Stellar properties of<i>z</i> ~ 1 Lyman-break galaxies from ACS slitless grism spectra

Nilsson, K.; Möller-Nilsson, O.; Rosati, P.; Lombardi, Marco; Kümmel, M.; Küntschner, H.; Walsh, J. R.; Fosbury, R. A. E.

doi:10.1051/0004-6361/201015595

Cited by 8 publications

(14 citation statements)

References 51 publications

(67 reference statements)

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“…The uncertainties in the UV continuum slope are considered as those obtained in the power law fitting and turn out to have a median value of 0.15. Nilsson et al (2011) studied the optical SED-derived physical properties of a sample of 15 GALEX-selected LBGs at z ∼ 1, taken from Burgarella et al (2007), by fitting with BC03 templates their photometric points derived from ACS slitless grism spectra. They obtain similar distributions for dust attenuation and stellar mass than those reported in the present work, but their ages tend to be lower.…”

Section: Sed-derived Stellar Populationsmentioning

confidence: 99%

“…Many samples of LBGs have been found and examined at different redshifts, mostly at z 3 (Madau et al 1996;Steidel et al 1996Steidel et al , 1999Steidel et al , 2003Stanway et al 2003;Giavalisco et al 2004;Bunker et al 2004;Verma et al 2007;Iwata et al 2007). At z 3 the number of LBGs reported and studied is much lower than that at higher redshifts (Burgarella et al 2006(Burgarella et al , 2007Ly et al 2009Ly et al , 2011Basu-Zych et al 2011;Hathi et al 2010;Nilsson et al 2011;Hathi et al 2013;Haberzettl et al 2012;Chen et al 2013) despite this redshift range is quite important since it is thought that the peak of the cosmic star formation of the universe took place in that epoch.…”

Section: Introductionmentioning

confidence: 99%

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Lyman break and ultraviolet-selected galaxies at z ∼ 1 – I. Stellar populations from the ALHAMBRA survey

Oteo

Bongiovanni

Cepa

et al. 2013

Monthly Notices of the Royal Astronomical Society

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We take advantage of the exceptional photometric coverage provided by the combination of GALEX data in the UV and the ALHAMBRA survey in the optical and near-IR to analyze the physical properties of a sample of 1225 GALEX-selected Lyman break galaxies (LBGs) at 0.8 z 1.2 located in the COSMOS field. This is the largest sample of LBGs studied at that redshift range so far. According to a spectral energy distribution (SED) fitting with synthetic stellar population templates, we find that LBGs at z ∼ 1 are mostly young galaxies with a median age of 341 Myr and have intermediate dust attenuation, E s (B − V ) ∼ 0.20. Due to their selection criterion, LBGs at z ∼ 1 are UV-bright galaxies and have high dust-corrected total SFR, with a median value of 16.9 M ⊙ yr −1 . Their median stellar mass is log (M * /M ⊙ ) = 9.74. We obtain that the dust-corrected total SFR of LBGs increases with stellar mass and the specific SFR is lower for more massive galaxies (downsizing scenario). Only 2% of the galaxies selected through the Lyman break criterion have an AGN nature. LBGs at z ∼ 1 are mostly located over the blue cloud of the color-magnitude diagram of galaxies at their redshift, with only the oldest and/or the dustiest deviating towards the green valley and red sequence. Morphologically, 69% of LBGs are disk-like galaxies, with the fraction of interacting, compact, or irregular systems being much lower, below 12%. LBGs have a median effective radius of 2.5 kpc and bigger galaxies have higher total SFR and stellar mass. Comparing to their high-redshift analogues, we find evidence that LBGs at lower redshifts are bigger, redder in the UV continuum, and have a major presence of older stellar populations in their SEDs. However, we do not find significant difference in the distributions of stellar mass or dust attenuation.1 In this work we apply the term SED to refer to a set of photometric points. However, it should be noted that SED is also applied to spectroscopic data in many works. Some of the limitations quoted here for the SED-fitting technique only apply to photometric SEDs but not to spectroscopic one

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Section: Sed-derived Stellar Populationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lyman break and ultraviolet-selected galaxies at z ∼ 1 – I. Stellar populations from the ALHAMBRA survey

Oteo

Bongiovanni

Cepa

et al. 2013

Monthly Notices of the Royal Astronomical Society

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“…In this case, UV measurements coming from spacebased telescopes are required for sampling the Lyman break. The combination of FUV and NUV GALEX channels or other filter sets in space-based UV telescopes allows us to identify LBGs at 0.8 z 1.2 (Burgarella et al 2006(Burgarella et al , 2007Nilsson et al 2011;Burgarella et al 2011;Basu-Zych et al 2011;Oteo et al 2013a,c;Chen et al 2013) and the combination of NUV and optical U-band filters segregates LBGs at 1.5 z 2.5, the so-called redshift desert (Hathi et al 2010;Ly et al 2009Ly et al , 2011Haberzettl et al 2012;Hathi et al 2013). The number of LBGs reported and studied at .08 z 2.5 is much lower than that at higher redshifts, despite the redshift range being very important since it is then that the peak of the cosmic star formation of the universe is thought to have taken place.…”

Section: Introductionmentioning

confidence: 99%

“…The analysis of the physical properties of LBGs and other SF galaxies at different redshifts has traditionally been carried out by fitting their UV-to-mid-IR photometry to stellar population templates, the so-call SED-fitting technique. This allows us to estimate the age, dust attenuation, stellar mass and SFR of the galaxies studied (Nilsson et al 2011;Basu-Zych et al 2011;Haberzettl et al 2012) to within certain limitations. For example, a typical source of uncertainty comes from the degeneracy between age, star formation history (SFH) and dust attenuation.…”

Section: Introductionmentioning

confidence: 99%

The ultraviolet to far-infrared spectral energy distribution of star-forming galaxies in the redshift desert

Oteo¹,

Bongiovanni²,

Magdis³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We analyse the rest-frame UV-to-near-IR spectral energy distribution (SED) of Lyman break galaxies (LBGs), star-forming (SF) BzK (sBzK), and UV-selected galaxies at 1.5 z 2.5 in the COSMOS, GOODS-N, and GOODS-S fields. Additionally, we complement the multi-wavelength coverage of the galaxies located in the GOODS fields with deep FIR data taken from the GOODS-Herschel project. According to their best-fitted SED-derived properties we find that, because of their selection criterion involving UV measurements, LBGs tend to be UV-brighter, bluer, have a less prominent Balmer break (are younger), and have higher dust-corrected total SFR than sBzK galaxies. In this way, sBzK galaxies represent the general population of SF galaxies at z ∼ 2 better than LBGs. In a colour-mass diagram, LBGs at z ∼ 2 are mostly located over the blue cloud, although galaxies with older age, higher dust attenuation, and redder UV continuum slope deviate to the green valley and red sequence. Furthermore, for a given stellar mass, LBGs tend to have bluer optical colours than sBzK and UV-selected galaxies. We find clean PACS (100 µm or 160 µm) individual detections for a subsample of 48 LBGs, 89 sBzK, and 91 UV-selected galaxies, that measure their dust emission directly. Their SFR total = SFR UV + SFR IR cannot be recovered with the dust-correction factors derived with their continuum slope and the IRX-β relations for local starbursts, similar to what happens at higher redshifts. This has implications, for example, in the definition of the main sequence (MS) at z ∼ 2, which is sensitive to the dust-correction factors adopted. In an SFR-mass diagram, PACS-detected galaxies are located above the Daddi et al. (2007) MS and thus their star formation is probably driven by starburst. This is in agreement with the shape of their IR SEDs. PACS-detected galaxies with redder UV continuum slope and higher stellar mass are more attenuated. We find that for a given UV continuum slope the dustiest galaxies at higher redshifts are more attenuated and that for a given stellar mass the dustiest galaxies at higher redshifts have stronger FIR emission. This suggests an evolution of their dust properties. However, we do not find significant evolution in the relation between dust attenuation and stellar mass with redshift, at least at z 2.5. There is a subpopulation of 17, 26, and 27 LBGs, sBzK, and UV-selected galaxies, respectively, that are detected in any of the SPIRE (250 µm, 350 µm and 500 µm) bands. We speculate that this sample of SPIRE-detected LBGs is the bridging population between sub-mm galaxies and LBGs.

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“…Other higher redshift science cases involve studying continuum features of high redshift galaxies such as the UV slope at z > 3.5. Nilsson et al (2011) show the fitting of the spectral energy distributions of a set of low redshift Lymanbreak (z ∼ 1) galaxies combining both photometric data points and ACS slitless spectra.…”

Section: Discussionmentioning

confidence: 99%

TheHubbleLegacy Archive ACS grism data

Kümmel

Rosati

Fosbury

et al. 2011

A&A

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A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55−1.00 μm, with a dispersion of 40 Å/pixel and a resolution of ∼80 Å for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73, 581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47 919 datasets (65% of the total number of extracted spectra) for 32 149 unique objects, with a median i AB -band magnitude of 23.7, reaching 26.5 AB for the faintest objects. Each released dataset contains science-ready 1D and 2D spectra, as well as multi-band image cutouts of corresponding sources and a useful preview page summarising the direct and slitless data, astrometric and photometric parameters. This release is part of the continuing effort to enhance the content of the Hubble Legacy Archive (HLA) with highly processed data products which significantly facilitate the scientific exploitation of the Hubble data. In order to characterize the slitless spectra, emission-line flux and equivalent width sensitivity of the ACS data were compared with public ground-based spectra in the GOODS-South field. An example list of emission line galaxies with two or more identified lines is also included, covering the redshift range 0.2−4.6. Almost all redshift determinations outside of the GOODS fields are new. The scope of science projects possible with the ACS slitless release data is large, from studies of Galactic stars to searches for high redshift galaxies.

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Stellar properties ofz ~ 1 Lyman-break galaxies from ACS slitless grism spectra

Cited by 8 publications

References 51 publications

Lyman break and ultraviolet-selected galaxies at z ∼ 1 – I. Stellar populations from the ALHAMBRA survey

Lyman break and ultraviolet-selected galaxies at z ∼ 1 – I. Stellar populations from the ALHAMBRA survey

The ultraviolet to far-infrared spectral energy distribution of star-forming galaxies in the redshift desert

TheHubbleLegacy Archive ACS grism data

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