A weak lensing analysis of the PLCK G100.2-30.4 cluster

We present a mass estimate of the Planck-discovered cluster PLCK G100.2-30.4, derived from a weak lensing analysis of deep SUBARU griz images. We perform a careful selection of the background galaxies using the multi-band imaging data, and undertake the weak lensing analysis on the deep (1hr) r-band image. The shape measurement is based on the KSB algorithm; we adopt the PSFex software to model the Point Spread Function (PSF) across the field and correct for this in the shape measurement. The weak lensing analysis is validated through extensive image simulations. We compare the resulting weak lensing mass profile and total mass estimate to those obtained from our re-analysis of XMM-Newton observations, derived under the hypothesis of hydrostatic equilibrium. The total integrated mass profiles are in remarkably good agreement, agreeing within 1$\sigma$ across their common radial range. A mass $M_{500} \sim 7 \times 10^{14} M_\odot$ is derived for the cluster from our weak lensing analysis. Comparing this value to that obtained from our reanalysis of XMM-Newton data, we obtain a bias factor of (1-b) = 0.8 $\pm$ 0.1. This is compatible within 1$\sigma$ with the value of (1-b) obtained by Planck Collaboration XXIV from their calibration of the bias factor using newly-available weak lensing reconstructed masses.Comment: 11 pages, 12 figures, accepted for publication on Astronomy & Astrophysics; updates in affiliation

A newly identified galaxy group thanks to tidal streams of intragroup light

In the accretion-driven growth scenario, part of the intracluster light is formed in the group environment. We report the serendipitous discovery of a group of galaxies with signs of diffuse light in the foreground of the known galaxy cluster MACS J0329-0211 at z=0.45. Our investigation began with the detection of diffuse light streams around a pair of bright galaxies in the southeastern region of a Suprime-Cam image of the galaxy cluster MACS J0329-0211. Our analysis is based on the extended CLASH-VLT redshift catalog and on new spectroscopic data obtained ad hoc with the Italian Telescopio Nazionale Galileo. We use the density reconstruction method to analyze the redshift distribution of the galaxies in the region around the galaxy pair. We also use available photometric and X-ray data to better characterize the properties of the group. Thanks to the large amount of redshift data collected in this region, we have been able to discover the existence of a group of galaxies, here called GrG J0330-0218, which is associated with the pair of galaxies. These are the two brightest group galaxies (BGG1 and BGG2). We extracted 41 group members from the redshift catalog and estimate a mean redshift z=0.1537 and a line-of-sight velocity dispersion sigmav=370 km/s. In the phase-space diagram, the distribution of the galaxies of GrG J0330-0218 follows the characteristic trumpet-shaped pattern, which is related to the escape velocity of galaxy clusters, suggesting that the group is a virialized structure. Under this assumption, the mass of the group is M200 about 6E13 Msun. We also measured a mass-to-light ratio of 130 Msun/Lsun and a luminosity fraction of diffuse light of about 20% within 0.5 R200. We conjecture that galaxy pairs that are surrounded by diffuse light, probably due to tidal interactions, can serve as signposts for groups.Comment: Astronomy & Astrophysics accepted, 13 pages, 10 figure

The JAK2V617 mutation induces constitutive activation and agonist hypersensitivity in basophils of polycythemia vera.

BACKGROUND: The JAK2V617F mutation has been associated with constitutive and enhanced activation of neutrophils, while no information is available concerning other leukocyte subtypes. DESIGN AND METHODS: We evaluated correlations between JAK2V617F mutation and the count of circulating basophils, the number of activated CD63(+) basophils, their response in vitro to agonists as well as the effects of a JAK2 inhibitor. RESULTS: We found that basophil count was increased in patients with JAK2V617F -positive myeloproliferative neoplasms, particularly in those with polycythemia vera, and was correlated with the V617F burden. The burden of V617F allele was similar in neutrophils and basophils from patients with polycythemia vera, while total JAK2 mRNA content was remarkably greater in the basophils; however, the content of JAK2 protein in basophils was not increased. The number of CD63(+) basophils was higher in patients with polycythemia vera than in healthy subjects or patients with essential thrombocythemia or primary myelofibrosis and was correlated with the V617F burden. Ultrastructurally, basophils from patients with polycythemia vera contained an increased number of granules, most of which were empty suggesting cell degranulation in vivo. Ex vivo experiments revealed that basophils from patients with polycythemia vera were hypersensitive to the priming effect of interleukin-3 and to f-MLP-induced activation; pre-treatment with a JAK2 inhibitor reduced polycythemia vera basophil activation. Finally, we found that the number of circulating CD63(+) basophils was significantly greater in patients suffering from aquagenic pruritus, who also showed a higher V617F allele burden. CONCLUSIONS: These data indicate that the number of constitutively activated and hypersensitive circulating basophils is increased in polycythemia vera, underscoring a role of JAK2V617F in these cells’ abnormal function and, putatively, in the pathogenesis of pruritus

The VIP Experiment

The Pauli Exclusion Principle (PEP) is a basic principle of Quantum Mechanics, and its validity has never been seriously challenged. However, given its importance, it is very important to check it as thoroughly as possible. Here we describe the VIP (Violation of PEP) experiment, an improved version of the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990) 438); VIP shall be performed at the Gran Sasso underground laboratories, and aims to test the Pauli Exclusion Principle for electrons with unprecedented accuracy, down to $\frac{\beta^2}{2} \sim 10^{-30}$Comment: 7 pages, 5 figures, PDF only, presented by Edoardo Milotti to the conference "Quantum Theory: reconsideration of foundations-3", Vaxjo (Sweden), June, 6-11 200

The Cosmic-Ray Proton and Helium Spectra measured with the CAPRICE98 balloon experiment

A new measurement of the primary cosmic-ray proton and helium fluxes from 3 to 350 GeV was carried out by the balloon-borne CAPRICE experiment in 1998. This experimental setup combines different detector techniques and has excellent particle discrimination capabilities allowing clear particle identification. Our experiment has the capability to determine accurately detector selection efficiencies and systematic errors associated with them. Furthermore, it can check for the first time the energy determined by the magnet spectrometer by using the Cherenkov angle measured by the RICH detector well above 20 GeV/n. The analysis of the primary proton and helium components is described here and the results are compared with other recent measurements using other magnet spectrometers. The observed energy spectra at the top of the atmosphere can be represented by (1.27+-0.09)x10^4 E^(-2.75+-0.02) particles (m^2 GeV sr s)^-1, where E is the kinetic energy, for protons between 20 and 350 GeV and (4.8+-0.8)x10^2 E^(-2.67+-0.06) particles (m^2 GeV nucleon^-1 sr s)^-1, where E is the kinetic energy per nucleon, for helium nuclei between 15 and 150 GeV nucleon^-1.Comment: To be published on Astroparticle Physics (44 pages, 13 figures, 5 tables

High-resolution tSZ cartography of clusters of galaxies with NIKA at the IRAM 30-m telescope

The thermal Sunyaev-Zeldovich effect (tSZ) is a powerful probe to study clusters of galaxies and is complementary with respect to X-ray, lensing or optical observations. Previous arcmin resolution tSZ observations ({\it e.g.} SPT, ACT and Planck) only enabled detailed studies of the intra-cluster medium morphology for low redshift clusters ($z < 0.2$). Thus, the development of precision cosmology with clusters requires high angular resolution observations to extend the understanding of galaxy cluster towards high redshift. NIKA2 is a wide-field (6.5 arcmin field of view) dual-band camera, operated at $100 \ {\rm mK}$ and containing $\sim 3300$ KID (Kinetic Inductance Detectors), designed to observe the millimeter sky at 150 and 260 GHz, with an angular resolution of 18 and 12 arcsec respectively. The NIKA2 camera has been installed on the IRAM 30-m telescope (Pico Veleta, Spain) in September 2015. The NIKA2 tSZ observation program will allow us to observe a large sample of clusters (50) at redshift ranging between 0.5 and 1. As a pathfinder for NIKA2, several clusters of galaxies have been observed at the IRAM 30-m telescope with the NIKA prototype to cover the various configurations and observation conditions expected for NIKA2.Comment: Proceedings of the 28th Texas Symposium on Relativistic Astrophysics, Geneva, Switzerland, December 13-18, 201

Non-Pauli Effects from Noncommutative Spacetimes

Noncommutative spacetimes lead to nonlocal quantum field theories (qft's) where spin-statistics theorems cannot be proved. For this reason, and also backed by detailed arguments, it has been suggested that they get corrected on such spacetimes leading to small violations of the Pauli principle. In a recent paper \cite{Pauli}, Pauli-forbidden transitions from spacetime noncommutativity were calculated and confronted with experiments. Here we give details of the computation missing from this paper. The latter was based on a spacetime $\mathcal{B}_{\chi\vec{n}}$ different from the Moyal plane. We argue that it quantizes time in units of $\chi$. Energy is then conserved only mod $\frac{2\pi}{\chi}$. Issues related to superselection rules raised by non-Pauli effects are also discussed in a preliminary manner.Comment: 15 Pages, 1 Table, Full details and further developments of arXiv:1003.2250. This version is close to the one accepted by JHE

High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: Multiwavelength analysis

The prototype of the NIKA2 camera, NIKA, is an instrument operating at the IRAM 30-m telescope, which can observe simultaneously at 150 and 260GHz. One of the main goals of NIKA2 is to measure the pressure distribution in galaxy clusters at high resolution using the thermal SZ (tSZ) effect. Such observations have already proved to be an excellent probe of cluster pressure distributions even at high redshifts. However, an important fraction of clusters host submm and/or radio point sources, which can significantly affect the reconstructed signal. Here we report on <20" resolution observations at 150 and 260GHz of the cluster MACSJ1424, which hosts both radio and submm point sources. We examine the morphology of the tSZ signal and compare it to other datasets. The NIKA data are combined with Herschel satellite data to study the SED of the submm point source contaminants. We then perform a joint reconstruction of the intracluster medium (ICM) electronic pressure and density by combining NIKA, Planck, XMM-Newton, and Chandra data, focusing on the impact of the radio and submm sources on the reconstructed pressure profile. We find that large-scale pressure distribution is unaffected by the point sources because of the resolved nature of the NIKA observations. The reconstructed pressure in the inner region is slightly higher when the contribution of point sources are removed. We show that it is not possible to set strong constraints on the central pressure distribution without accurately removing these contaminants. The comparison with X-ray only data shows good agreement for the pressure, temperature, and entropy profiles, which all indicate that MACSJ1424 is a dynamically relaxed cool core system. The present observations illustrate the possibility of measuring these quantities with a relatively small integration time, even at high redshift and without X-ray spectroscopy.Comment: 15 pages, 17 figures, submitted to A&

Mapping the kinetic Sunyaev-Zel'dovich effect toward MACS J0717.5+3745 with NIKA

Measurement of the gas velocity distribution in galaxy clusters provides insight into the physics of mergers, through which large scale structures form in the Universe. Velocity estimates within the intracluster medium (ICM) can be obtained via the Sunyaev-Zel'dovich (SZ) effect, but its observation is challenging both in term of sensitivity requirement and control of systematic effects, including the removal of contaminants. In this paper we report resolved observations, at 150 and 260 GHz, of the SZ effect toward the triple merger MACS J0717.5+3745 (z=0.55), using data obtained with the NIKA camera at the IRAM 30m telescope. Assuming that the SZ signal is the sum of a thermal (tSZ) and a kinetic (kSZ) component and by combining the two NIKA bands, we extract for the first time a resolved map of the kSZ signal in a cluster. The kSZ signal is dominated by a dipolar structure that peaks at -5.1 and +3.4 sigma, corresponding to two subclusters moving respectively away and toward us and coincident with the cold dense X-ray core and a hot region undergoing a major merging event. We model the gas electron density and line-of-sight velocity of MACS J0717.5+3745 as four subclusters. Combining NIKA data with X-ray observations from XMM-Newton and Chandra, we fit this model to constrain the gas line-of-sight velocity of each component, and we also derive, for the first time, a velocity map from kSZ data (i.e. that is model-dependent). Our results are consistent with previous constraints on the merger velocities, and thanks to the high angular resolution of our data, we are able to resolve the structure of the gas velocity. Finally, we investigate possible contamination and systematic effects with a special care given to radio and submillimeter galaxies. Among the sources that we detect with NIKA, we find one which is likely to be a high redshift lensed submillimeter galaxy.Comment: 19 pages, 9 figures, accepted in A&

NIKA2: a mm camera for cluster cosmology

Galaxy clusters constitute a major cosmological probe. However, Planck 2015 results have shown a weak tension between CMB-derived and cluster-derived cosmological parameters. This tension might be due to poor knowledge of the cluster mass and observable relationship. As for now, arcmin resolution Sunyaev-Zeldovich (SZ) observations ({\it e.g.} SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium for low redshift clusters ($z0.5$) high resolution and high sensitivity SZ observations are needed. With both a wide field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope (Pico Veleta, Spain) is particularly well adapted for these observations. The NIKA2 SZ observation program will map a large sample of clusters (50) at redshifts between 0.5 and 0.9. As a pilot study for NIKA2, several clusters of galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m telescope to cover the various configurations and observation conditions expected for NIKA2.