Beschäftigungsperspektiven des Dienstleistungssektors

Bade, Franz-Josef

doi:10.1007/978-3-663-08126-5_6

Cited by 25 publications

(31 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Citing previous work (Bade et al 1998;Motch et al 1997aMotch et al , 1997b, N99 estimated a 2% misidentification rate; however, we find no quantitative support for this estimation in any of the cited works. The limits derived by N99 for the number of cooling or accreting INSs therefore function only as lower limits.…”

Section: Source Confusion In Previous Workcontrasting

confidence: 50%

“…The observational problem of discovering INSs (for a recent review, see Treves et al 2000) from the RASS BSC is severely hampered by source confusion (Motch et al 1997a;Zickgraf et al 1997;Bade et al 1998;Danner 1998aDanner , 1998bThomas et al 1998). For example, the average number of optical sources in the USNO-A2 catalog in a 3 uncertainty region of a RASS BSC source is $3, and it is often much greater in the Galactic plane.…”

Section: Source Confusion In Previous Workmentioning

confidence: 97%

See 1 more Smart Citation

A Limit on the Number of Isolated Neutron Stars Detected in theROSATBright Source Catalogue

Rutledge

Fox

Bogosavljević

et al. 2003

ApJ

View full text Add to dashboard Cite

The challenge in searching for non-radio-pulsing isolated neutron stars (INSs) is in excluding association with objects in the very large error boxes ($13 00 , 1 radius) typical of sources from the largest X-ray all-sky survey, the ROSAT All-Sky Survey Bright Source Catalogue (RASS BSC). We search for candidate INSs using statistical analysis of optical (USNO-A2), infrared (IRAS), and radio (NVSS) sources near the ROSAT X-ray localization and show that this selection would find 20% of the INSs in the RASS BSC. This selection finds 32 candidates at declinations > À39 , among which are two previously known INSs, 17 sources that we show are not INSs, and 13 the classification of which are as yet undetermined. These results require a limit of less than 67 INSs (90% confidence, full sky, assuming isotropy) in the RASS BSC. This limit modestly constrains a naive and optimistic model for cooling neutron stars in the Galaxy.

show abstract

Section: Source Confusion In Previous Workcontrasting

confidence: 50%

Section: Source Confusion In Previous Workmentioning

confidence: 97%

A Limit on the Number of Isolated Neutron Stars Detected in theROSATBright Source Catalogue

Rutledge

Fox

Bogosavljević

et al. 2003

ApJ

View full text Add to dashboard Cite

show abstract

“…c Coordinates and magnitudes are taken from APM catalog (Irwin et al 1994), except for objects with notes. e Already cataloged in Bade et al 1998 f Already cataloged as HD 115781. g Coordinate determined by CCD image taken during the spectroscopic observations. h Determined by relative photometry with mosaic CCD image taken at KISO observatory.…”

Section: Optical Spectroscopymentioning

confidence: 99%

Optical Identification of theASCALarge Sky Survey

Akiyama

Ohta

Yamada

et al. 2000

ApJ

135

184

View full text Add to dashboard Cite

We present results of optical identiÐcation of the X-ray sources detected in the ASCA Large Sky Survey. Optical spectroscopic observations were done for 34 X-ray sources that were detected with the SIS in the 2È7 keV band above 3.5 p. The Ñux limit corresponds to D1 ] 10~13 ergs cm~2 s~1 in the 2È10 keV band. The sources are identiÐed with 30 active galactic nuclei (AGNs), two clusters of galaxies, and one Galactic star. Only one source is still unidentiÐed.All of the X-ray sources that have a hard X-ray spectrum with an apparent photon index of smaller than 1 in the 0.7È10 keV band are identiÐed with narrow-line or weak-broad-line AGNs at redshifts smaller than 0.5. This fact supports the idea that absorbed X-ray spectra of narrow-line and weak-broadline AGNs make the cosmic X-ray background (CXB) spectrum harder in the hard X-ray band than that of a broad-line AGN, which is the main contributor in the soft X-ray band. Assuming their intrinsic spectra are same as a broad-line AGN (a power-law model with a photon index of 1.7), their X-ray spectra are Ðtted with hydrogen column densities of at the objectÏs redshift. On log N H (cm~2) \ 22È23 the other hand, X-ray spectra of the other AGNs are consistent with that of a nearby type 1 Seyfert galaxy. In the sample, four high-redshift luminous broad-line AGNs show a hard X-ray spectrum with an apparent photon index of 1.3^0.3. The hardness may be explained by the reÑection component of a type 1 Seyfert galaxy. The hard X-ray spectra may also be explained by absorption with at the objectÏs redshift, if we assume an intrinsic photon index of 1.7. The origin log N H (cm~2) \ 22È23 of the hardness is not clear yet.Based on the log NÈlog S relations of each population, contributions to the CXB in the 2È10 keV band are estimated to be 9% for less-absorbed AGNs including the four high-(log N H (cm~2) \ 22) redshift broad-line AGNs with a hard X-ray spectrum, 4% for absorbed AGNs (22 \ log N H (cm~2) \ 23, without the four hard broad-line AGNs), and 1% for clusters of galaxies in the Ñux range from 3 ] 10~11 ergs cm~2 s~1 to 2 ] 10~13 ergs cm~2 s~1. If the four hard broad-line AGNs are included in the absorbed AGNs, the contribution of the absorbed AGNs to the CXB is estimated to be 6%.In optical spectra, there is no high-redshift luminous cousin of a narrow-line AGN in our sample. The redshift distribution of the absorbed AGNs is limited below z \ 0.5 excluding the four hard broad-line AGNs, in contrast to the existence of 15 less-absorbed AGNs above z \ 0.5. The redshift distribution of the absorbed AGNs suggests a deÐciency of AGNs with column densities of in log N H (cm~2) \ 22È23 the redshift range 0.5È2, or in the X-ray luminosity range larger than 1044 ergs s~1, or both. If the large column densities of the four hard broad-line AGNs are real, they could complement the deÐciency of X-ray absorbed luminous high-redshift AGNs.

show abstract

“…It was detected in the ROSAT All Sky Survey (RASS). An optical identification of the X-ray source was given by Bade et al (1998). Voges et al (1999) identified this source as a galaxy cluster.…”

Section: Introductionmentioning

confidence: 99%

SZ and X-ray combined analysis of a distant galaxy cluster, RX J2228+2037

Pointecouteau

Hattori

Neumann

et al. 2002

A&A

View full text Add to dashboard Cite

Abstract.We have performed a combined analysis of X-ray and Sunyaev-Zel'dovich data in the direction of the distant galaxy cluster, RX J2228+2037. Fitting a β-model to the high-resolution HRI data gives rc = 103±12 h . Our results on the temperature and on the cluster mass classify RX J2228+2037 among the distant, hot and very massive galaxy clusters. Our work highlights the power of the association of galaxy cluster mapping observations in X-ray and the SZ effect to derive the cluster's physical properties, even without X-ray spectroscopy.

show abstract

Beschäftigungsperspektiven des Dienstleistungssektors

Cited by 25 publications

References 4 publications

A Limit on the Number of Isolated Neutron Stars Detected in theROSATBright Source Catalogue

A Limit on the Number of Isolated Neutron Stars Detected in theROSATBright Source Catalogue

Optical Identification of theASCALarge Sky Survey

SZ and X-ray combined analysis of a distant galaxy cluster, RX J2228+2037

Contact Info

Product

Resources

About