Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTesting The Lamp-Post and Wind Reverberation Models with XMM-Newton Observations of NGC 5506
206
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The lamp-post geometry is often used to model X-ray data of accreting black holes. Despite its simple assumptions, it has proven to be powerful in inferring fundamental black hole properties such as the spin. Early results of X-ray reverberations showed support for such a simple picture, though wind-reverberation models have also been shown to explain the observed delays. Here, we analyze new and old XMM-Newton observations of the variable Seyfert-1 galaxy NGC 5506 to test these models. The source shows an emission line feature around 6.7 keV that is delayed relative to harder and softer energy bands. The spectral feature can be modeled with either a weakly relativistic disk line or by scattering in distant material. By modeling both the spectral and timing signatures, we find that the reflection fraction needed to explain the lags is larger than observed in the time-averaged spectrum, ruling out both a static lamp-post and simple wind reverberation models.
rate research
Read More
X-ray reverberation mapping has emerged as a new tool to probe accretion in AGN, providing a potentially powerful probe of accretion at the black hole scale. The lags, along with relativistic spectral signatures are often interpreted in light of the lamp-post model. Focusing specifically on testing the prediction of the relativistic reverberation model, we have targeted several of the brightest Seyfert Galaxies in X-rays with different observing programs. Here, we report the results from two large campaigns with NuSATR targeting MCG-5-23-16 and SWIFT J2127.4+5654 to test the model predictions in the 3-50 keV band. These are two of three sources that showed indications of a delayed Compton hump in early data. With triple the previously analyzed exposures, we find no evidence for relativistic reverberation in MCG-5-23-16, and the energy-dependent lags are consistent with a log-linear continuum. In SWIFT J2127.4+5654, although a continuum-only model explains the data, the relativistic reverberation model provides a significant improvement to the energy and frequency-dependent lags, but with parameters that are not consistent with the time-averaged spectrum. This adds to mounting evidence showing that the lag data is not consistent with a static lamp-post model.
We present results from a study of the non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources has been detected within the D25 regions of the target galaxies. The large collecting area of XMM-Newton makes the statistics sufficient to obtain spectral fitting for 16 (about 20%) of these sources. Compiling the extensive archival exposures available, we were able to obtain the detailed spectral shapes of diverse classes of point sources. We have also studied temporal properties of these luminous sources. 11 of them are found to show short-term (less than 80 ks) variation while 8 of them show long-term variation within factors of ~ 2 to 5 during a time interval of ~ 2 to 12 years. Timing analysis provides strong evidence that most of these sources are accreting X-ray binary (XRB) systems. One source that has properties different than others was suspected to be a Supernova Remnant (SNR), and our follow-up optical observation confirmed it. Our results indicate that sources within the three nearby galaxies are showing a variety of source populations, including several Ultraluminous X-Ray Sources (ULXs), X-ray binaries (XRBs), transients together with a Super Soft Source (SSS) and a background Active Galactic Nucleus (AGN) candidate.
We present here the results of our analysis of X-ray properties of Seyfert 2 galaxy NGC 3281, based on the observational data obtained by XMM-Newton and INTEGRAL within the energy ranges 0.2-12 keV and 20-150 keV, respectively. The XMM-Newton spectrum of this object is presented for the first time. We show that fitting the X-ray spectrum of this galaxy with models based on the reflection from the disc with infinite column density yields non-physical results. More appropriate fit takes into account both transmitted and reflected emission, passed through a gas-dusty torus-like structure. Keeping this in mind, to model the inhomogeneous clumpy torus, we used the MYTorus model. Hence, we propose that the torus of NGC 3281 is not continuous structure, but it consists of separate clouds, which is in a good agreement with the results of near-IR observations. Using this assumption, we found that the torus inclination angle and the hydrogen column density are 66.98^{+2.63}_{-1.34} degrees and 2.08^{+0.35}_{-0.18}x10^{24} cm^{-2}, respectively. Also, the emission of the hot diffuse gas with temperature ~590 eV and warm absorption were detected.
We present a high-quality hard X-ray spectrum of the ultraluminous X-ray source (ULX) NGC 5643 X-1 measured with NuSTAR in May-June 2014. We have obtained this spectrum by carefully separating the signals from the ULX and from the active nucleus of its host galaxy NGC 5643 located 0.8 arcmin away. Together with long XMM-Newton observations performed in July 2009 and August 2014, the NuSTAR data confidently reveal a high-energy cutoff in the spectrum of NGC 5643 X-1 above ~10 keV, which is a characteristic signature of ULXs. The NuSTAR and XMM-Newton data are consistent with the source having a constant luminosity ~1.5E40 erg/s (0.2-12 keV) in all but the latest observation (August 2014) when it brightened to ~3E40 erg/s. This increase is associated with the dominant, hard spectral component (presumably collimated emission from the inner regions of a supercritical accretion disc), while an additional, soft component (with a temperature ~0.3 keV if described by multicolor disk emission), possibly associated with a massive wind outflowing from the disk, is also evident in the spectrum but does not exhibit significant variability.
CTB 87 (G74.9+1.2) is an evolved supernova remnant (SNR) which hosts a peculiar pulsar wind nebula (PWN). The X-ray peak is offset from that observed in radio and lies towards the edge of the radio nebula. The putative pulsar, CXOU~J201609.2+371110, was first resolved with textit{Chandra} and is surrounded by a compact and a more extended X-ray nebula. Here we use a deep {textit{XMM-Newton}} observation to examine the morphology and evolutionary stage of the PWN and to search for thermal emission expected from a supernova shell or reverse shock interaction with supernova ejecta. We do not find evidence of thermal X-ray emission from the SNR and place an upper limit on the electron density of 0.05~cm$^{-3}$ for a plasma temperature $kTsim 0.8$ keV. The morphology and spectral properties are consistent with a $sim$20~kyr-old relic PWN expanding into a stellar wind-blown bubble. We also present the first X-ray spectral index map from the PWN and show that we can reproduce its morphology by means of 2D axisymmetric relativistic hydrodynamical simulations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
