Browsing by Autor "J. Rohlf"

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Cosmological implications of DESI DR2 BAO measurements in light of the latest ACT DR6 CMB data
(American Physical Society, 2025) C. Garcia-Quintero; H. E. Noriega; A. de Mattia; Alejandro Avilés; K. Lodha; D. Chebat; J. Rohlf; S. Nadathur; Willem Elbers; José Aguilar
We report cosmological results from the Dark Energy Spectroscopic Instrument (DESI) measurements of baryon acoustic oscillations (BAO) when combined with recent data from the Atacama Cosmology Telescope (ACT). By jointly analyzing ACT and data and applying conservative cuts to overlapping multipole ranges, we assess how different <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>P</a:mi><a:mi>l</a:mi><a:mi>a</a:mi><a:mi>n</a:mi><a:mi>c</a:mi><a:mi>k</a:mi><a:mo>+</a:mo><a:mi>ACT</a:mi></a:mrow></a:math> dataset combinations affect consistency with DESI. While ACT alone exhibits a tension with DESI exceeding <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>3</c:mn><c:mi>σ</c:mi></c:mrow></c:math> within the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi mathvariant="normal">Λ</e:mi><e:mi>CDM</e:mi></e:math> model, this discrepancy is reduced when ACT is analyzed in combination with . For our baseline DESI DR2 <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mrow><h:mi>BAO</h:mi><h:mo>+</h:mo><h:mi>P</h:mi><h:mi>l</h:mi><h:mi>a</h:mi><h:mi>n</h:mi><h:mi>c</h:mi><h:mi>k</h:mi></h:mrow></h:math> <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mi mathvariant="normal">P</j:mi><j:mrow><j:mi mathvariant="normal">R</j:mi><j:mn>4</j:mn><j:mo>+</j:mo><j:mi>ACT</j:mi></j:mrow></j:mrow></j:math> likelihood combination, the preference for evolving dark energy over a cosmological constant is about <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:mrow><n:mn>3</n:mn><n:mi>σ</n:mi></n:mrow></n:math>, increasing to over <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mrow><p:mn>4</p:mn><p:mi>σ</p:mi></p:mrow></p:math> with the inclusion of type Ia supernova data. While the dark energy results remain quite consistent across various combinations of and ACT likelihoods with those obtained by the DESI collaboration, the constraints on neutrino mass are more sensitive, ranging from <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mrow><r:mo>∑</r:mo><r:msub><r:mrow><r:mi>m</r:mi></r:mrow><r:mrow><r:mi>ν</r:mi></r:mrow></r:msub><r:mo><</r:mo><r:mn>0.061</r:mn><r:mtext> </r:mtext><r:mtext> </r:mtext><r:mi>eV</r:mi></r:mrow></r:math> in our baseline analysis, to <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:mo>∑</t:mo><t:msub><t:mi>m</t:mi><t:mi>ν</t:mi></t:msub><t:mo><</t:mo><t:mn>0.077</t:mn><t:mtext> </t:mtext><t:mtext> </t:mtext><t:mi>eV</t:mi></t:math> (95% confidence level) in the CMB likelihood combination chosen by ACT when imposing the physical prior <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mo>∑</v:mo><v:msub><v:mi>m</v:mi><v:mi>ν</v:mi></v:msub><v:mo>></v:mo><v:mn>0</v:mn><v:mtext> </v:mtext><v:mtext> </v:mtext><v:mi>eV</v:mi></v:math>.
Positive Neutrino Masses with DESI DR2 via Matter Conversion to Dark Energy
(American Physical Society, 2025) S. P. Ahlen; Alejandro Avilés; Brian G. Cartwright; Kevin S. Croker; Willem Elbers; D. Farrah; Nicolas Fernandez; Gustavo Niz; J. Rohlf; G. Tarlé
The Dark Energy Spectroscopic Instrument (DESI) is a massively parallel spectroscopic survey on the Mayall telescope at Kitt Peak, which has released measurements of baryon acoustic oscillations determined from over 14 million extragalactic targets. We combine DESI Data Release 2 with CMB datasets to search for evidence of matter conversion to dark energy (DE), focusing on a scenario mediated by stellar collapse to cosmologically coupled black holes (CCBHs). In this physical model, which has the same number of free parameters as ΛCDM, DE production is determined by the cosmic star formation rate density (SFRD), allowing for distinct early- and late-time cosmologies. Using two SFRDs to bracket current observations, we find that the CCBH model: accurately recovers the cosmological expansion history, agrees with early-time baryon abundance measured by BBN, reduces tension with the local distance ladder, and relaxes constraints on the summed neutrino mass ∑m_{ν}. For these SFRDs, we find a peaked positive ∑m_{ν}<0.149 eV (95% confidence) and ∑m_{ν}=0.106_{-0.069}^{+0.050} eV, respectively, in good agreement with lower limits from neutrino oscillation experiments. A peak in ∑m_{ν}>0 results from late-time baryon consumption in the CCBH scenario and is expected to be a general feature of any model that converts sufficient matter to dark energy during and after reionization.