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833 results on '"Mchardy, I. M."'

301. Radio observations of the XMM-Newton/Chandra 13hr deep survey field

Author

Gunn, K. F., McHardy, I. M., Seymour, N., Newsam, A. M., Page, M. J., Mason, K. O., Loaring, N., Jones, L. R., Muxlow, T., Takata, T., Sekiguchi, K., Sasseen, T., Gunn, K. F., McHardy, I. M., Seymour, N., Newsam, A. M., Page, M. J., Mason, K. O., Loaring, N., Jones, L. R., Muxlow, T., Takata, T., Sekiguchi, K., and Sasseen, T.

Abstract

Our VLA observations of the XMM-Newton/Chandra 13hr deep survey field (see Page et al., this proceedings) result in one of the two deepest 1.4GHz radio maps ever made. Within the 15' radius field covered by the deep X-ray data (0.19 sq deg), a total of 556 radio sources are detected, down to a 4 sigma flux limit of 28uJy. Of the 214 Chandra sources, 55 have radio counterparts. The sub-arcsecond accuracy of the VLA and Chandra positions enable us to determine with high confidence the sources common to both surveys. Here we present the relationship between the X-ray and radio source populations at the faintest radio flux limits yet probed by such a study. We discuss how the X-ray/radio relationship differs as a function of optical morphology, ie between unresolved `stellar' objects and well resolved galaxies. We then discuss the origin of the X-ray and radio emission, ie AGN, starburst or a mixture of both, in these two classes of object., Comment: Astronomische Nachrichten, in press (Feb 2003). Proceedings of "X-ray Surveys, in the Light of New Observatories", 4-6 September, Santander, Spain

Published
2002
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302. Soft X-ray properties of a high redshift sample of QSOs observed with ROSAT

Author

Dewangan, G. C., Singh, K. P., Gunn, K. F., Newsam, A. M., McHardy, I. M., Jones, L. R., Dewangan, G. C., Singh, K. P., Gunn, K. F., Newsam, A. M., McHardy, I. M., and Jones, L. R.

Abstract

In order to study systematically the soft X-ray emission of Active Galactic Nuclei (AGNs) at medium to high redshifts, we have analyzed ROSAT PSPC and HRI data of QSOs at 0.26 3.0), one of which is a narrow-line QSO - a high luminosity version of narrow-line Seyfert 1 galaxies. The average photon index () is 2.40+/-0.09 (with a dispersion of 0.57) in the 0.1-2 keV band. The average QSO spectra in four redshift bins flatten from an average photon index of ~ 2.53 at 0.25 < z < 1 to ~ 2 at 2 < z < 3.4. The flattening of the average photon index can be understood in terms of the redshift effect of the mean intrinsic QSO spectrum consisting of two components - a soft X-ray excess and a power-law component. We have also studied optical spectra of 12 of the 22 QSOs., Comment: 22 pages, uses mn2e.cls, To appear in MNRAS

Published
2002
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303. The X-ray spectrum of the Seyfert I galaxy Mrk 766: Dusty Warm Absorber or Relativistic Emission Lines?

Author

Mason, K. O., Branduardi-Raymont, G., Ogle, P. M., Page, M. J., Puchnarewicz, E. M., Behar, E., Cordova, F. A., Davis, S., Maraschi, L., McHardy, I. M., O'Brien, P. T., Priedhorsky, W. C., Sasseen, T. P., Mason, K. O., Branduardi-Raymont, G., Ogle, P. M., Page, M. J., Puchnarewicz, E. M., Behar, E., Cordova, F. A., Davis, S., Maraschi, L., McHardy, I. M., O'Brien, P. T., Priedhorsky, W. C., and Sasseen, T. P.

Abstract

Competing models for broad spectral features in the soft X-ray spectrum of the Seyfert I galaxy Mrk766 are tested against data from a 130 ks XMM-Newton observation. A model including relativistically broadened Ly-alpha emission lines of OVIII, NVII and CVI is a better fit to 0.3-2 keV XMM RGS data than a dusty warm absorber. Moreover, the measured depth of neutral iron absorption lines in the spectrum is inconsistent with the magnitude of the iron edge required to produce the continuum break at 17-18Angstroms in the dusty warm absorber model. The relativistic emission line model can reproduce the broad-band (0.1-12 keV) XMM-EPIC data with the addition of a fourth line to represent emission from ionized iron at 6.7 keV and an excess due to reflection at energies above the iron line. The profile of the 6.7 keV iron line is consistent with that measured for the low energy lines. There is evidence in the RGS data at the 3sigma level for spectral features that vary with source flux. The covering fraction of warm absorber gas is estimated to be ~12%. Iron in the warm absorber is found to be overabundant with respect to CNO compared to solar values., Comment: Accepted for publication in ApJ Letters

Published
2002
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304. X-ray spectral variability of the Seyfert galaxy NGC 4051

Author

Lamer, G., McHardy, I. M., Uttley, P., Jahoda, K., Lamer, G., McHardy, I. M., Uttley, P., and Jahoda, K.

Abstract

We report on the X-ray spectral variability of the Seyfert 1 galaxy NGC 4051 observed with the Rossi X-ray Timing Explorer (RXTE) during a 1000 day period between May 1996 and March 1999. The spectra were obtained as part of monitoring observations and from two long observations using the RXTE Proportional Counter Array (PCA). During the monitoring period the 2-10 keV flux of NGC 4051 varied between 10E-12 and 7x 10E11 (cgs). We re-analysed RXTE PCA observations from a distinct low state in May 1998 using the latest background and detector response models. The RXTE and BeppoSAX observations of NGC 4051 during the low state show a very hard spectrum with a strong unresolved fluorescence line. This emission, probably due to reflection from a molecular torus, is likely to be constant over long time-scales and is therefore assumed as an underlying component at all flux states. By subtracting the torus component we are able to determine the spectral variability of the primary continuum. In the variable component we observe a strong anti-correlation of X-ray flux and spectral hardness in the PCA energy band. We show that the changes in hardness are caused by slope variability of the primary power law spectrum rather than by changing reflection or variable photoelectric absorption. The primary spectral index varies between Gamma=1.6 for the faintest states and Gamma=2.3 during the brightest states, at which level the spectral index approaches an asympotic value. We find that the response of the flux of the 6.4 keV iron fluorescence line to changes in the continuum flux depends on the timescale of the observation. The profile of the line is very broad and indicates an origin in the innermost regions of the accretion disk., Comment: accepted for publication in MNRAS

Published
2002
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305. Measuring the broadband power spectra of active galactic nuclei with RXTE

Author

Uttley, P., McHardy, I. M., Papadakis, I. E., Uttley, P., McHardy, I. M., and Papadakis, I. E.

Abstract

We have developed a Monte Carlo technique to test models for the true power spectra of intermittently sampled lightcurves against the noisy, observed power spectra, and produce a reliable estimate of the goodness of fit of the given model. We apply this technique to constrain the broadband power spectra of a sample of four Seyfert galaxies monitored by the Rossi X-ray Timing Explorer (RXTE) over three years. We show that the power spectra of three of the AGN in our sample (MCG-6-30-15, NGC5506 and NGC3516) flatten significantly towards low frequencies, while the power spectrum of NGC5548 shows no evidence of flattening. We fit two models for the flattening, a `knee' model, analogous to the low-frequency break seen in the power spectra of BHXRBs in the low state (where the power-spectral slope flattens to \alpha=0) and a `high-frequency break' model (where the power-spectral slope flattens to \alpha=1), analogous to the high-frequency break seen in the high and low-state power spectra of the classic BHXRB Cyg X-1. Both models provide good fits to the power spectra of all four AGN. For both models, the characteristic frequency for flattening is significantly higher in MCG-6-30-15 than in NGC 3516 (by factor ~10) although both sources have similar X-ray luminosities, suggesting that MCG-6-30-15 has a lower black hole mass and is accreting at a higher rate than NGC 3516. Assuming linear scaling of characteristic frequencies with black hole mass, the high accretion rate implied for MCG-6-30-15 favours the high-frequency break model for this source and further suggests that MCG-6-30-15 and possibly NGC 5506, may be analogues of Cyg X-1 in the high state [ABRIDGED]., Comment: 23 pages, accepted for publication in MNRAS

Published
2002
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306. AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

Author

D'Ammando, F., primary, Pucella, G., additional, Raiteri, C. M., additional, Villata, M., additional, Vittorini, V., additional, Vercellone, S., additional, Donnarumma, I., additional, Longo, F., additional, Tavani, M., additional, Argan, A., additional, Barbiellini, G., additional, Boffelli, F., additional, Bulgarelli, A., additional, Caraveo, P., additional, Cattaneo, P. W., additional, Chen, A. W., additional, Cocco, V., additional, Costa, E., additional, Del Monte, E., additional, De Paris, G., additional, Di Cocco, G., additional, Evangelista, Y., additional, Feroci, M., additional, Ferrari, A., additional, Fiorini, M., additional, Froysland, T., additional, Fuschino, F., additional, Galli, M., additional, Gianotti, F., additional, Giuliani, A., additional, Labanti, C., additional, Lapshov, I., additional, Lazzarotto, F., additional, Lipari, P., additional, Marisaldi, M., additional, Mereghetti, S., additional, Morselli, A., additional, Pacciani, L., additional, Pellizzoni, A., additional, Perotti, F., additional, Piano, G., additional, Picozza, P., additional, Pilia, M., additional, Prest, M., additional, Rapisarda, M., additional, Rappoldi, A., additional, Sabatini, S., additional, Soffitta, P., additional, Trifoglio, M., additional, Trois, A., additional, Vallazza, E., additional, Zambra, A., additional, Zanello, D., additional, Agudo, I., additional, Aller, M. F., additional, Aller, H. D., additional, Arkharov, A. A., additional, Bach, U., additional, Benitez, E., additional, Berdyugin, A., additional, Blinov, D. A., additional, Buemi, C. S., additional, Chen, W. P., additional, Di Paola, A., additional, Di Rico, G., additional, Dultzin, D., additional, Fuhrmann, L., additional, Gómez, J. L., additional, Gurwell, M. A., additional, Jorstad, S. G., additional, Heidt, J., additional, Hiriart, D., additional, Hsiao, H. Y., additional, Kimeridze, G., additional, Konstantinova, T. S., additional, Kopatskaya, E. N., additional, Koptelova, E., additional, Kurtanidze, O., additional, Larionov, V. M., additional, Leto, P., additional, Lindfors, E., additional, Lopez, J. M., additional, Marscher, A. P., additional, McHardy, I. M., additional, Melnichuk, D. A., additional, Mommert, M., additional, Mujica, R., additional, Nilsson, K., additional, Pasanen, M., additional, Roca-Sogorb, M., additional, Sorcia, M., additional, Takalo, L. O., additional, Taylor, B., additional, Trigilio, C., additional, Troitsky, I. S., additional, Umana, G., additional, Antonelli, L. A., additional, Colafrancesco, S., additional, Cutini, S., additional, Gasparrini, D., additional, Pittori, C., additional, Preger, B., additional, Santolamazza, P., additional, Verrecchia, F., additional, Giommi, P., additional, and Salotti, L., additional

Published
2009
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310. The correlated optical and radio variability of BL Lacertae

Author

Villata, M., primary, Raiteri, C. M., additional, Larionov, V. M., additional, Nikolashvili, M. G., additional, Aller, M. F., additional, Bach, U., additional, Carosati, D., additional, Hroch, F., additional, Ibrahimov, M. A., additional, Jorstad, S. G., additional, Kovalev, Y. Y., additional, Lähteenmäki, A., additional, Nilsson, K., additional, Teräsranta, H., additional, Tosti, G., additional, Aller, H. D., additional, Arkharov, A. A., additional, Berdyugin, A., additional, Boltwood, P., additional, Buemi, C. S., additional, Casas, R., additional, Charlot, P., additional, Coloma, J. M., additional, Di Paola, A., additional, Di Rico, G., additional, Kimeridze, G. N., additional, Konstantinova, T. S., additional, Kopatskaya, E. N., additional, Kovalev, Yu. A., additional, Kurtanidze, O. M., additional, Lanteri, L., additional, Larionova, E. G., additional, Larionova, L. V., additional, Le Campion, J.-F., additional, Leto, P., additional, Lindfors, E., additional, Marscher, A. P., additional, Marshall, K., additional, McFarland, J. P., additional, McHardy, I. M., additional, Miller, H. R., additional, Nucciarelli, G., additional, Osterman, M. P., additional, Pasanen, M., additional, Pursimo, T., additional, Ros, J. A., additional, Sadun, A. C., additional, Sigua, L. A., additional, Sixtova, L., additional, Takalo, L. O., additional, Tornikoski, M., additional, Trigilio, C., additional, Umana, G., additional, Xie, G. Z., additional, Zhang, X., additional, and Zhou, S. B., additional

Published
2009
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313. Day-Scale Variability of 3C 279 and Searches for Correlations in Gamma-Ray, X-Ray, and Optical Bands

Author

Hartman, R. C., Villata, M., Balonek, T. J., Bertsch, D. L., Bock, H., Boettcher, M., Carini, M. T., Collmar, W., De Francesco, G., Ferrara, E. C., Heidt, J., Kanbach, G., Katajainen, S., Koskimies, M., Kurtanidze, O. M., Lanteri, L., Lawson, A., Lin, Y. C., Marscher, A. P., McFarland, J. P., McHardy, I. M., Miller, H. R., Nikolashvili, M., Nilsson, K., Noble, J. C., Nucciarelli, G., Ostorero, L., Pursimo, T., Raiteri, C. M., Rekola, R., Savolainen, T., Sillanpaa, A., Smale, A., Sobrito, G., Takalo, L. O., Thompson, D. J., Tosti, G., Wagner, S. J., Wilson, J. W., Hartman, R. C., Villata, M., Balonek, T. J., Bertsch, D. L., Bock, H., Boettcher, M., Carini, M. T., Collmar, W., De Francesco, G., Ferrara, E. C., Heidt, J., Kanbach, G., Katajainen, S., Koskimies, M., Kurtanidze, O. M., Lanteri, L., Lawson, A., Lin, Y. C., Marscher, A. P., McFarland, J. P., McHardy, I. M., Miller, H. R., Nikolashvili, M., Nilsson, K., Noble, J. C., Nucciarelli, G., Ostorero, L., Pursimo, T., Raiteri, C. M., Rekola, R., Savolainen, T., Sillanpaa, A., Smale, A., Sobrito, G., Takalo, L. O., Thompson, D. J., Tosti, G., Wagner, S. J., and Wilson, J. W.

Abstract

Light curves of 3C 279 are presented in optical (R-band), X-rays (RXTE/PCA), and gamma rays (CGRO/EGRET) for 1999 Jan-Feb and 2000 Jan-Mar. During both of those epochs the gamma-ray levels were high, and all three observed bands demonstrated substantial variation, on time scales as short as one day. Correlation analyses provided no consistent pattern, although a rather significant optical/gamma-ray correlation was seen in 1999, with a gamma-ray lag of ~2.5 days, and there are other suggestions of correlations in the light curves. For comparison, correlation analysis is also presented for the gamma-ray and X-ray light curves during the large gamma ray flare in 1996 Feb and the two gamma-bright weeks leading up to it; the correlation at that time was strong, with a gamma-ray/X-ray offset of no more than 1 day., Comment: 20 pages, including 7 figures; accepted by The Astrophysical Journal

Published
2001
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314. Identification of 4U 1849-31 with V1223 Sagittarii and discovery of optical pulsations

Author

Steiner, J. E, Schwartz, D. A, Jablonski, F. J, Busko, I. C, Watson, M. G, Pye, J. P, and Mchardy, I. M

Subjects
Astronomy
Abstract

The X-ray source 4U 1849-31 is identified with the 13 mag star V1223 Sgr, on the basis of a precise HEAO 1 modulation collimator X-ray position uniquely selected by the Ariel-5 sky survey location. It is shown by optical spectroscopy and photometry that V1223 Sgr is a cataclysmic variable, displaying a photometric period of 13.2 min that is interpreted as being due to the rotation of a degenerate dwarf. The similarity of this system to H2252-035 is noted.

Published
1981
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316. The optical identification of H2252-035 with a cataclysmic variable

Author

Griffiths, R. E, Lamb, D. Q, Ward, M. J, Wilson, A. S, Charles, P. A, Thorstensen, J, Mchardy, I. M, and Lawrence, A

Subjects
Astrophysics
Abstract

An improved position is presented for the X-ray source H2252-033 using the Ariel V Sky Survey Instrument, and precise positioning using the Scanning Modulation Collimator on HEAO-1. The source is identified optically with a 13th magnitude emission-line object, which is probably a white dwarf binary with a well formed accretion disk, with similarities to the dwarf novae (e.g., SS Cyg) at minimum.

Published
1980

322. The multiwavelength variability of 3C 273

Author

Soldi, S., primary, Türler, M., additional, Paltani, S., additional, Aller, H. D., additional, Aller, M. F., additional, Burki, G., additional, Chernyakova, M., additional, Lähteenmäki, A., additional, McHardy, I. M., additional, Robson, E. I., additional, Staubert, R., additional, Tornikoski, M., additional, Walter, R., additional, and Courvoisier, T. J.-L., additional

Published
2008
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329. 2003–2005INTEGRALandXMM-Newtonobservations of 3C 273

Author

Chernyakova, M., primary, Neronov, A., additional, Courvoisier, T. J.-L., additional, Türler, M., additional, Soldi, S., additional, Beckmann, V., additional, Lubinski, P., additional, Walter, R., additional, Page, K. L., additional, Stuhlinger, M., additional, Staubert, R., additional, and McHardy, I. M., additional

Published
2007
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331. The unprecedented optical outburst of the quasar 3C 454.3

Author

Villata, M., primary, Raiteri, C. M., additional, Balonek, T. J., additional, Aller, M. F., additional, Jorstad, S. G., additional, Kurtanidze, O. M., additional, Nicastro, F., additional, Nilsson, K., additional, Aller, H. D., additional, Arai, A., additional, Arkharov, A., additional, Bach, U., additional, Benítez, E., additional, Berdyugin, A., additional, Buemi, C. S., additional, Böttcher, M., additional, Carosati, D., additional, Casas, R., additional, Caulet, A., additional, Chen, W. P., additional, Chiang, P.-S., additional, Chou, Y., additional, Ciprini, S., additional, Coloma, J. M., additional, Di Rico, G., additional, Díaz, C., additional, Efimova, N. V., additional, Forsyth, C., additional, Frasca, A., additional, Fuhrmann, L., additional, Gadway, B., additional, Gupta, S., additional, Hagen-Thorn, V. A., additional, Harvey, J., additional, Heidt, J., additional, Hernandez-Toledo, H., additional, Hroch, F., additional, Hu, C.-P., additional, Hudec, R., additional, Ibrahimov, M. A., additional, Imada, A., additional, Kamata, M., additional, Kato, T., additional, Katsuura, M., additional, Konstantinova, T., additional, Kopatskaya, E., additional, Kotaka, D., additional, Kovalev, Y. Y., additional, Kovalev, Yu. A., additional, Krichbaum, T. P., additional, Kubota, K., additional, Kurosaki, M., additional, Lanteri, L., additional, Larionov, V. M., additional, Larionova, L., additional, Laurikainen, E., additional, Lee, C.-U., additional, Leto, P., additional, Lähteenmäki, A., additional, López-Cruz, O., additional, Marilli, E., additional, Marscher, A. P., additional, McHardy, I. M., additional, Mondal, S., additional, Mullan, B., additional, Napoleone, N., additional, Nikolashvili, M. G., additional, Ohlert, J. M., additional, Postnikov, S., additional, Pursimo, T., additional, Ragni, M., additional, Ros, J. A., additional, Sadakane, K., additional, Sadun, A. C., additional, Savolainen, T., additional, Sergeeva, E. A., additional, Sigua, L. A., additional, Sillanpää, A., additional, Sixtova, L., additional, Sumitomo, N., additional, Takalo, L. O., additional, Teräsranta, H., additional, Tornikoski, M., additional, Trigilio, C., additional, Umana, G., additional, Volvach, A., additional, Voss, B., additional, and Wortel, S., additional

Published
2006
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332. A historic jet-emission minimum reveals hidden spectral features in 3C 273

Author

Türler, M., primary, Chernyakova, M., additional, Courvoisier, T. J.-L., additional, Foellmi, C., additional, Aller, M. F., additional, Aller, H. D., additional, Kraus, A., additional, Krichbaum, T. P., additional, Lähteenmäki, A., additional, Marscher, A., additional, McHardy, I. M., additional, O'Brien, P. T., additional, Page, K. L., additional, Popescu, L., additional, Robson, E. I., additional, Tornikoski, M., additional, and Ungerechts, H., additional

Published
2006
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341. 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

342. 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

347. The X‐Ray Spectrum of the Seyfert I Galaxy Markarian 766: Dusty Warm Absorber or Relativistic Emission Lines?

Author

Mason, K. O., primary, Branduardi‐Raymont, G., additional, Ogle, P. M., additional, Page, M. J., additional, Puchnarewicz, E. M., additional, Behar, E., additional, Cordova, F. A., additional, Davis, S., additional, Maraschi, L., additional, McHardy, I. M., additional, O’Brien, P. T., additional, Priedhorsky, W. C., additional, and Sasseen, T. P., additional

Published
2003
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348. The evolution of X-ray-selected narrow-emission-line galaxies

Author

Science and Technology Facilities Council (UK), Page, Matt, Mason, Keith O., McHardy, I. M., Jones, L. R., Carrera, Francisco J., Science and Technology Facilities Council (UK), Page, Matt, Mason, Keith O., McHardy, I. M., Jones, L. R., and Carrera, Francisco J.

Abstract

We examine the cosmological evolution of X-ray-selected narrow-emission-line galaxies (NELGs), using a sample of 35 such objects identified in the combined ROSAT UK Deep Survey and RIXOS. This sample is entirely independent of those previously used to investigate the X-ray evolution of NELGs. We detect evolution which is at a similar rate to the evolution found in the optical luminosity function of blue galaxies. The lack of high-redshift (z > 0.6) NELGs detected in X-ray surveys, and the small, well-defined number of X-ray sources which are not optically identified indicate that the evolution of NELGs is probably not the same as the X-ray evolution of QSOs: NELG evolution is slower than the evolution of QSOs and/or ends at a lower redshift.

Published
1997

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