The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy

R. Landi, N. Masetti, L. Morelli, E. Palazzi, L. Bassani, A. Malizia, A. Bazzano, A. J. Bird, A. J. Dean, G. Galaz, D. Minniti, P. Ubertini

Resultado de la investigación: Article

28 Citas (Scopus)

Resumen

The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude survey in the 14-195 keV band at a flux limit of ∼10-11 ergs cm-2 s-1, leading to the discovery of new high-energy sources, most of which have not yet been properly classified. A similar work has also been performed with the RXTE slew survey, leading to the discovery of 68 sources detected above 8 keV, many of which are still unclassified. Follow-up observations with the Swift X-ray Telescope (XRT) provide, for many of these objects, source localization with a positional accuracy of a few arcseconds, thus allowing the search for optical counterparts to be more efficient and reliable. We present the results of optical/X-ray follow-up studies of 11 Swift BAT detections and one AGN detected in the RXTE Slew Survey, aimed at identifying their longer wavelength counterparts and at assessing their nature. These data allowed, for the first time, the optical classification of eight objects and a distance determination for three of them. For another object, a more refined optical classification than that available in the literature is also provided. For the remaining sources, optical spectroscopy provides a characterization of the source near in time to the X-ray measurement. The sample consists of six Seyfert 2 galaxies, five Seyferts of intermediate type 1.2-1.8, and one object of Galactic nature - an intermediate polar (i.e., magnetic) cataclysmic variable. Out of the 11 AGNs, 8 (∼70%), including 2 Seyferts of type 1.2 and 1.5, are absorbed with NH > 1022 cm -2. Up to 3 objects could be Compton thick (i.e., NH > 1.5 × 1024 cm-2), but only in one case (Swift J0609.1 - 8636) does all the observational evidence strongly suggest this possibility. The present data demonstrate the capability of coordinated hard X-ray and optical observations to discover absorbed AGNs.

Idioma originalEnglish
Páginas (desde-hasta)109-125
Número de páginas17
PublicaciónAstrophysical Journal
Volumen669
N.º1
DOI
EstadoPublished - 1 nov 2007

Huella dactilar

X-ray spectroscopy
X Ray Timing Explorer
telescopes
spectroscopy
bursts
x rays
cataclysmic variables
energy sources
erg
galaxies
wavelength
wavelengths

ASJC Scopus subject areas

  • Space and Planetary Science
  • Nuclear and High Energy Physics
  • Astronomy and Astrophysics

Citar esto

Landi, R., Masetti, N., Morelli, L., Palazzi, E., Bassani, L., Malizia, A., ... Ubertini, P. (2007). The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy. Astrophysical Journal, 669(1), 109-125. https://doi.org/10.1086/521208
Landi, R. ; Masetti, N. ; Morelli, L. ; Palazzi, E. ; Bassani, L. ; Malizia, A. ; Bazzano, A. ; Bird, A. J. ; Dean, A. J. ; Galaz, G. ; Minniti, D. ; Ubertini, P. / The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy. En: Astrophysical Journal. 2007 ; Vol. 669, N.º 1. pp. 109-125.
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abstract = "The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude survey in the 14-195 keV band at a flux limit of ∼10-11 ergs cm-2 s-1, leading to the discovery of new high-energy sources, most of which have not yet been properly classified. A similar work has also been performed with the RXTE slew survey, leading to the discovery of 68 sources detected above 8 keV, many of which are still unclassified. Follow-up observations with the Swift X-ray Telescope (XRT) provide, for many of these objects, source localization with a positional accuracy of a few arcseconds, thus allowing the search for optical counterparts to be more efficient and reliable. We present the results of optical/X-ray follow-up studies of 11 Swift BAT detections and one AGN detected in the RXTE Slew Survey, aimed at identifying their longer wavelength counterparts and at assessing their nature. These data allowed, for the first time, the optical classification of eight objects and a distance determination for three of them. For another object, a more refined optical classification than that available in the literature is also provided. For the remaining sources, optical spectroscopy provides a characterization of the source near in time to the X-ray measurement. The sample consists of six Seyfert 2 galaxies, five Seyferts of intermediate type 1.2-1.8, and one object of Galactic nature - an intermediate polar (i.e., magnetic) cataclysmic variable. Out of the 11 AGNs, 8 (∼70{\%}), including 2 Seyferts of type 1.2 and 1.5, are absorbed with NH > 1022 cm -2. Up to 3 objects could be Compton thick (i.e., NH > 1.5 × 1024 cm-2), but only in one case (Swift J0609.1 - 8636) does all the observational evidence strongly suggest this possibility. The present data demonstrate the capability of coordinated hard X-ray and optical observations to discover absorbed AGNs.",
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Landi, R, Masetti, N, Morelli, L, Palazzi, E, Bassani, L, Malizia, A, Bazzano, A, Bird, AJ, Dean, AJ, Galaz, G, Minniti, D & Ubertini, P 2007, 'The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy', Astrophysical Journal, vol. 669, n.º 1, pp. 109-125. https://doi.org/10.1086/521208

The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy. / Landi, R.; Masetti, N.; Morelli, L.; Palazzi, E.; Bassani, L.; Malizia, A.; Bazzano, A.; Bird, A. J.; Dean, A. J.; Galaz, G.; Minniti, D.; Ubertini, P.

En: Astrophysical Journal, Vol. 669, N.º 1, 01.11.2007, p. 109-125.

Resultado de la investigación: Article

TY - JOUR

T1 - The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy

AU - Landi, R.

AU - Masetti, N.

AU - Morelli, L.

AU - Palazzi, E.

AU - Bassani, L.

AU - Malizia, A.

AU - Bazzano, A.

AU - Bird, A. J.

AU - Dean, A. J.

AU - Galaz, G.

AU - Minniti, D.

AU - Ubertini, P.

PY - 2007/11/1

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N2 - The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude survey in the 14-195 keV band at a flux limit of ∼10-11 ergs cm-2 s-1, leading to the discovery of new high-energy sources, most of which have not yet been properly classified. A similar work has also been performed with the RXTE slew survey, leading to the discovery of 68 sources detected above 8 keV, many of which are still unclassified. Follow-up observations with the Swift X-ray Telescope (XRT) provide, for many of these objects, source localization with a positional accuracy of a few arcseconds, thus allowing the search for optical counterparts to be more efficient and reliable. We present the results of optical/X-ray follow-up studies of 11 Swift BAT detections and one AGN detected in the RXTE Slew Survey, aimed at identifying their longer wavelength counterparts and at assessing their nature. These data allowed, for the first time, the optical classification of eight objects and a distance determination for three of them. For another object, a more refined optical classification than that available in the literature is also provided. For the remaining sources, optical spectroscopy provides a characterization of the source near in time to the X-ray measurement. The sample consists of six Seyfert 2 galaxies, five Seyferts of intermediate type 1.2-1.8, and one object of Galactic nature - an intermediate polar (i.e., magnetic) cataclysmic variable. Out of the 11 AGNs, 8 (∼70%), including 2 Seyferts of type 1.2 and 1.5, are absorbed with NH > 1022 cm -2. Up to 3 objects could be Compton thick (i.e., NH > 1.5 × 1024 cm-2), but only in one case (Swift J0609.1 - 8636) does all the observational evidence strongly suggest this possibility. The present data demonstrate the capability of coordinated hard X-ray and optical observations to discover absorbed AGNs.

AB - The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude survey in the 14-195 keV band at a flux limit of ∼10-11 ergs cm-2 s-1, leading to the discovery of new high-energy sources, most of which have not yet been properly classified. A similar work has also been performed with the RXTE slew survey, leading to the discovery of 68 sources detected above 8 keV, many of which are still unclassified. Follow-up observations with the Swift X-ray Telescope (XRT) provide, for many of these objects, source localization with a positional accuracy of a few arcseconds, thus allowing the search for optical counterparts to be more efficient and reliable. We present the results of optical/X-ray follow-up studies of 11 Swift BAT detections and one AGN detected in the RXTE Slew Survey, aimed at identifying their longer wavelength counterparts and at assessing their nature. These data allowed, for the first time, the optical classification of eight objects and a distance determination for three of them. For another object, a more refined optical classification than that available in the literature is also provided. For the remaining sources, optical spectroscopy provides a characterization of the source near in time to the X-ray measurement. The sample consists of six Seyfert 2 galaxies, five Seyferts of intermediate type 1.2-1.8, and one object of Galactic nature - an intermediate polar (i.e., magnetic) cataclysmic variable. Out of the 11 AGNs, 8 (∼70%), including 2 Seyferts of type 1.2 and 1.5, are absorbed with NH > 1022 cm -2. Up to 3 objects could be Compton thick (i.e., NH > 1.5 × 1024 cm-2), but only in one case (Swift J0609.1 - 8636) does all the observational evidence strongly suggest this possibility. The present data demonstrate the capability of coordinated hard X-ray and optical observations to discover absorbed AGNs.

KW - Galaxies: Seyfert

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Landi R, Masetti N, Morelli L, Palazzi E, Bassani L, Malizia A y otros. The AGN nature of 11 out of 12 Swift/rxte unidentified sources through optical and X-ray spectroscopy. Astrophysical Journal. 2007 nov 1;669(1):109-125. https://doi.org/10.1086/521208