the HII region and the surrounding molecular shell meet. We have observed a field in the northwestern part of the Rosette nebula where we study the small globules protruding from the shell. Our aim is to measure their properties and study their star-formation history in continuation of our earlier study of the features of the region. We imaged the region in broadband near-infrared (NIR) JsHKs filters and narrowband H_2_ 1-0 S(1), P{beta}, and continuum filters using the SOFI camera at the ESO/NTT. The imaging was used to study the stellar population and surface brightness, create visual extinction maps, and locate star formation. Mid-infrared (MIR) Spitzer IRAC and WISE and optical NOT images were used to further study the star formation and the structure of the globules. The NIR and MIR observations indicate an outflow, which is confirmed with CO observations made with APEX.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A123
- Title:
- Rotational spectroscopy of CH_2_OH
- Short Name:
- J/A+A/644/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hydroxymethyl radical (CH_2_OH) is one of the two structural isomers, together with the methoxy radical (CH_3_O), that can be produced by abstraction of a hydrogen atom from methanol (CH_3_OH). In the interstellar medium (ISM), both CH_2_OH and CH_3_O are suspected to be intermediate species in many chemical reactions, including those of formation and destruction of methanol. The determination of the CH_3_O/CH_2_OH ratio in the ISM would bring important information concerning the formation processes of these species in the gas and solid phases. Interestingly, only CH_3_O has been detected in the ISM so far, despite the recent first laboratory measurement of the CH_2_OH rotation-tunneling spectrum. This lack of detection is possibly due to the non-observation in the laboratory of the most intense rotational-tunneling transitions at low temperature. To support further searches for the hydroxymethyl radical in space, we have performed a thorough spectroscopic study of its rotation-tunneling spectrum, with particular focus on transitions involving the lowest quantum numbers of the species. We have recorded the rotation-tunneling spectrum of CH_2_OH at room temperature in the millimeter-wave domain using a frequency multiplication chain spectrometer associated to a fluorine-induced H-abstraction method. The radical was produced from methanol precursor. About 180 transitions were observed including those involving the lowest N and Ka quantum numbers, predicted intense under cold astrophysical conditions. These transitions were fitted together with available millimeter-wave lines from the literature. The systematic observation of all components of the rotational transitions yields a large improvement of the spectroscopic parameters which now allow confident searches of the hydroxymethyl radical in cold to warm environments of the ISM.
- ID:
- ivo://CDS.VizieR/J/A+A/500/1109
- Title:
- Rotational spectrum of HCOO^13^CH_3_
- Short Name:
- J/A+A/500/1109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Laboratory measurements and analysis of the microwave and millimeter-wave spectra of potential interstellar molecules are a prerequisite for their subsequent identification by radioastronomical techniques. The spectral analysis provides spectroscopic parameters that are used in the assignment procedure of the laboratory spectra, and that also predict the frequencies of transitions not measured in the laboratory with a high degree of precision. An experimental laboratory study and its theoretical analysis is presented for ^13^C_2_-methyl formate (HCOO^13^CH_3_) allowing a search for this isotopologue in the Orion molecular cloud. The ^13^C_1_-methyl formate (H^13^COOCH_3_) molecule was also searched for in this interstellar cloud, using previously published spectroscopic data.
