Deep<i>R</i>-band counts of<i>z</i>≈ 3 Lyman-break galaxy candidates with the LBT

Boutsia, K.; Grazian, A.; Giallongo, E.; Castellano, M.; Pentericci, L.; Fontana, A.; Fiore, F.; Gallozzi, S.; Cusano, F.; Paris, D.; Speziali, R.; Testa, V.

doi:10.1051/0004-6361/201321654

Cited by 7 publications

(12 citation statements)

References 39 publications

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“…Deep U-and R-band images obtained by LBC at the prime focus of the LBT telescope (observations described in Boutsia et al 2014), reaching 1σ magnitude limits of U 29.7 and R 28.2, were used to measure the ionizing escape fraction from the galaxy sample down to a few percent level. The main results are the following: -A subsample of ten galaxies with R ≤ 25.5 has a measured U-band detection that corresponds to a LyC emission of f rel esc ≥ 28%.…”

Section: Discussionmentioning

confidence: 99%

“…survey, with the goal of providing complementary deep UV coverage with LBC to the northern fields (COSMOS, GOODS-North, EGS) of the CANDELS survey (Grogin et al 2011;Koekemoer et al 2011). The LBC imaging data set of the COSMOS field has been described in detail in Boutsia et al (2011) and Boutsia et al (2014).…”

Section: The Photometric Data Setmentioning

confidence: 99%

“…This imager has observed part (∼0.20 sq. deg) of the COSMOS (Scoville et al 2007) field in UGRIZ-bands to search for LBGs at 2.7 < z < 3.4 (Boutsia et al 2014). We obtained these data at the LBT with LBC, one of the most efficient ground-based, large-field UV imager's at an 8-meter class telescope, which has allowed us to derive a stringent limit of ≤5% to the escape fraction of eleven starforming galaxies at z ∼ 3.3 (Boutsia et al 2011), using the same technique that is adopted in this work.…”

Section: The Photometric Data Setmentioning

confidence: 99%

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The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

Grazian

Giallongo

Gerbasi

et al. 2015

A&A

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105

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Context. The ionizing Lyman continuum flux escaping from high-redshift galaxies into the intergalactic medium is a fundamental quantity to understand the physical processes involved in the reionization epoch. However, from an observational point of view, direct detections of HI ionizing photons at high redshifts are feasible for galaxies mainly in the interval z ∼ 3−4. Aims. We have investigated a sample of star-forming galaxies at z ∼ 3.3 to search for possible detections of Lyman continuum ionizing photons escaping from galaxy halos. Methods. We used deep ultraviolet (UV) imaging in the COSMOS field, obtained with the prime focus camera LBC at the LBT telescope, along with a catalogue of spectroscopic redshifts obtained by the VIMOS Ultra Deep Survey (VUDS) to build a sample of 45 galaxies at z ∼ 3.3 with L > 0.5 L * . We obtained deep LBC images of galaxies with spectroscopic redshifts in the interval 3.27 < z < 3.40 both in the R-and deep U-bands (magnitude limit U ∼ 29.7 at S /N = 1). At these redshifts, the R-band samples the non-ionizing 1500 Å rest-frame luminosity and the U-band samples the rest-frame spectral region just short-ward of the Lyman edge at 912 Å. Their flux ratio is related to the ionizing escape fraction after statistical removal of the absorption by the intergalactic medium along the line of sight. Results. A subsample of ten galaxies apparently shows escape fractions >28%, but a detailed analysis of their properties reveals that, with the exception of two marginal detections (S /N ∼ 2) in the U-band, all the other eight galaxies are most likely contaminated by the UV flux of lowredshift interlopers located close (in angular position) to the high-z targets. The average escape fraction derived from the stacking of the cleaned sample was constrained to f rel esc < 2%. The implied hydrogen photoionization rate is a factor two lower than that needed to keep the intergalactic medium ionized at z ∼ 3, as observed in the Lyman-α forest of high-z quasar spectra or by the proximity effect. Conclusions. These results support a scenario where high redshift, relatively bright (L ≥ 0.5L * ) star-forming galaxies alone are unable to sustain the level of ionization observed in the cosmic intergalactic medium at z ∼ 3. Star-forming galaxies at higher redshift and at fainter luminosities (L L * ) can only be major contributors to the reionization of the Universe if their physical properties are subject to rapid changes from z ∼ 3 to z ∼ 6-10. Alternatively, ionizing sources could be discovered looking for fainter sources among the active galactic nuclei population at high redshift.

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Section: Discussionmentioning

confidence: 99%

Section: The Photometric Data Setmentioning

confidence: 99%

Section: The Photometric Data Setmentioning

confidence: 99%

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The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

Grazian

Giallongo

Gerbasi

et al. 2015

A&A

Self Cite

105

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“…The dataset covers a spectral range from U band (λ central =355nm) to K band (λ central =2150nm), and it has been acquired by three different ground-based instruments. The U special filter, the G-Sloan, and the R-Sloan blue images were obtained with the Large Binocular Camera (Giallongo et al 2008) at the LBT on Mount Graham in Arizona, and are described in Boutsia et al (2014) (see also Grazian et al 2016Grazian et al , 2017. The I-and Z-band filter images (Taniguchi et al 2007;Capak et al 2007) have been acquired by the Suprime-Cam (Miyazaki et al 2002) mounted on the Subaru Telescope at Maunakea.…”

Section: Multi-band Observationsmentioning

confidence: 99%

UV slope ofz∼ 3 bright (L>L^*) Lyman-break galaxies in the COSMOS field

Pilo

Castellano²,

Fontana³

et al. 2019

A&A

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Context. The analysis of the UV slope β of Lyman-break galaxies (LBG) at different luminosities and redshifts is fundamental for understanding their physical properties, and in particular, their dust extinction. Aims. We analyse a unique sample of 517 bright (L > L * ) LBGs at redshift z∼3 in order to characterise the distribution of their UV slopes β and infer their dust extinction under standard assumptions. Methods. We exploited multi-band observations over 750 arcmin 2 of the COSMOS field that were acquired with three different ground-based facilities: the Large Binocular Camera (LBC) on the Large Binocular Telescope (LBT), the Suprime-Cam on the SUB-ARU telescope, and the VIRCAM on the VISTA telescope (ULTRAVISTA DR2). Our multi-band photometric catalogue is based on a new method that is designed to maximise the signal-to-noise ratio in the estimate of accurate galaxy colours from images with different point spread functions (PSF). We adopted an improved selection criterion based on deep Y-band data to isolate a sample of galaxies at z ∼ 3to minimise selection biases. We measured the UV slopes (β) of the objects in our sample and then recovered the intrinsic probability density function of β values (PDF(β)), taking into account the effect of observational uncertainties through detailed simulations. Results. The galaxies in our sample are characterised by mildly red UV slopes with < β > −1.70 throughout the enitre luminosity range that is probed by our data (−24 M 1600 −21). The resulting dust-corrected star formation rate density (SFRD) is log(S FRD) −1.6M /yr/M pc 3 , corresponding to a contribution of about 25% to the total SFRD at z∼3 under standard assumptions. Conclusions. Ultra-bright LBGs at z ∼ 3 match the known trends, with UV slopes being redder at decreasing redshifts, and brighter galaxies being more highly dust extinct and more frequently star-forming than fainter galaxies.

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“…Papovich et al 2001) and ultraviolet properties (e.g. Rafelski et al 2009;Ly et al 2011;Boutsia et al 2014). Selected local galaxies, including highly ultraviolet-luminous starbursts at z ∼ 0.1 − 0.2 (UVLGs, Heckman et al 2005Heckman et al , 2011 and the extreme optical emission line galaxies (EELS, EELGs or 'Green Peas ' Cardamone et al 2009;Amorín et al 2015), have been proposed as good local laboratories in which to study the physics of the z ∼ 3 Universe.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of local star-forming analogues toz ∼ 5 Lyman-break galaxies

Greis

Stanway

Davies

et al. 2016

Mon. Not. R. Astron. Soc.

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Intense, compact, star-forming galaxies are rare in the local Universe but ubiquitous at high redshift. We interpret the 0.1-22 µm spectral energy distributions (SED) of a sample of 180 galaxies at 0.05 < z < 0.25 selected for extremely high surface densities of inferred star formation in the ultraviolet. By comparison with well-established stellar population synthesis models we find that our sample comprises young (∼ 60 -400 Myrs), moderate mass (∼ 6 × 10 9 M ⊙ ) star-forming galaxies with little dust extinction (mean stellar continuum extinction E cont (B − V ) ∼ 0.1) and find star formation rates of a few tens of Solar masses per year. We use our inferred masses to determine a mean specific star formation rate for this sample of ∼ 10 −9 yr −1 , and compare this to the specific star formation rates in distant Lyman break galaxies (LBGs), and in other low redshift populations. We conclude that our sample's characteristics overlap significantly with those of the z ∼ 5 LBG population, making ours the first local analogue population well tuned to match those high redshift galaxies. We consider implications for the origin and evolution of early galaxies.

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DeepR-band counts ofz≈ 3 Lyman-break galaxy candidates with the LBT

Cited by 7 publications

References 39 publications

The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

UV slope ofz∼ 3 bright (L>L^*) Lyman-break galaxies in the COSMOS field

Physical properties of local star-forming analogues toz ∼ 5 Lyman-break galaxies

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DeepR-band counts ofz≈ 3 Lyman-break galaxy candidates with the LBT

Cited by 7 publications

References 39 publications

The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

The Lyman continuum escape fraction of galaxies atz= 3.3 in the VUDS-LBC/COSMOS field

UV slope ofz∼ 3 bright (L>L*) Lyman-break galaxies in the COSMOS field

Physical properties of local star-forming analogues toz ∼ 5 Lyman-break galaxies

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Product

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UV slope ofz∼ 3 bright (L>L^*) Lyman-break galaxies in the COSMOS field