Astronomical Review最新文献

{"title":"Notice of New Publication: Medical Research Archives","authors":"","doi":"10.1080/21672857.2014.11519740","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519740","url":null,"abstract":"","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124546999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low- and High- z Highly Accreting Quasars in the 4D Eigenvector 1 Context","authors":"P. Marziani, J. Sulentic, C. Negrete, D. Dultzin, M. D’Onofrio, A. Olmo, Deborah Martínez-Aldama","doi":"10.1080/21672857.2014.11519739","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519739","url":null,"abstract":"Abstract Highly accreting quasars are characterized by distinguishing properties in the 4D eigenvector 1 parameter space that make them easily recognizable over a broad range range of redshift and luminosity. The 4D eigenvector 1 approach allows us to define selection criteria that go beyond the restriction to Narrow Line Seyfert is identified at low redshift. These criteria are probably able to isolate sources with a defined physical structure i.e., a geometrically thick, optically thick advection-dominated accretion disk (a “slim” disk). We stress that the importance of highly accreting quasars goes beyond the understanding of the details of their physics: their Eddington ratio is expected to saturate toward values of order unity, making them possible cosmological probes.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133212941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Occurrence of Non-Pulsating Stars in the gamma Dor and delta Set Pulsation Instability Regions: Results from Kepler Quarter 14-17 Data","authors":"J. Guzik, P. Bradley, J. Jackiewicz, J. Molenda–Żakowicz, K. Uytterhoeven, K. Kinemuchi","doi":"10.1080/21672857.2014.11519738","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519738","url":null,"abstract":"Abstract In our October 2013 Astronomical Review article, we discussed the statistics of variability for 633 relatively faint (Kepler magnitude 14-16) spectral type A-F stars observed by the Kepler spacecraft as part of the Guest Observer program during Quarters 6-13 (June 2010-June 2012). We found six stars that showed no variability with with amplitude 20 ppm level or greater in the range 0.2 to 24.4 cycles/day, but whose positions in the log g – Teff plane put them in the delta Set or gamma Dor pulsation instability regions established from pre-Kepler groundbased observations. Here we present results for an additional 2100+ stars observed during Quarters 14-17 (June 2012-December 2013), until the second of Kepler’s four reaction-wheels failed, ending Kepler’s planet-search mission in the Cygnus-Lyra region. This sample is not unbiased, as we limited our target list to stars showing variability in Quarter 0 full-frame images to enhance our variable star discovery rate. We find that 46% of these stars show no frequencies in the Fourier transform of their light curves down to the 20-ppm level. We find 35 additional stars that lie within the ground-based gamma Dor /delta Set pulsation instability regions; their lack of pulsations requires explanation. In the analysis for our first paper, we included a +229 K offset to the Kepler Input Catalog Teff to take into account an average systematic difference between the KIC values and the Teff derived from SDSS color photometry for main-sequence F stars (Pinsonneault et al. 2012). Here we compare the KIC catalog Teff value and the Teff derived from spectroscopy taken by the LAMOST instrument (Molenda-Zakowicz et al. 2013) for 51 stars in common to determine whether the 229 K offset should be applied to our target stars, and the implications for the location of the constant stars relative to the instability region boundaries. Finally, we also review possible explanations for the constant stars that lie within the pulsation instability regions, and consider whether super-Nyquist frequencies (>24.4 cycles/day), if they existed, would have been detected in the long-cadence data via their reflections at low frequencies, as discussed by Murphy et al. (2013).","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126301793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of a Global Gravitational Potential","authors":"Michael Scott Peck","doi":"10.1080/21672857.2014.11519735","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519735","url":null,"abstract":"Abstract Substantial evidence of a global gravitational potential is discussed including galaxy counts, angular size-redshift relations, SNIa and large-scale B-mode polarization within the cosmic background radiation. Local morphological luminosity functions are derived from several surveys and transformed to the BRIHK-bands through color-magnitude relations. These precise luminosity functions are applied to determine the necessary evolution for LCDM and universe with global gravitational potential. Galaxy counts and redshift distributions are found to be in agreement with the later up to 0.25z, where the existence of a local hole has been recently proposed at optical and near infrared wavelengths. Several angular diameter-redshift tests are provided with models of evolution to confirm the galaxy results. Large-scale B-mode polarization of the CMB further provides a 3.5 sigma detection using WMAP three year polarization data, with the center of a cosmological-scale potential in the direction of (8.1° ± 10.1°, 4.9° ± 11.0°).","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127678788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Connection between Gravity and Electromagnetism","authors":"Octavian Balaci","doi":"10.1080/21672857.2014.11519731","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519731","url":null,"abstract":"Abstract A new interpretation of electrodynamics and gravity is presented, based on the idea that the electromagnetic and gravitational properties of vacuum are connected. The space and time are treated as imaginary concepts. With this, the electrodynamics and gravitational phenomena can be explained with a Galilean invariant vacuum. Also a new way to explain the gravitational attraction will result.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124049884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dark Matter Searches with Clusters of Galaxies","authors":"T. Jeltema","doi":"10.1080/21672857.2014.11519733","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519733","url":null,"abstract":"Abstract Dark matter may annihilate or decay to produce Standard Model particles including gamma-rays but also energetic electrons and positrons. These high energy particles diffuse, loose energy and produce a broad spectrum of secondary radiation including radio synchrotron emission in the presence of magnetic fields and the inverse Compton scattering of CMB photons and star light to X-ray and gamma-ray energies. Clusters of galaxies are prime targets for multiwavelength dark matter searches as they both host large dark matter densities and effective trap high-energy particles long enough for them to radiate. Clusters are also among the strongest probes of dark matter decay. We will review the utility of clusters for dark matter searches and current constraints. In particular, we will show that current radio observations of clusters are competitive with gamma-ray, and future facilities like LOFAR and ASKAP are expected to give large gains for dark matter searches.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"48 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127992519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly accreting quasars at low and high z.","authors":"P. Marziani","doi":"10.1080/21672857.2014.11519732","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519732","url":null,"abstract":"Abstract This paper aims at reviewing and discussing the multifrequency properties of quasars accreting at very high rate in the context of the 4DE1 conceptual framework. The 4DE1 approach allows us to define luminosity-independent selection criteria that go beyond the restriction to Narrow Line Seyfert tis identified at low redshift. Highly accreting quasars are characterised by observational properties (steep soft-and hard X continuum, strong Fell emission, and extreme high ionization line profile blueshifts) that make them easily recognisable, and indicate extreme physical properties with respect to the general quasar population as well: an optically thick ADAF, very high metallicity, and a strong high ionization wind. We discuss some puzzling aspects related to their formation and evolution. We stress that the importance of the sources goes beyond the understanding of quasar physics: their Eddington ratio is expected to saturate toward values of order unity, making them possible cosmological probes.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132579619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of a large correlator array configuration to maximize the coverage of υ-ν plane and minimize the sidelobes","authors":"Shahideh Kiehbadroudinezhad, N. Noordin","doi":"10.1080/21672857.2014.11519734","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519734","url":null,"abstract":"Abstract The synthesized array is commonly used in radio astronomy and the Giant Metrewave Radio Telescope (GMRT) is one of the world’s foremost telescopes of this kind. The aim of this paper is to optimize an array of antennas, similar to GMRT, by changing the position of antennas. The effect of only changing the configuration was studied and the results of circular and spiral arrangements are discussed. The results are shown, the spiral combined with a circle configuration which is able to cover the u-v plane very well and decreases sidelobes. The results and observations are discussed in this report.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115130781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low Ionization Emission Lines in Quasars: Clues from OI 8446 and the CaII Triplet","authors":"P. Marziani, M. Martínez-Aldama, D. Dultzin, J. Sulentic","doi":"10.1080/21672857.2014.11519729","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519729","url":null,"abstract":"Abstract The formation of low emission lines in quasars and active galactic nuclei is still an open issue. Aided by the organizing power of the 4D eigenvector 1 scheme, we review basic developments since the 1980s, devoting special attention to the CaII IR triplet and the OI 8446 emission lines. Coverage of these lines is cumbersome since they are shifted in an inconvenient IR domain already at modest redshifts (≈ 0.2). Their detection is also difficult since they are faint and often buried in the CaII absorption of the host galaxy. We discuss how these lines can provide unambiguous constraints on the physical conditions of the broad line emitting regions of quasars when detected in emission, and summarise preliminary results for a sample of luminous, intermediate redshift quasars.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"386 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124788659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmic Gamma-Ray Spectroscopy","authors":"R. Diehl","doi":"10.1080/21672857.2014.11519736","DOIUrl":"https://doi.org/10.1080/21672857.2014.11519736","url":null,"abstract":"Abstract Penetrating gamma-rays require complex instrumentation for astronomical spectroscopy measurements of gamma-rays from cosmic sources. Multiple-interaction detectors in space combined with sophisticated post-processing of detector events on ground have lead to a spectroscopy performance which is now capable to provide new astrophysical insights. Spectral signatures in the MeV regime originate from transitions in the nuclei of atoms (rather than in their electron shell). Nuclear transitions are stimulated by either radioactive decays or high-energy nuclear collisions such as with cosmic rays. Gamma-ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae, and from energetic-particle interactions in solar flares. Radioactive-decay gamma-rays from 56Ni directly reflect the source of supernova light. 44Ti is produced in core-collapse supernova interiors, and the paucity of corresponding 44Ti gamma-ray line sources reflects the variety of dynamical conditions herein. 26 Al and 60Fe are dispersed in interstellar space from massive-star nucleosynthesis over millions of years. Gamma-rays from their decay are measured in detail by gamma-ray telescopes, astrophysical interpretations reach from massive-star interiors to dynamical processes in the interstellar medium. Nuclear de-excitation gamma-ray lines have been found in solar-flare events, and convey information about energetic-particle production in these events, and their interaction in the solar atmosphere. The annihilation of positrons leads to another type of cosmic gamma-ray source. The characteristic annihilation gamma-rays at 511 keV have been measured long ago in solar flares, and now throughout the interstellar medium of our Milky Way galaxy. But now a puzzle has appeared , as a surprising predominance of the central bulge region was determined. This requires either new positron sources or transport processes not yet known to us. In this paper we discuss instrumentation and data processing for cosmic gamma-ray spectroscopy, and the astrophysical issues and insights from these measurements.","PeriodicalId":204186,"journal":{"name":"Astronomical Review","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121203406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}