ترغب بنشر مسار تعليمي؟ اضغط هنا

A prominent relativistic iron line in the Seyfert 1 MCG-02-14-009

97   0   0.0 ( 0 )
 نشر من قبل Delphine Porquet Dr.
 تاريخ النشر 2005
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Delphine Porquet




اسأل ChatGPT حول البحث

I report the discovery of a prominent broad and asymmetrical feature near 6.4 keV in the Seyfert 1 MCG-02-14-009 (z=0.028) with XMM-Newton/EPIC. The present short X-ray observation (PN net exposure time ~5 ks) is the first one above 2 keV for MCG-02-14-009. The feature can be explained by either a relativistic iron line around either a Schwarzschild (non-rotating) or a Kerr (rotating) black hole. If the feature is a relativistic iron line around a Schwarzschild black hole, the line energy is 6.51 (+0.21,-0.12) keV with an equivalent width of 631 (+259,-243) eV and that the inclination angle of the accretion disc should be less than 43 degrees. A relativistically blurred photoionized disc model gives a very good spectral fit over the broad band 0.2-12keV energy range. The spectrum is reflection dominated and this would indicate that the primary source in MCG-02-14-009 is located very close to the black hole, where gravitational light bending effect is important (about 3-4 Rg), and that the black hole may rapidly rotate.

قيم البحث

اقرأ أيضاً

Narrow-Line Seyfert 1 (NLS1) class of active galactic nuclei (AGNs) is generally radio-quiet, but a small percent of them are radio-loud. The recent discovery by Fermi/LAT of high-energy gamma-ray emission from 4 NLS1s proved the existence of relativ istic jets in these systems. It is therefore important to study this new class of gamma-ray emitting AGNs. Here we report preliminary results about the observations of the July 2010 gamma-ray outburst of PMN J0948+0022, when the source flux exceeded for the first time 10^-6 ph cm^-2 s^-1 (E > 100 MeV).
66 - Paul M. ONeill 2007
We report on a 133 ks XMM-Newton observation of the Seyfert 1 galaxy Markarian 335. The 0.4-12 keV spectrum contains an underlying power law continuum, a soft excess below 2 keV, and a double-peaked iron emission feature in the 6-7 keV range. We inve stigate the possibility that the double-peaked emission might represent the characteristic signature of the accretion disc. Detailed investigations show that a moderately broad, accretion disc line is most likely present, but that the peaks may be owing to narrower components from more distant material. The peaks at 6.4 and 7 keV can be identified, respectively, with the molecular torus in active galactic nucleus unification schemes, and very highly ionized, optically thin gas filling the torus. The X-ray variability spectra on both long (~100 ks) and short (~1 ks) timescales disfavour the recent suggestion that the soft excess is an artifact of variable, moderately ionized absorption.
We present the results of the simultaneous deep XMM and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a relativistically broadened iron K-alpha line. The time averaged sp ectral analysis shows that the iron K-shell complex is best modeled with an unresolved narrow emission component (FWHM < 5000 km/s, EW ~ 60 eV) plus a broad component. This latter component has FWHM ~ 44000 km/s and EW ~ 50 eV. Its profile is well described by an emission line originating from an accretion disk viewed with an inclination angle ~ 40^circ and with the emission arising from within a few tens of gravitational radii of the central black hole. The time-resolved spectral analysis of the XMM EPIC-pn spectrum shows that both the narrow and broad components of the Fe K emission line appear to be constant in time within the errors. We detected a narrow sporadic absorption line at 7.7 keV which appears to be variable on a time-scale of 20 ksec. If associated with Fe XXVI Ly-alpha this absorption is indicative of a possibly variable, high ionization, high velocity outflow. The variability of this absorption feature appears to rule out a local (z=0) origin. The analysis of the XMM RGS spectrum reveals that the soft X-ray emission of MCG-5-23-16 is likely dominated by several emission lines superimposed on an unabsorbed scattered power-law continuum. The lack of strong Fe L shell emission together with the detection of a strong forbidden line in the O VII triplet is consistent with a scenario where the soft X-ray emission lines are produced in a plasma photoionized by the nuclear emission.
We have carried out an extensive X-ray spectral study of the bare Seyfert-1 galaxy MCG--02--58--22 to ascertain the nature of the X-ray reprocessing media, using observations from Suzaku (2009) and simultaneous observations from XMM-Newton and NuSTAR (2016) . The most significant results of our investigation are: 1. The primary X-ray emission from the corona is constant in these observations, both in terms of the power law slope ($Gamma=1.80$) and luminosity ($L_{2-10 rm keV}= 2.55times 10^{44} $ erg/s). 2. The soft excess flux decreased by a factor of two in 2016, the Compton hump weakened/vanished in 2016, and the narrow FeK$alpha$ emission line became marginally broad ($sigma=0.35pm0.08$ keV) and its flux doubled in 2016. 3. From physical model fits we find that the normalization of the narrow component of the FeK$alpha$ line does not change in the two epochs, although the Compton hump vanishes in the same time span. Since the primary X-ray continuum does not change, we presume that any changes in the reprocessed emission must arise due to changes in the reprocessing media. Our primary conclusions are: A. The vanishing of the Compton hump in 2016 can probably be explained by a dynamic clumpy torus which is infalling/outflowing, or by a polar torus wind. B. The torus in this AGN possibly has two structures: an equatorial toroidal disk (producing the narrow FeK$alpha$ emission) and a polar component (producing the variable Compton hump), C. The reduction of the soft-excess flux by half and increase in the FeK$alpha$ flux by a factor of two in the same period cannot be adequately explained by ionized disk reflection model alone.
We found a possible ~ 1 hour quasi-periodic oscillation (QPO) in a ~ 55 ks X-ray observation of the narrow-line Seyfert 1 galaxy MCG--06--30--15 made with the XMM-Newton EPIC/pn detector in the energy range 0.3 -- 10 keV. We identify a total modulati on of ~ 16% in the light curve and find a $simeq$ 3670~s quasi-period using Lomb-Scargle periodogram (LSP) and weighted wavelet Z-transform (WWZ) techniques. Our analyses of eight light curves of MCG--06--30--15, indicated the possible presence of an oscillation during one of them. The LSP indicates a statistically significant ($simeq$ 3$sigma$) QPO detection. A WWZ analysis shows that the signal at this possible roughly 3670s period is present, and rather persistent, throughout the observation; however, a signal around 8735s is more persistent. We briefly discuss models that can produce X-ray QPOs with such periods in narrow line Seyfert 1 galaxies, as both other claimed QPO detections in this class of AGN had very similar periods.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا