A Group of Galaxies at Redshift 2.38

Francis, Paul; Woodgate, B. E.; Warren, S. J.; Møller, P.; Mazzolini, Marg; Bunker, A. J.; Lowenthal, James D.; Williams, T. B.; Minezaki, Takeo; Kobayashi, Yukiyasu; Yoshii, Yuzuru

doi:10.1086/176747

Cited by 123 publications

(166 citation statements)

References 43 publications

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“…It is presently unknown whether the galactic environments of GRB host galaxies are overdense or representative of the general field. Narrow-band Lyα observations are ideal to address this question as it has been shown to be an efficient way to probe the faint end of the galaxy population at redshifts 2 < z < 5 (Møller & Warren 1993;Francis et al 1995;Pascarelle et al 1996;Thommes et al 1997;Pascarelle et al 1998;Cowie & Hu 1998;Hu et al 1998;Fynbo et al 1999Fynbo et al , 2000Kudritzki et al 2000;Kurk et al 2000;Pentericci et al 2000Roche et al 2000;Rhoads et al 2000;Malhotra & Rhoads 2002;Fynbo et al 2001b). Lyα selection has the advantage that it is not continuum flux limited and hence allows the detection of high redshift proto-galaxies, or Lyα Emitting Galaxybuilding Objects (LEGOs, Møller & Fynbo 2001), that are intrinsically much fainter than those selected in continuum flux limited surveys.…”

Section: Introductionmentioning

confidence: 99%

Deep Lyαimaging of two ${\vec{z}}$ = 2.04 GRB host galaxy fields

Fynbo

Møller

Thomsen

et al. 2002

A&A

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Abstract. We report on the results of deep narrow-band Lyα and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyα emitter with a rest-frame equivalent width of 71 +20 −15Å . The galaxy consists of two main components and several fainter knots. GRB 000926 occurred in the western component, whereas most of the Lyα luminosity (about 65%) originates in the eastern component. Using archival HST images of the host galaxy we measure the spectral slopes (f λ ∝ λ β ) of the two components to β = −2.4 ± 0.3 (east) and −1.4 ± 0.2 (west). This implies that both components contain at most small amounts of dust, consistent with the observed strong Lyα emission. The western component has a slightly redder V − I colour than the eastern component, suggesting the presence of at least some dust. We do not detect the host galaxy of GRB 000301C in neither Lyα emission nor in U and I broad-band images. The strongest limit comes from combining the narrow and U -band imaging where we infer a limit of U (AB) > 27.7 (2σ limit per arcsec 2 ). The upper limits on the Lyα flux implies a Lyα equivalent width upper limit of ∼150Å. We find eleven and eight other galaxies with excess emission in the narrow filter in the fields of GRB 000301C and GRB 000926 respectively. These galaxies are candidate Lyα emitting galaxies in the environment of the host galaxies. Based on these detections we conclude that GRB 000926 occurred in one of the strongest centres of star formation within several Mpc, whereas GRB 000301C occurred in an intrinsically very faint galaxy far from being the strongest centre of star formation in its galactic environment. Under the hypothesis that GRBs trace star formation, the wide range of GRB host galaxy luminosities implies a very steep faint end slope of the high redshift galaxy luminosity function.

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Section: Introductionmentioning

confidence: 99%

Deep Lyαimaging of two ${\vec{z}}$ = 2.04 GRB host galaxy fields

Fynbo

Møller

Thomsen

et al. 2002

A&A

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“…Several studies have shown that Lyα narrow-band imaging is an alternative technique to identify high redshift galaxies (Møller & Warren 1993;Francis et al 1995;Pascarelle et al 1996;Pascarelle et al 1998;Hu et al 1998;Fynbo et al 1999Fynbo et al , 2000Kudritzki et al 2000;Kurk et al 2000;Pentericci et al 2000;Steidel et al 2000;Roche et al 2000;Rhoads et al 2000). So far it has not been considered efficient enough to seriously compete with the LBG technique, but it does have the advantage that spectroscopic confirmation is not limited by the broad band flux.…”

Section: Introductionmentioning

confidence: 99%

Probing the faint end of the Galaxy luminosity function at $\vec{z}=$ 3 with Lyαemission

Fynbo

Møller

Thomsen³

2001

A&A

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Abstract. We present spectroscopic observations obtained with the ESO Very Large Telecope (VLT) of seven candidate Lyα emitting galaxies in the field of the radio quiet Q1205-30 at z = 3.04 previously detected with deep narrow band imaging. Based on equivalent widths and limits on line ratios we confirm that all seven objects are Lyα emitting galaxies. Deep images also obtained with the VLT in the B and I bands show that five of the seven galaxies have very faint continuum fluxes (I(AB) ≈ 26.8 and B(AB) ≈ 27.3). The star formation rates of these seven galaxies estimated from the rest-frame UV continuum around 2000Å, as probed by the I-band detections, as well as from the Lyα luminosities, are 1-4 M yr −1 assuming a Hubble constant of 65 km s −1 Mpc −1 , Ωm = 0.3, and ΩΛ = 0.7. This is 1-3 orders of magnitude lower than for other known populations of star-forming galaxies at similar redshifts (the Lyman-Break galaxies and the sub-mm selected sources). The inferred density of the objects is high, 16 ± 4 per arcmin 2 per unit redshift. This is consistent with the integrated luminosity function for Lyman-Break galaxies down to R = 27 if the fraction of Lyα emitting galaxies is ≈70% at the faint end of the luminosity function. However, if this fraction is 20% as reported for the bright end of the luminosity function then the space density in this field is significantly larger (by a factor of 3.5) than expected from the luminosity function for Lyman-Break galaxies in the HDF-North. This would be an indication that at least some radio quiet QSOs at high redshift reside in overdense environments or that the faint end slope of the high redshift luminosity function has been underestimated. We find evidence that the faint Lyα galaxies are essentially dust-free. These observations show that Lyα emission is an efficient method by which to probe the faint end of the luminosity function at high redshifts.

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“…A small number of such objects have been seen in the fields of z ∼ 2 → 3.5 quasars, which are well separated from the quasar and which may represent neighboring galaxies either with AGN 14 or with intense star formation that can excite the Lyα emission line but without so much dust that the line is suppressed. [15][16][17] The latter class of objects, which are relatively unobscured by foreground absorption, may provide the most direct estimates of star formation at the earliest epochs. It appears that the quasar may mark the sites of such formation and thus identify a redshift for targeted wavelength searches.…”

mentioning

confidence: 99%