454 research outputs found

    The Wide-Angle Outflow of the Lensed z = 1.51 AGN HS 0810+2554

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    We present results from X-ray observations of the gravitationally lensed z = 1.51 AGN HS 0810+2554 performed with the Chandra X-ray Observatory and XMM-Newton. Blueshifted absorption lines are detected in both observations at rest-frame energies ranging between ~1-12 keV at > 99% confidence. The inferred velocities of the outflowing components range between ~0.1c and ~0.4c. A strong emission line at ~6.8 keV accompanied by a significant absorption line at ~7.8 keV is also detected in the Chandra observation. The presence of these lines is a characteristic feature of a P-Cygni profile supporting the presence of an expanding outflowing highly ionized iron absorber in this quasar. Modeling of the P-Cygni profile constrains the covering factor of the wind to be > 0.6, assuming disk shielding. A disk-reflection component is detected in the XMM-Newton observation accompanied by blueshifted absorption lines. The XMM-Newton observation constrains the inclination angle to be < 45 degrees at 90% confidence, assuming the hard excess is due to blurred reflection from the accretion disk. The detection of an ultrafast and wide-angle wind in an AGN with intrinsic narrow absorption lines (NALs) would suggest that quasar winds may couple efficiently with the intergalactic medium and provide significant feedback if ubiquitous in all NAL and BAL quasars. We estimate the mass-outflow rate of the absorbers to lie in the range of 1.5 and 3.4 Msolar/yr for the two observations. We find the fraction of kinetic to electromagnetic luminosity released by HS 0810+2554 is large (epsilon = 9 (-6,+8)) suggesting that magnetic driving is likely a significant contributor to the acceleration of this outflow.Comment: 27 pages, 13 figures, Accepted for publication in Ap

    Direct Measurement of the X-ray Time-Delay Transfer Function in Active Galactic Nuclei

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    The origin of the observed time lags, in nearby active galactic nuclei (AGN), between hard and soft X-ray photons is investigated using new XMM-Newton data for the narrow-line Seyfert I galaxy Ark 564 and existing data for 1H0707-495 and NGC 4051. These AGN have highly variable X-ray light curves that contain frequent, high peaks of emission. The averaged light curve of the peaks is directly measured from the time series, and it is shown that (i) peaks occur at the same time, within the measurement uncertainties, at all X-ray energies, and (ii) there exists a substantial tail of excess emission at hard X-ray energies, which is delayed with respect to the time of the main peak, and is particularly prominent in Ark 564. Observation (i) rules out that the observed lags are caused by Comptonization time delays and disfavors a simple model of propagating fluctuations on the accretion disk. Observation (ii) is consistent with time lags caused by Compton-scattering reverberation from material a few thousand light-seconds from the primary X-ray source. The power spectral density and the frequency-dependent phase lags of the peak light curves are consistent with those of the full time series. There is evidence for non-stationarity in the Ark 564 time series in both the Fourier and peaks analyses. A sharp `negative' lag (variations at hard photon energies lead soft photon energies) observed in Ark 564 appears to be generated by the shape of the hard-band transfer function and does not arise from soft-band reflection of X-rays. These results reinforce the evidence for the existence of X-ray reverberation in type I AGN, which requires that these AGN are significantly affected by scattering from circumnuclear material a few tens or hundreds of gravitational radii in extent.Comment: Accepted for publication in Ap

    Ocular manifestations in Gorlin-Goltz syndrome

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    Background: Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients. Results: Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients. Conclusions: The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients

    The rest-frame UV-to-optical spectroscopy of APM 08279+5255 - BAL classification and black hole mass estimates

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    We present the analysis of the rest-frame optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z=3.911z = 3.911. The spectroscopic data are taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between C III] λ\lambda1910 and [O III] λλ\lambda\lambda4959,5007. We investigate the possible presence of multiple BALs by computing "balnicity" and absorption indexes (i.e. BI, BI0_0 and AI) for the transitions Si IV λ\lambda1400, C IV λ\lambda1549, Al III λ\lambda1860 and Mg II λ\lambda2800. No clear evidence for the presence of absorption features is found in addition to the already known, prominent BAL associated to C IV, which supports a high-ionization BAL classification for APM 08279+5255. We also study the properties of the [O III], Hβ\beta and Mg II emission lines. We find that [O III] is intrinsically weak (F[OIII]/FHβ≲0.04F_{\rm [OIII]}/F_{\rm H\beta} \lesssim 0.04), as it is typically found in luminous quasars with a strongly blueshifted C IV emission line (∼\sim2500 km s−1^{-1} for APM 08279+5255). We compute the single-epoch black hole mass based on Mg II and Hβ\beta broad emission lines, finding MBH=(2÷3)×1010μ−1M_{\rm BH} = (2 \div 3) \times 10^{10}\mu^{-1} M⊙_\odot, with the magnification factor μ\mu that can vary between 4 and 100 according to CO and rest-frame UV-to-mid-IR imaging respectively. Using a Mg II equivalent width (EW)-to-Eddington ratio relation, the EWMgII∼27_{\rm MgII} \sim 27 \AA\ measured for APM 08279+5255 translates into an Eddington ratio of ∼\sim0.4, which is more consistent with μ=4\mu=4. This magnification factor also provides a value of MBHM_{\rm BH} that is consistent with recent reverberation-mapping measurements derived from C IV and Si IV.Comment: 10 pages, 4 figures, 4 tables, accepted for publication in A&

    Grotta Romanelli (Southern Italy, Apulia). Legacies and issues in excavating a key site for the Pleistocene of the Mediterranean

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    Grotta Romanelli, located on the Adriatic coast of southern Apulia (Italy), is considered a key site for the Mediterranean Pleistocene for its archaeological and palaeontological contents. The site, discovered in 1874, was re-evaluated only in 1900, when P. E. Stasi realised that it contained the first evidence of the Palaeolithic in Italy. Starting in 1914, G. A. Blanc led a pioneering excavation campaign, for the first-time using scientific methods applied to systematic palaeontological and stratigraphical studies. Blanc proposed a stratigraphic framework for the cave. Different dating methods (C-14 and U/Th) were used to temporally constrain the deposits. The extensive studies of the cave and its contents were mostly published in journals with limited distribution and access, until the end of the 1970s, when the site became forgotten. In 2015, with the permission of the authorities, a new excavation campaign began, led by a team from Sapienza University of Rome in collaboration with IGAG CNR and other research institutions. The research team had to deal with the consequences of more than 40 years of inactivity in the field and the combined effect of erosion and legal, as well as illegal, excavations. In this paper, we provide a database of all the information published during the first 70 years of excavations and highlight the outstanding problems and contradictions between the chronological and geomorphological evidence, the features of the faunal assemblages and the limestone artefacts

    A Spectropolarimetric Test of the Structure of the Intrinsic Absorbers in the Quasar HS1603+3820

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    We report the results of a spectropolarimetric observation of the C IV mini-BAL in the quasar HS1603+3820. The observations were carried out with the FOCAS instrument on the Subaru telescope and yielded an extremely high polarization sensitivity of 0.1%, at a resolving power of 1500. HS1603+3820 has been the target of a high-resolution spectroscopic monitoring campaign for more than four years, aimed at studying its highly variable C IV mini-BAL profile. Using the monitoring observations, in an earlier paper we were able to narrow down the causes of the variability to the following two scenarios: (1) scattering material of variable optical depth redirecting photons around the absorber, and (2) a variable, highly-ionized screen between the continuum source and the absorber which modulates the UV continuum incident on the absorber. The observations presented here provide a crucial test of the scattering scenario and lead us to disfavor it because (a) the polarization level is very small (p~0.6%) throughout the spectrum, and (b) the polarization level does not increase across the mini-BAL trough. Thus, the variable screen scenario emerges as our favored explanation of the C IV mini-BAL variability. Our conclusion is bolstered by recent X-ray observations of nearby mini-BAL quasars, which show a rapidly variable soft X-ray continuum that appears to be the result of transmission through an ionized absorber of variable ionization parameter and optical depth.Comment: To appear in the Astrophysical Journal, vol. 719, August 201
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