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Table 2

Main properties of the Lyα  envelopes for all six quasars measured to date (Paper I and this work).

Object λ FWHM Extent Integrated flux 3 − σ detection limit Surface brightness
[Å] [Å] (′′; kpc) [erg s-1 cm-2 [erg s-1 cm-2] [erg s-1 cm-2′′-2]

SDSS J0939+0039  −  − (7;45)  − 3.9 × 10-18a  <2.8 × 10-19a
BR 1033−0327 6725.0 ± 0.5 50 ± 10 10;64 1.4(±0.1) × 10-17 6.7 × 10-18 7.2(±0.5) × 10-19
SDSS J14472+0401 6756.3 ± 0.5 30 ± 3 6;38 4.3( ± 0.7) × 10-18 2.5 × 10-18 3.6( ± 0.6) × 10-19
Q 2139−4324 6641.0 ± 0.3  − (7;45)  − 2.2 × 10-18a  < 1.6 × 10-19a
SDSS J21474−0838 6808.2 ± 1.0 50 ± 8 8;51 3.1(±0.2) × 10-16 3.3 × 10-18 1.9(±0.1) × 10-17
BR 2237−0607 6773.6 ± 2.0 19 ± 2 4;26 2.6(±0.8) × 10-18 2.4 × 10-18 3.3(±1.0) × 10-19

Notes. All parameters are given in the observer’s frame. The 3 − σ detection limit is based on the standard deviation of the background noise according to Eq. (2). The surface brightness is integrated in wavelength but given per arcsec2, while the 3 − σ limit is spatially and spectrally integrated.

(a)

Assuming an average extent of 7′′.

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