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23 results on '"McMahon, Richard"'

1. Molecular Gas in Threez∼ 7 Quasar Host Galaxies

Author

Venemans, Bram P., primary, Walter, Fabian, additional, Decarli, Roberto, additional, Ferkinhoff, Carl, additional, Weiß, Axel, additional, Findlay, Joseph R., additional, McMahon, Richard G., additional, Sutherland, Will J., additional, and Meijerink, Rowin, additional

Published
2017
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4. BLACK HOLE MASS ESTIMATES AND EMISSION-LINE PROPERTIES OF A SAMPLE OF REDSHIFTz> 6.5 QUASARS

Author

De Rosa, Gisella, primary, Venemans, Bram P., additional, Decarli, Roberto, additional, Gennaro, Mario, additional, Simcoe, Robert A., additional, Dietrich, Matthias, additional, Peterson, Bradley M., additional, Walter, Fabian, additional, Frank, Stephan, additional, McMahon, Richard G., additional, Hewett, Paul C., additional, Mortlock, Daniel J., additional, and Simpson, Chris, additional

Published
2014
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6. Dust and Gas Obscuration in ELAIS Deep X‐Ray Survey Reddened Quasars

Author

Willott, Chris J., primary, Simpson, Chris, additional, Almaini, Omar, additional, Johnson, Olivia, additional, Lawrence, Andrew, additional, Dunlop, James S., additional, Roche, Nathan D., additional, Mann, Robert G., additional, Manners, James C., additional, Gonzalez‐Solares, Eduardo, additional, Perez‐Fournon, Ismael, additional, Ivison, Rob J., additional, Serjeant, Stephen, additional, Oliver, Seb J., additional, McMahon, Richard G., additional, and Rowan‐Robinson, Michael, additional

Published
2004
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8. The Afterglow and Complex Environment of the Optically Dim Burst GRB 980613

Author

Hjorth, Jens, primary, Thomsen, Bjarne, additional, Nielsen, Svend R., additional, Andersen, Michael I., additional, Holland, Stephen T., additional, Fynbo, Johan U., additional, Pedersen, Holger, additional, Jaunsen, Andreas O., additional, Halpern, Jules P., additional, Fesen, Robert, additional, Gorosabel, Javier, additional, Castro‐Tirado, Alberto, additional, McMahon, Richard G., additional, Hoenig, Michael D., additional, Bjornsson, Gunnlaugur, additional, Amati, Lorenzo, additional, Tanvir, Nial R., additional, and Natarajan, Priyamvada, additional

Published
2002
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12. First Results from theISO‐IRASFaint Galaxy Survey

Author

Levine, Deborah A., primary, Lonsdale, Carol J., additional, Hurt, Robert L., additional, Smith, Harding E., additional, Helou, George, additional, Beichman, Charles, additional, Cesarsky, Catherine, additional, Elbaz, David, additional, Klaas, Ulrich, additional, Laureijs, Rene, additional, Lemke, Detrich, additional, Lord, Steven, additional, McMahon, Richard, additional, Moshir, Mehrdad, additional, Neugebauer, Gerry, additional, Soifer, B. T., additional, Van Buren, Dave, additional, Wehrle, Ann, additional, and Wolstencroft, Ray, additional

Published
1998
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18. Hubble Space Telescope Imaging and Keck Spectroscopy of z 6 i-Band Dropout Galaxies in the Advanced Camera for Surveys GOODS Fields

Author

Stanway, Elizabeth R., Bunker, Andrew J., McMahon, Richard G., Ellis, Richard S., Treu, Tommaso, and McCarthy, Patrick J.

Abstract

We measure the surface density of i'-band dropout galaxies at z ~ 6 through wide-field Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging and ultradeep Keck DEIMOS spectroscopy. Using deep HST ACS SDSS i' (F775W) and SDSS z' (F850LP) imaging from the Great Observatories Origins Deep Survey-North (GOODS-N; 200 arcmin2), we identify nine i'-drops satisfying (i'-z')AB > 1.5 to a depth of zimg1.gif = 25.6 (corresponding to Limg2.gif at z ~ 3). We use HK' imaging data to improve the fidelity of our sample, discriminating against lower redshift red galaxies and cool Galactic stars. Three i'-drops are consistent with M/L/T dwarf stars. We present ultradeep Keck DEIMOS spectroscopy of 10 objects from our combined GOODS-N and GOODS-S i'-drop sample. We detect Lya emission at z = 5.83 from one object in the GOODS-S field, which lies only 8' (i.e., 3 himg3.gif Mpc) away from a previously confirmed z = 5.78 object. One possible Lya emitter at z = 6.24 is found in the GOODS-N field (although identification of this spatially offset emission line is ambiguous). Using the rest-frame UV continuum from our six candidate z ~ 6 galaxies from the GOODS-N field, we determine a lower limit to the unobscured volume-averaged global star formation rate at z ~ 6 of (5.4 +- 2.2) x 10-4 h70 M yr-1 Mpc-3. We find that the cosmic star formation density in Lyman break galaxies (LBGs) with unobscured star formation rates greater than 15 M yr-1 falls by a factor of 8 between z ~ 3 and z ~ 6. Hence, the luminosity function of LBGs must evolve in this redshift interval: a constant integrated star formation density at z > 3 requires a much steeper faint-end slope, or a brighter characteristic luminosity. This result is in agreement with our previous measurement from the GOODS-S field, indicating that cosmic variance is not a dominant source of uncertainty.

Published
2004

19. First Results from the ISO-IRAS Faint Galaxy Survey

Author

Levine, Deborah A., Lonsdale, Carol J., Hurt, Robert L., Smith, Harding E., Helou, George, Beichman, Charles, Cesarsky, Catherine, Elbaz, David, Klaas, Ulrich, Laureijs, Rene, Lemke, Detrich, Lord, Steven, McMahon, Richard, Moshir, Mehrdad, Neugebauer, Gerry, Van, Dave, Wehrle, Ann, and Wolstencroft, Ray

Abstract

We present the first results from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12 mm ISOCAM and 90 mm ISOPHOT observations. As of 1997 October, over 500 sources have been observed, with an ISOCAM detection rate over 80%, covering over 1.25 deg2 of sky to an 11.5 mm point-source completeness limit of approximately 1.0 mJy (corresponding to a ~10 s detection sensitivity). Observations are presented for nine sources detected by ISOPHOT and ISOCAM early in the survey for which we have ground-based G- and I-band images and optical spectroscopy. The ground-based data confirm that the IIFGS strategy efficiently detects moderate-redshift (z = 0.11-0.38 for this small sample) strong emission line galaxies with L60 mm [?] 1011 L; one of our sample has L60 mm > 1012 L (H0 = 75 km s-1 Mpc-1, O = 1). The infrared-optical spectral energy distributions are comparable to those of nearby luminous infrared galaxies, which span the range from pure starburst (e.g., Arp 220) to infrared QSO (Mrk 231). Two of the systems show signs of strong interaction, and four show active galactic nucleus (AGN)-like excitation; one of the AGNs, F15390+6038, which shows a high excitation Seyfert 2 spectrum, has an unusually warm far- to mid-infrared color and may be an obscured QSO. The IIFGS sample is one of the largest and deepest samples of infrared-luminous galaxies available, promising to be a rich sample for studying infrared-luminous galaxies up to z ~ 1 and for understanding the evolution of infrared galaxies and the star formation rate in the universe.

Published
1998

20. First Results from the ISO-IRASFaint Galaxy SurveyISOis an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) and with the participation of ISAS and NASA.

Author

Levine, Deborah A., Lonsdale, Carol J., Hurt, Robert L., Smith, Harding E., Helou, George, Beichman, Charles, Cesarsky, Catherine, Elbaz, David, Klaas, Ulrich, Laureijs, Rene, Lemke, Detrich, Lord, Steven, McMahon, Richard, Moshir, Mehrdad, Neugebauer, Gerry, Soifer, B. T., Van Buren, Dave, Wehrle, Ann, and Wolstencroft, Ray

Abstract

We present the first results from the ISO-IRASFaint Galaxy Survey (IIFGS), a program designed to obtain ISOobservations of the most distant and luminous galaxies in the IRASFaint Source Survey by filling short gaps in the ISOobserving schedule with pairs of 12 ?m ISOCAM and 90 ?m ISOPHOT observations. As of 1997 October, over 500 sources have been observed, with an ISOCAM detection rate over 80%, covering over 1.25 deg2of sky to an 11.5 ?m point-source completeness limit of approximately 1.0 mJy (corresponding to a ~10 ? detection sensitivity). Observations are presented for nine sources detected by ISOPHOT and ISOCAM early in the survey for which we have ground-based G- and I-band images and optical spectroscopy. The ground-based data confirm that the IIFGS strategy efficiently detects moderate-redshift (z= 0.11-0.38 for this small sample) strong emission line galaxies with L60 ?m1011L?; one of our sample has L60 ?m> 1012L?(H0= 75 km s-1Mpc-1, ? = 1). The infrared-optical spectral energy distributions are comparable to those of nearby luminous infrared galaxies, which span the range from pure starburst (e.g., Arp 220) to infrared QSO (Mrk 231). Two of the systems show signs of strong interaction, and four show active galactic nucleus (AGN)-like excitation; one of the AGNs, F15390+6038, which shows a high excitation Seyfert 2 spectrum, has an unusually warm far- to mid-infrared color and may be an obscured QSO. The IIFGS sample is one of the largest and deepest samples of infrared-luminous galaxies available, promising to be a rich sample for studying infrared-luminous galaxies up to z~ 1 and for understanding the evolution of infrared galaxies and the star formation rate in the universe.

Published
1998
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