A GBT Survey of the HALOGAS Galaxies and Their Environments. I. Revealing the Full Extent of H i around NGC 891, NGC 925, NGC 4414, and NGC 4565
| Autor: | E. Jütte, Thomas H. Jarrett, Gyula I. G. Józsa, W. J. G. de Blok, Tom Oosterloo, Daniel J. Pisano, R. J. Rand, Nickolas M. Pingel, Benjamin Winkel, George Heald |
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| Přispěvatelé: | Astronomy |
| Rok vydání: | 2018 |
| Předmět: |
NGC 925
FOS: Physical sciences Flux galaxies: individual (NGC 891 NGC 925 NGC 4414 NGC 4565) SHARP EDGES Astrophysics Spatial distribution 01 natural sciences Radio telescope 0103 physical sciences galaxies: formation NGC 4565) HIGH-VELOCITY CLOUDS 010303 astronomy & astrophysics Physics NGC-891 galaxies: individual (NGC 891 NEUTRAL HYDROGEN OBSERVATIONS Spiral galaxy 010308 nuclear & particles physics EXTRAPLANAR GAS M31 Green Bank Telescope Local Group Astronomy and Astrophysics STAR-FORMATION HISTORY Astrophysics - Astrophysics of Galaxies GAS ACCRETION Galaxy Accretion (astrophysics) Space and Planetary Science NGC 4414 Astrophysics of Galaxies (astro-ph.GA) galaxies: evolution SPIRAL GALAXIES LOCAL GROUP |
| Zdroj: | Astrophysical Journal, 865(1):36. IOP PUBLISHING LTD |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.3847/1538-4357/aad816 |
| Popis: | We present initial results from a deep neutral hydrogen (HI) survey of the HALOGAS galaxy sample, which includes the spiral galaxies NGC891, NGC925, NGC4414, and NGC4565, performed with the Robert C. Byrd Green Bank Telescope (GBT). The resulting observations cover at least four deg$^2$ around these galaxies with an average 5$\sigma$ detection limit of 1.2$\times$10$^{18}$ cm$^{-2}$ over a velocity range of 20 km s$^{-1}$ and angular scale of 9.1$'$. In addition to detecting the same total flux as the GBT data, the spatial distribution of the GBT and original Westerbork Synthesis Radio Telescope (WSRT) data match well at equal spatial resolutions. The HI mass fraction below HI column densities of 10$^{19}$ cm$^{-2}$ is, on average, 2\%. We discuss the possible origins of low column density HI of nearby spiral galaxies. The absence of a considerable amount of newly detected HI by the GBT indicates these galaxies do not have significant extended diffuse HI structures, and suggests future surveys planned with the SKA and its precursors must go \textit{at least} as deep as 10$^{17}$ cm$^{-2}$ in column density to significantly increase the probability of detecting HI associated with the cosmic web and/or cold mode accretion. Comment: Accepted for publication in The Astrophysical Journal; 28 pages, 15 figures |
| Databáze: | OpenAIRE |
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