7 research outputs found
Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI). IV. Lensed quasar search in the HSC survey
Large scale structure and cosmolog
Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI): VII. Discovery and confirmation of three strongly lensed quasars
Large scale structure and cosmolog
The Atacama Cosmology Telescope: A Catalog of >4000 SunyaevâZelâdovich Galaxy Clusters
We present a catalog of 4195 optically confirmed SunyaevâZel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 Ă 1014 Mâ, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2farcm4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr
Discovery of an unusually compact lensed Lyman-break galaxy from the Hyper Suprime-Cam Survey
Large scale structure and cosmolog
Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps
Large scale structure and cosmolog
Accessing the strong interaction between Î baryons and charged kaons with the femtoscopy technique at the LHC
The interaction between Î baryons and kaons/antikaons is a crucial ingredient for the strangeness S=0 and S=â2 sector of the mesonâbaryon interaction at low energies. In particular, the ÎK⟠might help in understanding the origin of states such as the Î(1620), whose nature and properties are still under debate. Experimental data on ÎâK and ÎâK⟠systems are scarce, leading to large uncertainties and tension between the available theoretical predictions constrained by such data. In this Letter we present the measurements of ÎâKâ+ÎâŸâKâ and ÎâKââÎâŸâK+ correlations obtained in the high-multiplicity triggered data sample in pp collisions at s=13 TeV recorded by ALICE at the LHC. The correlation function for both pairs is modeled using the LednickĂœâLyuboshits analytical formula and the corresponding scattering parameters are extracted. The ÎâKââÎâŸâK+ correlations show the presence of several structures at relative momenta kâ above 200 MeV/c, compatible with the Ω baryon, the Î(1690), and Î(1820) resonances decaying into ÎâKâ pairs. The low kâ region in the ÎâKââÎâŸâK+ also exhibits the presence of the Î(1620) state, expected to strongly couple to the measured pair. The presented data allow to access the ÎK+ and ÎKâ strong interaction with an unprecedented precision and deliver the first experimental observation of the Î(1620) decaying into ÎKâ
Energy dependence of coherent photonuclear production of J/Ï mesons in ultra-peripheral Pb-Pb collisions at = 5.02 TeV
International audienceThe cross section for coherent photonuclear production of J/Ï is presented as a function of the electromagnetic dissociation (EMD) of Pb. The measurement is performed with the ALICE detector in ultra-peripheral Pb-Pb collisions at a centre-of-mass energy per nucleon pair of = 5.02 TeV. Cross sections are presented in five different J/Ï rapidity ranges within |y| < 4, with the J/Ï reconstructed via its dilepton decay channels. In some events the J/Ï is not accompanied by EMD, while other events do produce neutrons from EMD at beam rapidities either in one or the other beam direction, or in both. The cross sections in a given rapidity range and for different configurations of neutrons from EMD allow for the extraction of the energy dependence of this process in the range 17 < W < 920 GeV, where W is the centre-of-mass energy per nucleon of the ÎłPb system. This range corresponds to a Bjorken-x interval spanning about three orders of magnitude: 1.1 Ă 10 < x < 3.3 Ă 10. In addition to the ultra-peripheral and photonuclear cross sections, the nuclear suppression factor is obtained. These measurements point to a strong depletion of the gluon distribution in Pb nuclei over a broad, previously unexplored, energy range. These results, together with previous ALICE measurements, provide unprecedented information to probe quantum chromodynamics at high energies.[graphic not available: see fulltext