Physical conditions in high - redshift GRB - DLA absorbers observed with VLT / UVES : Implications for molecular hydrogen searches ⋆
نویسندگان
چکیده
Aims. We aim to understand the nature of the absorbing neutral gas in the galaxies hosting high-redshift long-duration gamma-ray bursts (GRBs) and to determine their physical conditions. Methods. A detailed analysis of high-quality VLT/UVES spectra of the optical afterglow of GRB 050730 and other Swift-era bursts is presented. Results. We report the detection of a significant number of previously unidentified allowed transition lines of Fe + , involving the fine structure of the ground term (6
منابع مشابه
Statistics and characteristics of MgII absorbers along GRB lines of sight observed with VLT-UVES
We analyse the properties of Mg ii absorption systems detected along the sightlines toward GRBs using a sample of 10 GRB afterglow spectra obtained with VLT-UVES over the past six years. The signal-to-noise ratio is sufficiently high that we can extend previous studies to smaller equivalent widths (typically Wr > 0.3 Å). Over a pathlength of ∆z ∼ 14, we detect 9 intervening Mg ii systems with W...
متن کاملThe VLT-UVES survey for molecular hydrogen in high-redshift damped Lyman-α systems⋆
We have searched for molecular hydrogen in damped Lyman-α (DLA) and subDLA systems at high redshift (zabs > 1.8) using UVES at the VLT down to a detection limit of typically N(H2) = 2×10 14 cm. Out of the 33 systems in our sample, 8 have firm and 2 have tentative detections of associated H2 absorption lines. Considering that 3 detections were already known from past searches, molecular hydrogen...
متن کاملMetallicity as a criterion to select H2 bearing Damped Lyman-α systems
We characterize the importance of metallicity on the presence of molecular hydrogen in damped Lyman-α (DLA) systems. We construct a representative sample of 18 DLA/subDLA systems with log N(H ) > 19.5 at high redshift (zabs > 1.8) with metallicities relative to solar [X/H] > −1.3 (with [X/H] = log N(X)/N(H)−log(X/H)⊙ and X either Zn, S or Si). We gather data covering the expected wavelength ra...
متن کاملMolecular hydrogen and the nature of damped Lyman-α systems
We report results from our mini-survey for molecular hydrogen in eight high-redshift damped Lyman-α (DLA) systems using the ESO Ultra-violet and Visible Spectrograph on the VLT. In addition, we investigate two systems using ESO public data. We include in the sample the only system where H2 was previously detected and studied at high-spectral resolution. Altogether our sample consists of eleven ...
متن کاملHot Halos around High Redshift Protogalaxies Observations of O Vi and N V Absorption in Damped Lyman-α Systems
Aims. We present a study of the highly ionized gas (plasma) associated with damped Lyman-α (DLA) systems at z=2.1–3.1. Methods. We search for Ovi absorption and corresponding Si iv, C iv, and Nv in a Very Large Telescope/Ultraviolet-Visible Echelle Spectrograph (VLT/UVES) sample of 35 DLA systems with data covering Ovi at S/N>10. We then use optical depth profile comparisons and ionization mode...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2009