Chandra and Hubble Space Telescope observations of dark gamma-ray bursts and their host galaxies
Chandra and Hubble Space Telescope observations of dark gamma-ray bursts and their host galaxies
复制标题
DOI：
10.1093/mnras/stz1039
复制
发表时间：
2019-04
影响因子：
4.8
通讯作者：
A. Chrimes;A. Levan;E. Stanway;J. Lyman;A. Fruchter;P. Jakobsson;P. O’Brien;D. Perley;N. Tanvir;P. Wheatley;K. Wiersema
中科院分区：
文献类型：
--
作者：
A. Chrimes;A. Levan;E. Stanway;J. Lyman;A. Fruchter;P. Jakobsson;P. O’Brien;D. Perley;N. Tanvir;P. Wheatley;K. Wiersema
我们提出了一个研究的21个暗伽马射线暴（GRB）的主机星系，主要是使用X射线余辉获得的钱德拉X射线天文台（CXO），以精确地定位在深哈勃太空望远镜（HST）成像的爆发区域的爆发。在F160W中，除了一个案例外，所有案例都能很好地检测到宿主星系，在F606W成像中，有60%的案例都能检测到宿主星系。我们测量星等并对每个星系进行形态分析。的不对称性，浓度和椭圆度的暗爆发主机进行比较对宿主星系的光学明亮的伽玛暴。与其他研究一致，我们发现，黑暗的伽玛射线暴主机是红色和更明亮的比大部分的伽玛射线暴主机人口。暗伽马射线暴从其宿主星系质心的投影空间偏移的分布与光学亮暴的分布相当。暗伽马射线暴的主体在物理上更大，更重，更红，但在浓度和不对称性方面与亮伽马射线暴的主体在形态上相似。我们的分析将样本中高红移（z > 5）的伽玛暴的比例限制在14%，这意味着整个长伽玛暴的上限≤ 4.4%。如果尘埃是暗伽玛暴余辉变暗的主要原因，那么测量到的消光可能需要一个星团尘埃成分来解释观测到的偏移和椭圆度分布。
We present a study of 21 dark gamma-ray burst (GRB) host galaxies, predominantly using X-ray afterglows obtained with the Chandra X-Ray Observatory (CXO) to precisely locate the burst in deep Hubble Space Telescope (HST) imaging of the burst region. The host galaxies are well-detected in F160W in all but one case and in F606W imaging in 60 per cent of cases. We measure magnitudes and perform a morphological analysis of each galaxy. The asymmetry, concentration, and ellipticity of the dark burst hosts are compared against the host galaxies of optically bright GRBs. In agreement with other studies, we find that dark GRB hosts are redder and more luminous than the bulk of the GRB host population. The distribution of projected spatial offsets for dark GRBs from their host galaxy centroids is comparable to that of optically bright bursts. The dark GRB hosts are physically larger, more massive and redder, but are morphologically similar to the hosts of bright GRBs in terms of concentration and asymmetry. Our analysis constrains the fraction of high redshift (z > 5) GRBs in the sample to 14 per cent, implying an upper limit for the whole long-GRB population of ≤4.4 per cent. If dust is the primary cause of afterglow darkening amongst dark GRBs, the measured extinction may require a clumpy dust component in order to explain the observed offset and ellipticity distributions.