bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solar rotation effect on the measurement of sub‐photospheric flows at high latitudes in a synoptic view using ring diagram analysis
Authors: Zaatri A. 
Published: October 2014

AbstractThe dense‐pack grid is commonly used to get a synoptic view of the sub‐photospheric dynamics when using ring diagram analysis (Haber et al 2002). This grid is based on a fixed distribution of patches in central meridian distance (cmd) at all latitudes. A shortcoming of the dense‐pack grid is that the true motion of tracked areas at slower rotating latitudes is not handled correctly. For instance, a 15° × 15° area, centered at a cmd of 0° and a latitude of 60°, that rotates only 12° in 1664 minutes (ring day), is considered tobe centered at cmd = 15° in the subsequent ring day. In order to avoid this issue, another distribution is suggested where the grid point in central meridian distance is latitude dependant (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The spectroscopic orbit of the K‐giant binary γ Canis Minoris
Authors: Fekel F. C. , Wiliamson M. H. , Weber M. , Strassmeier K. G. , Pourbaix D. 
Published: October 2014

AbstractWe have determined an improved orbit for the bright, evolved, double lined binary γ Canis Minoris. The system has an orbital period of 389.31 days and an eccentricity of 0.2586. We have revised the secondary to primary mass ratio to 0.987. The spectral types of the primary and secondary are K4 III and K1: III, respectively, and the components have a V magnitude difference of 2.2. Orbital fits to the Hipparcos astrometry are not definitive, but they suggest an orbital inclination of ∼ 66°, which produces masses of 1.88 and 1.85 M⊙ for the components. A comparison with evolutionary tracks results in an age of 1.3 Gyr. STELLA very low amplitude radial velocity residuals of the secondary indicate a period of 278 days. We interpret this as the rotation period of the secondary, detectable because of star spots rotating in and out of view. This period is nearly identical to the pseudosynchronous rotation period of the star. The primary is rotating more slowly than its pseudosynchronous rate. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenized effective temperatures for metal deficient stars from stellar catalogues
Authors: Malyuto V. 
Published: October 2014

AbstractHomogeneous independent subsamples from selected catalogues and libraries of effective temperatures for metal deficient F–G stars are treated here by combining them in triples and pairs for the stars in common to determine their external errors from data intercomparisons. The effective temperatures are then averaged (with the weights inversely proportional to the squared errors) to produce mean homogenized catalogues which may be used for calibration of spectral and photometric data in large Galactic surveys. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Long‐term photometry of three active red giants in close binary systems: V2253 Oph, IT Com and IS Vir
Authors: Oláh K. , Moór A. , Strassmeier K.G. , Borkovits T. , Granzer T. 
Published: October 2014

AbstractWe present and analyze long‐term optical photometric measurements of the three active stars V2253 Oph, IT Com and IS Vir. All three systems are single‐lined spectroscopic binaries with an early K giant as primary component but in different stages of orbital‐rotational synchronization. Our photometry is supplemented by 2MASS and WISE near‐IR and mid‐IR magnitudes and then used to obtain more accurate effective temperatures and extinctions. For V2253 Oph and IT Com, we found their spectral energy distributions consistent with pure photospheric emission. For IS Vir, we detect a marginal mid‐IR excess which hints towards a dust disk. The orbital and rotational planes of IT Com appear tobe coplanar, contrary to previous findings in the literature. We apply a multiple frequency analysis technique to determine photometric periods, and possibly changes of periods, ranging from days to decades. New rotational periods of 21.55±0.03 d, 65.1±0.3 d, and 23.50±0.04 d were determined for V2253 Oph, IT Com, and IS Vir, respectively. Splitting of these periods led to tentative detections of differential surface rotations of δP/P ≈ 0.02 for V2253 Oph and 0.07 for IT Com. Using a time‐frequency technique based on short‐term Fourier transforms we present evidence of cyclic light variations of length ≈ 10 yr for V2253 Oph and 5–6 yr for IS Vir. A single flip‐flop event has been observed for IT Com of duration 2–3 yr. Its exchange of the dominant active longitude had happened close to a time of periastron passage, suggesting some response of the magnetic activity from the orbital dynamics. The 21.55‐d rotational modulation of V2253 Oph showed phase coherence also with the orbital period, which is 15 times longer than the rotational period, thus also indicating a tidal feedback with the stellar magnetic activity. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The “Sausage” and “Toothbrush” clusters of galaxies and the prospects of LOFAR observations of clusters of galaxies
Authors: Röttgering H. , van Weeren R. , Brüggen M. , Croston J. , Hoeft M. , Ogrean G. , Barthel P. , Best P. , Bonafede A. , Brunetti G. , Cassano R. , Chyży K. , Conway J. , De Gasperin F. , Ferrari C. , Heald G. , Jackson N. , Jarvis M. , Lehnert M. , Macario G. , Miley G. , Orrú E. , Pizzo R. , Rafferty D. , Stroe A. , Tasse C. , van der Tol S. , White G. , Wise M. , on behalf of the LOFAR collaboration  
Published: October 2014

AbstractLOFAR, the Low Frequency Radio Array, is a new pan‐European radio telescope that is almost fully operational. One of its main drivers is to make deep images of the low frequency radio sky. To be able to do this a number of challenges need to be addressed. These include the high data rates, removal of radio frequency interference, calibration of the beams and correcting for the corrupting influence of the ionosphere. One of the key science goals is to study merger shocks, particle acceleration mechanisms and the structure of magnetic fields in nearby and distant merging clusters. Recent studies with the GMRT and WSRT radio telescopes of the “Sausage” and the “Toothbrush” clusters have given a very good demonstration of the power of radio observations to study merging clusters. Recently we discovered that both clusters contain relic and halo sources, large diffuse regions of radio emission not associated with individual galaxies. The 2 Mpc northern relic in the Sausage cluster displays highly aligned magnetic fields and and exhibits a strong spectral index gradient that is a consequence of cooling of the synchrotron emitting particles in the post‐shock region. We have argued that these observations provide strong evidence that shocks in merging clusters are capable of accelerating particles. For the Toothbrush cluster we observe a puzzling linear relic that extends over 2 Mpc. The proposed scenario is that a triplemerger can lead to such a structure. With LOFAR's sensitivity it will not only be possible to trace much weaker shocks, but also to study those shocks due to merging clusters up to redshifts of at least one. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observing simulated galaxy clusters: The prospects of ICM velocity diagnostics
Authors: Biffi V. , Dolag K. , Böhringer H. 
Published: October 2014

AbstractNon‐thermal motions in the intra‐cluster medium (ICM) are believed to play a non‐negligible role in the pressure support to the total gravitating mass of galaxy clusters. Future high‐precision X‐ray missions will allow us to directly detect the signature of these motions from highly resolved spectra of the ICM. With this perspective, we will present here a study on a set of clusters extracted from a cosmological hydrodynamical simulation, for which we simulated X‐ray observations and characterized them via the non‐thermal velocity amplitude of the ICM. We have applied the X‐ray virtual telescope PHOX to generate mock observations of the simulated clusters and estimated in an observational fashion global X‐ray properties. We included ICM non‐thermal motions as additional parameter to further identify non‐regular clusters. In particular, the influence of internal gas motions on the location of clusters in the LX‐T plane was investigated and was found that objects with the largest amount of non‐thermal velocity have on average higher X‐ray luminosities. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray study of clusters at the outer edge and beyond
Authors: Ohashi T. , Akamatsu H. , Kawahara H. , Sekiya N. , Takei Y. 
Published: October 2014

AbstractWe report on recent Suzaku results on cluster outer regions. Relaxed clusters show a monotonous temperature decline to the virial radii, reaching 1/3 to 1/4 of the central levels. Significant temperature jumps have been confirmed for a number of radio relics, including A 3667, A 3376, and CIZA J2242.8+5301. This confirms that the radio relics generally correspond to shock fronts with the Mach numbers around 3. New filament junctions are identified by a new algorithm applied to the SDSS galaxy distribution and show significant X‐ray emission with Suzaku. The emission agrees with the LX‐kT relation for elliptical galaxies and galaxy groups, and the junctions can be a important baryon reservoir. We propose a small X‐ray mission DIOS (Diffuse Intergalactic Oxygen Surveyor), equipped with microcalorimeters with a wide field of view (∼50′), which will detect the emission from warm‐hot intergalactic medium (WHIM) and measure detailed thermal and dynamical properties of the gas accreting onto clusters from the filaments. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray and optical substructures of the DAFT/FADA survey clusters
Authors: Guennou L. , Durret F. , Adami C. , Lima Neto G.B. 
Published: October 2014

AbstractWe have undertaken the DAFT/FADA survey with the double aim of setting constraints on dark energy based on weak lensing tomography and of obtaining homogeneous and high quality data for a sample of 91 massive clusters in the redshift range 0.4–0.9 for which there were HST archive data. We have analysed the XMM‐Newton data available for 42 of these clusters to derive their X‐ray temperatures and luminosities and search for substructures. Out of these, a spatial analysis was possible for 30 clusters, but only 23 had deep enough X‐ray data for a really robust analysis. This study was coupled with a dynamical analysis for the 26 clusters having at least 30 spectroscopic galaxy redshifts in the cluster range. Altogether, the X‐ray sample of 23 clusters and the optical sample of 26 clusters have 14 clusters in common. We present preliminary results on the coupled X‐ray and dynamical analyses of these 14 clusters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radio observations of Planck clusters
Authors: Kale R. 
Published: October 2014

AbstractRecently, a number of new galaxy clusters have been detected by the ESA‐Planck satellite, the South Pole Telescope, and the Atacama Cosmology Telescope using the Sunyaev‐Zel'dovich effect. Several of the newly detected clusters are massive, merging systems with disturbed morphology in the X‐ray surface brightness. Diffuse radio sources in clusters, called giant radio halos and relics, are direct probes of cosmic rays and magnetic fields in the intra‐cluster medium. These radio sources are found to occur mainly in massive merging clusters. Thus, the new SZ‐discovered clusters are good candidates to search for new radio halos and relics. We have initiated radio observations of the clusters detected by Planck with the Giant Metrewave Radio Telescope. These observations have already led to the detection of a radio halo in PLCKG171.9–40.7, the first giant halo discovered in one of the new Planck clusters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scaling relations with a complete sample of galaxy groups
Authors: Lovisari L. , Reiprich T.H. 
Published: October 2014

AbstractGalaxy clusters are an attractive tool to constrain cosmological parameters and well‐determined scaling relations between X‐ray observables and cluster mass give us a precious diagnostic to study the thermodynamical history of the intra‐cluster medium (ICM). We are in the process of improving the accuracy of scaling relations using a complete sample of galaxy groups to study if there is a systematic difference between clusters and groups and the influence of non‐gravitational physics on low‐mass systems. By combining this sample with the HIFLUGCS sample creates a master sample of 86 groups and clusters ranging over more than three orders of magnitude in luminosity. This large leverage will directly allow us to place tight constraints on cosmological parameters. We present here the results of an ongoing work in which we analyze a complete sample of galaxy groups from observations taken with XMM. The results are compared with the ones obtained using the HIFLUGCS sample. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The fundamental plane of clusters of galaxies
Authors: D'Onofrio M. , Bettoni D. , Bindoni D. , Cava A. , Fasano G. , Marziani P. , Moles M. , Moretti A. , Poggianti B.M. , Varela J. 
Published: October 2014

AbstractWe have analyzed the growth curves and the surface brightness light profiles of the clusters of the WINGS sample (Fasano et al. 2006) in the B and V bands, measuring the effective radii, the effective surface brightnesses and the total luminosities of our clusters. The similarly of the radial surface brightness profiles of early‐type galaxies (ETGs) and clusters indicate that within r200 almost all clusters are virialized structures. The total luminosities LB of clusters are found to correlate with the X‐ray luminosity LX, following approximately the same relation measured for galaxies by Eskridge et al. (1995). By coupling the photometric data with the central velocity dispersions, derived from the radial velocities of the galaxies measured by Cava et al. (2009), we were able to fit the fundamental plane (FP) of clusters of galaxies. We find that it has approximately the same slope of the FPs of early‐type galaxies (ETGs) and globular clusters (GCs), but differs from them in the zero‐point. This behavior can be easily explained in terms of a different contribution of dark matter (DM). (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TheHerschel view of clusters of galaxies
Authors: Edge A.C. , Oonk J.B.R. , Mittal R. 
Published: October 2014

AbstractClusters of galaxies provide a rich variety of phenomena in the far‐infrared and the Herschel Space Observatory has performed a number of comprehensive imaging and spectroscopic observations of clusters over a wide redshift range. This talk gives an overview of the results available to date and the prospects for the observations yet to come. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The duty cycle of the radio mode feedback
Authors: Bîrzan L. , Rafferty D.A. , Nulsen P.E.J. , McNamara B.R. , Röttgering H.J.A. , Wise M.W. 
Published: October 2014

AbstractThe Chandra X‐ray Observatory has revealed X‐ray bubbles in the intracluster medium (ICM) of many nearby clusters, which are thought to be created by the central active galactic nucleus (AGN). However, the duty cycle of such AGN outbursts is not well understood. In order to further understand how cooling is balanced by bubble heating we studied complete samples of cooling flow clusters (from the Brightest 55 clusters of galaxies sample, B55, and the HIghest X‐ray FLUx Galaxy Cluster Sample, HIFLUGCS). We found that there is a radio luminosity cut‐off of 2.5×1030 erg s–1 Hz–1 for the cooling flow clusters. Furthermore, we find a duty cycle for radio mode feedback, the fraction of time that a system possesses bubbles inflated by its central radio source, of ≳ 69 % for the B55 sample and ≳ 63 % for the HIFLUGCS sample. These duty cycles are lower limits since some bubbles are likely missed in existing images. We used simulations to constrain the bubble power that might be present and remain undetected in the cooling flow systems without detected bubbles. Among theses systems, almost all could have significant bubble power. Therefore, our results imply that the duty cycle of AGN outbursts with the potential to heat the gas significantly in cooling flow clusters is at least 60% and could approach 100 %. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The origin of the chemical elements in cluster cores
Authors: de Plaa J. 
Published: October 2014

AbstractMetals play a fundamental role in ICM cooling processes in cluster cores through the emission of spectral lines. But when and how were these metals formed and distributed through the ICM? The X‐ray band has the unique property of containing emission lines from all elements from carbon to zinc within the 0.1–10 keV band. Using XMM‐Newton, the abundances of about 11 elements are studied, which contain valuable information about their origin. Most elements were formed in type Ia and core‐collapse supernovae, which have very different chemical yields. Massive stars and AGB stars also contribute by providing most of the carbon and nitrogen in the ICM. Because feedback processes suppress star formation in the cluster centre, the element abundances allow us to directly probe the star formation history of the majority of stars that are thought to have formed between z = 2–3. The spatial distribution in the core and the evolution with redshift also provide information about how these elements are transported from the member galaxies to the ICM. I review the current progress in chemical enrichment studies of the ICM and give an outlook to the future opportunities provided by XMM‐Newton's successors, like Astro‐H. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Clusters of galaxies in the Planck survey
Authors: Pointecouteau E. 
Published: October 2014

AbstractThe Planck satellite has surveyed the whole sky more than four times. The nominal mission of two all‐sky surveys will be released to the public in 2013. From the first all‐sky survey, we have demonstrated the ability to detect clusters via the Sunyaev‐Zel'dovich effect with high reliability and out to large redshifts. We have released the first large sample of 189 high signal‐to‐noise SZ clusters. We also presented the detection of 45 new Planck clusters, confirmed in X‐ray with the XMM‐Newton satellite. The Planck collaboration is engaged in a massive identification and follow‐up programme of its SZ sources at X‐ray, optical, and SZ wavelengths. Dedicated cluster studies are also conducted by the consortium in order to better constrain the scaling and structural properties of the cluster population. We have thus provided high precision calibration of scaling relation between the SZ signal and the clusters physical quantities. The excellent agreement found between SZ and X‐ray measurements have demonstrated our good understanding of the hot intra‐cluster gas at least within R500. These results together with those from other operating SZ instruments are shading new light on our understanding of the most massive bound structure of the Universe. With its whole sky reach and unprecedented frequency coverage, the Planck mission is a crucial asset to these endeavours. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detection and characterisation of the first Planck high‐z candidates
Authors: Flores‐Cacho I. 
Published: October 2014

AbstractWith its unprecedented ability to scrutinise the sub‐millimetre (sub‐mm) to centimetre full sky, the Planck satellite is uniquely suited to search for the progenitors of clusters of galaxies. The forming massive halos at z ≳1–2 are expected to host massive galaxies with high star formation rates. Clustered in the growing potential well that is being established, these galaxies are within Planck 's reach via their sub‐mm emission. We have applied a new colour‐based method combining Planck and IRAS data to detect the rarest and brightest sub‐mm cold sources on the sky. In this work, we describe the method and present the first confirmations of our high‐z candidates, particularly focusing on 17p732, a newly discovered high‐z (proto)cluster candidate at z ⋍ 1.7 for which we carried a multi‐wavelength follow‐up. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CL0024+1652 as seen by the Galaxy Cluster Evolution survey (GLACE)
Authors: Pérez‐Martínez R. , ´Sanchez‐Portal M. , Pintos‐Castro I. , Pérez‐García A.M. , Cepa J. , the GLACE Team  
Published: October 2014

AbstractThe GaLAxy Cluster Evolution survey (GLACE) is aimed to study the evolution of emission line galaxies in clusters across the cosmic time. It takes advantage of the tunable filter mode of OSIRIS (first light instrument of GTC) to scan Hα /[N II], Hβ, [O II]3727 and [O III]5007 searching for star formation activity and AGNs in clusters in three different redshift windows (z ∼ 0.40, 0.63, and 0.86), providing a unique view of the evolution of cluster galaxies along such redshift range. Moreover, the OSIRIS large field of view (8×8 arcmin2) together with GTC large collective area (D ∼ 10 m) make it possible to detect SFR ∼ 2 M⊙ yr–1 in an angular area up to 2Rvir. We present here the first results of the program together with a brief description of this novel technique focusing in the cluster CL0024+1654 (z ∼ 0.39). (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The XMM Cluster Survey: Present status and latest results
Authors: Viana P.T.P. , Mehrtens N. , Harrison C.D. , Romer A.K. , Collins C.A. , Hilton M. , Hoyle B. , Kay S.T. , Liddle A.R. , Mayers J.A. , Miller C.J. , Rooney P.J. , Sahlén M. , Stott J.P. 
Published: October 2014

AbstractThe XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM‐Newton Science Archive. Our recent first data release (XCS‐DR1) contains 503 optically confirmed groups and clusters, among which 256 new to the literature and 357 whose X‐ray emission was detected for the first time. We discuss their properties and provide an update on the work being done. As examples of the applications of XCS‐DR1, we mention the 17 fossil groups/clusters identified with the help of the Sloan Digital Sky Survey. Their brightest galaxies have stellar populations and star‐formation histories which are similar to normal brightest cluster galaxies, but their stellar masses are significantly larger and correspond to a much bigger fraction of the total group/cluster optical luminosity. We also highlight the 15 clusters expected tobe also detected by the Planck satellite, and characterize the expected overlap between the final XCS and Planck cluster catalogues. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distant clusters of galaxies in a deep XMM‐Newton observation
Authors: de Hoon A. , Lamer G. , Schwope A. , Mühlegger M. , Fassbender R. , Böhringer H. , Lerchster M. , Nastasi A. , Šuhada R. , Rosati P. , Pierini D. , Santos J.S. , Quintana H. 
Published: October 2014

AbstractThe XMM‐Newton Distant Cluster Project (XDCP) aims at the identification of a well defined sample of X‐ray selected clusters of galaxies at redshifts z ≥ 0.8. As part of this project, we analyse the deep archival XMM‐Newton exposure of LBQS 2212–1759 to quantify the cluster content. We validate the optical follow‐up strategy as well as the X‐ray selection function. We base the cluster identification of the extended X‐ray sources on deep imaging with the ESO‐VLT and on the CFHT‐LS. The confirmation of cluster candidates is done by VLT/FORS2 spectroscopy. Photometric redshifts from CFTH‐LS D4 are utilised to confirm the effectiveness of the X‐ray cluster selection method. The survey sensitivity is computed to have a flux limit of S0.5–2.0 keV ∼ 2.5×10–15 erg s–1 for 50% completeness in an area ∼0.13 deg2. We detect six clusters of galaxies above this level both in X‐rays and the optical. Two newly discovered X‐ray luminous clusters of galaxies in this work are at z ≥ 1.0 and one is at z = 0.41. The constructed log N ‐log S tends to favour a scenario where no evolution in the cluster X‐ray luminosity function takes place. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)