EDP Sciences
Free access
Volume 400, Number 3, March IV 2003
Page(s) 871 - 875
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20030082

A&A 400, 871-875 (2003)
DOI: 10.1051/0004-6361:20030082

Observations of the high-redshift galaxy B2 0902+343 at 92 cm

A. M. Cody1, 2 and R. Braun1

1  Netherlands Foundation for Research in Astronomy, PO Box 2, 7990 AA Dwingeloo, The Netherlands
2  Dept. of Astronomy, Harvard University, 60 Garden St., Cambridge, MA 02138, USA

(Received 21 November 2002 / Accepted 17 January 2003 )

We present 92 cm observations of the high-redshift galaxy B2 0902+343 (z=3.40) with the Westerbork Synthesis Radio Telescope (WSRT). Twenty-one cm $\ion{H}{i}$ is detected in absorption, at a depth of 15.9 mJy (= $6\sigma$) and rest frame velocity width 120 km s -1. We also report a null detection of OH emission or absorption at the 1665/1667 MHz rest-frame transitions. Based on our spectral sensitivity, we derive an upper limit on OH maser luminosity of $\log(L/L_{\odot})<5.2$. In addition, we consider the possibility of absorption, and estimate a maximum column depth N(OH) of $1\times10^{15}~\mathrm{cm}^{-2}$, corresponding to at most $2\times10^5-9\times10^6~M_{\odot}$ of OH in the galaxy. The implications of these results are discussed in the context of current efforts to extend the OH megamaser luminosity function and galactic merger rate to high redshift.

Key words: galaxies: individual: B2 0902+343 -- radio lines: galaxies -- galaxies: high-redshift -- cosmology: observations

Offprint request: A. M. Cody, acody@cfa.harvard.edu

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