698 research outputs found

    The Spectacular Ionized Interstellar Medium of NGC55

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    We present deep Halpha+[NII], [SII] (6716,6731A) and [OII] (3726,3729A) images of the highly inclined, actively star--forming SBm galaxy NGC 55, located in the nearby Sculptor Group. Due to its proximity, NGC 55 provides a unique opportunity to study the disk--halo interface in a late--type galaxy with unprecedented spatial resolution. Our images reveal a spectacular variety of ionized gas features, ranging from giant HII region complexes, to supergiant filamentary and shell features, to patches of very faint diffuse emission. Many of these features protrude well above the plane of the galaxy, including a very faint fragmented shell of emission which is visible at 2.6 kpc above the disk. We identify candidate `chimneys' extending out of the disk, which could be the conduits into the halo for hot gas around disk star-forming regions, and could also provide low-density paths for the passage of UV photons from the disk to the halo. Several of the identified chimneys are `capped' with clumps of ionized gas, one of which, located at 1.5 kpc above the disk plane, appears to be the site of recent star formation. Emission--line ratios ([OII]/Halpha+[NII], [SII]/Halpha+[NII]) constrain the ionization mechanism of the gas, and our images allow the first measurement of [OII]/Halpha+[NII] in extra-planar diffuse ionized gas. The diffuse gas is characterized by emission--line ratios which are enhanced on average by a factor of two compared to those of bright HII regions. Each line ratio increases in value smoothly from the cores of HII regions, through the haloes of HII regions, into the diffuse ionized gas. Such a continuous trend is predicted by models in which the diffuse gas is ionized by photons produced by massive stars in HII regions.Comment: 19 pages, including 4 figures, plus 2 external tables. Accepted for publication in the Astronomical Journal. Compressed, postscript versions of the plates are available at ftp://skysrv.pha.jhu.edu/ferguson

    Assessment and forecasting of lightning potential and its effect on launch operations at Cape Canaveral Air Force Station and John F. Kennedy Space Center

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    Lightning plays a pivotal role in the operation decision process for space and ballistic launches at Cape Canaveral Air Force Station and Kennedy Space Center. Lightning forecasts are the responsibility of Detachment 11, 4th Weather Wing's Cape Canaveral Forecast Facility. These forecasts are important to daily ground processing as well as launch countdown decisions. The methodology and equipment used to forecast lightning are discussed. Impact on a recent mission is summarized

    Young children's agency in the science museum: insights from the use of storytelling in object-rich galleries

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    This paper draws on a multi-phase project that sought to understand and increase young children’s engagement with Science, Technology, Engineering and Mathematics (STEM) objects. The paper presents findings from one aspect of this project that involved using storytelling to support young children’s agency with STEM objects in a UK science museum. The qualitative research involved observing and interviewing 25 children aged 4–7 years in family and school groups. The findings demonstrate the importance of acknowledging and promoting young children’s agency in museum settings. They suggest that providing children with opportunities to exercise agency by them taking control and activating their prior knowledge and interests during museum visits increases their engagement, enjoyment, and confidence. The study also highlights the important role that adults, including parents, teachers, and museum staff, play in facilitating children’s agency and increasing their engagement with museum objects and spaces

    Paper Session I-A - Weather Impacts on Space Operations

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    The 45th Weather Squadron of the United States Air Force provides weather support to Patrick Air Force Base, Cape Canaveral Air Force Station (CCAFS), Eastern Range, and Kennedy Space Center (KSC). The support includes weather observations, forecasts, climatological studies and consultant services to a wide variety of Range users. The most visible to the general public is weather support to space vehicles, particularly the Space Shuttle. That support includes resource protection, ground processing, launch, and Ferry Flight; as well as consultant to the Spaceflight Meteorology Group (at Johnson Space Center) for landing forecasts

    On the Nature of Andromeda IV

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    Lying at a projected distance of 40' or 9 kpc from the centre of M31, Andromeda IV is an enigmatic object first discovered during van den Bergh's search for dwarf spheroidal companions to M31. Being bluer, more compact and higher surface brightness than other known dwarf spheroidals, it has been suggested that And IV is either a relatively old `star cloud' in the outer disk of M31 or a background dwarf galaxy. We present deep HST WFPC2 observations of And IV and the surrounding field which, along with ground-based long-slit spectroscopy and Halpha imagery, are used to decipher the true nature of this puzzling object. We find compelling evidence that And IV is a background galaxy seen through the disk of M31. The moderate surface brightness (SB(V)~24), very blue colour (V-I<~0.6), low current star formation rate (~0.001 solar mass/yr) and low metallicity (~10% solar) reported here are consistent with And IV being a small dwarf irregular galaxy, perhaps similar to Local Group dwarfs such as IC 1613 and Sextans A. Although the distance to And IV is not tightly constrained with the current dataset, various arguments suggest it lies in the range 5<~D<~8 Mpc, placing it well outside the confines of the Local Group. It may be associated with a loose group of galaxies, containing major members UGC 64, IC 1727 and NGC 784. We report an updated position and radial velocity for And IV.Comment: 26 pages, LaTex with 9 figures (including 6 jpg plates). Accepted for publication in A

    Evaluation Protocol: Speech Bubbles

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    The Speech Bubbles intervention aims to improve children’s communication and social skills by providing them with weekly creative drama sessions. The benefit to pupils’ communication skills is also thought to have an effect on pupils’ reading skills. This is an intervention targeted at pupils with below expected communication and social skills. During the sessions trained practitioners encourage children to tell, act out and reflect on their own stories by creating a safe and playful environment, promoting children’s communication, confidence and wellbeing. This is based on the Helicopter Stories pedagogical approach.1 Speech Bubbles is part of a broader programme of work entitled ‘Learning about Culture’, which aims to improve the evidence base around arts-based education programmes. This is coordinated by the Education Endowment Foundation and the Royal Society for the Arts.2 It consists of five programmes: two in Key Stage 1 (Reception and Year 1) and three in Key Stage 2 (Year 5). Despite the unique aspects of these intervention models, there are many similarities in how they are delivered and what they hope to achieve.

    Chemical Evolution in the Carina Dwarf Spheroidal

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    We present metallicities for 487 red giants in the Carina dwarf spheroidal (dSph) galaxy that were obtained from FLAMES low-resolution Ca triplet (CaT) spectroscopy. We find a mean [Fe/H] of -1.91 dex with an intrinsic dispersion of 0.25 dex, whereas the full spread in metallicities is at least one dex. The analysis of the radial distribution of metallicities reveals that an excess of metal poor stars resides in a region of larger axis distances. These results can constrain evolutionary models and are discussed in the context of chemical evolution in the Carina dSph.Comment: 3 pages, 2 figures, to be published in the proceedings of the ESO/Arcetri-workshop on "Chemical Abundances and Mixing in Stars", 13.-17. Sep. 2004, Castiglione della Pescaia, Italy, L. Pasquini, S. Randich (eds.
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