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31 results on '"Craig, W.W."'

1. Sensitivity of the GAPS experiment to low-energy cosmic-ray antiprotons

Author

Rogers, F., Aramaki, T., Boezio, M., Boggs, S.E., Bonvicini, V., Bridges, G., Campana, D., Craig, W.W., von Doetinchem, P., Everson, E., Fabris, L., Feldman, S., Fuke, H., Gahbauer, F., Gerrity, C., Hailey, C.J., Hayashi, T., Kawachi, A., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S.A.I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R.A., Osteria, G., Perez, K.M., Quinn, S., Re, V., Riceputi, E., Roach, B., Ryan, J., Saffold, N., Scotti, V., Shimizu, Y., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., Wada, T., Xiao, M., Yamatani, M., Yee, K., Yoshida, A., Yoshida, T., Zampa, G., Zeng, J., and Zweerink, J.

Published
2023
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2. Cosmic antihelium-3 nuclei sensitivity of the GAPS experiment

Author

Saffold, N., Aramaki, T., Bird, R., Boezio, M., Boggs, S.E., Bonvicini, V., Campana, D., Craig, W.W., von Doetinchem, P., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C.J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mognet, S.I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R.A., Osteria, G., Perez, K., Pope, I., Quinn, S., Re, V., Reed, M., Riceputi, E., Roach, B., Rogers, F., Ryan, J.L., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Published
2021
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4. An ultraluminous X-ray source powered by an accreting neutron star

Author

Bachetti, M., Harrison, F.A., Walton, D.J., Grefenstette, B.W., Chakrabarty, D., Furst, F., Barret, D., Beloborodov, A., Boggs, S.E., Christensen, F.E., Craig, W.W., Fabian, A.C., Hailey, C.J., Hornschemeier, A., Kaspi, V., Kulkarni, S.R., Maccarone, T., Miller, J.M., Rana, V., Stern, D., Tendulkar, S.P., Tomsick, J., Webb, N.A., and Zhang, W.W.

Subjects
Galaxies -- Observations, Galactic center -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes (1,2). Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from [10.sup.39] to [10.sup.41] ergs per second (3). Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems (1,2). The most challenging sources to explain are those at the luminous end of the range (more than [10.sub.40] ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity in the 3-30 kiloelectronvolt range of 4.9 x [10.sup.39] ergs per second. The pulsating source is spatially coincident with a variable source (4) that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 x [10.sup.40] ergs per second (1). This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects., The brightest accretion-powered X-ray pulsars, A0538-66 (5), SMCX-1 (6) and GRO J1744-28 (7), are variable, with reported X-ray luminosities up to [L.sub.X] (2-20 keV) ≅ [10.sup.39] erg [s.sup.-1], which are [...]

Published
2014

5. Asymmetries in core-collapse supernovae from maps of radioactive [sup.44]Ti in Cassiopeia A

Author

Grefenstette, B.W., Harrison, F.A., Boggs, S.E., Reynolds, S.P., Fryer, C.L., Madsen, K.K., Wik, D.R., Zoglauer, A., Ellinger, C.I., Alexander, D.M., An, H., Barret, D., Christensen, F.E., Craig, W.W., Forster, K., Giommi, P., Hailey, C.J., Hornstrup, A., Kaspi, V.M., Kitaguchi, T., Koglin, J.E., Mao, P.H., Miyasaka, H., Mori, K., Perri, M., Pivovaroff, M.J., Puccetti, S., Rana, V., Stern, D., Westergaard, N.J., and Zhang, W.W.

Subjects
Supernovae -- Natural history, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distribution of radioactive [sup.44]Ti, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surrounding medium (1), directly probes the explosion asymmetries. Cassiopeia A is a young (2), nearby (3), core-collapse (4) remnant from which [sup.44]Ti emission has previously been detected (5-8) but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed [sup.44]Ti emission to estimated [sup.56]Ni emission (9), from optical light echoes (10), and from jet-like features seen in the X-ray (11) and optical (12) ejecta. Here we report spatial maps and spectral properties of the [sup.44]Ti in Cassiopeia A. This may explain the unexpected lack of correlation between the [sup.44]Ti and iron X-ray emission, the latter being visible only in shock-heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast-rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae., Titanium-44 is produced in Si burning in the innermost regions of the material ejected in core-collapse supernovae, in the same processes that produce Fe and [56.sup]Ni (ref. 13). The decay [...]

Published
2014
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9. Nustar and Chandra Insight into the Nature of the 3-40 Kev Nuclear Emission in Ngc 253

Author

Lehmer, Bret D, Wik, Daniel R, Hornschemeier, Ann E, Ptak, Andrew, Antoniu, V, Argo, M.K, Bechtol, K, Boggs, S, Christensen, F.E, Craig, W.W, Hailey, C.J, Harrison, F.A, Krivonos, R, Leyder, Jean-Christophe Xavier Georges, Maccarone, T.J, Stern, D, Venters, T, Zezas, A, and Zhang, W.W

Subjects
Astrophysics, Astronomy
Abstract

We present results from three nearly simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR) and Chandra monitoring observations between 2012 September 2 and 2012 November 16 of the local star-forming galaxy NGC 253. The 3-40 kiloelectron volt intensity of the inner approximately 20 arcsec (approximately 400 parsec) nuclear region, as measured by NuSTAR, varied by a factor of approximately 2 across the three monitoring observations. The Chandra data reveal that the nuclear region contains three bright X-ray sources, including a luminous (L (sub 2-10 kiloelectron volt) approximately few × 10 (exp 39) erg per s) point source located approximately 1 arcsec from the dynamical center of the galaxy (within the sigma 3 positional uncertainty of the dynamical center); this source drives the overall variability of the nuclear region at energies greater than or approximately equal to 3 kiloelectron volts. We make use of the variability to measure the spectra of this single hard X-ray source when it was in bright states. The spectra are well described by an absorbed (power-law model spectral fit value, N(sub H), approximately equal to 1.6 x 10 (exp 23) per square centimeter) broken power-law model with spectral slopes and break energies that are typical of ultraluminous X-ray sources (ULXs), but not active galactic nuclei (AGNs). A previous Chandra observation in 2003 showed a hard X-ray point source of similar luminosity to the 2012 source that was also near the dynamical center (Phi is approximately equal to 0.4 arcsec); however, this source was offset from the 2012 source position by approximately 1 arcsec. We show that the probability of the 2003 and 2012 hard X-ray sources being unrelated is much greater than 99.99% based on the Chandra spatial localizations. Interestingly, the Chandra spectrum of the 2003 source (3-8 kiloelectron volts) is shallower in slope than that of the 2012 hard X-ray source. Its proximity to the dynamical center and harder Chandra spectrum indicate that the 2003 source is a better AGN candidate than any of the sources detected in our 2012 campaign; however, we were unable to rule out a ULX nature for this source. Future NuSTAR and Chandra monitoring would be well equipped to break the degeneracy between the AGN and ULX nature of the 2003 source, if again caught in a high state.

Published
2013
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10. A rapidly spinning supermassive black hole at the centre of NGC 1365

Author

Risaliti, G., Harrison, F.A., Madsen, K.K., Walton, D.J., Boggs, S.E., Christensen, F.E., Craig, W.W., Grefenstette, B.W., Hailey, C.J., Nardini, E., Stern, Daniel, and Zhang, W.W.

Subjects
Black holes (Astronomy) -- Observations, Spiral galaxies -- Observations -- Spectra, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge [...]

Published
2013
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13. 南極周回気球による宇宙線反粒子探索計画GAPS の現状報告

Author

Hailey, C.J., Gahbauer, F., Madden, N., Boggs, S., Hoberman, J., Craig, W.W., Doetinchem, P.v., Fabris, R., Ziock, K.P., Mognet, S.A.I., Ong, R., Zweerink, J., Perez, K., Fuke, Hideyuki, Nonomura, Taku, Ogawa, Hiroyuki, Okazaki, Shun, Sakimoto, Kazuhiro, Yoshida, Tetsuya, Takahashi, Katsumasa, Yamada, Noboru, Daimaru, Takuro, Nagai, Hiroki, Inoue, Takayoshi, Hashimoto, Takeshi, Wada, Takuya, Yoshida, Atsumasa, Kawachi, Akiko, Takahashi, Shun, Kato, C., Munakata, Kazuoki, Koike, Takahisa, Shimizu, Yuki, Aramaki, Tsuguo, and Mori, Kaya

Abstract

大気球シンポジウム 平成27年度（2015年11月5-6日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県, Balloon Symposium 2015 (November 5-6, 2015. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 39名, 資料番号: SA6000044045, レポート番号: isas15-sbs-045

Published
2015

14. GAPSプロトタイプ気球実験「pGAPS」フライト報告

Author

Gahbauer, F., Hailey, C.J., Koglin, J., Madden, N., Perez, K., Stefanik, D., Tajiri, G., Boggs, S., Doetinchem, P.v., Hoberman, J., Christensen, F., Craig, W.W., Fabris, R., Ziock, K.P., Mognet, I., Ong, R. A., Zweerink, J., Fuke, Hideyuki, Bando, Nobutaka, Ogawa, Hiroyuki, Okazaki, Shun, Shoji, Yasuhiro, Yoshida, Tetsuya, and Miyazaki, Yoshiro

Abstract

第13回宇宙科学シンポジウム (2013年1月8日-9日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 13th Space Science Symposium (January 8-9, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 著者人数: 30名, 資料番号: SA6000063227, レポート番号: P4-023

Published
2013

15. GAPS プロトタイプ気球実験'pGAPS'フライト報告

Author

Gahbauer, F., Hailey, C. J., Koglin, J., Madden, N., Perez, K., Stefanik, D., Tajiri, G., Boggs, S., Hoberman, J., Doetinchem, P.v., Christensen, F., Craig, W.W., Fabris, R., Ziock, K.P., Mognet, I., Ong, R., Zhang, T., Zweerink, J., Fuke, Hideyuki, Bando, Nobutaka, Ogawa, Hiroyuki, Okazaki, Shun, Shibano, Yasuko, Shoji, Yasuhiro, Yoshida, Tetsuya, Aramaki, Tsuguo, Mori, Kaya, K.P., Ziock, Kawachi, Akiko, Koike, Takahisa, Miyazaki, Yoshio, I., Mognet, R., Ong, T., Zhang, and J., Zweerink

Abstract

大気球シンポジウム 平成24年度（2012年10月16-17日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県), Balloon Symposium 2012 (October 16-17, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 31名, 資料番号: SA6000066018, レポート番号: isas12-sbs-018

Published
2012

16. 宇宙線反粒子探索計画GAPS全体報告

Author

Gahbauer, F., Hailey, C.J., Koglin, J., Madden, N., Perez, K., Tajiri, G., Boggs, S., Hoberman, J., Doetinchem, P.v., Christensen, F., Craig, W.W., Fabris, R., Ziock, K.P., Mognet, I., Ong, R., Zhang, T., Zweerink, J., Fuke, Hideyuki, Bando, Nobutaka, Ogawa, Hiroyuki, Okazaki, Shun, Shoji, Yasuhiro, Yoshida, Tetsuya, Aramaki, Tsuguo, Mori, Kaya, Kawai, Hiroki, Miyazaki, Yoshiro, Okubo, Takuma, Koike, T., and Takada, Atsushi

Abstract

第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 著者人数: 30名, 資料番号: SA6000064273, レポート番号: P4-481

Published
2012

17. GAPS プロトタイプ気球実験計画の全体報告

Author

Gahbauer, F., Hailey, C.J., Koglin, J., Madden, N., Perez, K., Tajiri, G., Boggs, S., Hoberman, J., Doetinchem, P.v., Christensen, F., Craig, W.W., Fabris, R., Ziock, K.P., Mognet, I., Ong, R., Zhang, T., Zweerink, J., Fuke, Hideyuki, Bando, Nobutaka, Ogawa, Hiroyuki, Okazaki, Shun, Shoji, Yasuhiro, Yoshida, Tetsuya, Aramaki, Tsuguo, Mori, Kaya, Kawai, Hiroki, Miyazaki, Yoshiro, Okubo, Takuma, Koike, T., and Takada, Atsushi

Abstract

大気球シンポジウム 平成23年度（2011年10月6-7日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県), Balloon Symposium 2011 (October 6-7, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 30名, 資料番号: SA6000067016, レポート番号: isas11-sbs-016

Published
2011

23. Growth, structure, and performance of depth-graded W/Si multilayers for hard x-ray optics

Author

Windt, D.L., Christensen, F.E., Craig, W.W., Hailey, C., Harrison, F.A., Jimenez-Garate M., Kalyanaraman, R., and Mao, P.H.

Subjects
Astronomical instruments -- Materials, Sputtering (Physics) -- Usage, Thin films, Multilayered -- Research, Physics
Abstract

A new study uses specular and nonspecular x-ray reflectance analysis to investigate the growth, structure, and performance of depth-graded W/Si multilayer structures.

Published
2000

28. NuSTAR reveals the extreme properties of the super-Eddington accreting supermassive black hole in PG 1247+267

Author

Duncan Farrah, Franz E. Bauer, M. Cappi, W. N. Brandt, W. W. Zhang, Giorgio Lanzuisi, M. Dadina, Enrico Piconcelli, Fausto Vagnetti, Andrea Comastri, C. J. Hailey, William W. Craig, S. E. Boggs, Fiona A. Harrison, Giorgio Matt, Claudio Ricci, A. C. Fabian, Dom Walton, Andrea Marinucci, F. E. Christensen, Michele Perna, S. Puccetti, David R. Ballantyne, Alberto Masini, D. Stern, C. Vignali, Cristian Saez, B. Luo, Marcella Brusa, Lanzuisi, G., Perna, M., Comastri, A., Cappi, M., Dadina, M., Marinucci, Andrea, Masini, A., Matt, Giorgio, Vagnetti, F., Vignali, C., Ballantyne, D. R., Bauer, F. E., Boggs, S. E., Brandt, W. N., Brusa, M., Christensen, F. E., Craig, W. W., Fabian, A. C., Farrah, D., Hailey, C. J., Harrison, F. A., Luo, B., Piconcelli, E., Puccetti, S., Ricci, C., Saez, C., Stern, D., Walton, D. J., Zhang, W. W., Marinucci, A., Matt, G., Ballantyne, D.R., Bauer, F.E., Boggs, S.E., Brandt, W.N., Christensen, F.E., Craig, W.W., Fabian, A.C., Hailey, C.J., Harrison, F.A., Walton, D.J., and Zhang, W.W.

Subjects
Accretion, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Power law, Relativistic disk, Quasars: individual: PG 1247+267, Accretion, accretion disk, Settore FIS/05 - Astronomia e Astrofisica, individual: PG 1247+267 [Quasars], Ionization, 0103 physical sciences, Cutoff, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Galaxies: nuclei, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Quasar, Plasma, Galaxies: active, Astronomy and Astrophysic, Redshift, Space and Planetary Science, nuclei [Galaxies], Accretion disks
Abstract

PG1247+267 is one of the most luminous known quasars at z similar to 2 and is a strongly super-Eddington accreting supermassive black hole (SMBH) candidate. We obtained NuSTAR data of this intriguing source in December 2014 with the aim of studying its high-energy emission, leveraging the broad band covered by the new NuSTAR and the archival XMM-Newton data. Several measurements are in agreement with the super-Eddington scenario for PG1247+267: the soft power law (Gamma = 2.3 +/- 0.1); the weak ionized Fe emission line; and a hint of the presence of outflowing ionized gas surrounding the SMBH. The presence of an extreme reflection component is instead at odds with the high accretion rate proposed for this quasar. This can be explained with three different scenarios; all of them are in good agreement with the existing data, but imply very different conclusions: i) a variable primary power law observed in a low state, superimposed on a reflection component echoing a past, higher flux state; ii) a power law continuum obscured by an ionized, Compton thick, partial covering absorber; and iii) a relativistic disk reflector in a lamp-post geometry, with low coronal height and high BH spin. The first model is able to explain the high reflection component in terms of variability. The second does not require any reflection to reproduce the hard emission, while a rather low high-energy cutoff of similar to 100 keV is detected for the first time in such a high redshift source. The third model require a face-on geometry, which may affect the SMBH mass and Eddington ratio measurements. Deeper X-ray broad-band data are required in order to distinguish between these possibilities.

Published
2016

29. The Phoenix galaxy as seen by NuSTAR

Author

Stephanie M. LaMassa, Matteo Guainazzi, Fiona A. Harrison, Dominic J. Walton, Walter Craig, C. J. Hailey, Michael Koss, S. E. Boggs, Daniel Stern, Andrea Comastri, Franz E. Bauer, Finn Erland Christensen, Claudio Ricci, M. Brightman, Mislav Baloković, Duncan Farrah, Simonetta Puccetti, P. G. Boorman, William W. Zhang, Poshak Gandhi, Alberto Masini, Masini, A., Comastri, A., Puccetti, S., Baloković, M., Gandhi, P., Guainazzi, M., Bauer, F.E., Boggs, S.E., Boorman, P.G., Brightman, M., Christensen, F.E., Craig, W.W., Farrah, D., Hailey, C.J., Harrison, F.A., Koss, M.J., Lamassa, S.M., Ricci, C., Stern, D., Walton, D.J., and Zhang, W.W.

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Seyfert [Galaxies], active [Galaxies], biology, 010308 nuclear & particles physics, galaxies: active, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Astronomy and Astrophysic, biology.organism_classification, 01 natural sciences, Galaxy, galaxies: Seyfert, galaxies [X-rays], X-rays: galaxies, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Phoenix, 010303 astronomy & astrophysics, X-rays: galaxie
Abstract

著者人数: 21名, Accepted: 2016-09-01, 資料番号: SA1160316000

Published
2016
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30. NuSTAR reveals extreme absorption in z < 0.5 Type 2 quasars

Author

Finn Erland Christensen, Fiona A. Harrison, C. J. Hailey, Franz E. Bauer, A. Del Moro, Francesca Civano, James Aird, Roberto J. Assef, Birong Luo, Brian W. Grefenstette, Daniel Stern, Michael Koss, David M. Alexander, L. Zappacosta, Stephanie M. LaMassa, A. Annuar, Simonetta Puccetti, Ryan C. Hickox, M. Brightman, Andrea Comastri, S. E. Boggs, George B. Lansbury, William W. Craig, Poshak Gandhi, William W. Zhang, Mislav Baloković, W. N. Brandt, Ezequiel Treister, David R. Ballantyne, Cristian Vignali, Lansbury, G.B., Gandhi, P., Alexander, D.M., Assef, R.J., Aird, J., Annuar, A., Ballantyne, D.R., Baloković, M., Bauer, F.E., Boggs, S.E., Brandt, W.N., Brightman, M., Christensen, F.E., Civano, F., Comastri, A., Craig, W.W., Del Moro, A., Grefenstette, B.W., Hailey, C.J., Harrison, F.A., Hickox, R.C., Koss, M., Lamassa, S.M., Luo, B., Puccetti, S., Stern, D., Treister, E., Vignali, C., Zappacosta, L., Zhang, W.W., ITA, and USA

Subjects
Physics, education.field_of_study, active [Galaxies], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, galaxies: active, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Type (model theory), 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Redshift, galaxies [X-rays], X-rays: galaxies, Space and Planetary Science, 0103 physical sciences, Source counts, Absorption (electromagnetic radiation), education, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics
Abstract

The intrinsic column density (NH) distribution of quasars is poorly known. At the high obscuration end of the quasar population and for redshifts z 1.5e24 cm^-2) type 2 quasars (CTQSO2s); five new NuSTAR observations are reported herein, and four have been previously published. The candidate CTQSO2s lie at z~ 90 net source counts at 8-24 keV). For these NuSTAR-detected sources direct (i.e., X-ray spectral) constraints on the intrinsic AGN properties are feasible, and we measure column densities ~2.5-1600 times higher and intrinsic (unabsorbed) X-ray luminosities ~10-70 times higher than pre-NuSTAR constraints from Chandra and XMM-Newton. Assuming the NuSTAR-detected type 2 quasars are representative of other Compton-thick candidates, we make a correction to the NH distribution for optically selected type 2 quasars as measured by Chandra and XMM-Newton for 39 objects. With this approach, we predict a Compton-thick fraction of f_CT = 36^{+14}_{-12} %, although higher fractions (up to 76%) are possible if indirect absorption diagnostics are assumed to be reliable., Comment: 19 pages, 13 figures, 5 tables. Accepted for publication in ApJ

Published
2015

31. NuSTAR J033202-2746.8: direct constraints on the Compton reflection in a heavily obscured quasar at z~2

Author

Piero Ranalli, Simonetta Puccetti, James Aird, Meg Urry, Stephanie M. LaMassa, S. E. Boggs, David M. Alexander, Fiona A. Harrison, C. J. Hailey, George B. Lansbury, William W. Zhang, Francesca Civano, Andrea Comastri, Finn Erland Christensen, James Mullaney, W. N. Brandt, William W. Craig, Mislav Baloković, Daniel Stern, Poshak Gandhi, Ryan C. Hickox, Birong Luo, A. Del Moro, David R. Ballantyne, Cristian Vignali, Ezequiel Treister, Roberto Gilli, Franz E. Bauer, Del Moro A., Mullaney J.R., Alexander D.M., Comastri A., Bauer F.E., Treister E., Stern D., Civano F., Ranalli P., Vignali C., Aird J.A., Ballantyne D., Balokovic M., Boggs S.E., Brandt W.N., Christensen S.E., Craig W.W., Gandhi P., Gilli R., Hailey C.J., Harrison F.A., Hickox R.C., LaMassa S.M., Lansbury G.B., Luo B., Puccetti S., Urry M., and Zhang W.W.

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Spectral shape analysis, active [Galaxies], 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Population, galaxies: active, General [quasars], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, Galaxies [infrared], quasars: individual (NuSTAR J033202-2746.8), quasars: general, X-rays, 0103 physical sciences, Spectral slope, individual (NuSTAR J033202-2746.8) [quasars], Spectroscopy, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, education.field_of_study, infrared: galaxie, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Redshift, X-rays: galaxies, K-edge, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report NuSTAR observations of NuSTAR J033202-2746.8, a heavily obscured, radio-loud quasar detected in the Extended Chandra Deep Field-South, the deepest layer of the NuSTAR extragalactic survey (~400 ks, at its deepest). NuSTAR J033202-2746.8 is reliably detected by NuSTAR only at E>8 keV and has a very flat spectral slope in the NuSTAR energy band (Gamma=0.55^{+0.62}_{-0.64}; 3-30 keV). Combining the NuSTAR data with extremely deep observations by Chandra and XMM-Newton (4 Ms and 3 Ms, respectively), we constrain the broad-band X-ray spectrum of NuSTAR J033202-2746.8, indicating that this source is a heavily obscured quasar (N_H=5.6^{+0.9}_{-0.8}x10^23 cm^-2) with luminosity L_{10-40 keV}~6.4x10^44 erg s^-1. Although existing optical and near-infrared (near-IR) data, as well as follow-up spectroscopy with the Keck and VLT telescopes, failed to provide a secure redshift identification for NuSTAR J033202-2746.8, we reliably constrain the redshift z=2.00+/-0.04 from the X-ray spectral features (primarily from the iron K edge). The NuSTAR spectrum shows a significant reflection component (R=0.55^{+0.44}_{-0.37}), which was not constrained by previous analyses of Chandra and XMM-Newton data alone. The measured reflection fraction is higher than the R~0 typically observed in bright radio-loud quasars such as NuSTAR J033202-2746.8, which has L_{1.4 GHz}~10^27 W Hz^-1. Constraining the spectral shape of AGN, including bright quasars, is very important for understanding the AGN population, and can have a strong impact on the modeling of the X-ray background. Our results show the importance of NuSTAR in investigating the broad-band spectral properties of quasars out to high redshift., 13 pages, 5 figures; accepted for publication in ApJ

Published
2014

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