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Date and Time of the Query: 2019-04-25 T23:00:38 PDT
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For refcode 2010ApJ...710..385B:
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2010ApJ...710..385B Detection of Diffuse Neutral Intragroup Medium in Hickson Compact Groups Borthakur, Sanchayeeta; Yun, Min Su; Verdes-Montenegro, Lourdes Abstract. We present new Green Bank Telescope (GBT) 21 cm neutral hydrogen (H I) observations of a complete distance-limited sample of 22 Hickson Compact Groups (HCGs) with at least four true members. We detected an average H I mass of 8 x 10^9^ M_sun_ (median = 6 x 10^9^ M_sun_), which is significantly larger than previous single-dish measurements. Consequently, the H I deficiencies for these HCGs have been reduced, although not completely eliminated. Spectral comparison of the GBT data with complementary Very Large Array data shows significant H I excess in the GBT spectra. The observed excess is primarily due to the high surface brightness (HSB) sensitivity of the GBT detecting diffuse, low column density H I in these groups. The excess gas forms a faint diffused neutral medium which is an intermediate stage in the evolution of HSB H I tidal debris in the intragroup medium (IGM) before it is fully ionized. The excess gas mass fraction, (M(H I)_GBT_ -- M(H I)_VLA_)/M(H I)_GBT_, for our complete sample varies from 5% to 81% with an average of 36% (median = 30%). The excess gas mass fraction is highest in slightly H I deficient groups where the tidal debris has had enough time to evolve. We also find the excess gas content increases with the evolutionary phase of the group described in Verdes-Montenegro et al. Theoretical calculations indicate that an H I cloud of radius >= 200 pc would survive in an IGM of 2 x 10^6^ K for more than the typical dynamical lifetime of a group. However, smaller clouds get evaporated and assimilated into the hot IGM in a much shorter timescale. Key words: galaxies: evolution, galaxies: interactions =========================================================================== 2011ApJ...729..149B Erratum: "Detection of Diffuse Neutral Intragroup Medium in Hickson Compact Groups" (2010, ApJ, 710, 385) Borthakur, Sanchayeeta; Yun, Min Su; Verdes-Montenegro, Lourdes Abstract. Column 2 of Table 3 corresponding to HCG 31 should read BC instead of CD. The VLA H i data for HCG 31 presented in this paper were obtained by Verdes-Montenegro et al. (2005) in the VLA "CnB" configuration. We apologize for this error. ===========================================================================
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