Reply to the comment of Lovera et al. (2015) on “Systematic variations of argon diffusion in feldspars and implications for thermochronometry” by Cassata and Renne

Cassata, William S.; Renne, Paul R.

doi:10.1016/j.gca.2015.02.035

Cited by 51 publications

(115 citation statements)

References 6 publications

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“…This effect has recently been tentatively confirmed by z ∼ > 6 observations of color-selected Lyα emitting galaxies (e.g. Ouchi et al 2010;Fontana et al 2010;Stark et al 2010;Kashikawa et al 2011;Caruana et al 2012;Treu et al 2013;Konno et al 2014;Schenker et al 2014;Caruana et al 2014;Pentericci et al 2014;Cassata et al email: emanuele.sobacchi@sns.it 2015). However, it is difficult to disentangle a genuine EoR signature from an intrinsic evolution of galaxy properties (e.g.…”

Section: Introductionmentioning

confidence: 74%

Cross-correlation of the cosmic 21-cm signal and Lyman α emitters during reionization

Sobacchi

Mesinger

Greig

2016

Mon. Not. R. Astron. Soc.

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Interferometry of the cosmic 21-cm signal is set to revolutionize our understanding of the Epoch of Reionization (EoR), eventually providing 3D maps of the early Universe. Initial detections however will be low signal-to-noise, limited by systematics. To confirm a putative 21-cm detection, and check the accuracy of 21-cm data analysis pipelines, it would be very useful to cross-correlate against a genuine cosmological signal. The most promising cosmological signals are wide-field maps of Lyman alpha emitting galaxies (LAEs), expected from the Subaru Hyper-Suprime Cam (HSC) Ultra-Deep field. Here we present estimates of the correlation between LAE maps at z ∼ 7 and the 21-cm signal observed by both the Low Frequency Array (LOFAR) and the planned Square Kilometer Array Phase 1 (SKA1). We adopt a systematic approach, varying both: (i) the prescription of assigning LAEs to host halos; and (ii) the large-scale structure of neutral and ionized regions (i.e. EoR morphology). We find that the LAE-21cm cross-correlation is insensitive to (i), thus making it a robust probe of the EoR. A 1000 h observation with LOFAR would be sufficient to discriminate at ∼ > 1σ a fully ionized Universe from one with a mean neutral fraction ofx HI ≈ 0.50, using the LAE-21cm cross-correlation function on scales of R ≈3-10 Mpc. Unlike LOFAR, whose detection of the LAE-21cm cross-correlation is limited by noise, SKA1 is mostly limited by ignorance of the EoR morphology. However, the planned 100 h wide-field SKA1-Low survey will be sufficient to discriminate an ionized Universe from one withx HI = 0.25, even with maximally pessimistic assumptions.

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Section: Introductionmentioning

confidence: 74%

Cross-correlation of the cosmic 21-cm signal and Lyman α emitters during reionization

Sobacchi

Mesinger

Greig

2016

Mon. Not. R. Astron. Soc.

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“…These include narrow band imaging (e.g., Ouchi et al 2003, Gronwall et al 2007, serendipitous slit spectroscopy (e.g., Cassata et al 2011) and integral field spectroscopy (e.g., van Bruekelen et al 2005, Blanc et al 2011. These techniques have resulted in the compilation of catalogs of several hundred to a few thousand Lyα emitting galaxies from redshifts z ∼ 2.1 to the redshifts associated with the end of reionization.…”

mentioning

confidence: 99%

“…These techniques have resulted in the compilation of catalogs of several hundred to a few thousand Lyα emitting galaxies from redshifts z ∼ 2.1 to the redshifts associated with the end of reionization. These samples have been used to show that Lyα emitters of line luminosity Lα = 10 42 erg s −1 found at z = 3 have space densities of ∼ 10 −3 Mpc −3 (e.g., Gawiser et al 2007, Cassata et al 2015 and are therefore expected to be the progenitors of L * galaxies at redshift z = 0. The clustering of these galaxies has been measured on scales of up to 10 Mpc by Gauita et al (2010) and Gawiser et al (2007), who find that at redshifts z = 2 − 3 they have a bias factor with respect to the underlying matter (in CDM models) of b ∼ 1.5 − 2.…”

mentioning

confidence: 99%

“…The clustering of these galaxies has been measured on scales of up to 10 Mpc by Gauita et al (2010) and Gawiser et al (2007), who find that at redshifts z = 2 − 3 they have a bias factor with respect to the underlying matter (in CDM models) of b ∼ 1.5 − 2. Integrating the luminosity functions of Lyα emitting galaxies, assuming a power-law extrapolation for the faint end slope, has revealed that the comoving volume emissivity of Lyα photons declines significantly from z ∼ 6 to z ∼ 2 (Cassata et al 2011, Gronwall et al 2007, Ouchi et al 2008). This behaviour can be compared to the opposite evolution in redshift of galaxies measured in optically thin parts of the rest-frame UV spectrum (or using the Hα line, e.g., Hayes et al 2011).…”

mentioning

confidence: 99%

“…This behaviour can be compared to the opposite evolution in redshift of galaxies measured in optically thin parts of the rest-frame UV spectrum (or using the Hα line, e.g., Hayes et al 2011). This comparison has been used to infer (e.g., by Hayes et al 2011 andCassata et al 2011) that the escape fraction of Lyα photons produced in star forming regions has significantly decreased from z = 6 to z = 2.…”

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confidence: 99%

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Large-scale clustering of Lyman α emission intensity from SDSS/BOSS

Croft¹,

Miralda-Escudé²,

Zheng³

et al. 2016

Mon. Not. R. Astron. Soc.

106

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We detect the large-scale structure of Lyα emission in the Universe at redshifts z = 2 − 3.5 by measuring the cross-correlation of Lyα surface brightness with quasars in the Sloan Digital Sky Survey (SDSS/BOSS). We use nearly a million spectra targeting Luminous Red Galaxies (LRGs) at z < 0.8, after subtracting a best fit model galaxy spectrum from each one, as an estimate of the high-redshift Lyα surface brightness. The quasar-Lyα emission cross-correlation we detect has a shape consistent with a linear ΛCDM model with Ω m = 0.30 +0.10 −0.07 . The predicted amplitude of this crosscorrelation is proportional to the product of the mean Lyα surface brightness, µ α , the amplitude of mass density fluctuations, and the quasar and Lyα emission bias factors. Using published cosmological observations to constrain the amplitude of mass fluctuations and the quasar bias factor, we infer the value of the product µ α (b α /3) = (3.9±0.9)×10 −21 erg s −1 cm −2Å−1 arcsec −2 , where b α is the Lyα emission linear bias factor. If the dominant sources of Lyα emission we measure are star forming galaxies, we infer a total mean star formation rate density of ρ SFR = (0.28 ± 0.07)(3/b α ) yr −1 Mpc −3 at z = 2 − 3.5. For b α = 3, this value is a factor of 21 − 35 above previous estimates relying on individually detected Lyα emitters, although it is consistent with the total star-formation density derived from dust-corrected, continuum UV surveys. Our observations therefore imply that 97% of the Lyα emission in the Universe at these redshifts is undetected in previous surveys of Lyα emitters. Our detected Lyα emission is also much greater, by at least an order of magnitude, than that measured from stacking analyses of faint halos surrounding previously detected Lyα emitters, but we speculate that it arises from similar low surface brightness Lyα halos surrounding all luminous star-forming galaxies. We also detect a redshift space anisotropy of the quasar-Lyα emission cross-correlation, finding evidence at the 3.0σ level that it is radially elongated, contrary to the prediction for linear gravitational evolution, but consistent with distortions caused by radiative-transfer effects, as predicted by Zheng et al. (2011). Our measurements represent the first application of the intensity mapping technique to optical observations.

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Diffusive loss of argon in response to melt vein formation in polygenetic impact melt breccias

Mercer

Hodges

2017

JGR Planets

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Many planetary surfaces in the solar system have experienced prolonged bombardment. With each impact, new rocks can be assembled that incorporate freshly generated impact melts with fragments of older rocks. Some breccias can become polygenetic, containing multiple generations of impact melt products, and can potentially provide important insights into the extensive bombardment history of a region. However, the amount of chronological information that can be extracted from such samples depends on how well the mineral isotopic systems of geochronometers can preserve the ages of individual melt generations without being disturbed by younger events. We model the thermal evolution of impact melt veins and the resulting loss of Ar from K‐bearing phases common in impact melt breccias to assess the potential for preserving the 40Ar/39Ar ages of individual melt generations. Our model results demonstrate that millimeter‐scale, clast‐free melt veins cause significant heating of adjacent host rock minerals and can cause detectable Ar loss in contact zones that are generally thinner than, and at most about the same thickness as, the vein width. The incorporation of cold clasts in melt veins reduces the magnitudes of heating and Ar loss in the host rocks, and Ar loss can be virtually undetectable for sufficiently clast‐rich veins. Quantitative evidence of the timing of impacts, as measured with the 40Ar/39Ar method, can be preserved in polygenetic impact melt breccias, particularly for those containing millimeter‐scale bodies of clast‐bearing melt products.

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Reply to the comment of Lovera et al. (2015) on “Systematic variations of argon diffusion in feldspars and implications for thermochronometry” by Cassata and Renne

Cited by 51 publications

References 6 publications

Cross-correlation of the cosmic 21-cm signal and Lyman α emitters during reionization

Cross-correlation of the cosmic 21-cm signal and Lyman α emitters during reionization

Large-scale clustering of Lyman α emission intensity from SDSS/BOSS

Diffusive loss of argon in response to melt vein formation in polygenetic impact melt breccias

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