We present a detailed analysis of the X-ray emission of HS 1700+6416, a high-redshift (z = 2.7348) luminous quasar classified as a narrow absorption line (NAL) quasar on the basis of its SDSS spectrum. The source has been observed nine times by Chandra and once by XMM-Newton from 2000 to 2007. Long-term variability is clearly detected between the observations in the 2-10 keV flux, where it varies by a factor of three (~3-9 × 10-14 erg s-1 cm-2), and in the amount of neutral absorption (NH < 10^22 cm-2 in 2000 and 2002 and NH = 4.4 ± 1.2 × 10^22 cm-2 in 2007). Most interestingly, one broad absorption feature is clearly detected at 10.3 ± 0.7 keV (rest frame) in the 2000 Chandra observation, while two similar features at 8.9 ± 0.4 and at 12.5 ± 0.7 keV are visible when the eight contiguous Chandra observations of 2007 are stacked together. In the XMM-Newton observation of 2002, which is strongly affected by background flares, there is a hint of a similar feature at 8.0 ± 0.3 keV. We interpreted these features as absorption lines from a high-velocity highly ionized (i.e. Fe XXV, FeXXVI) outflowing gas. In this scenario, the outflow velocities inferred are in the range v = 0.12-0.59c. To reproduce the observed features, the gas must have a high column density (NH > 3 × 10^23 cm-2), high ionization parameter (log ξ > 3.3 erg cm s-1) and a wide range of velocities (ΔV ~ 104 km s-1). This absorption line quasar is the fourth high-z quasar that displays X-ray signatures of variable high-velocity outflows, and among these, it is the only one that is not lensed. A rough estimate of the minimum kinetic energy carried by the wind of up to 18% Lbol, based on a biconical geometry of the wind, implies that the amount of energy injected into the outflow environment is large enough to produce effective mechanical feedback.
Lanzuisi G., Giustini M., Cappi M., Dadina M., Malaguti G., Vignali C., et al. (2012). HS 1700+6416: the first high redshift unlensed narrow absorption-line QSO showing variable high-velocity outflows. ASTRONOMY & ASTROPHYSICS, 544, A2-A2 [10.1051/0004-6361/201219481].
HS 1700+6416: the first high redshift unlensed narrow absorption-line QSO showing variable high-velocity outflows
LANZUISI, GIORGIO;GIUSTINI, MARGHERITA;VIGNALI, CRISTIAN;
2012
Abstract
We present a detailed analysis of the X-ray emission of HS 1700+6416, a high-redshift (z = 2.7348) luminous quasar classified as a narrow absorption line (NAL) quasar on the basis of its SDSS spectrum. The source has been observed nine times by Chandra and once by XMM-Newton from 2000 to 2007. Long-term variability is clearly detected between the observations in the 2-10 keV flux, where it varies by a factor of three (~3-9 × 10-14 erg s-1 cm-2), and in the amount of neutral absorption (NH < 10^22 cm-2 in 2000 and 2002 and NH = 4.4 ± 1.2 × 10^22 cm-2 in 2007). Most interestingly, one broad absorption feature is clearly detected at 10.3 ± 0.7 keV (rest frame) in the 2000 Chandra observation, while two similar features at 8.9 ± 0.4 and at 12.5 ± 0.7 keV are visible when the eight contiguous Chandra observations of 2007 are stacked together. In the XMM-Newton observation of 2002, which is strongly affected by background flares, there is a hint of a similar feature at 8.0 ± 0.3 keV. We interpreted these features as absorption lines from a high-velocity highly ionized (i.e. Fe XXV, FeXXVI) outflowing gas. In this scenario, the outflow velocities inferred are in the range v = 0.12-0.59c. To reproduce the observed features, the gas must have a high column density (NH > 3 × 10^23 cm-2), high ionization parameter (log ξ > 3.3 erg cm s-1) and a wide range of velocities (ΔV ~ 104 km s-1). This absorption line quasar is the fourth high-z quasar that displays X-ray signatures of variable high-velocity outflows, and among these, it is the only one that is not lensed. A rough estimate of the minimum kinetic energy carried by the wind of up to 18% Lbol, based on a biconical geometry of the wind, implies that the amount of energy injected into the outflow environment is large enough to produce effective mechanical feedback.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
