Stellar Metallicities from SkyMapper Photometry II: Precise photometric metallicities of $sim$280,000 giant stars with [Fe/H] $< -0.75$ in the Milky Way

Posted by klaurent MIT

Kavli Affiliate: Anna Frebel | First 5 Authors: Anirudh Chiti, Anna Frebel, Mohammad K. Mardini, Tatsuya W. Daniel, Xiaowei Ou | Summary: The Milky Way’s metal-poor stars are nearby ancient objects that are used to study early chemical evolution and the assembly and structure of the Milky Way. Here we present reliable metallicities of $sim280,000$ […]


Continue.. Stellar Metallicities from SkyMapper Photometry II: Precise photometric metallicities of $sim$280,000 giant stars with [Fe/H] $< -0.75$ in the Milky Way

The Metal-Poor Metallicity Distribution of the Ancient Milky Way

Posted by klaurent MIT

Kavli Affiliate: Anna Frebel | First 5 Authors: Anirudh Chiti, Mohammad K. Mardini, Anna Frebel, Tatsuya Daniel, | Summary: We present a low metallicity map of the Milky Way consisting of $sim$111,000 giants with $-3.5 lesssim$ [Fe/H] $lesssim -$0.75, based on public photometry from the second data release of the SkyMapper survey. These stars extend […]


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Gaia EDR3 Parallax Zero-point Offset based on W Ursae Majoris-type Eclipsing Binaries

Posted by klaurent Peking

Kavli Affiliate: Huawei Zhang | First 5 Authors: Fangzhou Ren, Xiaodian Chen, Huawei Zhang, Richard de Grijs, Licai Deng | Summary: We independently determine the zero-point offset of the Gaia early Data Release-3 (EDR3) parallaxes based on $sim 110,000$ W Ursae Majoris (EW)-type eclipsing binary systems. EWs cover almost the entire sky and are characterized […]


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Narain to Narnia

Posted by klaurent Tokyo

Kavli Affiliate: Hirosi Ooguri | First 5 Authors: Nathan Benjamin, Christoph A. Keller, Hirosi Ooguri, Ida G. Zadeh, | Summary: We generalize the holographic correspondence between topological gravity coupled to an abelian Chern-Simons theory in three dimensions and an ensemble average of Narain’s family of massless free bosons in two dimensions, discovered by Afkhami-Jeddi et […]


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Inference of the optical depth to reionization from low multipole temperature and polarisation Planck data

Posted by klaurent Cambridge

Kavli Affiliate: George Efstathiou | First 5 Authors: Roger de Belsunce, Steven Gratton, William Coulton, George Efstathiou, | Summary: This paper explores methods for constructing low multipole temperature and polarisation likelihoods from maps of the cosmic microwave background anisotropies that have complex noise properties and partial sky coverage. We use Planck 2018 High Frequency Instrument […]


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Conformal gravity does not predict flat galaxy rotation curves

Posted by klaurent Cambridge

Kavli Affiliate: Anthony Lasenby | First 5 Authors: Michael Hobson, Anthony Lasenby, , , | Summary: We reconsider the widely held view that the Mannheim–Kazanas (MK) vacuum solution for a static, spherically-symmetric system in conformal gravity (CG) predicts flat rotation curves, such as those observed in galaxies, without the need for dark matter. This prediction […]


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The HST See Change Program: I. Survey Design, Pipeline, and Supernova Discoveries

Posted by klaurent Stanford

Kavli Affiliate: Risa Wechsler | First 5 Authors: Brian Hayden, David Rubin, Kyle Boone, Greg Aldering, Jakob Nordin | Summary: The See Change survey was designed to make $z>1$ cosmological measurements by efficiently discovering high-redshift Type Ia supernovae (SNe Ia) and improving cluster mass measurements through weak lensing. This survey observed twelve galaxy clusters with […]


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Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions

Posted by klaurent MIT

Kavli Affiliate: Roland K. Vanderspek | First 5 Authors: Teruyuki Hirano, John H. Livingston, Akihiko Fukui, Norio Narita, Hiroki Harakawa | Summary: We present observations of two bright M dwarfs (TOI-1634 and TOI-1685: $J=9.5-9.6$) hosting ultra-short period (USP) planets, identified by the TESS mission. The two stars are similar in temperature, mass, and radius ($T_mathrm{eff},approx,3500$ […]


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Gravitational wave backgrounds from coalescing black hole binaries at cosmic dawn: an upper bound

Posted by klaurent Peking

Kavli Affiliate: Kohei Inayoshi | First 5 Authors: Kohei Inayoshi, Kazumi Kashiyama, Eli Visbal, Zoltan Haiman, | Summary: The successive discoveries of binary merger events by Advanced LIGO-Virgo have been revealing the statistical properties of binary black hole (BBH) populations. A stochastic gravitational wave background (GWB) is a useful tool to probe the cosmological evolution […]


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Understanding mechanisms of thermal expansion in PbTiO$_3$ thin-films from first principles: role of high-order phonon-strain anharmonicity

Posted by klaurent Cornell

Kavli Affiliate: Nicole A. Benedek | First 5 Authors: Ethan T. Ritz, Nicole A. Benedek, , , | Summary: The thermal properties of materials are critically important to various technologies and are increasingly the target of materials design efforts. However, it is only relatively recent advances in first-principles computational techniques that have enabled researchers to […]


Continue.. Understanding mechanisms of thermal expansion in PbTiO$_3$ thin-films from first principles: role of high-order phonon-strain anharmonicity