Search

The nuclear transient AT2019cuk/Tick Tock/SDSS J1430+2303 has been suggested to harbor a supermassive black hole (SMBH) binary near coalescence. We report results from high-cadence NICER X-ray monitoring with multiple visits per day from January-August 2022, as well as continued optical monitoring during the same time period. We find no evidence of periodic/quasi-periodic modulation in the X-ray, UV, or optical bands, however we do observe exotic hard X-ray variability that is unusual for a typical AGN. The most striking feature of the NICER light curve is repetitive hard (2-4 keV) X-ray flares that result in distinctly harder X-ray spectra compared to the non-flaring data. In its non-flaring state, AT2019cuk looks like a relatively standard AGN, but it presents the first case of day-long, hard X-ray flares in a changing-look AGN. We consider a few different models for the driving mechanism of these hard X-ray flares, including: (1) corona/jet variability driven by increased magnetic activity, (2) variable obscuration, and (3) self-lensing from the potential secondary SMBH. We prefer the variable corona model, as the obscuration model requires rather contrived timescales and the self-lensing model is difficult to reconcile with a lack of clear periodicity in the flares. These findings illustrate how important high-cadence X-ray monitoring is to our understanding of the rapid variability of the X-ray corona and necessitate further high-cadence, multi-wavelength monitoring of changing-look AGN like AT2019cuk to probe the corona-jet connection., 23 pages, 13 figures, 1 table, accepted for publication in ApJL

X-ray binaries provide exceptional laboratories for understanding the physics of matter under the most extreme conditions. Until recently, there were few, if any, observational constraints on the circumbinary environments of X-ray binaries at $\sim$ 100-5000 AU scales; it remains unclear how the accretion onto the compact objects or the explosions giving rise to the compact objects interact with their immediate surroundings. Here, we present the first high-contrast adaptive optics images of X-ray binaries. These observations target all X-ray binaries within $\sim$ 3 kpc accessible with the Keck/NIRC2 vortex coronagraph. This paper focuses on one of the first key results from this campaign: our images reveal the presence of 21 sources potentially associated with the $\gamma$ Cassiopeiae analog high-mass X-ray binary RX J1744.7$-$2713. By conducting different analyses - a preliminary proper motion analysis, a color-magnitude diagram and a probability of chance alignment calculation - we found that three of these 21 sources have a high probability of being bound to the system. If confirmed, they would be in wide orbits ($\sim$ 450 AU to 2500 AU). While follow-up astrometric observations will be needed in $\sim$ 5-10 years to confirm further the bound nature of these detections, these discoveries emphasize that such observations may provide a major breakthrough in the field. In fact, they would be useful not only for our understanding of stellar multiplicity but also for our understanding of how planets, brown dwarfs and stars can form even in the most extreme environments., Comment: Accepted for publication in AJ

The degree to which the thin accretion disks of black hole X-ray binaries are truncated during hard spectral states remains a contentious open question in black hole astrophysics. During its singular observed outburst in $2009\mbox{--}2010$, the black hole X-ray binary XTE J1752-223 spent $\sim1$~month in a long-stable hard spectral state at a luminosity of $\sim0.02\mbox{--}0.1~L_{\rm Edd}$. It was observed with 56 RXTE pointings during this period, with simultaneous Swift-XRT daily coverage during the first 10 days of the RXTE observations. Whilst reflection modeling has been extensively explored in the analysis of these data, there is a disagreement surrounding the geometry of the accretion disk and corona implied by the reflection features. We re-examine the combined, high signal-to-noise, simultaneous Swift and RXTE observations, and perform extensive reflection modeling with the latest relxill suite of reflection models, including newer high disk density models. We show that reflection modeling requires that the disk be within $\sim5~R_{\rm ISCO}$ during the hard spectral state, whilst weaker constraints from the thermal disk emission imply higher truncation ($R_{\rm in}=6\mbox{--}80~R_{\rm ISCO}$). We also explore more complex coronal continuum models, allowing for two Comptonization components instead of one, and show that the reflection features still require only a mildly truncated disk. Finally we present a full comparison of our results to previous constraints found from analyses of the same dataset., 18 pages, 9 figures, accepted by ApJ

著者人数: Hitomi Collaboration 194名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 堂谷, 忠靖; 海老沢, 研; 林, 克洋; 飯塚, 亮; 井上, 芳幸; 石田, 学; 石川, 久美; 岩井, 将親; 国分, 紀秀; 小山, 志勇; 前田, 良知; 満田, 和久; 中川, 貴雄; 尾崎, 正伸; 佐藤, 悟郎; 佐藤, 理江; Simionescu, Aurora; 菅原, 泰晴; 高橋, 忠幸; 竹井, 洋; 田村, 隆幸; 田中, 靖郎; 冨田, 洋; 辻本, 匡弘; 上田, 周太朗; 渡辺, 伸; 山崎, 典子）, Number of authors: Hitomi Collaboration 194 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Dotani, Tadayasu; Ebisawa, Ken; Hayashi, Katsuhiro; Iizuka, Ryo; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Iwai, Masachika; Kokubun, Motohide; Koyama, Shu; Maeda, Yoshitomo; Mitsuda, Kazuhisa; Nakagawa, Takao; Ozaki, Masanobu; Sato, Goro; Sato, Rie; Simionescu, Aurora; Sugawara, Yasuharu; Takahashi, Tadayuki; Takei, Yoh; Tamura, Takayuki; Tanaka, Yasuo; Tomida, Hiroshi; Tsujimoto, Masahiro; Ueda, Shutaro; Watanabe, Shin; Yamasaki, Noriko Y.), Accepted: 2017-12-13, 資料番号: SA1170337000

著者人数: Hitomi Collaboration 193名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 堂谷, 忠靖; 海老沢, 研; 林, 克洋; 飯塚, 亮; 井上, 芳幸; 石田, 学; 石川, 久美; 岩井, 将親; 国分, 紀秀; 小山, 志勇; 前田, 良知; 満田, 和久; 中川, 貴雄; 尾崎, 正伸; 佐藤, 悟郎; 佐藤, 理江; Simionescu, Aurora; 菅原, 泰晴; 高橋, 忠幸; 竹井, 洋; 田村, 隆幸; 田中, 靖郎; 冨田, 洋; 辻本, 匡弘; 上田, 周太朗; 渡辺, 伸; 山崎, 典子）, Number of authors: Hitomi Collaboration 193 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Dotani, Tadayasu; Ebisawa, Ken; Hayashi, Katsuhiro; Iizuka, Ryo; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Iwai, Masachika; Kokubun, Motohide; Koyama, Shu; Maeda, Yoshitomo; Mitsuda, Kazuhisa; Nakagawa, Takao; Ozaki, Masanobu; Sato, Goro; Sato, Rie; Simionescu, Aurora; Sugawara, Yasuharu; Takahashi, Tadayuki; Takei, Yoh; Tamura, Takayuki; Tanaka, Yasuo; Tomida, Hiroshi; Tsujimoto, Masahiro; Ueda, Shutaro; Watanabe, Shin; Yamasaki, Noriko Y.), Masahiro; Ueda, Shutaro; Watanabe, Shin; Yamasaki, Noriko Y.), Accepted: 2017-12-06, 資料番号: SA1170341000

著者人数: Hitomi Collaboration 203名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 堂谷, 忠靖; 海老沢, 研; 萩野, 浩一; 林, 克洋; 飯塚, 亮; 井上, 芳幸; 石田, 学; 石川, 久美; 岩井, 将親; 国分, 紀秀; 小山, 志勇; 前田, 良知; 満田, 和久; 中川, 貴雄; 尾崎, 正伸; 佐藤, 悟郎; 佐藤, 理江; Simionescu, Aurora; 菅原, 泰晴; 高橋, 忠幸; 竹井, 洋; 田村, 隆幸; 冨田, 洋; 辻本, 匡弘; 上田, 周太朗; 渡辺, 伸; 山崎, 典子）, Number of authors: Hitomi Collaboration 203 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Dotani, Tadayasu; Ebisawa, Ken; Hagino, Kouichi; Hayashi, Katsuhiro; Iizuka, Ryo; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Iwai, Masachika; Kokubun, Motohide; Koyama, Shu; Maeda, Yoshitomo; Mitsuda, Kazuhisa; Nakagawa, Takao; Ozaki, Masanobu; Sato, Goro; Sato, Rie; Simionescu, Aurora; Sugawara, Yasuharu; Takahashi, Tadayuki; Takei, Yoh; Tamura, Takayuki; Tomida, Hiroshi; Tsujimoto, Masahiro; Ueda, Shutaro; Watanabe, Shin; Yamasaki, Noriko Y.), Masahiro; Ueda, Shutaro; Watanabe, Shin; Yamasaki, Noriko Y.), Accepted: 2017-07-27, 資料番号: SA1170340000

We analyse a long archival XMM-Newton observation of the narrow-line Seyfert 1 galaxy Ton S180, using the latest reflection models to explore the high quality X-ray spectrum. We find that the iron line is relatively narrow and sharp, and the soft excess is extremely smooth. We cannot find an acceptable reflection model that describes both components, and conclude that the soft excess cannot be produced by relativistic reflection. Fitting the 3-10 keV band with relativistic reflection to model the iron line strongly prefers low spin values (< 0.4), with the exact value depending on the model and not well constrained. We then model the broad- band spectrum with a two-component Comptonization continuum plus relativistic reflection. This gives a much better fit than a pure reflection model, which again prefers a low spin value. The photon index of the reflection component is intermediate between the two Comptoniza- tion components, suggesting that both illuminate the disk a similar amount and therefore both contribute to the reflection.

© 2017. The American Astronomical Society. All rights reserved. High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E ≈ 3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of S xvi (E ≃ 3.44 keV rest-frame) - a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment.

Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with $L_{IR}$ > 10$^{13}$ L$_\odot$. They are thought to be closer counterparts of the more distant sub-millimeter galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present deep $\textit{Chandra}$ observations of IRAS F15307+3252 (100 ks), a classical HyLIRG located at $z$=0.93 and hosting a radio-loud AGN ($L_{1.4 GHz}$ ~3.5 × 10$^{25}$ W Hz$^{−1}$). The $\textit{Chandra}$ images reveal the presence of extended ($r$ = 160 kpc), asymmetric X-ray emission in the soft 0.3–2.0 keV band that has no radio counterpart. We therefore argue that the emission is of thermal origin originating from a hot intragroup or intracluster medium virializing in the potential. We find that the temperature (~2 keV) and bolometric X-ray luminosity (~3 × 10$^{43}$ erg s$^{−1}$) of the gas follow the expected $L_{X-ray}$–$T$ correlation for groups and clusters, and that the gas has a remarkably short cooling time of 1.2 Gyr. In addition, VLA radio observations reveal that the galaxy hosts an unresolved compact steep-spectrum (CSS) source, most likely indicating the presence of a young radio source similar to 3C186. We also confirm that the nucleus is dominated by a redshifted 6.4 keV Fe K$\alpha$ line, strongly suggesting that the AGN is Compton-thick. Finally, $\textit{Hubble}$ images reveal an overdensity of galaxies and sub-structure in the galaxy that correlates with soft X-ray emission. This could be a snapshot view of on-going groupings expected in a growing cluster environment. IRAS F15307+3252 might therefore be a rare example of a group in the process of transforming into a cluster.

We report the detection of a 78.1 ± 0.5 day period in the X-ray light curve of the extreme ultraluminous X-ray source NGC 5907 ULX1 (L$_\text{X,peak}$ ~ 5 × 10$^{40}$ erg s$^{-1}$), discovered during an extensive monitoring program with $\textit{Swift}$. These periodic variations are strong, with the observed flux changing by a factor of ~3-4 between the peaks and the troughs of the cycle; our simulations suggest that the observed periodicity is detected comfortably in excess of 3$\sigma$ significance. We discuss possible origins for this X-ray period, but conclude that at the current time we cannot robustly distinguish between orbital and super-orbital variations., A.C.F. acknowledges support from ERC Advanced Grant 340442. The work of D.J.W./D.S. was performed at JPL/Caltech, under contract with NASA. D.B. and N.W. acknowledge financial support from the French Space Agency (CNES), M.J.M. acknowledges support from an Ernest Rutherford STFC fellowship, and T.P.R. acknowledges support from the STFC consolidated grant ST/L00075X/1. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester, and also made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. We acknowledge the use of public data from the Swift data archive. This research has also made use of a collection of ISIS functions (ISISscripts) provided by ECAP/Remeis observatory and MIT.

Chandra observations of 3C432, 3C191 and B2 0902+34 are presented as part of an ongoing search for inverse-Compton scattering of the cosmic microwave background (CMB) from high redshift radio sources (Schwartz, 2000). The energy density of the CMB increases with redshift, z, as (1 + Z)(4), so the relatively high redshift of these powerful radio galaxies makes them good candidates for detecting extended inverse-Compton scattering along the radio jet axis: we do indeed detect radio-aligned X-ray emission.

We present new Giant Metre-wave Radio Telescope (GMRT) observations of Hubble Deep Field (HDF)130, an inverse-Compton (IC) ghost of a giant radio source that is no longer being powered by jets. We compare the properties of HDF130 with the new and important constraint of the upper limit of the radio flux density at 240 MHz to an analytic model. We learn what values of physical parameters in the model for the dynamics and evolution of the radio luminosity and X-ray luminosity [due to IC scattering of the cosmic microwave background (CMB)] of a Fanaroff-Riley type II (FR II) source are able to describe a source with features (lobe length, axial ratio, X-ray luminosity, photon index and upper limit of radio luminosity) similar to those of the observations. HDF130 is found to agree with the interpretation that it is an IC ghost of a powerful double-lobed radio source, and we are observing it at least a few Myr after jet activity (which lasted 5-100 Myr) has ceased. The minimum Lorentz factor of injected particles into the lobes from the hotspot is preferred to be γ~ 103 for the model to describe the observed quantities well, assuming that the magnetic energy density, electron energy density and lobe pressure at time of injection into the lobe are linked by constant factors according to a minimum energy argument, so that the minimum Lorentz factor is constrained by the lobe pressure. We also apply the model to match the features of 6C0905+3955, a classical double FR II galaxy thought to have a low-energy cut-off of γ~ 104 in the hotspot due to a lack of hotspot IC X-ray emission. The models suggest that the low-energy cut-off in the hotspots of 6C0905+3955 is γ≳ 103, just slightly above the particles required for X-ray emission. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling - a process known as active galactic nucleus feedback. Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 ± 10 kilometres per second in the region 30-60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 ± 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure., Please visit the publisher's website for funding information.

We present an analysis of ionized X-ray disk winds observed in the Fe K band of four stellar-mass black holes observed with Chandra, including 4U 1630-47, GRO J1655-40, H 1743-322, and GRS 1915+105. High-resolution photoionization grids were generated in order to model the data. Third-order gratings spectra were used to resolve complex absorption profiles into atomic effects and multiple velocity components. The Fe XXV line is found to be shaped by contributions from the intercombination line (in absorption), and the Fe XXVI line is detected as a spin-orbit doublet. The data require 2-3 absorption zones, depending on the source. The fastest components have velocities approaching or exceeding 0.01c, increasing mass outflow rates and wind kinetic power by orders of magnitude over prior single-zone models. The first-order spectra require re-emission from the wind, broadened by a degree that is loosely consistent with Keplerian orbital velocities at the photoionization radius. This suggests that disk winds are rotating with the orbital velocity of the underlying disk, and provides a new means of estimating launching radii -- crucial to understanding wind driving mechanisms. Some aspects of the wind velocities and radii correspond well to the broad-line region (BLR) in active galactic nuclei, suggesting a physical connection. We discuss these results in terms of prevalent models for disk wind production and disk accretion itself, and implications for massive black holes in active galactic nuclei., Accepted for publication in ApJ

We report on partially overlapping XMM-Newton (similar to 260 ks) and Suzaku (similar to 100 ks) observations of the iron K band in the nearby, bright type 1 Seyfert galaxy Mrk 509. The source shows a resolved neutral Fe K line, most probably produced in the outer part of the accretion disc. Moreover, the source shows further emission bluewards of the 6.4 keV line due to ionized material. This emission is well reproduced by a broad line produced in the accretion disc, while it cannot be easily described by scattering or emission from photoionized gas at rest. The summed spectrum of all XMM-Newton observations shows the presence of a narrow absorption line at 7.3 keV produced by highly ionized outflowing material. A spectral variability study of the XMM-Newton data shows an indication for an excess of variability at 6.6-6.7 keV. These variations may be produced in the red wing of the broad ionized line or by variation of a further absorption structure. The Suzaku data indicate that the neutral Fe K alpha line intensity is consistent with being constant on long time-scales (of a few years), and they also confirm as most likely the interpretation of the excess blueshifted emission in terms of a broad ionized Fe line. The average Suzaku spectrum differs from the XMM-Newton one in the disappearance of the 7.3 keV absorption line and around 6.7 keV, where the XMM-Newton data alone suggested variability.

The X-ray quasi-periodic oscillation (QPO) at $\sim 2.6 \times 10^{-4}$ Hz in RE J1034+396 has been robustly observed in the 0.2-10 keV band of one $\sim 90$ ks XMM-Newton observation, but was not detected in subsequent observations. Here, we investigate the power spectral density (PSD) of 8 archival XMM-Newton observations of RE J1034+396, and search for the presence of QPOs in three energy bands: soft (0.3-0.8 keV); hard (1.0-4.0 keV) and total (0.2-10.0 keV). We find a significant detection of a QPO feature in the hard-band PSD of 5 low flux/spectrally-harder observations. The QPO frequency has remained persistent at $\sim 2.6 \times 10^{-4}$ Hz over $\sim 4$ years of observations, though it is no longer detected in the soft band, except in the original observation. This result increases the duration where the QPO is present by a factor of three (now $\sim 250$ ks), allowing for a better understanding of the QPO phenomenon observed in both Active Galactic Nuclei (AGN) and black hole X-ray binaries (BHBs).

XEUS is under study by ESA as part of the Horizon 2000+ program to utilize the International Space Station (ISS) for astronomical applications. XEUS will be a long-term X-ray observatory with an initial mirror area of 6 m2 at 1 keV that will be grown to 30 m2 following a visit to the ISS. The 1 keV spatial resolution is expected to be 2–5″ HEW. XEUS will consist of separate detector and mirror spacecraft aligned by active control to provide a focal length of 50 m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting sensitivity will then be ∼4×10−18 erg cm−2 s−1 around 250 times better than XMM. The properties of a 350 eV (rest-frame) equivalent width Fe line from a 1044 erg s−1 AGN will be measurable out to z=10, paving the way for detailed spectroscopic X-ray studies of some of the earliest known objects.XEUS is under study by ESA as part of the Horizon 2000+ program to utilize the International Space Station (ISS) for astronomical applications. XEUS will be a long-term X-ray observatory with an initial mirror area of 6 m2 at 1 keV that will be grown to 30 m2 following a visit to the ISS. The 1 keV spatial resolution is expected to be 2–5″ HEW. XEUS will consist of separate detector and mirror spacecraft aligned by active control to provide a focal length of 50 m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting sensitivity will then be ∼4×10−18 erg cm−2 s−1 around 250 times better than XMM. The properties of a 350 eV (rest-frame) equivalent width Fe line from a 1044 erg s−1 AGN will be measurable out to z=10, paving the way for detailed spectroscopic X-ray studies of some of the earliest known objects.

We present and discuss Chandra and XMM-Newton observations of the Seyfert 2 galaxy and Compton-thick absorbed source, Tololo 0109-383. The hard X-ray emission (i.e. above similar to2 keV), is dominated by a spatially unresolved reflection component, as already discovered by previous ASCA and BeppoSAX observations. The soft X-ray emission is partly (similar to15%) extended over about 1 kpc. Below 2 keV, the spectrum is very steep and two emission lines, probably due to recombination to He-like ions of oxygen and neon, are clearly present. Combining X-rays and optical information taken from the literature, we propose an overall scenario for the nuclear regions of this source.

We report on a dramatic flux (similar to 50% increase in the LECS and MECS band) and spectral variation between two BeppoSAX observations of the Circinus Galaxy performed almost three years apart. Through the analysis of all Chandra observations available in the archive, including a new DDT observation on May 2001, we show that a high flux state of an extremely variable Ultra Luminous X-ray source (CG X-1: Bauer et al. 2001), which is within the adopted BeppoSAX source extraction region of 20, is the most likely explanation for most of the observed variation. However, the presence of a high flux 6.7 keV line and the spectral variation of the PDS in the new BeppoSAX data could be partly due to intrinsic variation of the nucleus. Comparing the longest Chandra observation and the BeppoSAX one, we find that the long-term flux variability of CG X-1 is not accompanied by a significant spectral variability. We also re-analysed the Chandra HEG nuclear spectra and report on the presence of a Compton shoulder with a flux of about 20% the line core, in agreement with theoretical expectations for Compton-thick matter.

We report on the BeppoSAX detection of a hard X-ray excess in the X-ray spectrum of the classical high-ionization Seyfert 2 galaxy Tot 0109-383. The X-ray emission of this source observed below 7 keV is dominated by reflection from both cold and ionized gas, as seen in the ASCA data. The excess hard X-ray emission is presumably caused by the central source absorbed by an optically thick obscuring torus with N-H similar to 2 x 10(24) cm(-2). The strong cold X-ray reflection, if it is produced at the inner surface of the torus, is consistent with the picture where much of the inner nucleus of Tot 0109-383 is exposed to direct view, as indicated by optical and infrared properties. However, the X-ray absorption must occur at small radii in order to hide the central X-ray source but leave the optical high-ionization emission-line region unobscured. This may also be the case for objects such as the Seyfert 1 galaxy Mrk231.

We present new GMRT observations of HDF 130, an inverse-Compton (IC) ghost of a giant radio source that is no longer being powered by jets. We compare the properties of HDF 130 with the new and important constraint of the upper limit of the radio flux density at 240 MHz to an analytic model. We learn what values of physical parameters in the model for the dynamics and evolution of the radio luminosity and X-ray luminosity (due to IC scattering of the cosmic microwave background (CMB)) of a Fanaroff-Riley II (FR II) source are able to describe a source with features (lobe length, axial ratio, X-ray luminosity, photon index and upper limit of radio luminosity) similar to the observations. HDF 130 is found to agree with the interpretation that it is an IC ghost of a powerful double-lobed radio source, and we are observing it at least a few Myr after jet activity (which lasted 5--100 Myr) has ceased. The minimum Lorentz factor of injected particles into the lobes from the hotspot is preferred to be $\gamma\sim10^3$ for the model to describe the observed quantities well, assuming that the magnetic energy density, electron energy density, and lobe pressure at time of injection into the lobe are linked by constant factors according to a minimum energy argument, so that the minimum Lorentz factor is constrained by the lobe pressure. We also apply the model to match the features of 6C 0905+3955, a classical double FR II galaxy thought to have a low-energy cutoff of $\gamma\sim10^4$ in the hotspot due to a lack of hotspot inverse-Compton X-ray emission. The models suggest that the low-energy cutoff in the hotspots of 6C 0905+3955 is $\gamma\gtrsim 10^3$, just slightly above the particles required for X-ray emission., Comment: 9 pages, 3 figures

The Circinus Galaxy has been observed, for the first time above 10 keV, by BeppoSAX. An excess emission above the extrapolation of the best fit 0.1-10keV spectrum is apparent in the PDS data. The most likely explanation is that we are observing the nucleus through a column density of similar to 4 x 10(24) cm(-2), i.e. large enough to completely block the radiation below 10 keV but small enough to permit partial transmission above this energy.

The direct nuclear X-ray emission of the ultraluminous IRAS galaxy NGC 6240 has been observed by BeppoSAX. It is seen through an absorber with N-H similar to 2 x 10(24) cm(-2) The 2-10 keV X-ray luminosity of > 10(44) erg s(-1) definitely proves that a powerful AGN is hosted in this galaxy, despite the LINER optical appearance. Assuming the typical L-X/L-bol ratio for quasars, our result implies that it is the AGN and not the starburst that dominates the energy output of NGC 6240.

We discuss the iron K line complex in NGC 1068. The line complex basically consists of three components, as previously reported. A new analysis of the ASCA data shows that cold reflection appears to dominate the observed X-ray emission above 4 keV based on the detection of 'Compton shoulder', a weak red wing of the 6.4 keV fluorescence iron K line, and a very flat continuum. The other two weaker lines at higher energies can be identified with FeXXV and FeXXVI and suggest an highly ionized X-ray mirror as well, although the line energies are systematically lower than those expected from the resonant lines, consistent with a redshift by 1.5%.