Deep Ly<i>α</i>imaging of two ${\vec{z}}$ = 2.04 GRB host galaxy fields

Fynbo, J. P. U.; Møller, P.; Thomsen, B.; Hjorth, J.; Gorosabel, J.; Andersen, M. I.; Egholm, M. P.; Holland, S. T.; Jensen, B. L.; Pedersen, H.; Weidinger, M.

doi:10.1051/0004-6361:20020427

Cited by 67 publications

(81 citation statements)

References 69 publications

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“…This final catalogue includes 386 objects. Following the procedure of Fynbo et al (2002), three co-authors then individually ranked these 386 candidates by visual inspection into three categories; first a category of rejected detections (caused by CCD or stellar artifacts or enhancement due to airplane/satellite tracks), then into two categories of likely candidates and candidates that are unlikely to be real but for which no obvious reason was found to reject them (see also Fig. 2).…”

Section: Object Detection and Candidate Selectionmentioning

confidence: 99%

“…In practice, the lower redshift limit is in fact higher than z ≈ 1.6 because of the drop-off in CCD sensitivity and a more typical lower redshift limit is z ∼ 2.0. Eight narrow-band surveys have so far been published below z ∼ 3; Fynbo et al (1999), Pentericci et al (2000), Stiavelli et al (2001), Fynbo et al (2002Fynbo et al ( , 2003a, Francis et al (2004) and Venemans et al (2007). Furthermore, Van Breukelen et al (2005) published a sample of Lyα emitters (LAEs) at z ∼ 2.5 using integral-field spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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Evolution in the properties of Lyman-αemitters from redshiftsz~ 3 toz ~ 2

Nilsson¹,

Tapken²,

Møller

et al. 2009

A&A

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156

237

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Context. Narrow-band surveys to detect Lyα emitters are powerful tools for identifying high, and very high, redshift galaxies. Although samples are increasing at redshifts z = 3−6, the nature of these galaxies is still poorly known. The number of galaxies detected at redshifts below z ∼ 3 are also small. Aims. We study the properties of z = 2.25 Lyα emitters and compare them with those of z > 3 Lyα emitters.Methods. We present narrow-band imaging made with the MPG/ESO 2.2m telescope and the WFI (Wide Field Imager) detector. Using this data, we have searched for emission-line objects. We find 170 candidate typical Lyα emitters and 17 candidates that we regard as high UV-transmission Lyα emitters. We have derived the magnitudes of these objects in 8 photometric bands from u * to K s , and studied whether they have X-ray and/or radio counterparts. Results. We demonstrate that there has been significant evolution in the properties of Lyα emitters between redshift z ∼ 3 and z = 2.25. The spread in spectral energy distributions (SEDs) at the lower redshift is larger and we detect a significant AGN contribution in the sample. The distribution of the equivalent widths is narrower than at z ∼ 3, with only a few candidates with rest-frame equivalent width above the predicted limit of 240 Å. The star formation rates derived from the Lyα emission compared to those derived from the UV emission are lower by on average a factor of ∼1.8, indicative of a significant absorption by dust. Conclusions. Lyα emitters at redshift z = 2.25 may be more evolved than Lyα emitters at higher redshift. The red SEDs imply more massive, older and/or dustier galaxies at lower redshift than observed at higher redshifts. The decrease in equivalent widths and star formation rates indicate more quiescent galaxies, with in general less star formation than in higher redshift galaxies. At z = 2.25, AGN appear to be more abundant and also to contribute more to the Lyα emitting population.

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Section: Object Detection and Candidate Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evolution in the properties of Lyman-αemitters from redshiftsz~ 3 toz ~ 2

Nilsson¹,

Tapken²,

Møller

et al. 2009

A&A

Self Cite

156

237

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“…The selection of LAE candidates is based on the "narrow minus on-band broad" versus "narrow minus off-band broad" colour/colour plot technique (Møller & Warren 1993;Fynbo et al 1999Fynbo et al , 2000Fynbo et al , 2002Fynbo et al 2003). The object identification and photometry was carried out in SExtractor (Bertin & Arnouts 1996) using the dual-image mode having a detection image and measuring the photometric properties on the individual images.…”

Section: Lae Candidate Selectionmentioning

confidence: 99%

The Building the Bridge survey for z = 3 Lyα emitting galaxies

Grove

Fynbo

Ledoux

et al. 2009

A&A

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Context. We have substantial information about the kinematics and abundances of galaxies at z ≈ 3 studied in absorption against the light of background QSOs. At the same time we have already studied 1000s of galaxies detected in emission mainly through the Lyman-break selection technique; however, we know very little about how to make the connection between the two data sets. Aims. We aim at bridging the gap between absorption-selected and emission-selected galaxies at z ≈ 3 by probing the faint end of the luminosity function of star-forming galaxies at z ≈ 3. Methods. Narrow-band surveys for Lyman-α (Lyα) emitters have proven to be an efficient probe of faint, star-forming galaxies in the high-redshift universe. We performed narrow-band imaging in three fields with intervening QSO absorbers (a damped Lyα absorber and two Lyman-limit systems) using the VLT. We target Lyα at redshifts 2.85, 3.15, and 3.20. Results. We find a consistent surface density of about 10 Lyα-emitters per square arcmin per unit redshift in all three fields down to our detection limit of about 3 × 10 41 erg s −1 . The luminosity function is consistent with what has been found by other surveys at similar redshifts. About 85% of the sources are fainter than the canonical limit of R = 25.5 for most Lyman-break galaxy surveys. In none of the three fields do we detect the emission counterparts of the QSO absorbers. In particular we do not detect the counterpart of the z = 2.85 damped Lyα absorber towards Q2138−4427. This implies that the DLA galaxy is either not a Lyα emitter or is fainter than our flux limit. Conclusions. Narrow-band surveys for Lyα emitters are excellent for probing the faint end of the luminosity function at z ≈ 3. There is a very high surface density of this class of objects; yet, we only detect galaxies with Lyα in emission, so the density of galaxies with similar broad band magnitudes will be substantially higher. This is consistent with a very steep slope of the faint end of the luminosity function as has been inferred by other studies. This faint population of galaxies is playing a central role in the early Universe. There is evidence that this popualtion is dominating the intergrated star-formation activity, responsible for the bulk of the ionising photons at z 3 and likely also responsible for the bulk of the enrichment of the intergalactic medium.

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“…Unlike the LBGs, and as expected from their colours, these galaxies are often massive and dusty (Förster-Schreiber et al 2004;Papovich et al 2006). Other types of high redshift galaxies include starbursting galaxies such as those detected with sub-mm arrays (SMGs; Ivison et al 1998Ivison et al , 2000Blain et al 1999;Chapman et al 2005) and smaller galaxies detected when gamma-ray bursts occur in them (Bloom et al 1998;Fynbo et al 2002;Christensen et al 2004). One selection method that has become increasingly popular is that of narrow-band imaging of the Based on observations carried out at the European Southern Observatory (ESO) under prog.…”

Section: Introductionmentioning

confidence: 99%

The nature ofz ~ 2.3 Lyman-αemitters

Nilsson

Östlin

Møller

et al. 2011

A&A

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We study the multi-wavelength properties of a set of 171 Lyα emitting candidates at redshift z = 2.25 found in the COSMOS field, with the aim of understanding the underlying stellar populations in the galaxies. We especially seek to understand what the dust contents, ages and stellar masses of the galaxies are, and how they relate to similar properties of Lyα emitters at other redshifts. The candidates here are shown to have different properties from those of Lyα emitters found at higher redshift, by fitting the spectral energy distributions (SEDs) using a Monte-Carlo Markov-Chain technique and including nebular emission in the spectra. The stellar masses, and possibly the dust contents, are higher, with stellar masses in the range log M * = 8.5−11.0 M and A V = 0.0−2.5 mag. Young population ages are well constrained, but the ages of older populations are typically unconstrained. In 15% of the galaxies only a single, young population of stars is observed. We show that the Lyα fluxes of the best fit galaxies are correlated with their dust properties, with higher dust extinction in Lyα faint galaxies. Testing for whether results derived from a light-weighted stack of objects correlate to those found when fitting individual objects we see that stellar masses are robust to stacking, but ages and especially dust extinctions are derived incorrectly from stacks. We conclude that the stellar properties of Lyα emitters at z = 2.25 are different from those at higher redshift and that they are diverse. Lyα selection appears to be tracing systematically different galaxies at different redshifts.

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

Cited by 67 publications

References 69 publications

Evolution in the properties of Lyman-αemitters from redshiftsz~ 3 toz ~ 2

Evolution in the properties of Lyman-αemitters from redshiftsz~ 3 toz ~ 2

The Building the Bridge survey for z = 3 Lyα emitting galaxies

The nature ofz ~ 2.3 Lyman-αemitters

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