bluuebunny/crossref_metadata_2025 huggingface dataset:
Is there an excess of significant findings in published studies of psychotherapy for depression?
Authors: Flint J. , Cuijpers P. , Horder J. , Koole S. L. , Munafò M. R.
Published: July 2014

Background

Many studies have examined the efficacy of psychotherapy for major depressive disorder (MDD) but publication bias against null results may exist in this literature. However, to date, the presence of an excess of significant findings in this literature has not been explicitly tested.

Method

We used a database of 1344 articles on the psychological treatment of depression, identified through systematic search in PubMed, PsycINFO, EMBASE and the Cochrane database of randomized trials. From these we identified 149 studies eligible for inclusion that provided 212 comparisons. We tested for an excess of significant findings using the method developed by Ioannidis and Trikalinos (2007), and compared the distribution of p values in this literature with the distribution in the antidepressant literature, where publication bias is known to be operating.

Results

The average statistical power to detect the effect size indicated by the meta-analysis was 49%. A total of 123 comparisons (58%) reported a statistically significant difference between treatment and control groups, but on the basis of the average power observed, we would only have expected 104 (i.e. 49%) to do so. There was therefore evidence of an excess of significance in this literature (p = 0.010). Similar results were obtained when these analyses were restricted to studies including a cognitive behavioural therapy (CBT) arm. Finally, the distribution of p values for psychotherapy studies resembled that for published antidepressant studies, where publication bias against null results has already been established.

Conclusions

The small average size of individual psychotherapy studies is only sufficient to detect large effects. Our results indicate an excess of significant findings relative to what would be expected, given the average statistical power of studies of psychotherapy for major depression.
The impact of the embryo quality on the risk of multiple pregnancies
Authors: Braga Daniela Paes de Almeida Ferreira , Setti Amanda S. , Figueira Rita de Cássia S. , Iaconelli Assumpto , Borges Edson
Published: July 2014

The aim of the present study was to determine the chance of pregnancy and the risk of multiple pregnancies taking into account the number and quality of transferred embryos in patients >36 years old or ≤36 years old. For this study, 1497 patients undergoing intra-cytoplasmic sperm injection (ICSI) cycles in a private assisted reproduction centre were split into groups according to the number and quality of the transferred embryos on the third or fifth day of development. The pregnancy rate and multiple pregnancy rate were compared between the embryo quality groups in patients <36 years old or ≥36 years old. In patients <36 years old, for the day 3 embryo transfer, no significant difference was noted in the pregnancy rate when the groups were compared. However the multiple pregnancy rate was increased by the transfer of an extra low-quality embryo (17.1 versus 28.2%, P = 0.020). For day 5 embryo transfer, the transfer of an extra blastocyst significantly increased the pregnancy rate (36.0 versus 42.4%, P < 0.001) and the multiple pregnancy rate (4.4 versus 16.9%, P < 0.001). In older patients, no significant difference was noted in the pregnancy rate when the groups were compared. However, when an extra low-quality embryo was transferred, a significantly increased rate of multiple pregnancies was observed for day 3 (18.2 versus 26.4%, P = 0.049) and day 5 embryo transfers (5.2 versus 16.1%, P < 0.001). In conclusion, the transfer of an extra low-quality embryo may increase the risk of a multiple pregnancy. In younger patients, the transfer of an extra low-quality blastocyst may also increase the chance of pregnancy.
ADULT LONGEVITY AND GROWTH TAKEOFF
Authors: Yasui Daishin
Published: July 2014

This paper develops an overlapping-generations model in which agents make educational and fertility decisions under life-cycle considerations and retirement from work is distinguished from death. Gains in adult longevity induce agents to decrease fertility, invest in education, and achieve higher income in order to save more for retirement. Even if working life is shortened by early retirement, this mechanism works as long as adult longevity increases sufficiently. Our model can explain the positive effect of life expectancy on education without contradicting the fact that working life length has not substantially increased, because of retirement. We also provide new insights into the interaction between fertility and retirement decisions.
DOUGLAS–RACHFORD FEASIBILITY METHODS FOR MATRIX COMPLETION PROBLEMS
Authors: ARAGÓN ARTACHO FRANCISCO J. , BORWEIN JONATHAN M. , TAM MATTHEW K.
Published: July 2014

In this paper, we give general recommendations for successful application of the Douglas–Rachford reflection method to convex and nonconvex real matrix completion problems. These guidelines are demonstrated by various illustrative examples.
WHITE TIME
Authors: Mills Charles W.
Published: July 2014

The racialization of space is the subject of a huge body of literature, most recently in George Lipsitz’s (2011)How Racism Takes Place. But less has been done on the ways in which time could be racialized. Inspired by provocative treatments of the subject in writings by Michael Hanchard (1999) and Lawrie Balfour (2011), I suggest in this paper that we need to explore the workings of a “White temporal imaginary” analogous to Lipsitz’s “White spatial imaginary,” which likewise serves to protect White racial privilege from the threatening encroachments of racial justice. Using Eviatar Zerubavel’s (2003)Time Mapsas a jumping-off point, I argue accordingly for the recognition of a “White time,” a “sociomental” representation of temporality shaped by the interests and experience of the White “mnemonic community.” The concept is obviously one of potentially very general usefulness, but in this essay I seek to apply it specifically to the dominant discourse on justice in political philosophy, as framed for the past forty years by John Rawls’ ([1971] 1999c) “ideal theory.” The relevance to the postracial theme of this issue is that, because of the peculiarity of philosophy as a discipline, it can claim it was always, or always-already, postracial, dealing as it ostensibly does with the (timeless) human condition as such. By making ideal theory—the normative theory of a perfectly just society—central to the conceptualization of social justice, by never exploring how radically different actual societies are from the ideal of society as “a cooperative venture for mutual advantage,” an exclusionary sociohistorical framework is established that makes the Euro-time of the West—abstracted out of the West’s relations of domination over people of color—the Greenwich Mean Time of normativity, while the alternative non-White temporality of structurally unjust societies requiring rectificatory racial justice remains a subject permanently untimely.
Markarian survey and Markarian galaxies
Authors: Mickaelian Areg M.
Published: July 2014

Markarian survey (or the First Byurakan Survey, FBS) was the first systematic survey for active galaxies and was a new method for search for such objects. Until now, it is the largest objective prism survey of the sky (17,000 deg2). It was carried out in 1965–1980 by B. E. Markarian and his colleagues and resulted in discovery of 1517 UV-excess (Markarian) galaxies. They contain many active galaxies, as well as powerful gamma-, X-ray, IR and radio sources (Mrk 180, 231, 421, 501, etc.), BCDGs (Mrk 116) and interacting/merging systems (Mrk 266, 273, etc.). They led to the classification of Seyfert galaxies into Sy1 and Sy2 and the definition of Starbursts (SB). Several catalogs of Markarian galaxies have been published (Mazzarella & Balzano 1986; Markarian et al. 1989; Bicay et al. 1995; Petrosian et al. 2007) and they are accessible in all corresponding databases. Markarian survey also served as a basis for search for UVX stellar objects (including QSOs and Seyferts), late-type stars and optical identification of IR sources. At present the survey is digitized and DFBS database is available. I will review the main characteristics of the Markarian survey, its comparison with other similar surveys and the importance of Markarian galaxies in modern astrophysics.
The discovery of eight z ~ 6 quasars from Pan-STARRS1
Authors: Bañados E. , Venemans B. P. , Morganson E. , Decarli R. , Walter F. , Chambers K. C. , Rix H-W. , Farina E. P. , Fan X. , Jiang L. , McGreer I. , De Rosa G. , Simcoe R. , Weiß A. , Price P. A. , Morgan J. S. , Burgett W. S. , Greiner J. , Kaiser N. , Kudritzki R.-P. , Magnier E. A. , Metcalfe N. , Stubbs C. W. , Sweeney W. , Tonry J. L. , Wainscoat R. J. , Waters C.
Published: July 2014

High-redshift quasars are unique probes of the evolution of supermassive black holes and the intergalactic medium at the end of the epoch of reionization. We present the optical spectra of eight new z ~ 6 quasars selected from the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). Details of the selection strategy can be found in Bañados et al. (2014). With this work we increase the number of known quasars at z < 5.7 by more than 10%. The quasars discovered here span a large range of luminosities (19.6 ≤ zP1 ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show weak or no Lyα emission line. We find a larger fraction of weak–line emission quasars than in lower redshift studies, although still based on low number statistics, this may imply that the quasar population could be more diverse than previously thought.
A Deep Narrow Band Imaging Search for CIVλ1548Å and HeIIλ1640Å Emission from Lyman Alpha Blobs
Authors: Arrigoni Battaia Fabrizio , Yang Y. , Hennawi J. F. , Matsuda Y. , Yamada T. , Hayashino T.
Published: July 2014

To study the nature of Lyα blobs (aka LABs), we conduct a deep C IV and He II narrowband imaging survey of 13 Lyα blobs located in SSA22 proto-cluster at z ~ 3.1. We reach the unprecedented sensitivity, 5σ surface brightness limit of 2.1 − 3.4 × 10−18 erg s−1 cm−2 arcsec−2 per 1 arcsec2 aperture for two emission lines. We do not detect any extended C IV and He II emission, placing strong upper limits on the He II/Lyα and C IV/Lyα line ratios. We compare our limits with data in the literature related to the nebulae associated with high-redshift radio galaxies (HzRGs) and quasars, and we recover the data by modeling the LABs as nebulosities powered by a central QSO. For further information see Arrigoni Battaia et al. (2014).
Complex Investigation of SBS Galaxies in Seven Selected Fields
Authors: Hakopian Susanna
Published: July 2014

It is known that the main criterion for the selection of active objects in the First Byurakan, otherwise Markarian survey was the presence of signs of UV-excess in their low-dispersion spectra. Using the presence of emission lines as the second criteria became real during the Second Byurakan survey because of its improved technique. Extended (not stellated) objects, selected with the use of this criterion, made the main part of the separate sample of SBS galaxies. Originally, this sample included 1286 objects, selected in 65 fields of the survey (16 square degree each), to which, with the help of other sources than the survey, there were later added some objects. We studied a subsample of SBS galaxies in seven selected fields (the deepest according to the V/Vmax criterion), including about the third of the whole sample. The first, already completed phase of this program was started with carrying out a follow-up slit spectroscopy of all, about 500 objects, based on observations with long-slit spectrographs with 6m telescope of SAO Russia and 2.6.m telescope of Byurakan. As a result redshifts were determined, as well as spectral classification was made for all of objects, using the scheme adapted to the spectral material. Besides other, obtained data allowed us to estimate the efficiency of used criteria for the selection of galaxies of different classes of starformation and nuclear activity along the full scale of the apparent magnitudes, including close to the limit values (18.5 < mpg < 19.5), etc. The fact that the total area of seven fields as the total number of objects in them comparable with these values for the survey as a whole, allows us to extrapolate the results to the whole sample of galaxies as an upper estimate. The second stage is to conduct detailed studies of individual galaxies in the first place, the most interesting in terms of morphology. They are based on panoramic spectroscopy obtained from observations at 6 m telescope of Russia and 2.6m telescope of Byurakan carried out with multipupil spectrographs MPFS and VAGR, correspondently. Processing of the data obtained for more than twenty objects are at different stages (see arXiv:1403.0127 for extended version).
Obscured AGN
Authors: Barger Amy
Published: July 2014

Obscured AGN may correspond to a substantial fraction of the supermassive black hole growth rate. I will present new surveys with the SCUBA-2 instrument on the James Clerk Maxwell Telescope of the Chandra Deep Fields and discuss whether we can distinguish obscured AGN in hard X-ray and radio selected samples using submillimeter observations.
AGN torus properties with WISE
Authors: Nikutta Robert , Nenkova Maia , Ivezić Željko , Hunt-Walker Nicholas , Elitzur Moshe
Published: July 2014

The Wide-field Infrared Survey Explorer (WISE) has scanned the entire sky with unprecedented sensitivity in four infrared bands, at 3.4, 4.6, 12, and 22 μm. The WISE Point Source Catalog contains more than 560 million objects, among them hundreds of thousands of galaxies with Active Nuclei (AGN). While type 1 AGN, owing to their bright and unobscured nature, are easy to detect and constitute a rather complete and unbiased sample, their type 2 counterparts, postulated by AGN unification, are not as straightforward to identify. Matching the WISE catalog with known QSOs in the Sloan Digital Sky Survey we confirm previous identification of the type 1 locus in the WISE color space. Using a very large database of the popular Clumpy torus models, we find the colors of the putative type 2 counterparts, and also, for the first time, predict their number vs. flux relation that can be expected to be observed in any given WISE color range. This will allow us to put statistically very significant constraints on the torus parameters. Our results are a successful test of the AGN unification scheme.
Dusty Active Galaxies
Authors: Andreasian-Thomas Nora
Published: July 2014

Most astronomers know about B. E. Markarians discovery and further study of galaxies with UV excess. It is less known that in 1963 Markarian drew attention to a small group of galaxies with color index-spectral type discrepancy. Early spectral type of these galaxies is combined with large color index (e.g. M82). Later studies showed that galaxies with large intrinsic color indices (CI ≥ 0.85) exhibit properties typical for active galaxies - galaxies with “red excess” are as active as galaxies with UV excess.
A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs with AKARI
Authors: Castro A. , Miyaji T. , Shirahata M. , Oyabu S. , Clark D. , Ichikawa K. , Imanishi M. , Nakagawa T. , Ueda Y.
Published: July 2014

We explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L14-195keV versus log L3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L14-195keV/MBH) versus log (L3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.
Analysis and Statistics of the Spectroscopic Sample of Byurakan-IRAS Galaxies
Authors: Harutyunyan Gohar S. , Mickaelian Areg M.
Published: July 2014

A summary and general analysis of optical spectroscopic data for 255 Byurakan-IRAS Galaxies (BIG) obtained with BAO 2.6m, SAO 6m, OHP 1.93m telescopes, as well as SDSS DR7, DR8, and DR9 is given. The BIG sample is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra. Among the 1178 objects most are spiral galaxies and there is a number of ULIRGs. All but one have emission lines; we have discovered 68 AGN and composite spectrum objects among them and the others are mostly Starburst Galaxies (SB). All possible physical characteristics have been measured and/or calculated, including physical sizes and optical and IR/FIR luminosities. The masses have been estimated based on mass-luminosity relations for spiral galaxies. As it appears, most of these objects are giant massive galaxies. Various multiwavelength (MW) data have been retrieved from recent catalogues from X-ray to radio and MW SEDs have been built, which have been matched to their optical classifications. Luminosity evolution of these objects has been studies.
Very Long Baseline Interferometry observations: the closest look at the cores of AGN
Authors: Giroletti Marcello , Lico Rocco , Hada Kazuhiro , Giovannini Gabriele
Published: July 2014

Very Long Baseline Interferometry (VLBI) provides the highest angular resolution achievable in astronomy, reaching sub-milliarcsecond scales. For radio loud AGNs, this offers the unique opportunity to directly image and monitor the fine details of the jet structure, approaching the event horizon in the nearest and most supermassive black holes, like in M87. After a quick review of various VLBI facilities, we present results from recent VLBI monitoring projects on two remarkable radio and high energy sources: the radio galaxy M87 and the BL Lac object Mrk421. For the latter, we present a detailed analysis of the jet structure in total intensity and polarization through the whole 2011, during which a multi-wavelength campaign took place. We reveal flux density variability but no significant changes in the jet structure. In M87, we detect and follow the evolution of the core and of the jet feature HST-1; we reveal superluminal motion of components within HST-1, with a possible connection between ejection of new such components and the occurrence of very high energy flares. Estimates on the physical parameters for both sources are given (Doppler factor, viewing angle, magnetic field, etc.).
Unveiling the nature of the unidentified gamma-ray sources: blazar counterparts at low radio frequencies
Authors: Massaro Francesco , D'Abrusco R. , Giroletti M. , Paggi A. , Masetti N. , Tosti G.
Published: July 2014

About one third of the gamma-ray sources detected by Fermi have still no firmly established counterpart at lower energies. Here we propose a new approach to find candidate counterparts for the unidentified gamma-ray sources (UGSs) based on the 325 MHz radio survey performed with Westerbork Synthesis Radio Telescope (WSRT) in the northern hemisphere. First we investigate the low-frequency radio properties of blazars, the largest known population of gamma-ray sources; then we search for sources with similar radio properties combining the information derived from the Westerbork Northern Sky Survey (WENSS) with those of the NRAO VLA Sky survey (NVSS). We present a list of candidate counterparts for 32 UGSs with at least one counterpart in the WENSS. We also performed an extensive research in literature to look for infrared and optical counterparts of the gamma-ray blazar candidates selected with the low-frequency radio observations to confirm their nature. On the basis of our multifrequency research we identify 23 new gamma-ray blazar candidates out of 32 UGSs investigated. I will also present the first analysis of very low frequency radio emission of blazars based on the recent Very Large Array Low-Frequency Sky Survey (VLSS) at 74 MHz. I show that blazars present radio flat spectra when evaluated at 74 MHz, about an order of magnitude in frequency lower than previous analyses. The implications of these findings in the contest of the blazars – radio galaxies connection will be discussed.
Independent estimates of energies of steep-spectrum radio sources
Authors: Miroshnichenko Alla
Published: July 2014

We examine properties of galaxies and quasars with steep low-frequency spectra from the UTR-2 catalogue. The number of the objects have the non-thermal X-ray emission due to the inverse Compton scattering of radio photons of the microwave background by relativistic electrons. So, it is possible to estimate the magnetic field strength and the ratio of energies of the magnetic field and relativistic particles, independently. As we have received the determined values of magnetic field strength are near to one order less than those at the well-known energy equipartition condition. We conclude from the obtained energy ratio that the energy of relativistic particles prevails over the energy of magnetic field in the galaxies and quasars with steep radio spectra.
Investigation of Extragalactic Radio Sources by Cross-Matching of Radio Catalogs
Authors: Abrahamyan Hayk V. , Mickaelian Areg M.
Published: July 2014

To search for variable radio sources, we used two well-known radio catalogs NVSS and FIRST, both providing fluxes at 1400 MHz. Cross-correlation enabled us to find 556,282 radio sources present in both catalogs. Using the 3σ criteria we distinguished 6,301 variable radio sources, and with certain limitations specified the 260 strongest radio variables. We cross-correlated these 260 sources with other catalogs at different wavelengths (APM, SDSS DR10, VCV-13, BZCAT, 2MASS, and WISE). As a result we obtained photometric data for optical, NIR, MIR and radio ranges for these 260 variable radio sources to study them in details.
The Lockman Hole Project: A Multi-frequency Study of the Faint Radio Population down to LOFAR bands
Authors: Guglielmino G. , Prandoni I. , Morganti R. , Heald G. , Mahony E. , van Bemmel I.
Published: July 2014

We are performing a multi-frequency radio analysis of a well-known deep field: the Lockman Hole, which is one of the best studied sky regions in different wavebands. This will provide us with important complementary data (for example redshifts) to the radio data, allowing us to characterize the physical and evolutionary properties of the various classes of sources composing the faint radio population. LOFAR imaging of the Lockman Hole can play an important role in this project, allowing, for the very first time, to observe the sub-mJy source population at very low frequencies (30-200 MHz), where self-absorption phenomena are expected to be very important. Here we present some preliminary results.
The MASIV survey: spectroscopic identifications of compact radio sources
Authors: Pursimo T. , Ojha R. , Jauncey D. , Lovell J. , Dutka M. , Bignall H. , Macquart J.-P. , Rickett B. , Kedziora-Chudczer L. , Koay J. Y.
Published: July 2014

Interstellar scintillation (ISS) has been shown to be primarily responsible for the short term intraday variability (IDV) exhibited by extragalactic sources at centimeter wavelengths (e.g. Bignall et al. 2006 and references therein). For a source to scintillate its angular size must be comparable to that of the first Fresnel zone (Narayan 1992) which implies microarcsecond angular sizes for screen distances of tens to hundreds of parsecs. This has the potential to probe within a few light months of the central black hole (Bignall et al. 2006). The aim of the Microarcsecond Scintillation-Induced Variability (MASIV) survey was to provide a catalogue of at least a hundred AGNs that vary on timescales of hours to days to provide the basis of detailed studies of the IDV population drawn from a well-defined sample.
Compton Thick AGN
Authors: Levenson N. A.
Published: July 2014

Compton thick active galactic nuclei (AGN), which are obscured by column density NH > 1.5 × 104 cm−2, can be difficult to identify. They are certainly cosmically significant, both in producing the observed cosmic X-ray background, and in providing a location where black hole growth is hidden from view. Here I review some recent results from surveys that provide indications of Compton thick AGN, considering X-ray, radio, and infrared selection techniques. I also offer a caution against using mid-infrared silicate features to measure line-of-sight obscuration to active galactic nuclei. Instead, these features better indicate the geometric distribution of dust that the central engine heats. I conclude that the outstanding problem of Compton thick AGN is not the cases where the obscuration is directly associated with the environment of the active nucleus itself, even in the most obscured examples. Instead, we still risk missing the completely buried AGN, which are obscured by large amounts of gas and dust over large solid angles. The solution to finding Compton thick AGN may be to begin the search based on infrared emission and star formation, and then select for nuclear activity.
Very High Energy gamma-rays from blazars
Authors: Sol Helene
Published: July 2014

The extragalactic very high energy (VHE) gamma-ray sky is dominated at the moment by more than fifty blazars detected by the present imaging atmospheric Cherenkov telescopes (IACT), with a majority (about 90%) of high-frequency peaked BL Lac objects (HBL) and a small number of low-frequency peaked and intermediate BL Lac objects (LBL and IBL) and flat spectrum radio quasars (FSRQ). A significant variability is often observed, with time scales from a few minutes to months and years. The spectral energy distribution (SED) of these blazars typically shows two bumps from the radio to the TeV range, which can usually be described by leptonic or hadronic processes. While elementary bricks of the VHE emission scenarios seem now reasonably well identified, a global picture of these sources, describing the geometry and dynamics of the VHE zone, is not yet available. Multiwavelength monitoring and global alert network will be important to better constrain the picture, especially with the perspective of CTA, a major project of the next generation in ground-based gamma-ray astronomy.
Cosmological Evolution of X-ray Selected AGNs and Synthesis of the X-ray Background
Authors: Ueda Yoshihiro , Akiyama Masayuki , Hasinger Günther , Miyaji Takamitsu , Watson Michael G.
Published: July 2014

X-ray surveys provide us with one of the least biased samples of Active Galactic Nuclei (AGNs) against obscuration. Here we present the most up-to-date AGN X-ray luminosity function (XLF) and absorption function over the redshift range from 0 to 5, using the largest, highly complete sample ever available obtained from surveys of various depth, depth, and energy bands. We utilize a maximum likelihood method to reproduce the count-rate versus redshift distribution for each survey, by taking into account the evolution of the absorbed fraction, contribution from Compton-thick AGNs, and AGN broad band X-ray spectra including reflection components from tori based on the luminosity and redshift dependent unified scheme. We find that the shape of the XLF at z ~ 1–3 is significantly different from that in the local universe, for which the luminosity dependent density evolution (LDDE) model gives the best description. These results establish the standard population synthesis model of the X-Ray Background (XRB), which well reproduces the source counts in both soft and hard bands, the observed fractions of Compton-thick AGNs, and the spectrum of the XRB.
Gamma-ray emitting narrow-line Seyfert 1 galaxies. New discoveries and open questions
Authors: D'Ammando F. , Orienti M. , Finke J. , Larsson J. , Giroletti M.
Published: July 2014

The discovery of γ-ray emission from 5 radio-loud narrow-line Seyfert 1 galaxies revealed the presence of a possible emerging third class of AGNs with relativistic jets, in addition to blazars and radio galaxies. The existence of relativistic jets also in this subclass of Seyfert galaxies opened an unexplored research space for our knowledge of the radio-loud AGNs. Here, we discuss the radio-to-γ-rays properties of the γ-ray emitting narrow-line Seyfert 1 galaxies, also in comparison with the blazar scenario.
Compton thick AGN in Chandra sureys
Authors: Brightman Murray , Nandra Kirpal
Published: July 2014

We present the results from the X-ray spectral analysis of active galactic nuclei (AGN) in the Chandra Deep Field-South, AEGIS-XD and Chandra-COSMOS surveys, focussing on the identification and characterisation of the most heavily obscured, Compton thick (CT, NH > 104 cm−2) sources. Our sample is comprised of 3088 X-ray selected sources, which has a high rate of redshift completeness (97%). The aim is to produce the largest and cleanest uniform sample of these sources from the data as possible. We identify these sources through X-ray spectral fitting, utilising torus spectral models designed for heavily obscured AGN which self consistently include the spectral signatures of heavy absorption, being Compton scattering, photoelectric absorption and iron Kα fluorescence. We identify a total of 163 CT AGN covering an intrinsic 2-10 keV X-ray luminosity range of 102 −3 × 105 erg s−1 and from z = 0.1-7.
Study of a homogeneous X-ray selected AGN sample
Authors: Paronyan Gurgen M. , Mickaelian Areg M. , Abrahamyan Hayk V.
Published: July 2014

Based on optical identifications of ROSAT sources, we have created a large homogeneous catalog of X-ray selected AGN. The Hamburg-RASS Catalog (HRC) and Byurakan-Hamburg-RASS Catalog (BHRC) made up on the basis of optical identification of X-ray sources from ROSAT Bright Source (BSC) and Faint Source (FSC) catalogues, respectively, have been used. These identiifcations were based on low-dispersion spectra of Hamburg Quasar Survey (HQS). As a result, a new large sample of X-ray selected AGN has been compiled containing 4253 sources with photon count rate CR > 0.04 ct/s in the area with galactic latitudes |b|>20 and declinations δ>0. All these sources are classified as AGN or candidate AGN. We have carried out multiwavelength studies in several wavelength ranges (X-ray, optical, radio). Catalogues that more or less guarantee the completeness condition (all-sky or large area surveys) were used. A number of erroneous classifications were found (some AGN had been classified as stars or galaxies); 1024 and 59 from HRC and BHRC, respectively. Out of 4253 sources, 3352 are spectroscopically confirmed AGN (given in Veron-Cetty & Veron and Roma Blazar catalogs), and the rest 901 are candidate AGN. For 210 of them spectra are available in SDSS DR9, and the results of their classification are given in another paper. We calculated absolute magnitudes, fluxes, improved coordinates and redshifts. An attempt is made to find a connection between the radiation fluxes in different bands for different types of sources, and identify their typical characteristics, thus confirming candidate AGN and in some cases finding new ones.
Luminosity Correlations, Luminosity Evolutions, and Radio Loudness of AGNs from Multiwavelength Observations
Authors: Petrosian Vahe , Singal Jack , Stawarz Lukasz
Published: July 2014

The dichotomy of jet dominated versus accretion disk dominated AGNs or “radio-loud” vs “radio-quiet” quasars can be investigated by a simultaneous determination of the relative shape and evolution of the radio and optical luminosity functions, and the distribution of the radio loudness R defined as the ratio of radio to optical luminosities. This can be done from a multivariate data set containing observed fluxes, redshift, spectra, etc. We emphasize that when dealing with a multivariate data set it is imperative to first determine the true correlations, not those introduced by the observational selection effects, among the variables (e.g. Luminosity-luminosity, redshift-luminosity) before obtaining the individual distributions of the variables (e.g. Luminosity functions and density evolution). We use data from several sources including the SDSS (Data Release 7) and FIRST radio catalogs, with well defined optical and radio flux limits, and employ the non-parametric methods developed by Efron and Petrosian, designed to obtain unbiased correlations, distributions and evolution with redshift from data truncated due to observational biases. We determine the density and the luminosity evolutions in both wavebands, which shows significantly higher radio than optical luminosity evolution. From these we obtain true distribution of the radio loudness parameter which shows no sign of bi-modality and indicates that quasars were more radio loud at earlier epochs.
ALMA: HI and He+ Lines and Dust in Starbursts, AGN and High-z Galaxies
Authors: Scoville Nick
Published: July 2014

We describe preliminary results for two ALMA projects – 1) imaging the HCN(4-3) line and H26α lines in Arp 220 and 2) measurements of the dust continuum in a sample of 107 high redshift galaxies to probe the evolution of the ISM masses. The HCN observations in Arp 220 at 1/2″ resolution provide the first high resolution imaging of the dense star forming gas in this prototypical ULIRG. The HCN is seen in two clearly delineated, counter-rotating disks. The H26α line is a definitive probe of the star formation rate in Arp 220, avoiding obscuration by dust and contamination by AGN luminosity contributions. In the second project, the remarkable continuum sensitivity of ALMA in Band 7 is used to measure the long wavelength Rayleigh-Jeans tail of the dust emission from a sample of 120 galaxies in COSMOS at z = 0.3 to 2.2, providing estimates for the dust masses and hence their ISM masses. This technique will enable measurements for hundreds of galaxies at high-z with observations of typically ~10 min per galaxy. This is in contrast to CO line imaging which typically requires a few hours per galaxy even with the sensitivity of ALMA. The dust-based mass estimates also avoid the uncertainties associated with the CO-to-H2 conversion factor.
Effectiveness of WISE colour-based selection techniques to uncover obscured AGN
Authors: Mateos S.
Published: July 2014

We present a highly reliable and efficient mid-infrared colour-based selection technique for luminous active galactic nuclei (AGN) using the Wide-field Infrared Survey Explorer (WISE) survey. Our technique is designed to identify objects with red mid-infrared power-law spectral energy distributions. We studied the dependency of our mid-infrared selection on the AGN intrinsic luminosity and the effectiveness of our technique to uncover obscured AGN missed in X-ray surveys. To do so we used two samples of luminous AGN independently selected in hard X-ray and optical surveys. We used the largest catalogue of 887 [OIII] λ5007-selected type 2 quasars (QSO2s) at z≲0.83 in the literature from the Sloan Digital Sky Survey (SDSS), and the 258 hard (>4.5 keV) X-ray-selected AGN from the Bright Ultrahard XMM-Newton Survey (BUXS). The effectiveness of our mid-infrared selection technique increases with the AGN luminosity. At high luminosities and at least up to z~1 our technique is very effective at identifying both Compton-thin and Compton-thick AGN.
Identifying Distant AGNs
Authors: Trouille Laura , Barger Amy , Tremonti Christy
Published: July 2014

The Baldwin, Phillips, and Terlevich emission-line ratio diagnostic ([OIII]/Hβ versus [NII]/Hα, hereafter BPT diagram) efficiently separates galaxies whose signal is dominated by star formation (BPT-SF) from those dominated by AGN activity (BPT-AGN). Yet the BPT diagram is limited to z<0.5, the redshift at which [NII]λ6584 leaves the optical spectral window. Using the Sloan Digital Sky Survey (SDSS), we construct a new diagnostic, or TBT diagram, that is based on rest-frame g−z color, [NeIII]λ3869, and [OII]λλ3726+3729 and can be used for galaxies out to z<1.4. The TBT diagram identifies 98.7% of the SDSS BPT-AGN as TBT-AGN and 97% of the SDSS BPT-SF as TBT-SF. Furthermore, it identifies 97% of the OPTX Chandra X-ray selected AGNs as TBT-AGN. This is in contrast to the BPT diagram, which misidentifies 20% of X-ray selected AGNs as BPT-SF.
Wide-field observations in the SDSS Stripe 82 with the European VLBI Network
Authors: Cao H.-M. , Gurvits L. I. , Yang J. , Hong X.-Y. , Frey S. , Paragi Z. , Deller A. T. , Ivezić Ž.
Published: July 2014

We observed an area of sky located within the SDSS Stripe 82 field at 1.6 GHz with the European VLBI Network (EVN). There are fifteen mJy/sub-mJy radio sources within the primary beam of a typical 30-m class EVN radio telescope. Our aim was to obtain information on compact radio structures of all VLBI-detectable sources within this primary beam area. The source of particular interest is the recently identified radio quasar J222843.54+011032.2 (J2228+0110) at z = 5.95. The data correlation was performed at the EVN software correlator at JIVE (SFXC). Three targets (J2228+0110, J222851.45+011203.4, J222941.76+011428.5) were detected, all three with position offsets not exceeding the 3σ accuracy of the original low-resolution radio surveys. The detection rate of 20% is consistent with other wide-field VLBI experiments carried out recently (e.g. Middelberg et al. 2013). The project presented here demonstrates the ability of EVN in multiple-phase-centre experiments and paves the way for future large-scale EVN surveys of compact structures in extragalactic radio sources using the multiple-phase-centre VLBI technique.
An Updated Multi-Wavelength Radio and Optical Catalog of Quasars and Radio Galaxies
Authors: Kimball Amy E. , Ivezić Željko
Published: July 2014

We present a catalog of millions of radio sources, created by consolidating large-area radio and optical surveys GB6 (6cm), FIRST (20cm), NVSS (20cm), WENSS (92cm), VLSS (4m), and SDSS DR9 (optical). The region where all surveys overlap covers 3269 deg2 in the North Galactic Cap, and contains >160,000 20-cm sources, with about 12,000 detected in all five radio surveys and over one-third detected optically. Combining parameters from the sky surveys allows easy and efficient classification by radio and optical morphology and radio spectral index. The catalog is available at http://www.atnf.csiro.au/people/Amy.Kimball/radiocat.shtml.
The Chandra 3C Snapshot Surveys
Authors: Harris Daniel E. , Massaro Francesco
Published: July 2014

The Chandra X-ray Observatory is the only X-ray facility with sub arcsec resolution, permitting detailed studies of radio galaxies and quasars. We review a short list of projects contributing to our goal of obtaining Chandra observations of all 3C extragalactic sources. Radio source samples, unlike most surveys at other wavelengths, should be completely unbiased with respect to viewing angle: the radio lobes are sign posts indicating the location of AGN (obscured or unobscured nuclei). The X-ray data allow us to estimate excess absorption towards nuclei, to find new examples of X-ray emission from jet knots and hotspots, and to isolate sources in clusters of galaxies together with signatures of feedback (e.g. cavities in the ICM). This work is supported by NASA grants GO1-12125A and GO2-13115X.
A wide search of obscured Active Galactic Nuclei using XMM-Newton and WISE
Authors: Rovilos E. , Georgantopoulos I. , Akylas A. , Aird J. , Alexander D. M. , Comastri A. , Del Moro A. , Gandhi P. , Georgakakis A. , Harrison C. M. , Mullaney J. R.
Published: July 2014

We use the WISE all sky survey observations to look for counterparts of hard X-ray selected sources from the XMM-Newton-SDSS survey. We then measure the 12 μm luminosity of the AGN by decomposing their optical to infrared SEDs with a host and an AGN component and compare it to the X-ray luminosity and their expected intrinsic relation. This way we select 20 X-ray under-luminous heavily obscured candidates and examine their X-ray and optical properties in more detail. We find evidence for a Compton-thick nucleus for six sources, a number lower than what expected from X-ray background synthesis models, which shows the limitations of our method.
Imminent understanding of the structure of nearby AGN from IFUs
Authors: Davies Richard
Published: July 2014

Integral field spectroscopy provides us with immensely rich datasets about spatially resolved distributions and kinematics of emission and absorption lines. In this contribution I will describe some of the key insights that have been made about AGN using optical, near infrared, and far infrared IFUs. These encompass gas inflow and outflow mechanisms, and the relations between star formation, the torus, and accretion onto the black hole. Progress so far has largely relied on archetypal and small sets of objects. In the future, a more statistically robust approach will be required. I will end by discussing a number of issues that can easily confuse an emerging picture, and need to be borne in mind for such surveys.
FLASHLIGHT: Fluorescent Lyman-Alpha Survey of cosmic Hydrogen iLlumInated by hIGH-redshifT quasars.
Authors: Battaia Fabrizio Arrigoni , Hennawi J. F. , Cantalupo S. , Prochaska J. X.
Published: July 2014

The current galaxy formation paradigm postulates that a significant amount of gas accretes onto galaxies from the IGM in a cold T ~ 104K phase, and many have argued that this gas should be detectable in diffuse Lyα emission. However, so far, there are no convincing direct detections.

We are conducting a deep (down to 1σ ~ 5 − 10 × 10−19 erg s−1 cm−2 arcsec−2) and the first statistical survey matching the Lyα line around radio-quiet quasars at z ~ 2. By taking advantage of the boost in fluorescent Lyα emission due to the ionizing radiation emitted by a luminous QSO that, like a flashlight, can illuminate the hydrogen in its vicinity, we will be able to constrain some of the properties of the gas sorrounding z ~ 2 QSOs. In particular, with this unique dataset, we can conduct the first deep statistical census of the size, morphology, luminosity, frequency, and covering factor of Lyα emission around QSOs.
AGN with faint broad line regions: Some ‘True’-Seyfert 2s might be Narrow Line Seyfert 1s
Authors: Valencia-S. Mónica , Busch G. , Smajić S. , Fazeli N. , Behroozian S. , Zuther J. , Fischer S. , Eckart A.
Published: July 2014

The intriguing existence of ‘True’-Seyfert 2s has opened a debate on the validity of the unified model of active galactic nuclei (AGN). These objects, also called ‘Naked’-AGN, seem to lack a broad line region. In some cases, their X-ray emission is unabsorbed, typical of Seyfert 1 galaxies, indicating a clear view toward the nucleus, but no broad lines are seen in the optical. In ‘True’-Seyfert 2s with higher column densities, observations of polarized light have failed to reveal the hidden broad emission. We performed high-resolution near-infrared integral-field observations of two ‘True’-Seyfert 2 candidates: IRAS 01072+4954 and NGC 7496. We found that the AGN in these sources might power very faint and narrow broad emission lines (FWHMbroad < 1500km s−1). Here, we discuss the properties of the broad components estimated from published X-ray and/or optical measurements and present their near-infrared candidate identification. Both galaxies host intermediate-mass black holes, with masses ~ 105−106 M⊙. Our results favor the unified model in the cases of high accretion rates, and stress the necessity of a multiwavelength approach to unveil the nature of ‘Naked’-AGN.
The origin of the IR emission of low-luminosity AGN
Authors: Mason R. E. , Almeida C. Ramos , Levenson N. A. , Nemmen R. , Herrero A. Alonso
Published: July 2014

To test recent suggestions that the infrared emission of low-luminosity AGN arises in a truncated thin accretion disk, we compare recent, high-resolution IR data with published SED model fits that include emission from the truncated disk. We also fit the data with clumpy torus and optically thin dust shell models. These comparisons suggest that dust can better account for the IR emission of the objects in question than can the truncated disk. That optically thin models give a good fit to the data may support a scenario in which the torus of the AGN unified model does not persist in low accretion rate AGN.
Powerful Molecular Outflows in Nearby Active Galaxies
Authors: Veilleux Sylvain , Meléndez Marcio ,   the SHINING Team
Published: July 2014

We report the results from a systematic search for molecular (OH 119 μm) outflows with Herschel-PACS† in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7-μm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than −50 km s−1, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (~ 145°) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km s−1, is seen in only 4 objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of ~ −1000 km s−1 are measured in several objects, but median outflow velocities are typically ~ −200 km s−1. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large AGN fractions and luminosities [log (LAGN/L⊙) ≥ 11.8 ± 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. In contrast, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.
A correlation between star formation rate and average black hole accretion rate in star forming galaxies
Authors: Chen Chien-Ting J. , Hickox Ryan C.
Published: July 2014

We present the results of recent studies on the co-evolution of galaxies and the supermassive black holes (SMBHs) using Herschel far-infrared and Chandra X-ray observations in the Boötes survey region. For a sample of star-forming (SF) galaxies, we find a strong correlation between galactic star formation rate and the average SMBH accretion rate in SF galaxies. Recent studies have shown that star formation and AGN accretion are only weakly correlated for individual AGN, but this may be due to the short variability timescale of AGN relative to star formation. Averaging over the full AGN population yields a strong linear correlation between accretion and star formation, consistent with a simple picture in which the growth of SMBHs and their host galaxies are closely linked over galaxy evolution time scales.