First results of an Hα based search of classical Be stars in the Perseus Arm and beyond

We investigate a region of the Galactic plane, between 120° ≤ l ≤ 140° and-1° ≤ b≤+4°, and uncover a population of moderately reddened (E(B-V) ~ 1) classical Be stars within and beyond the Perseus and Outer Arms. 370 candidate emission-line stars (13≲r≲16) selected from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane have been followed up spectroscopically. A subset of these, 67 stars with properties consistent with those of classical Be stars, have been observed at sufficient spectral resolution (δλ ≈ 2-4 Å) at blue wavelengths to narrow down their spectral types. We determine these to a precision estimated to be ±1 subtype and then we measure reddenings via spectral energy distribution fitting with reference to appropriate model atmospheres. Corrections for contribution to colour excess from circumstellar discs are made using an established scaling to Ha emission equivalent width. Spectroscopic parallaxes are obtained after luminosity class has been constrained via estimates of distances to neighbouring A/F stars with similar reddenings. Overwhelmingly, the stars in the sample are confirmed as luminous classical Be stars at heliocentric distances ranging from 2 kpc up to ~12 kpc. However, the errors are presently too large to enable the cumulative distribution function with respect to distance to distinguish between models placing the stars exclusively in spiral arms, or in a smooth exponentially declining distribution.Peer reviewe

Galactic Plane Hα\alpha Surveys: IPHAS & VPHAS+

The optical Galactic Plane H$\alpha$ surveys IPHAS and VPHAS+ are dramatically improving our understanding of Galactic stellar populations and stellar evolution by providing large samples of stars in short lived, but important, evolutionary phases, and high quality homogeneous photometry and images over the entire Galactic Plane. Here I summarise some of the contributions these surveys have already made to our understanding of a number of key areas of stellar and Galactic astronomy.Comment: 5 pages, 2 figures, refereed proceeding of the "The Universe of Digital Sky Surveys" conference, November 2014, to be published in the Astrophysics and Space Science Proceeding

Studying young recipients of alcohol marketing : Two research paradigms and their possible consolidation

Peer reviewe

Three-dimensional extinction mapping using Gaussian random fields

Disentangling the 3D structure of interstellar extinction is a key requirement for understanding the Galaxy and a crucial step towards taking full advantage of the data Gaia will provide. We present a scheme for using stellar catalogues to map the three-dimensional distributions of extinction and dust within our Galaxy, employing Gaussian random fields and a simple physical model of the interstellar medium that assumes a Kolmogorov-like power spectrum of turbulent fluctuations. As extinction is modelled as a random field, the spatial resolution of the resulting maps is set naturally by the data available; there is no need to impose any spatial binning

Three-dimensional extinction mapping using Gaussian random fields

Disentangling the 3D structure of interstellar extinction is a key requirement for understanding the Galaxy and a crucial step towards taking full advantage of the data Gaia will provide. We present a scheme for using stellar catalogues to map the three-dimensional distributions of extinction and dust within our Galaxy, employing Gaussian random fields and a simple physical model of the interstellar medium that assumes a Kolmogorov-like power spectrum of turbulent fluctuations. As extinction is modelled as a random field, the spatial resolution of the resulting maps is set naturally by the data available; there is no need to impose any spatial binning

The ongoing outburst of the new symbiotic star IPHASJ190832.31+051226.6

Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO)Aims. Eleven new symbiotic stars have recently been discovered with IPHAS, the INT Hα survey of the Northern Galactic plane. The star IPHAS J190832.31+051226.6 was proposed as an additional candidate on the basis of the existing spectrum. Here, we investigate the nature of this source by means of additional observations. Methods. Photometric data, optical spectra obtained in 2006 and 2009, a higher resolution spectrum resolving the Hα profile, and near-IR spectra of IPHAS J190832.31+051226.6 are all presented. Results. The source brightened in the r band by 2.3 mag from 2004 to 2009. From 2006 to 2009, the spectrum has evolved from one with the obvious continuum of an M giant star plus HI and HeI lines in emission to a lower excitation nebular spectrum with HI, CaII, and FeII emission and a bluer continuum in which the absorption bands of the red giant are only visible at wavelengths longer than 7500 Å. The Hα line is broad with a deep central absorption and extended wings. Conclusions. The averaged rate of the brightness increase, the rise of a blue continuum overwhelming the absorption bands of the M giant, and the corresponding decline of the ionization condition of the emission-line spectrum, are all consistent with the hypothesis that IPHAS J190832.31+051226.6 is a new symbiotic star picked up during the onset of a symbiotic nova outburst that is still in progress at the time of writing.Peer reviewe

Tracing the structure of the Perseus arm with IPHAS

Research aiming to describe the spiral structure of the Milky Way disc has to confront both difficulties in obtaining distances and the high interstellar extinction found in the Galactic plane. We present a study of a section of the Perseus Arm, between Galactic longitudes. (120°, 140°) and Galactic latitudes .(-1°+4°), including a number of young clusters. Determination of physical parameters of young stellar objects (YSO) and mapping of the A-star surface density are used to analyse evidence of young structures (typically 10-100 Myrs old) defined in spac

Fish oil, melatonin and vitamin e attenuates midbrain cyclooxygenase-2 activity and oxidative stress after the administration of 1-methyl-4-phenyl-1,2, 3,6- tetrahydropyridine

We investigate a region of the Galactic plane, between 120 ? l ? 140 and-1 ? b?+4 , and uncover a population of moderately reddened (E(B-V) ~ 1) classical Be stars within and beyond the Perseus and Outer Arms. 370 candidate emission-line stars (13?r?16) selected from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane have been followed up spectroscopically. A subset of these, 67 stars with properties consistent with those of classical Be stars, have been observed at sufficient spectral resolution (?? ? 2-4 ) at blue wavelengths to narrow down their spectral types. We determine these to a precision estimated to be 1 subtype and then we measure reddenings via spectral energy distribution fitting with reference to appropriate model atmospheres. Corrections for contribution to colour excess from circumstellar discs are made using an established scaling to Ha emission equivalent width. Spectroscopic parallaxes are obtained after luminosity class has been constrained via estimates of distances to neighbouring A/F stars with similar reddenings. Overwhelmingly, the stars in the sample are confirmed as luminous classical Be stars at heliocentric distances ranging from 2 kpc up to ~12 kpc. However, the errors are presently too large to enable the cumulative distribution function with respect to distance to distinguish between models placing the stars exclusively in spiral arms, or in a smooth exponentially declining distribution. " 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.",,,,,,"10.1093/mnras/stt038",,,"http://hdl.handle.net/20.500.12104/41535","http://www.scopus.com/inward/record.url?eid=2-s2.0-84876811129&partnerID=40&md5=7c537a0a3a76c0f1bd980e198a951b74",,,,,,"3",,"Monthly Notices of the Royal Astronomical Society",,"216

Transgenerational marking of embryonic otoliths in marine fishes using barium stable isotopes

Author Posting. © National Research Council Canada, 2006. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 63 (2006): 1193-1197, doi:10.1139/F06-048.We describe a new technique for transgenerational marking of embryonic otoliths that promises significant advancements in the study of larval dispersal and population connectivity in marine fishes. The approach is based on maternal transmission of 137Ba from spawning females to egg material that is ultimately incorporated into the otoliths of embryos produced by an individual after exposure to the isotope. We injected females of a benthic-spawning clownfish (Amphiprion melanopus) and a pelagic-spawning serranid (Centropristis striata) with enriched 137BaCl2 and then reared the resulting progeny through to settlement. Barium isotope ratios in the cores of larval otoliths were quantified using laser ablation inductively coupled plasma mass spectrometry. Larval otoliths from both species contained unequivocal Ba isotope signatures over a wide range of doses (0.8–23 μg 137Ba·g female–1). Female A. melanopus continued to produce marked larvae over multiple clutches and for at least 90 days after a single injection. The ability to administer different combinations of stable Ba isotopes provides a new means of mass-marking larvae of benthic- and pelagic-spawning fishes from multiple populations over extended spawning periods.Funding for this study was provided by the National Science Foundation through grants OCE-0215905 and OCE- 0424688, Discovery Grant DP 0208120 from the Australian Research Council, and the Oak Foundation