The CORALS survey

Ellison, Sara L.; Yan, Lin; Hook, I. M.; Pettini, Max; Wall, J. V.; Shaver, P. A.

doi:10.1051/0004-6361:20011738

Cited by 121 publications

(180 citation statements)

References 46 publications

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“…In addition, it seems that the RLQs generally reside in richer environments than RQQs (Ellison et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of extended Lyαenvelopes aroundz = 4.5 quasars

North¹,

Courbin²,

Eigenbrod³

et al. 2012

A&A

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What are the frequency, shape, kinematics, and luminosity of Lyα envelopes surrounding radio-quiet quasars at high redshift, and is the luminosity of these envelopes related to that of the quasar or not? As a first step towards answering these questions, we have searched for Lyα envelopes around six radio-quiet quasars at z ∼ 4.5, using deep spectra taken with the FORS2 spectrograph attached to the UT1 of the Very Large Telescope (VLT). Using the multi-slit mode allows us to observe several point spread function stars simultaneously with the quasar, and to remove the point-like emission from the quasar, unveiling the faint underlying Lyα envelope with unprecedented depth. An envelope is detected around four of the six quasars, which suggests that these envelopes are very frequent. Their diameter varies in the range 26 < ∼ d < ∼ 64 kpc, their surface brightness in the range 3 × 10 −19 < ∼ μ < ∼ 2 × 10 −17 erg s −1 cm −2 arcsec −2 , and their luminosity in the range 10 42 < ∼ L(Lyα) < ∼ 10 44 erg s −1 . Their shape may be strongly asymmetric. The Lyα emission line full width at half maximum (FWHM) is 900 < FWHM < 2200 km s −1 and its luminosity correlates with that of the broad line region (BLR) of the quasar, with the notable exception of BR2237-0607, the brightest object in our sample. The same holds for the relation between the envelope Lyα luminosity and the ionizing luminosity of the quasar. While the deep slit spectroscopy presented in this paper is very efficient at detecting very faint Lyα envelopes, narrow-band imaging is now needed to measure accurately their spatial extent, radial luminosity profile, and total luminosity. These observables are crucial to help us discriminate between the three possible radiation processes responsible for the envelope emission: (i) cold accretion, (ii) fluorescence induced by the quasar, and (iii) scattering of the BLR photons by cool gas.

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“…In addition, it seems that the RLQs generally reside in richer environments than RQQs (Ellison et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of extended Lyαenvelopes aroundz = 4.5 quasars

North¹,

Courbin²,

Eigenbrod³

et al. 2012

A&A

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“…It has provided the basis for a study of damped Lyman-α absorption systems along the lines of sight to the quasars (Ellison et al 2001(Ellison et al , 2002. In this paper we also Send offprint requests to: I. M. Hook, e-mail: imh@astro.ox.ac.uk Table A.1 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/399/469…”

Section: Introductionmentioning

confidence: 99%

The Parkes quarter-Jansky flat-spectrum sample

Hook

Shaver

Jackson

et al. 2003

A&A

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Abstract. We present optical spectra and redshift measurements for 178 flat-spectrum objects from the Parkes quarter-Jansky flat-spectrum sample. These spectra were obtained in order to compile a complete sample of quasars for use in a study of quasar evolution. We present a composite optical spectrum made from the subset of 109 quasars that have flux densities in the range 0.25 Jy < S 2.7 GHz < 0.5 Jy, and make a comparison with a composite for radio-quiet QSOs from the Large Bright Quasar Survey. Our large sample of radio-loud quasars allows us to strengthen previous reports that the Lyα and CIV emission lines have larger equivalent width in radio-loud quasars than radio-quiet QSOs to greater than the 3σ level. However we see no significant difference in the equivalent widths of CIII] or MgII. We also show that the flux decrements across the Lyman-α line (D A ) measured from these spectra show the same trend with redshift as for optically selected QSOs.

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“…The first results, reported by Ellison et al (2001), showed that Ω DLA had not been significantly underestimated. To that conclusion we now add the findings that:…”

Section: Discussionmentioning

confidence: 98%

“…They found values which were only marginally higher than the corresponding quantities previously determined from optically selected QSO samples. In particular, within the limitations imposed by the small size of their sample, Ellison et al (2001) concluded that selection effects due to intervening dust may at most account for an underestimate by a factor of ∼2 in Ω DLA .…”

Section: The Corals Samplementioning

confidence: 99%

Zn and Cr Abundances in Damped Lyman Alpha Systems from the CORALS Survey

Akerman¹,

Ellison²,

Steidel³

2005

Proc. IAU

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Abstract.We have recently completed the measurement of the abundances of the elements Zn and Cr in a small, but complete, sample of damped Lyman alpha systems selected irrespectively of their dust content (the CORALS radio sample). We find that at a mean redshift z = 2.4 their metallicity and degree of dust depletion are statistically indistinguishable from those of larger samples of DLAs assembled from optical surveys. Thus we conclude that reasons other than a dust-induced bias must be found to explain the lack of redshift evolution in the metallicity of the galaxies giving rise to DLAs, and their generally low degree of chemical enrichment compared with luminous galaxies observed at the same epoch.

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The CORALS survey

Cited by 121 publications

References 46 publications

Spectroscopy of extended Lyαenvelopes aroundz = 4.5 quasars

Spectroscopy of extended Lyαenvelopes aroundz = 4.5 quasars

The Parkes quarter-Jansky flat-spectrum sample

Zn and Cr Abundances in Damped Lyman Alpha Systems from the CORALS Survey

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