Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'487'895
Articles rated: 2609

28 March 2024
 
  » arxiv » 2004.0847

 Article overview


FLASH Early Science -- Discovery of an intervening HI 21-cm absorber from an ASKAP survey of the GAMA 23 field
J. R. Allison ; E. M. Sadler ; S. Bellstedt ; L. J. M. Davies ; S. P. Driver ; S. L. Ellison ; M. Huynh ; A. D. Kapinska ; E. K. Mahony ; V. A. Moss ; A. S. G. Robotham ; M. T. Whiting ; S. J. Curran ; J. Darling ; A. W. Hotan ; R. W. Hunstead ; B. S. Koribalski ; C. D. P. Lagos ; M. Pettini ; K. A. Pimbblet ; M. A. Voronkov ;
Date 2 Apr 2020
AbstractWe present early science results from the First Large Absorption Survey in HI (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen HI gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for HI absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between $z = 0.34$ and $0.79$ over a sky area of approximately 50 square degrees. In a purely blind search we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the HI spin temperature of $T_{ m spin}$ = 100 K and source covering fraction $c_{ m f} = 1$, the total comoving absorption path length sensitive to all Damped Lyman-$alpha$ Absorbers (DLAs; $N_{ m HI} geq 2 imes 10^{20}$ cm$^{-2}$) is $Delta{X} = 6.6 pm 0.3$ ($Delta{z} = 3.7 pm 0.2$) and super-DLAs ($N_{ m HI} geq 2 imes 10^{21}$ cm$^{-2}$) is $Delta{X} = 111 pm 6$ ($Delta{z} = 63 pm 3$). We estimate upper limits on the HI column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at $z = 0.3562$ towards NVSS J224500$-$343030, with a column density of $N_{ m HI} = (1.2 pm 0.1) imes 10^{20} (T_{ m spin}/100~mathrm{K})$ cm$^{-2}$. The absorber is associated with GAMA J22450.05$-$343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive ($M_{ m HI} gtrsim 3 imes 10^{9}$ M$_{odot}$) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.
Source arXiv, 2004.0847
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica