تقرير
Lyman `bump' galaxies - II. A possible signature of massive extremely metal-poor or metal-free stars in z=3.1 Ly-alpha emitters
| العنوان: | Lyman `bump' galaxies - II. A possible signature of massive extremely metal-poor or metal-free stars in z=3.1 Ly-alpha emitters |
|---|---|
| المؤلفون: | Inoue, Akio K., Kousai, K., Iwata, I., Matsuda, Y., Nakamura, E., Horie, M., Hayashino, T., Tapken, C., Akiyama, M., Noll, S., Yamada, T., Burgarella, D. |
| سنة النشر: | 2010 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | (Abridged) Deep NB359 imaging with Subaru by Iwata et al. have detected surprisingly strong Lyman continuum (LyC; ~900A in the rest-frame) from some LAEs at z=3.1. However, the redshifts might be misidentified due to a narrow wavelength coverage in previous spectroscopy. We here present new deep spectroscopy covering the observed 4,000-7,000A with VLT/VIMOS and Subaru/FOCAS of 8 LAEs detected in NB359. All the 8 objects have only one detectable emission line around 4,970A which is most likely to be Ly-A at z=3.1, and thus, the objects are certainly LAEs at the redshift. However, 5 of them show a ~0.''8 spatial offset between the Ly-A emission and the source detected in NB359. No indications of the redshifts of the NB359 sources are found although it is statistically difficult that all the 5 LAEs have a foreground object accounting for the NB359 flux. The rest 3 LAEs show no significant offset from the NB359 position. Therefore, they are truly LyC emitting LAEs at z=3.1. We also examine the stellar population which simultaneously accounts for the strength of the LyC and the spectral slope of non-ionizing ultraviolet of the LAEs. We consider the latest statistics of Lyman limit systems to estimate the LyC optical depth in the IGM and an additional contribution of the bound-free LyC from photo-ionized nebulae to the LyC emissivity. As a result, we find that stellar populations with metallicity Z>=1/50Z_sun can explain the observed LyC strength only with a very top-heavy initial mass function (IMF; Comment: MNRAS accepted (18 pages, 14 figures, 5 tables) |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1111/j.1365-2966.2010.17851.x |
| URL الوصول: | http://arxiv.org/abs/1010.2582 |
| رقم الأكسشن: | edsarx.1010.2582 |
| قاعدة البيانات: | arXiv |
كن أول من يترك تعليقا!