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2. The Origin of the Cosmic Soft X-Ray Background: Optical Identification of an Extremely Deep ROSAT Survey

Author

McHardy, I. M., Jones, L. R., Merrifield, M. R., Mason, K. O., Abraham, R. G., Newsam, A. M., Dalton, G. B., Carrera, F., Smith, P. J., Rowan-Robinson, M., Wegner, G. A., Ponman, T. J., Lehto, H. J., Branduardi-Raymont, G., Luppino, G. A., Efstathiou, G., Allan, D. J., and Quenby, J. J.

Subjects
Astrophysics
Abstract

We present the results of the deepest optically identified X-ray survey yet made. The X-ray survey was made with the ROSAT PSPC and reaches a flux limit of 1.6x10^-15 erg cm^-2 s^-1 (0.5--2.0 keV). Above a flux limit of 2x10^-15 erg cm^-2 s^-1 we define a complete sample of 70 sources of which 59 are identified. Some (5) other sources have tentative identifications and in a further 4 the X-ray error-boxes are blank to R=23 mag. At the brighter flux levels (>= 10^-14 erg cm^-2 s^-1) we confirm the results of previous less deep X-ray surveys with 84% of the sources begin QSOs. At fainter fluxes, however, the survey is dominated by a population of galaxies with narrow optical emission lines (NELGs). In addition, a number of groups and clusters of galaxies are found at intermediate fluxes. Most of these are poor systems of low X-ray luminosity and are generally found at redshifts of > 0.3. Their numbers are consistent with a zero evolutionary scenario, in contrast to the situation for high luminosity clusters at the same redshift. We discuss the significance of these results to the determination of the cosmic soft X-ray background (XRB) and show that at 2x10^-15 erg cm^-2 s^-1, we have resolved more than 50% of the background. We also briefly consider the probable importance of NELG objects to the residual background and look at some of the properties of these unusual objects., Comment: 28 pages, LaTeX, 17 figures from 32 postscript files. Uses mn.sty and epsf.sty. Accepted by MNRAS. Revised version now contains data table. For more information see http://www.astro.soton.ac.uk/~amn/UKdeep

Published
1997
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4. Aeschylus: Agamemnon

Author

Himmelhoch, Leah R., primary, Bowen, A., primary, Muir, J. V., primary, Stanford, W. B., primary, Oldaker, W. H., primary, Liddle, Aidan, primary, Ussher, R. G., primary, Goodwin, W. W., primary, McQueen, E. I., primary, Rowe, Christopher, primary, Simmonds, D. M., primary, Tierney, Michael, primary, Ferguson, John, primary, Kennedy, E. C., primary, Macdowell, D. M., primary, Campbell, David A., primary, Lesher, J. H., primary, Sleeman, J. H., primary, Powell, J. Enoch, primary, Harrison, J. A., primary, Hooker, J. T., primary, Willcock, M. M., primary, Watson, Janet, primary, Christensen, Joel P., primary, Sidwell, Keith C., primary, Edwards, M. J., primary, Handley, E. W., primary, Emlyn-Jones, C. J., primary, Allan, D. J., primary, Wright, M. R., primary, Adam, Adela Marion, primary, Jebb, Richard C., primary, Farnell, G. S., primary, Dover, K. J., primary, Marchant, E. C., primary, Horn, Theodore, primary, Doty, Ralph, primary, Usher, Stephen, primary, Timberlake, R. R., additional, Jordan, R. H., additional, Robinson, Erik, additional, Adam, James, additional, Goff, Marie, additional, and Wiedemann, Thomas, additional

Published
2023
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9. New Books

Author

Acton, H. B., Campbell, C. A., Macnabb, D., Woozley, A. D., Allan, D. J., Nowell-Smith, P. H., and Ewing, A. C.

Published
1952

10. New Books

Author

Duncan-Jones, Austin, Broad, C. D., Kneale, William, Kneale, Martha, Russell, L. J., Allan, D. J., Korner, S., Black, Percy, Urmson, J. O., Toulmin, Stephen, Smart, J. J. C., Flew, Antony, Cross, R. C., Hughes, George E., Holloway, John, Raphael, D. Daiches, Corbett, J. P., Gellner, E. A., Henderson, G. P., von Leyden, W., Heath, P. L., Macdonald, Margaret, Mayo, B., Nowell-Smith, P. H., Findlay, J. N., and MacIver, A. M.

Published
1950

11. New Books

Author

Toulmin, Stephen, Dummett, M., Medawar, P. B., Urmson, J. O., Warnock, G. J., Grant, C. K., Flew, Antony, Scrutton, Mary, Ewing, A. C., Cross, R. C., Robinson, Richard, Allan, D. J., Minio-Paluello, L., Henry, D. P., and Horsburgh, H. J. N.

Published
1954

12. New Books

Author

Britton, Karl, Leon, Philip, Allan, D. J., Wisdom, J. O., Helmer, Olaf, Schiller, F. C. S., Ewing, A. C., Gwynn, A., de Burgh, W. G., and Laird, John

Published
1937

13. New Books

Author

Edwards, E. W., Allan, D. J., Braithwaite, R. B., Jessop, T. E., Sprott, W. J. H., Acton, H. B., and Carritt, E. F.

Published
1939

21. Abstracts of papers presented at the 7th International Symposium of Scale Insect Studies (ISSIS-VII): June 12–17, 1994

Author

Danzig, Evelyna M., Hodgson, Chris J., Giliomee, Jan H., Foldi, Imré, Lambdin, Paris L., Marotta, Salvatore, Tranfaglia, Antonio, Porcelli, Francesco, Xingping, Hu, Shizhu, Li, Hendricks, Harlan Judson, Beardsley, John W., Henderson, Rosa, Miller, Douglass R., Williams, Douglas J., Ordögh, Gizela, Fang-Teh, Tang, Frey, Jürg E., Frey, Beatrice, Kozár, Ferenc, Kosztarab, Michael, Rhoades, Mary, Varshne, R. K., Kozarzhevskaya, Elga, Longo, Santi, Pellizzari, Giuseppina, Russo, Agatino, Jansen, Maurice, Williams, Michael L., MacVean, Charles M., Sheble, Diaa A. F., Sinacori, Angela, Jactel, Hervé, Perthuisot, N., Menassieu, P., Einhorn, J., Mendel, Zvi, Assael, Fabienne, Nestel, David, Saphir, Nitza, Zehavi, Amiram, Broza, Meir, Poliakov, D., Weber, S., Ben-Dov, Yair, Yingping, Xie, Xianqian, Liu, Jingping, Li, Min, Tang, Hippe, Carsten, Mani, E., Tanne, Edna, Gupta, Moti Lal, Sinha, P. K., Labuschagne, Thomas I., Hamburg, H. Van, Hadar, Dror, Wysoki, Manes, Rosen, David, Longo, S., Mazzeo, G., Myartseva, Svetlana N., Kalagina, G. A., Potaeva, A. G., Pinhassi, Nili, Peleg, Ben-Ami, Bar-Zakay, Itzhaq, Havron, Abraham, Rubin, Amos, Luna-Salas, Juan Fidencio, Martinez-Shio, M. E., Ruiz-Cancino, Enrique, Coronado-Blanco, J. M., Uygun, Nedim, Karaca, Ismail, Sekeroğlu, E., Israeli, Yossi, Viggiani, Gennaro, Loia, M., Yasnosh, Valentina A., Aleksidze, Guram, Erkiliç, Lerzan, Podsiadlo, Elzbieta, Katsoyannos, Panayotis, Stathas, G. J., Halevy, Miri, Rose, Mike, Stauffer, Steve, Smith, Daniel, Papacek, Daniel, Lambdin, P., Yardeni, Aharon, Shapira, Elyakim, Paloukis, Stergios S., Navrozidis, Emmanuel I., Michelakis, Stelios, Hamid, H. A., Sugonyaev, Eugeny S., Panis, A., Oi, E., Pinet, Ch., Argov, Yael, Zchori-Fein, Einat, Blumberg, Daniel, Ben-Shalom, Shai, Rössler, Yoram, Izraylevich, Sergey, Gerson, Uri, Charles, John G., Hill, M. G., Allan, D. J., di Chiara, Salvatore Ragusa, and Tsolakis, H.

Published
1994
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36. Editorial

Author

Allan, D. J. and Skemp, J. B.

Published
1955

37. The UK ROSAT Deep Survey

Author

McHardy, I. M., Jones, L. R., Merrifield, M. R., Mason, Keith O., Newsam, A. M., Abraham, R. G., Dalton, G. B., Carrera, Francisco J., Smith, P. J., Rowan-Robinson, M., Wegner, G. A., Ponman, T. J., Lehto, Harry J., Branduardi-Raymont, G., Luppino, G. A., Efstathiou, G., Allan, D. J., Quenby, J. J., McHardy, I. M., Jones, L. R., Merrifield, M. R., Mason, Keith O., Newsam, A. M., Abraham, R. G., Dalton, G. B., Carrera, Francisco J., Smith, P. J., Rowan-Robinson, M., Wegner, G. A., Ponman, T. J., Lehto, Harry J., Branduardi-Raymont, G., Luppino, G. A., Efstathiou, G., Allan, D. J., and Quenby, J. J.

Abstract

We present a summary of the identification content of the UK ROSAT Deep Survey. The survey is based on a 115ksec PSPC observation and comprises a sample of 70 sources to a flux limit of 2 × 10-15 ergs cm-2 s-1 (0.5-2 keV). At bright fluxes the survey is dominated by broad line QSOs, at intermediate fluxes it contains a number of groups and clusters of galaxies, but at faint fluxes the survey contains many galaxies with narrow optical emission lines (NELGs). The average X-ray spectrum of the NELGs is harder than that of the QSOs and similar to that of the X-ray background. The NELGs have optical spectra similar to the majority of the field galaxy population in the same redshift range and may simply be the more luminous members of the emission line field galaxy population. Based on optical line ratios and X-ray/optical ratios, the NELGs, both as a sample and within individual galaxies, appear to be a mixture of starburst galaxies and true AGN.

Published
1998

38. The origin of the cosmic soft X-ray background: Optical identification of an extremely deep ROSAT survey

Author

Research Councils UK, Royal Society (UK), McHardy, I. M., Jones, L. R., Merrifield, M. R., Mason, Keith O., Newsam, A. M., Abraham, R. G., Dalton, G. B., Carrera, Francisco J., Smith, P. J., Rowan-Robinson, M., Wegner, G. A., Ponman, T. J., Lehto, Harry J., Branduardi-Raymont, G., Luppino, G. A., Efstathiou, G., Allan, D. J., Quenby, J. J., Research Councils UK, Royal Society (UK), McHardy, I. M., Jones, L. R., Merrifield, M. R., Mason, Keith O., Newsam, A. M., Abraham, R. G., Dalton, G. B., Carrera, Francisco J., Smith, P. J., Rowan-Robinson, M., Wegner, G. A., Ponman, T. J., Lehto, Harry J., Branduardi-Raymont, G., Luppino, G. A., Efstathiou, G., Allan, D. J., and Quenby, J. J.

Abstract

We present the results of the deepest optically identified X-ray survey yet made. The X-ray survey was obtained with the ROSAT position-sensitive proportional counter (PSPC) and reaches a flux limit of 1.6 × 10-15 erg cm-2 s-1 (0.5-2.0 keV). Above a flux limit of 2 × 10-15 erg cm-2 s-1 we define a complete sample of 70 sources, of which 59 are identified. For a further five sources we have tentative identifications and for a further four the X-ray error boxes are blank to R = 23 mag. At brighter fluxes (≥10-14 erg cm-2 s-1) we confirm the results of previous less deep X-ray surveys, with 84 per cent of our sources being QSOs. However, at the faint flux limit the survey is dominated by a population of galaxies with narrow emission lines (NELGs). In addition, at intermediate fluxes we find a small number of groups and clusters of galaxies at redshifts generally >0.3. Most of these groups are poor systems of low X-ray luminosity and the number that we find is consistent with a zero evolutionary scenario, unlike the situation for high-luminosity clusters at the same redshift. To a flux limit of 2 × 10-15 erg cm-2 s-1, QSOs contribute >31 percent of the cosmic soft X-ray background (XRB), groups/clusters contribute ∼10 per cent and NELGs contribute ∼8 per cent. However, the QSO differential source count slope below 10-14 erg cm-2 s-1 is ∼ -1.4, severely sub-Euclidean, as is the (poorly defined) group/cluster slope, whereas the differential NELG slope is close to Euclidean (∼ -2.4). If the NELG source counts continue to rise at that slope, all of the remaining cosmic soft XRB will be explained by a flux limit of ∼1-2 × 10-16 erg cm-2 s-1, with NELGs contributing about one quarter of the XRB. The average NELG X-ray spectrum is harder than that of the QSOs, and similar to that of the remaining unresolved cosmic XRB, suggesting that NELGs will also be substantial contributors to the XRB at higher energies. The observed NELGs lie in the redshift range 0.1-0.6 and have MR= -20

Published
1998

42. The origin of the cosmic soft X-ray background: optical identification of an extremely deep ROSAT survey

Author

McHardy, I. M., primary, Jones, L. R., additional, Merrifield, M. R., additional, Mason, K. O., additional, Newsam, A. M., additional, Abraham, R. G., additional, Dalton, G. B., additional, Carrera, F., additional, Smith, P. J., additional, Rowan-Robinson, M., additional, Wegner, G. A., additional, Ponman, T. J., additional, Lehto, H. J., additional, Branduardi-Raymont, G., additional, Luppino, G. A., additional, Efstathiou, G., additional, Allan, D. J., additional, and Quenby, J. J., additional

Published
1998
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43. The UK ROSAT Deep Survey

Author

McHardy, I. M., primary, Merrified, M. R., additional, Newsam, A. M., additional, Jones, L. R., additional, Allan, D. J., additional, Ponman, T. J., additional, Mason, K. O., additional, Smith, P. J., additional, Branduardi-Raymont, G., additional, Carrera, F., additional, Abraham, R. G., additional, Dalton, G. B., additional, Efstathiou, G., additional, Rowan-Robinson, M., additional, Quenby, J. J., additional, Wegner, G. A., additional, Lehto, H. J., additional, and Luppino, G. A., additional

Published
1998
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48. A possible fossil galaxy group

Author

Ponman, T. J., primary, Allan, D. J., additional, Jones, L. R., additional, Merrifield, M., additional, McHardy, I. M., additional, Lehto, H. J., additional, and Luppino, G. A., additional

Published
1994
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50. The ROSAT Wide Field Camera all-sky survey of extreme-ultraviolet sources – I. The Bright Source Catalogue

Author

Pounds, K. A., primary, Allan, D. J., additional, Barber, C., additional, Barstow, M. A., additional, Bertram, D., additional, Branduardi-Raymont, G., additional, Brebner, G. E. C., additional, Buckley, D., additional, Bromage, G. E., additional, Cole, R. E., additional, Courtier, M., additional, Cruise, A. M., additional, Culhane, J. L., additional, Denby, M., additional, Donoghue, D. O., additional, Dunford, E., additional, Georgantopoulos, I., additional, Goodall, C. V., additional, Gondhalekar, P. M., additional, Gourlay, J. A., additional, Harris, A. W., additional, Hassall, B. J. M., additional, Hellier, C., additional, Hodgkin, S., additional, Jeffries, R. D., additional, Kellett, B. J., additional, Kent, B. J., additional, Lieu, R., additional, Lloyd, C., additional, McGale, P., additional, Mason, K. O., additional, Matthews, L., additional, Mittaz, J. P. D., additional, Page, C. G., additional, Pankiewicz, G. S., additional, Pike, C. D., additional, Ponman, T. J., additional, Puchnarewicz, E. M., additional, Pye, J. P., additional, Quenby, J. J., additional, Ricketts, M. J., additional, Rosen, S. R., additional, Sansom, A. E., additional, Sembay, S., additional, Sidher, S., additional, Sims, M. R., additional, Stewart, B. C., additional, Sumner, T. J., additional, Vallance, R. J., additional, Watson, M. G., additional, Warwick, R. S., additional, Wells, A. A., additional, Willingale, R., additional, Willmore, A. P., additional, Willoughby, G. A., additional, and Wonnacott, D., additional

Published
1993
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