Complex Optical-X-ray Correlations in the Narrow-Line Seyfert 1 Galaxy NGC 4051

This paper presents the results of a dense and intensive X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051 carried out in 2000. Results of the optical analysis are consistent with previous measurements. The amplitude of optical emission line variability is a factor of two larger than that of the underlying optical continuum, but part or all of the difference can be due to host-galaxy starlight contamination or due to the lines being driven by the unseen UV continuum, which is more variable than the optical continuum. We measured the lag between optical lines and continuum and found a lower, more accurate broad line region size of 3.0+-1.5 light days in this object. The implied black hole mass is M_BH=5(+6,-3)x10^5 M_sun; this is the lowest mass found, so far, for an active nucleus. We find significant evidence for an X-ray-optical (XO) correlation with a peak lag of about <1 day, although the centroid of the asymmetric correlation function reveals that part of the optical flux varies in advance of the X-ray flux by 2.4+-1.0 days. This complex XO correlation is explained as a possible combination of X-ray reprocessing and perturbations propagating from the outer (optically emitting) parts of the accretion disc into its inner (X-ray emitting) region.Comment: 8 pages, 4 figures included, LaTeX mn.sty, accepted for publication in MNRA

Near Infrared Spectroscopy of High Redshift Active Galactic Nuclei. II. Disappearing Narrow Line Regions and the Role of Accretion

We present new near infrared spectroscopic measurements for 29 luminous high-z quasars and use the data to discuss the size and other properties of the NLRs in those sources. The high resolution spectra have been used to carefully model the Fe II blends and to provide reliable [O III], Fe II and Hb measurements. We find that about 2/3 of all high luminosity sources show strong [O III] lines while the remaining objects show no or very weak such line. While weak [O III] emitters are also found among lower luminosity AGN, we argue that the implications for very high luminosity objects are different. In particular, we suggest that the averaging of these two populations in other works gave rise to claims of a Baldwin relationship in [O III] which is not confirmed by our data. We also argue that earlier proposed relations of the type R_NLR \propto L_[O III]^{1/2}, where R_NLR is the NLR radius, are theoretically sound yet they must break down for R_NLR exceeding a few kpc. This suggests that the NLR properties in luminous sources are different from those observed in nearby AGN. In particular, we suggest that some sources lost their very large, dynamically unbound NLR while others are in a phase of violent star-forming events that produce a large quantity of high density gas in the central kpc. This gas is ionized and excited by the central radiation source and its spectroscopic properties may be different from those observed in nearby, lower luminosity NLRs. We also discuss the dependence of EW(Hb) and Fe II/Hb on L, M_BH, and accretion rate for a large sample of AGNs. The strongest dependence of the two quantities is on the accretion rate and the Fe II/Hb correlation is probably due to the EW(Hb) dependence on accretion rate. We show the most extreme values measured so far of Fe II/Hb and address its correlation with EW([O III]).Comment: 10 pages (emulateapj), 9 figures. Accepted by Ap

Locating Star-Forming Regions in Quasar Host Galaxies

We present a study of the morphology and intensity of star formation in the host galaxies of eight Palomar-Green quasars using observations with the Hubble Space Telescope. Our observations are motivated by recent evidence for a close relationship between black hole growth and the stellar mass evolution in its host galaxy. We use narrow-band [O II] $\lambda$3727, H$\beta$, [O III] $\lambda$5007 and Pa$\alpha$ images, taken with the WFPC2 and NICMOS instruments, to map the morphology of line-emitting regions, and, after extinction corrections, diagnose the excitation mechanism and infer star-formation rates. Significant challenges in this type of work are the separation of the quasar light from the stellar continuum and the quasar-excited gas from the star-forming regions. To this end, we present a novel technique for image decomposition and subtraction of quasar light. Our primary result is the detection of extended line-emitting regions with sizes ranging from 0.5 to 5 kpc and distributed symmetrically around the nucleus, powered primarily by star formation. We determine star-formation rates of order a few tens of M$_\odot$/yr. The host galaxies of our target quasars have stellar masses of order $10^{11}$ M$_\odot$ and specific star formation rates on a par with those of M82 and luminous infrared galaxies. As such they fall at the upper envelope or just above the star-formation mass sequence in the specific star formation vs stellar mass diagram. We see a clear trend of increasing star formation rate with quasar luminosity, reinforcing the link between the growth of the stellar mass of the host and the black hole mass found by other authors.Comment: Accepted for publication in M.N.R.A.

Vogt-Koyanagi-Harada syndrome - current perspectives

Vogt-Koyanagi-Harada syndrome is a cause of noninfectious panuveitis, leading to significant vision loss in many patients. It is an autoimmune disease occurring in genetically susceptible individuals and clinically presents as bilateral panuveitis with serous retinal detachments and hyperemic, swollen optic discs, which are associated with neurological and auditory manifestations. Early diagnosis and prompt and adequate treatment with immunosuppressive agents (corticosteroids and other immunosuppressive drugs) may halt disease progression and prevent recurrences and vision loss. This review summarizes the current knowledge on the variable clinical aspects of this disease, highlighting diagnostic and treatment strategies

State-Dependence Effects in Surveys

In recent years academic research has focused on understanding and modeling the survey response process. This paper examines an understudied systematic response tendency in surveys: the extent to which observed responses are subject to state dependence, i.e., response carryover from one item to another independent of specific item content. We develop a statistical model that simultaneously accounts for state dependence, item content, and scale usage heterogeneity. The paper explores how state dependence varies by response category, item characteristics, item sequence, respondent characteristics, and whether it becomes stronger as the survey progresses. Two empirical applications provide evidence of substantial and significant state dependence. We find that the degree of state dependence depends on item characteristics and item sequence, and it varies across individuals and countries. The article demonstrates that ignoring state dependence may affect reliability and predictive validity, and it provides recommendations for survey researchers

Predictors of Long-Term Visual Outcome in Intermediate Uveitis

PURPOSE: To describe factors that predict visual loss and complications in intermediate uveitis. DESIGN: Cross-sectional study. PARTICIPANTS: Subjects with intermediate uveitis were identified from a database of 1254 uveitis patients seen in the clinic of a single consultant (S.L.L.) between 2011 and 2013. S METHODS: Information was gathered from the clinical notes of all subjects examined in clinic. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), moderate visual loss (MVL; ≤20/50), severe visual loss (SVL; ≤20/200). RESULTS: Three hundred and five subjects (550 eyes) were included in the study, comprising 24.3% of subjects seen in clinic. Mean (± standard deviation) age at diagnosis was 40.9±16.9 years, and 64.6% of subjects were female. Median follow-up was 8.2 years (mean, 9.7 years, 5452 eye-years). Systemic diagnosis was made in 36.1% of patients, with sarcoidosis (22.6%) and multiple sclerosis (4.6%) the most frequent systemic associations. Median BCVA was 20/30 (mean logarithm of the minimum angle of resolution [logMAR] 0.26±0.38, n = 550 eyes) at presentation, 20/30 (mean logMAR 0.22±0.42, n = 430) at 5 years, and 20/30 (mean logMAR 0.23±0.46, n = 260) at 10 years. Macular edema was observed in 224 eyes (40.7%) and was associated with idiopathic disease (P = 0.001) and diabetes (P = 0.001). Topical therapy was used in 82.7%, and 34.2% received local injections of corticosteroids. A total of 50.5% required oral steroids and 13.8% required second-line immunosuppression. Subjects with a diagnosis of sarcoidosis were less likely to require a second-line agent (4.3% vs. 16.2%, P = 0.011). On multivariate analysis, visual acuity at referral, retinal pigment epithelial atrophy, and macular scarring were associated with increased risk of MVL; and visual acuity at referral, local therapy, macular scarring, retinal detachment, and hypotony and phthisis were associated with increased risk of SVL. CONCLUSIONS: Intermediate uveitis has a long disease course with frequent complications and often requires systemic treatment. Despite this, most subjects are still able to achieve good long-term visual outcomes

Rhizobium radiobacter Endophthalmitis following Intravitreal Ranibizumab Injection.

We present the first reported case of acute endophthalmitis due to Rhizobium radiobacter after an intravitreal injection of ranibizumab for neovascular age-related macular degeneration

Narrow Components within the Fe Kalpha Profile of NGC 3516: Evidence for the Importance of General Relativistic Effects?

We present results from a simultaneous Chandra HETG and XMM-Newton observation of NGC 3516. We find evidence for several narrow components of Fe Kalpha along with a broad line. We consider the possibility that the lines arise in an blob of material ejected from the nucleus with velocity ~0.25c. We also consider an origin in a neutral accretion disk, suffering enhanced illumination at 35 and 175 gravitational radii, perhaps due to magnetic reconnection. The presence of these narrow features indicates there is no Comptonizing region along the line-of-sight to the nucleus. This in turn is compelling support for the hypothesis that broad Fe Kalpha components are, in general, produced by strong gravity.Comment: 12 pages, 3 color figures. LaTeX with postscript figures. Resubmitted June 7 2002, to Astrophysical Journal Letter