A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems

By M. Rauch, M. Haehnelt, A. Bunker, George D. Becker, F. Marleau, J. Graham, S. Cristiani, M. Jarvis, C. Lacey, S. Morris and 3 more. 2007

204 citations recorded by the source corpus.

We have conducted a long-slit search for low surface brightness Lyα emitters at redshift 2.67 < z < 3.75. A 92 hr long exposure with the ESO VLT FORS2 instrument down to a 1 σ surface brightness detection limit of 8 × 10−20 erg cm−2 s−1 arcsec−2 per arcsec2 aperture yielded a sample of 27 single line emitters with fluxes of a few × 10−18 erg s−1 cm−2. We present arguments that most objects are indeed Lyα. The large comoving number density, 3 × 10−2 h370 Mpc−3, the large covering factor, dN/dz ∼ 0.2–1, and the often extended Lyα emission suggest that the emitters can be identified with the elusive host population of damped Lyα systems (DLAS) and high column density Lyman limit systems (LLS). A small inferred star formation rate, perhaps supplemented by cooling radiation, appears to energetically dominate the Lyα emission, and is consistent with the low metallicity, low dust content, and theoretically inferred low masses of DLAS, and with the relative lack of success of earlier searches for their optical counterparts. Some of the line profiles show evidence for radiative transfer in galactic outflows. Stacking surface brightness profiles, we find emission out to at least 4″. The centrally concentrated emission of most objects appears to light up the outskirts of the emitters (where LLS arise) down to a column density where the conversion from UV to Lyα photon becomes inefficient. DLAS, high column density LLS, and the emitter population discovered in this survey appear to be different observational manifestations of the same low-mass, protogalactic building blocks of present-day L* galaxies.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/42c4ef4725f7cc1866bff52d972ea0cdbb9c37f9

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Citations in the corpus

The MUSE 3D view of the Hubble Deep Field South (2014, background): “For example, Rauch et al. (2008) performed a long slit integration of 92 hours with FORS2 at the VLT.”
THE HETDEX PILOT SURVEY. II. THE EVOLUTION OF THE Lyα ESCAPE FRACTION FROM THE ULTRAVIOLET SLOPE AND LUMINOSITY FUNCTION OF 1.9 (2010, methodology): “…∼ 6 using slit spectroscopy failed to do so, and could only set upper limits to their number density (Martin & Sawicki 2004; Tran et al. 2004), more recent attempts at lower redshifts (2 < z < 6) like the ones by Rauch et al. (2008) and Cassata et al. (2011), have produced large samples of objects.”
DIFFUSE Lyα EMITTING HALOS: A GENERIC PROPERTY OF HIGH-REDSHIFT STAR-FORMING GALAXIES (2011, background): “An exception is the extremely deep spectroscopic survey for Lyα emission conducted by Rauch et al. (2008) [R08].”
Lyα Emitting Galaxies as a Probe of Reionisation (2014, background): “…presence of spatially extended Lyα halos around star-forming galaxies (Fynbo, Møller, & Warren 1999; Hayashino et al. 2004; Hayes et al. 2005, 2007; Rauch et al. 2008; Östlin et al. 2009; Steidel et al. 2011; Matsuda et al. 2012; Hayes et al. 2013; Momose et al. 2014, but also see Jiang et al.…”
Extended Lyman α haloes around individual high-redshift galaxies revealed by MUSE (2015, background): “A significant step forward in terms of statistics was the study by Rauch et al. (2008) who identified 27 faint LAEs between z ' 2.6 and 3.8 in an ultradeep longslit exposure of 92 h coadded observing time on the ESO-VLT.”
The MUSE Hubble Ultra Deep Field Survey - VIII. Extended Lyman-α haloes around high-z star-forming galaxies (2017, methodology): “Over a similar period and using a different approach, Rauch et al. (2008) performed an ultra-deep (92h) long-slit observation and identified 27 faint LAEs (few ×10−18 erg s−1 cm−2) at redshift 2.67< z < 3.75.”
STATISTICS OF 207 Lyα EMITTERS AT A REDSHIFT NEAR 7: CONSTRAINTS ON REIONIZATION AND GALAXY FORMATION MODELS (2010, methodology): “We also estimate the best-fit Schechter parameters with a fixed α = −1.7, because the value of α ≃ −1.7 is recently reported for z = 2−6 LAEs (Cassata et al. 2010; see also Rauch et al. 2008) as well as z ∼ 7 dropouts (e.g. Ouchi et al. 2009b; Oesch et al. 2010; McLure et al. 2010).”