Implications of 21-cm observations for damped Ly systems
نویسندگان
چکیده
منابع مشابه
Implications of 21cm observations for damped Ly-α systems
We present Giant Metrewave Radio Telescope HI 21cm absorption observations, of candidate and confirmed damped Lyman-α systems. The derived spin temperatures Tspin are high, in all cases, ∼ 1000 K or higher. We have also collated from the published literature a list of damped absorbers for which 21cm observations exist, and discuss the implications of the observations for the nature of these sys...
متن کاملATCA search for 21 cm emission from a candidate damped
We report a deep search for 21 cm emission/absorption from the z ∼ 0.101 candidate damped Lyman-α system towards PKS 0439−433, using the Australia Telescope Compact Array (ATCA). The spectrum shows a weak absorption feature — at the 3.3σ level — which yields a lower limit of 730 K on the spin temperature of the system. No H i emission was detected: the 3σ upper limit on the H i mass of the abso...
متن کاملA deep search for 21 cm absorption in high redshift damped Lyman - α systems .
We present deep GMRT 21cm absorption spectra of 10 damped Lyman-α systems (DLAs), of which 8 are at redshifts z >∼ 1.3. HI absorption was detected in only one DLA, the z = 0.5318 absorber toward PKS 1629+12. This absorber has been identified with a luminous spiral galaxy; the spin temperature limit (Ts ≤ 310 K) derived from our observations continues the trend of DLAs associated with bright spi...
متن کاملConstraining dark matter through 21 cm observations
Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21 cm line signal. If dark matter (DM) decays or annihilates the corresponding energy input affects the hydrogen kinetic temperature and ionized fraction, and contributes to the Lyα background. The changes induced by these processes on the 21 cm signal can then be used to constrain the proposed DM cand...
متن کاملThe detectability of H I 21 - cm absorption in damped Lyman - α systems
In this paper we investigate the possible reasons why H I 21-cm absorption in damped Lyman-α systems (DLAs) has only been detected at low redshift: To date, no 21-cm absorption has yet been detected at zabs > 2.3 and at redshifts less than this, there is a mix of detections and non-detections in the DLAs searched. This has been attributed to the morphologies of the galaxies hosting the DLAs, wh...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2000
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.2000.03793.x