Letter to the Editor
HST observations of the QSO pair Q1026-0045A,B *
Patrick Petitjean 1, 2,
Jean Surdej 3, 7,
Alain Smette 4,
Peter Shaver 5,
Jan Mücket 6 and
Marc Remy 3
Received 12 February 1998 / Accepted 23 April 1998
The spatial distribution of the Ly forest is studied using new HST data for the quasar pair Q 1026-0045 A and B at = 1.438 and 1.520 respectively. The angular separation is 36 arcsec and corresponds to transverse linear separations between lines of sight of 300 kpc ( = 0.5) over the redshift range 0.833 z 1.438. From the observed numbers of coincident and anti-coincident Ly absorption lines, we conclude that, at this redshift, the Ly structures have typical dimensions of 500 kpc, larger than the mean separation of the two lines of sight. The velocity difference, , between coincident lines is surprisingly small (4 and 8 pairs with 50 and 200 km s-1 respectively).
Metal line systems are present at = 1.2651 and 1.2969 in A, = 0.6320, 0.7090, 1.2651 and 1.4844 in B. In addition we tentatively identify a weak Mg II system at = 0.11 in B. It is remarkable that the = 1.2651 system is common to both lines of sight. The system at = 1.4844 has strong O VI absorption.
There is a metal-poor associated system at = 1.4420 along the line of sight to A with complex velocity profile. We detect a strong Ly absorption along the line of sight to B redshifted by only 300 km s-1 relatively to the associated system. It is tempting to interpret this as the presence of a disk of radius larger than 300 kpc surrounding quasar A.
Key words: quasars: individual: Q 1026 0045A,B, galaxies: ISM, quasars:absorption lines, galaxies: halo
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© European Southern Observatory (ESO) 1998
Online publication: May 15, 1998