XMM-Newton and NuSTAR joint observations of Mrk 915: a deep look into the X-ray properties

We report on the X-ray monitoring programme (covering slightly more than 11 days) carried out jointly by XMM-Newton and NuSTAR on the intermediate Seyfert galaxy Mrk 915. The light curves extracted in different energy ranges show a variation in intensity but not a significant change in spectral shape. The X-ray spectra reveal the presence of a two-phase warm absorber: a fully covering mildly ionized structure [log xi/(erg cm/s)~2.3, NH~1.3x10^21 cm-2] and a partial covering (~90 per cent) lower ionized one [log xi/(erg cm/s)~0.6, NH~2x10^22 cm-2]. A reflection component from distant matter is also present. Finally, a high-column density (NH~1.5x10^23 cm-2) distribution of neutral matter covering a small fraction of the central region is observed, almost constant, in all observations. Main driver of the variations observed between the datasets is a decrease in the intrinsic emission by a factor of ~1.5. Slight variations in the partial covering ionized absorber are detected, while the data are consistent with no variation of the total covering absorber. The most likely interpretation of the present data locates this complex absorber closer to the central source than the narrow line region, possibly in the broad line region, in the innermost part of the torus, or in between. The neutral obscurer may either be part of this same stratified structure or associated with the walls of the torus, grazed by (and partially intercepting) the line of sight.Comment: 14 pages, 10 figures, 4 tables. Accepted for publication in MNRA

Investigating the origin of X-ray variability through XMM-Newton and WISE data

An efficient diagnostic method to find local (z<0.1) Compton-thick AGN consists in selecting sources characterized by hard X-ray colors and low X-ray to mid-IR flux ratio (HR vs. F_{X}/F_{IR}). This has been done efficiently in the past using 2XMM and IRAS data (Severgnini et al. 2012). I will here summarize my master thesis work, in which I tested the stability of the method outlined above using the latest 3XMM and WISE data, and I investigated its potentialities in finding interesting spectrally variable (including changing-look) XMM-Newton sources

AGN Diagnostic Plot In The WISE And 3XMM Era: The Role Of Variability

An efficient diagnostic method to find local (z<0.1) Compton-thick AGN consists in selecting sources characterized by hard X- ray colors and low hard X-ray over mid-IR flux ratio. This has been done efficiently in the past using 2XMM and IRAS data (Severgnini et al. 2012). In this talk I will present my thesis work in which I tested this technique using the latest 3XMM and WISE data for the sample presented by Severgnini et al. I will also briefly discuss the X-ray spectral properties of all of those sources showing flux and/or spectral variability in the XMM-Newton observations

A possible sub-kiloparsec dual AGN buried behind the galaxy curtain

Although thousands of galaxy mergers are known, only a handful of sub-kiloparsec-scale supermassive black hole (SMBH) pairs have been confirmed so far, leaving a huge gap between the observed and predicted numbers of such objects. In this work, we present a detailed analysis of the Sloan Digital Sky Survey optical spectrum and of near-infrared (NIR) diffraction limited imaging of SDSS J1431+4358. This object is a local radio-quiet type 2 active galactic nucleus (AGN) previously selected as a double AGN candidate on the basis of the double-peaked [OIII] emission line. The NIR adaptive optics-assisted observations were obtained at the Large Binocular Telescope with the LUCI+FLAO camera. We found that most of the prominent optical emission lines are characterized by a double-peaked profile, mainly produced by AGN photoionization. Our spectroscopical analysis disfavors the hypothesis that the double-peaked emission lines in the source are the signatures of outflow kinematics, leaving open the possibility that we are detecting either the rotation of a single narrow-line region or the presence of two SMBHs orbiting around a common central potential. The latter scenario is further supported by the high-spatial resolution NIR imaging: After subtracting the dominant contribution of the stellar bulge component in the host galaxy, we detect two faint nuclear sources at r &lt; 0.5 kpc projected separation. Interestingly, the two sources have a position angle consistent with that defined by the two regions where the [OIII] double peaks most likely originate. Aside from the discovery of a promising sub-kiloparsec scale dual AGN, our analysis shows the importance of an appropriate host galaxy subtraction in order to achieve a reliable estimate of the incidence of dual AGNs at small projected separations

Unveiling Sub-Pc supermassive black hole binary candidates in active galactic nuclei

The elusive supermassive black hole binaries (SMBHBs) are thought to be the penultimate stage of galaxy mergers, preceding a final coalescence phase. SMBHBs are sources of continuous gravitational waves, possibly detectable by pulsar timing arrays; the identification of candidates could help in performing targeted gravitational wave searches. Due to SMBHBs\u2019 origin in the innermost parts of active galactic nuclei (AGN), X-rays are a promising tool for unveiling their presence, by means of either double Fe K\u3b1 emission lines or periodicity in their light curve. Here we report on a new method for selecting SMBHBs by means of the presence of a periodic signal in their Swift Burst Alert Telescope (BAT) 105 month light curves. Our technique is based on Fisher\u2019s exact g-test and takes into account the possible presence of colored noise. Among the 553 AGN selected for our investigation, only the Seyfert 1.5 galaxy Mrk 915 emerges as a candidate SMBHB; from subsequent analysis of its light curve we find a period P0 = 35 \ub1 2 months, and the null hypothesis is rejected at the 3.7\u3c3 confidence level. We also present a detailed analysis of the BAT light curve of the only previously X-ray-selected binary candidate source in the literature, the Seyfert 2 galaxy MCG+11-11-032. We find P0 = 26.3 \ub1 0.6 months, consistent with the one inferred from previously reported double Fe K\u3b1 emission lines

Swift data hint at a binary Super Massive Black Hole candidate at sub-parsec separation

Dual/binary Supermassive Black Hole (SMBH) systems are the inevitable consequence of the current Lambda Cold Dark Matter cosmological paradigm. In this context, we discuss here the properties of MCG+11-11-032, a local (z=0.0362) Seyfert 2 galaxy. This source was proposed as a dual AGN candidate on the basis of the presence of double-peaked [OIII] emission lines in its optical spectrum. MCG+11-11-032 is also an X-ray variable source and was observed several times by the Swift X-ray Telescope (XRT) on time scales from days to years. In this work, we analyze the SDSS-DR13 spectrum and find evidence for double-peaked profiles in all the strongest narrow emission lines. We also study the XRT light curve and unveil the presence of an alternating behavior of the intrinsic 0.3-10 keV flux, while the 123-month Swift BAT light curve supports the presence of almost regular peaks and dips almost every 25 months. In addition, the XRT spectrum suggests for the presence of two narrow emission lines with rest-frame energies of E~6.16 keV and E~6.56 keV. Although by considering only the optical emission lines, different physical mechanisms may be invoked to explain the kinematical properties, the X-ray results are most naturally explained by the presence of a binary SMBH in the center of this source. In particular, we evidence a remarkable agreement between the putative SMBH pair orbital velocity derived from the BAT light curve and the velocity offset derived by the rest-frame Delta_E between the two X-ray line peaks in the XRT spectrum (i.e. Delta_v~0.06c).Comment: 11 pages, 9 figures, 3 tables. Accepted for publication in MNRA

Dysplastic Ichthyosis Uteri-like changes of the entire endometrium associated with a squamous cell carcinoma of the uterine cervix

Ichthyosis uteri is an exceedingly rare condition in which the entire surface of the endometrium is replaced by stratified squamous epithelium. Originally described as an endometrial response to iatrogenically-introduced caustic substances, similar changes have since been described in association with a variety of inflammatory conditions of the endometrium. We describe herein a heretofore undescribed example of a moderately differentiated squamous cell carcinoma of the uterine cervix associated with extensive ichthyosis uteri-like changes of the entire adjacent endometrium. Additionally, the squamous epithelium of the latter also showed multifocal changes diagnostic of a low-grade squamous intraepithelial lesion. The potential genesis of this composite of findings is discussed, as is the neoplastic potential of ichthyosis uteri. It is concluded that a squamous cell carcinoma of the cervix extended proximally into the endometrium, and that there was a colonization of a pre-existing ichthyosis uteri by associated human papillomavirus. The possibility of significant cervical pathology should be considered when plaques of squamous epithelium with low grade dysplastic changes are identified in an endometrial biopsy or curettage

Adult granulosa cell tumor associated with endometrial carcinoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>If strict criteria for the diagnosis of carcinoma are used and all patients with granulosa cell tumors are considered, the best estimate of the incidence of associated endometrial carcinomas is under 5%. In patients with granulosa cell tumors, estrogen-dependent endometrial cancers are rarely found, and most of these endometrial cancers are well-differentiated endometrioid adenocarcinomas that carry a good prognosis when detected early.</p> <p>Case presentation</p> <p>We report the case of a 65-year-old post-menopausal Nigerian woman of the Igbo tribe with an adult granulosa cell tumor that was initially treated as endometrial carcinoma. She underwent a total abdominal hysterectomy and a bilateral salpingo-oophorectomy after histopathologic confirmation of a well-differentiated granulosa cell tumor of the ovary and a nuclear grade 1 adenocarcinoma of the endometrium (International Federation of Obstetricians and Gynecologists stage 1B). She had a good post-operative recovery and was discharged 10 days after treatment.</p> <p>Conclusion</p> <p>The association between adult granulosa cell tumors of the ovary and endometrial carcinomas is rare. A high index of suspicion as well as good imaging and histopathologic analyses are important in making this diagnosis.</p

Surgical site infection after caesarean section. Space for post-discharge surveillance improvements and reliable comparisons

Surgical site infections (SSI) after caesarean section (CS) represent a substantial health system concern. Surveying SSI has been associated with a reduction in SSI incidence. We report the findings of three (2008, 2011 and 2013) regional active SSI surveillances after CS in community hospital of the Latium region determining the incidence of SSI. Each CS was surveyed for SSI occurrence by trained staff up to 30 post-operative days, and association of SSI with relevant characteristics was assessed using binomial logistic regression. A total of 3,685 CS were included in the study. A complete 30 day post-operation follow-up was achieved in over 94% of procedures. Overall 145 SSI were observed (3.9% cumulative incidence) of which 131 (90.3%) were superficial and 14 (9.7%) complex (deep or organ/space) SSI; overall 129 SSI (of which 89.9% superficial) were diagnosed post-discharge. Only higher NNIS score was significantly associated with SSI occurrence in the regression analysis. Our work provides the first regional data on CS-associated SSI incidence, highlighting the need for a post-discharge surveillance which should assure 30 days post-operation to not miss data on complex SSI, as well as being less labour intensive