21 research outputs found

    The second data release of the INT Photometric Ha Survey of the Northern Galactic Plane (IPHAS DR2)

    Get PDF
    The INT/WFC Photometric Hα Survey of the Northern Galactic Plane (IPHAS) is a 1800 deg2 imaging survey covering Galactic latitudes |b| < 5° and longitudes ℓ = 30°–215° in the r, i, and Hα filters using the Wide Field Camera (WFC) on the 2.5-m Isaac Newton Telescope (INT) in La Palma. We present the first quality-controlled and globally calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92 per cent of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec pixel−1) and to a mean 5σ depth of 21.2 (r), 20.0 (i), and 20.3 (Hα) in the Vega magnitude system. We explain the data reduction and quality control procedures, describe and test the global re-calibration, and detail the construction of the new catalogue. We show that the new calibration is accurate to 0.03 mag (root mean square) and recommend a series of quality criteria to select accurate data from the catalogue. Finally, we demonstrate the ability of the catalogue's unique (r − Hα, r − i) diagram to (i) characterize stellar populations and extinction regimes towards different Galactic sightlines and (ii) select and quantify Hα emission-line objects. IPHAS is the first survey to offer comprehensive CCD photometry of point sources across the Galactic plane at visible wavelengths, providing the much-needed counterpart to recent infrared surveys

    A search for white dwarfs in the Galactic plane: : the field and the open cluster population

    Get PDF
    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. The Version of Record [R. Raddi, et al, ‘A search for white dwarfs in the Galactic plane: the field and the open cluster population’, Monthly Notices of the Royal Astronomical Society, Vol. 457 (2): 1988-2004, first published online 5 February 2016] is available online at doi: https://doi.org/10.1093/mnras/stw042. © 2016 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We investigated the prospects for systematic searches of white dwarfs at low Galactic latitudes, using the VLT Survey Telescope (VST) Hα\alpha Photometric Survey of the Galactic plane and Bulge (VPHAS+). We targeted 17 white dwarf candidates along sightlines of known open clusters, aiming to identify potential cluster members. We confirmed all the 17 white dwarf candidates from blue/optical spectroscopy, and we suggest five of them to be likely cluster members. We estimated progenitor ages and masses for the candidate cluster members, and compared our findings to those for other cluster white dwarfs. A white dwarf in NGC 3532 is the most massive known cluster member (1.13 M⊙_{\odot}), likely with an oxygen-neon core, for which we estimate an 8.8−4.3+1.28.8_{-4.3}^{+1.2} M⊙_{\odot} progenitor, close to the mass-divide between white dwarf and neutron star progenitors. A cluster member in Ruprecht 131 is a magnetic white dwarf, whose progenitor mass exceeded 2-3 M⊙_{\odot}. We stress that wider searches, and improved cluster distances and ages derived from data of the ESA Gaia mission, will advance the understanding of the mass-loss processes for low- to intermediate-mass stars.Peer reviewedFinal Published versio

    A small-N cross-sectional study of British unions' environmental attitudes and activism - and the prospect of a green-led renewal

    Get PDF
    Unions understand the environmental agenda as a technocentric one but also believe it can function as a vehicle for renewal. It is developing slowly, with unions behaving cautiously—resources are scarce. Although popular with members, there is limited evidence that it is effective as a recruitment tool and whilst employers are willing to work in partnership with unions on it, this may confer only phony insider status. Overall, the agenda has limited appeal to the types of employees and employers unions must recruit in order to grow. Identifying a clear environmental premium for members may help

    VST photometric H-alpha survey of the Southern Galactic Plane and Bulge (VPHAS+)

    No full text
    The VST Photometric H-alpha survey of the Southern Galactic Plane and Bulge (VPHAS+) is collecting single-epoch Sloan u, g, r, i and H-alpha narrowband photometry, at arcsecond resolution, down to point-source (Vega) magnitudes of ~ 21. The survey footprint encloses the entire southern Galactic Plane within the Galactic latitude range -5° &lt;b &lt;+5°, expanding to b = ±10° in the Galactic Bulge. This brief description of VPHAS+ includes sample data and examples of early science validation

    The influence of written information during the consenting process on patients’ recall of operative risks. A prospective randomised study

    No full text
    In a recent article, Leigh (J Bone Joint Surg [Br] 88-B:16–18, 2006) notes that patients do not lay down memory when being counselled as to the risks involved in prospective surgery. In our article we focused on the patients’ recall of risk factors involved in elective spinal surgery. We assessed the influence of written information provided to the patients during the consenting process on their recall of operative risks. The study was a prospective randomised study. All patients having elective spinal surgery were included in our study from February 2006 to November 2006 as a consecutive series. Patients were randomised into two groups, one of which received routine consent with verbal explanations (group 1), the other received the same information supplemented by a written sheet explaining the risks of the surgery (group 2). Two weeks later we assessed patients’ recall of the risk involved in the surgery with a questionnaire and compared both groups with a Student t-test. Fifty-three patients (twenty in group 1 and twenty three in group 2) were involved. We noted a significant difference between the two groups in terms of mean number of risks recalled and number of patients recalling each risk (p < 0.001 and p < 0.005, respectively). The addition of a written sheet given to patients during the consenting process makes a significant difference in terms of their recall of the surgical risks in elective lumbar spine surgery. We advocate the routine use of written booklets during the consenting process

    Initial data release of the Kepler-INT survey

    No full text
    This paper describes the first data release of the Kepler-INT Survey (KIS), that covers a 116 deg2 region of the Cygnus and Lyra constellations. The Kepler field is the target of the most intensive search for transiting planets to date. Despite the fact that the Kepler mission provides superior time series photometry, with an enormous impact on all areas of stellar variability, its field lacks optical photometry complete to the confusion limit of the Kepler instrument necessary for selecting various classes of targets. For this reason, we follow the observing strategy and data reduction method used in the IPHAS and UVEX galactic plane surveys in order to produce a deep optical survey of the Kepler field. This initial release concerns data taken between May and August 2011, using the Isaac Newton Telescope on the island of La Palma. Four broadband filters were used, U, g, r, i, as well as one narrowband one, Halpha, reaching down to a 10-sigma limit of around 20th mag in the Vega system. Observations covering around 50 deg2, thus about half of the field, passed our quality control thresholds and constitute this first data release. We derive a global photometric calibration by placing the KIS magnitudes as close as possible to the Kepler Input Catalog (KIC) photometry. The initial data release catalogue containing around 6 million sources from all the good photometric fields is available for download from the KIS webpage, as well as via MAST

    VPHAS+ DR2 survey

    No full text
    The Second VPHAS data release (DR2) covers the first 21 months of data-taking in which the survey progressed to 24 percent completion. Much of the Galactic mid-plane is now covered (especially in the r, i and Hα filters). This images release supersedes DR1. The full description of the catalogue, including a discussion of how the catalogue was made and advice on best use of the data, is available as file vphas-dr2-desc.pdf (ftp://cdsarc.u-strasbg.fr/pub/cats/II/341/vphas-dr2-desc.pdf). The current photometric scale is linked to APASS in g, r and i, while the u and Hα bands are calibrated by local offsetting from g and r. For ESO archive entry, see ESO's public survey pages (http://eso.org/rm/publicAccess#/dataReleases)

    VST Photometric H-alpha Survey of the Southern Galactic Plane and Bulge (VPHAS+)

    No full text
    The VST Photometric H-alpha survey of the Southern Galactic Plane and Bulge (VPHAS+) is collecting single-epoch Sloan u, g, r, i and H-alpha narrowband photometry, at arcsecond resolution, down to point-source (Vega) magnitudes of ~ 21. The survey footprint encloses the entire southern Galactic Plane within the Galactic latitude range -5° < b < +5°, expanding to b = ±10° in the Galactic Bulge. This brief description of VPHAS+ includes sample data and examples of early science validation
    corecore