scholarly journals Impact of ICM disturbances on the mean pressure profile of galaxy clusters: A prospective study of the NIKA2 SZ large program with MUSIC synthetic clusters

2019 ◽  
Vol 631 ◽  
pp. A21 ◽  
Author(s):  
F. Ruppin ◽  
F. Sembolini ◽  
M. De Petris ◽  
R. Adam ◽  
G. Cialone ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Galaxy Clusters ◽  
High Redshift ◽  
Pressure Profile ◽  
Cluster Sample ◽  
Large Program ◽  
Mean Pressure ◽  
The Mean ◽  
The Impact

Context. The mean pressure profile of the galaxy cluster population plays an essential role in cosmological analyses. An accurate characterization of the shape, intrinsic scatter, and redshift evolution of this profile is necessary to estimate some of the biases and systematic effects that currently prevent cosmological analyses based on thermal Sunyaev-Zel’dovich (tSZ) surveys from obtaining precise and unbiased cosmological constraints. This is one of the main goals of the ongoing NIKA2 SZ large program, which aims at mapping the tSZ signal of a representative cluster sample selected from the Planck and ACT catalogs and spans a redshift range 0.5 <  z <  0.9. Aims. To estimate the impact of intracluster medium (ICM) disturbances that can be detected by NIKA2 on the mean pressure profile of galaxy clusters, we realized a study based on a synthetic cluster sample that is similar to that of the NIKA2 SZ large program. Methods. To reach this goal we employed the hydrodynamical N-body simulation Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC). We simulated realistic NIKA2 and Planck tSZ observations, which were jointly analyzed to estimate the ICM pressure profile of each cluster. A comparison of the deprojected profiles with the true radial profiles directly extracted from the MUSIC simulation allowed us to validate the NIKA2 tSZ pipeline and to study the impact of ICM disturbances on the characterization of the ICM pressure distribution even at high redshift. After normalizing each profile by the integrated quantities estimated under the hydrostatic equilibrium hypothesis, we evaluated the mean pressure profile of the twin sample and show that it is compatible with that extracted directly from the MUSIC simulation in the scale range that can be recovered by NIKA2. We studied the impact of cluster dynamical state on both its shape and associated scatter. Results. We observe that at R500 the scatter of the distribution of normalized pressure profiles associated with the selected morphologically disturbed clusters is 65% larger than that associated with relaxed clusters. Furthermore, we show that using a basic modeling of the thermal pressure distribution in the deprojection procedure induces a significant increase of the scatter associated with the mean normalized pressure profile compared to the true distribution extracted directly from the simulation. Conclusions. We conclude that the NIKA2 SZ large program will facilitate characterization of the potential redshift evolution of the mean pressure profile properties due to the performance of the NIKA2 camera, thereby allowing for a precise measurement of cluster morphology and ICM thermodynamic properties up to R500 at high redshift.

scholarly journals First Sunyaev–Zel’dovich mapping with the NIKA2 camera: Implication of cluster substructures for the pressure profile and mass estimate

2018 ◽  
Vol 615 ◽  
pp. A112 ◽  
Author(s):  
F. Ruppin ◽  
F. Mayet ◽  
G.W. Pratt ◽  
R. Adam ◽  
P. Ade ◽  
...  
Keyword(s):  
High Redshift ◽  
Pressure Profile ◽  
Dual Band ◽  
Morphological Properties ◽  
Scaling Relation ◽  
Electronic Density ◽  
Mass Scaling ◽  
Large Program ◽  
The Impact

The complete characterization of the pressure profile of high-redshift galaxy clusters, from their core to their outskirts, is a major issue for the study of the formation of large-scale structures. It is essential to constrain a potential redshift evolution of both the slope and scatter of the mass-observable scaling relations used in cosmology studies based on cluster statistics. In this paper, we present the first thermal Sunyaev–Zel’dovich (tSZ) mapping of a cluster from the sample of the New IRAM Kids Arrays (NIKA2) SZ large program that aims at constraining the redshift evolution of cluster pressure profiles and the tSZ-mass scaling relation. We observed the galaxy cluster PSZ2 G144.83+25.11 at redshift z = 0.58 with the NIKA2 camera, a dual-band (150 and 260 GHz) instrument operated at the Institut de Radioastronomie Millimtrique (IRAM) 30-m telescope. We identify a thermal pressure excess in the south-west region of PSZ2 G144.83+25.11 and a high-redshift sub-millimeter point source that affect the intracluster medium (ICM) morphology of the cluster. The NIKA2 data are used jointly with tSZ data acquired by the Multiplexed SQUID/TES Array at Ninety Gigahertz (MUSTANG), Bolocam, and Planck experiments in order to non-parametrically set the best constraints on the electronic pressure distribution from the cluster core (R ~ 0.02R500) to its outskirts (R ~ 3R500). We investigate the impact of the over-pressure region on the shape of the pressure profile and on the constraints on the integrated Compton parameter Y500. A hydrostatic mass analysis is also performed by combining the tSZ-constrained pressure profile with the deprojected electronic density profile from XMM-Newton. This allows us to conclude that the estimates of Y500 and M500 obtained from the analysis with and without masking the disturbed ICM region differ by 65% and 79%, respectively. This work highlights that NIKA2 will have a crucial impact on the characterization of the scatter of the Y500−M500 scaling relation due to its high potential to constrain the thermodynamic and morphological properties of the ICM when used in synergy with X-ray observations of similar angular resolution. This study also presents the typical products that will be delivered to the community for all clusters included in the NIKA2 tSZ Large Program.

scholarly journals Exploiting NIKA2/XMM-Newton imaging synergy for intermediate-mass high-z galaxy clusters within the NIKA2 SZ large program

2020 ◽  
Vol 644 ◽  
pp. A93
Author(s):  
F. Kéruzoré ◽  
F. Mayet ◽  
G. W. Pratt ◽  
R. Adam ◽  
P. Ade ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
High Redshift ◽  
Angular Size ◽  
Galaxy Cluster ◽  
Pressure Profile ◽  
Point Sources ◽  
Joint Analysis ◽  
Intermediate Mass ◽  
X Ray ◽  
Large Program

High-resolution mapping of the intracluster medium (ICM) up to high redshift and down to low masses is crucial to derive accurate mass estimates of the galaxy cluster and to understand the systematic effects affecting cosmological studies based on galaxy clusters. We present a spatially resolved Sunyaev-Zel’dovich (SZ)/X-ray analysis of ACT-CL J0215.4+0030, a high-redshift (z = 0.865) galaxy cluster of intermediate mass (M500 ≃ 3.5 × 1014 M⊙) observed as part of the ongoing NIKA2 SZ large program, which is a follow-up of a representative sample of objects at 0.5 ≤ z ≤ 0.9. In addition to the faintness and small angular size induced by its mass and redshift, the cluster is contaminated by point sources that significantly affect the SZ signal. This is therefore an interesting case study for the most challenging sources of the NIKA2 cluster sample. We present the NIKA2 observations of this cluster and the resulting data. We identified the point sources that affect the NIKA2 maps of the cluster as submillimeter galaxies with counterparts in catalogs of sources constructed by the SPIRE instrument on board the Herschel observatory. We reconstructed the ICM pressure profile by performing a joint analysis of the SZ signal and of the point-source component in the NIKA2 150 GHz map. This cluster is a very weak source that lies below the selection limit of the Planck catalog. Nonetheless, we obtained high-quality estimates of the ICM thermodynamical properties with NIKA2. We compared the pressure profile extracted from the NIKA2 map to the pressure profile obtained from X-ray data alone by deprojecting the public XMM-Newton observations of the cluster. We combined the NIKA2 pressure profile with the X-ray deprojected density to extract detailed information on the ICM. The radial distribution of its thermodynamic properties (the pressure, temperature and entropy) indicate that the cluster has a highly disturbed core. We also computed the hydrostatic mass of the cluster, which is compatible with estimations from SZ and X-ray scaling relations. We conclude that the NIKA2 SZ large program can deliver quality information on the thermodynamics of the ICM even for one of its faintest clusters after a careful treatment of the contamination by point sources.

scholarly journals Impact of the mean pressure profile of galaxy clusters on the cosmological constraints from the Planck tSZ power spectrum

2019 ◽  
Vol 490 (1) ◽  
pp. 784-796 ◽  
Author(s):  
F Ruppin ◽  
F Mayet ◽  
J F Macías-Pérez ◽  
L Perotto
Keyword(s):  
Power Spectrum ◽  
Galaxy Clusters ◽  
Extreme Values ◽  
Cosmological Parameters ◽  
Pressure Profile ◽  
Bias Parameter ◽  
Cosmological Constraints ◽  
Pressure Profiles ◽  
Mean Pressure ◽  
The Mean

ABSTRACT Cosmological analyses based on surveys of galaxy clusters observed through the Sunyaev–Zel’dovich (SZ) effect strongly rely on the mean pressure profile of the cluster population. A tension is currently observed between the cosmological constraints obtained from the analyses of the CMB primary anisotropies and those from cluster abundance in SZ surveys. This discrepancy may be explained by a wrong estimate of the hydrostatic bias parameter that links the hydrostatic mass to the true mass of galaxy clusters. However, a variation of both the amplitude and the shape of the mean pressure profile could also explain part of this tension. We analyse the effects of a modification of this profile on the constraints of the σ8 and Ωm parameters through the analysis of the SZ power spectrum measured by the Planck collaboration. We choose two mean pressure profiles that are respectively lower and higher than the one obtained from the observation of nearby clusters by Planck. The selection of the parameters of these two profiles is based on the current estimates of the pressure and gas mass fraction profile distributions at low redshift. The cosmological parameters found for these two profiles are significantly different from the ones obtained with the Planck pressure profile. We conclude that an ${\sim }15{{\ \rm per\ cent}}$ decrease of the amplitude of the mean normalized pressure profile would alleviate the tension observed between the constraints of σ8 and Ωm from the CMB and cluster analyses without requiring extreme values of the mass bias parameter.

scholarly journals Cluster cosmology with the NIKA2 SZ Large Program

2020 ◽  
Vol 228 ◽  
pp. 00017 ◽  
Author(s):  
F. Mayet ◽  
R. Adam ◽  
P. Ade ◽  
P. André ◽  
A. Andrianasolo ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Redshift ◽  
High Sensitivity ◽  
Pressure Profile ◽  
Large Field ◽  
Limiting Factor ◽  
High Angular Resolution ◽  
Systematic Uncertainties ◽  
Large Program ◽  
Mean Pressure

The main limiting factor of cosmological analyses based on thermal Sunyaev-Zel’dovich (SZ) cluster statistics comes from the bias and systematic uncertainties that affect the estimates of the mass of galaxy clusters. High-angular resolution SZ observations at high redshift are needed to study a potential redshift or morphology dependence of both the mean pressure profile and of the mass-observable scaling relation used in SZ cosmological analyses. The NIKA2 camera is a new generation continuum instrument installed at the IRAM 30-m telescope. With a large field of view, a high angular resolution and a high-sensitivity, the NIKA2 camera has unique SZ mapping capabilities. In this paper, we present the NIKA2 SZ large program, aiming at observing a large sample of clusters at redshifts between 0.5 and 0.9, and the characterization of the first cluster oberved with NIKA2.

scholarly journals NIKA: a mm camera for Sunyaev-Zel’dovich science in clusters of galaxies

2020 ◽  
Vol 228 ◽  
pp. 00016
Author(s):  
J.F. Macías-Pérez ◽  
R. Adam ◽  
P. Ade ◽  
P. André ◽  
A. Andrianasolo ◽  
...  
Keyword(s):  
Dark Matter ◽  
Angular Resolution ◽  
High Redshift ◽  
Radial Pressure ◽  
Pressure Profile ◽  
Field Of View ◽  
Dual Band ◽  
Clusters Of Galaxies ◽  
The Universe

Clusters of galaxies, the largest bound objects in the Universe, constitute a cosmological probe of choice, which is sensitive to both dark matter and dark energy. Within this framework, the Sunyaev-Zel’dovich (SZ) effect has opened a new window for the detection of clusters of galaxies and for the characterization of their physical properties such as mass, pressure and temperature. NIKA, a KID-based dual band camera installed at the IRAM 30-m telescope, was particularly well adapted in terms of frequency, angular resolution, field-of-view and sensitivity, for the mapping of the thermal and kinetic SZ effect in high-redshift clusters. In this paper, we present the NIKA cluster sample and a review of the main results obtained via the measurement of the SZ effect on those clusters: reconstruction of the cluster radial pressure profile, mass, temperature and velocity.

Studies on high speed jets from nozzles with internal grooves

2004 ◽  
Vol 108 (1079) ◽  
pp. 43-50 ◽  
Author(s):  
S. Elangovan ◽  
E. Rathakrishnan
Keyword(s):  
High Speed ◽  
Cell Structure ◽  
Pressure Profile ◽  
Equivalent Diameter ◽  
Streamwise Vortices ◽  
Shock Cell ◽  
Underexpanded Jets ◽  
Pitot Pressure ◽  
Mean Pressure ◽  
The Mean

Experiments were carried out on jets issuing from circular nozzles with grooved exits and the results compared with those of the plain nozzle. The plain nozzle had an exit diameter of 10mm. Because of the introduction of semi-circular grooves at the exit, the effective or equivalent diameter of the grooved nozzles was 10·44mm. The groove lengths were varied as 3, 5 and 8mm. The nozzles were operated at fully expanded sonic and underexpanded exit conditions. The corresponding fully expanded Mach numbers were 1·0 and 1·41. The shock cell structure of the underexpanded jets from grooved nozzles appeared to be weaker than that of the plain nozzle, as indicated by lesser amplitudes of the cyclic variation of the Pitot pressure. The iso-Mach contours indicate that the jet spread along the grooved plane is significantly higher than that along the ungrooved plane. Off-centre peaks were observed in the mean pressure profile of underexpanded jets from grooved nozzles. They were probably due to the streamwise vortices shed from the grooves.

scholarly journals Residential status of medical students as a factor affecting formative and summative academic performance in Forensic Medicine at Rehman Medical College, Peshawar, Pakistan

2020 ◽  
Vol 6 (1) ◽  
pp. 07-10
Author(s):  
Khalil-Ur -Rehman ◽  
Rizwan Faisal ◽  
Rizwan Qaisar ◽  
Mian Mujahid Shah
Keyword(s):  
Academic Performance ◽  
Medical Students ◽  
Forensic Medicine ◽  
Residential Status ◽  
Medical College ◽  
Significant Difference ◽  
The Subject ◽  
The Mean ◽  
The Impact

Introduction: A rigorous characterization of the impact of residential status of medical students (hostelites vs. day scholars) on the particulars of their academic performance has been lacking in Pakistan. Objective: To determine the relation of residential status of third year MBBS students to their academic performance in Forensic Medicine based on comparison of their pre-professional and professional examinations results during 2019. Materials & Methods: A comparative study was conducted from August to October 2019 on the examination performance of third year MBBS students of Rehman Medical College, Peshawar in the subject of Forensic Medicine. The results of theory and viva pre-professional and professional examinations were compared and categorized by residential status of students (Hostelites or Day Scholars). Students were categorized into groups according to their academic performance. Descriptive and Comparative data analysis was performed by SPSS 22.0, keeping p≤0.05 as significant. Results: No significant difference was found in the mean marks of hostelites and day scholars in pre-professional and professional examinations. The trend of significant improvement from pre-professional to professional examinations was similar in both groups, and it applied to both the theory and viva examinations. A significant correlation existed between the performance in two examinations among all students with no difference between the hostelites and day scholars. Conclusion: Residential status of MBBS students had no effect on their academic performance in the subject of Forensic Medicine. Keywords: Academic performance, Forensic Medicine, hostelites, day scholars

Impact of Flow Characteristics on the Pressure Distribution on Sluice Gates

2021 ◽  
Author(s):  
Michael Steppert ◽  
Philipp Epple ◽  
Andreas Malcherek
Keyword(s):  
Pressure Distribution ◽  
Flow Characteristics ◽  
Pressure Profile ◽  
3D Flow ◽  
Sluice Gate ◽  
Cfd Simulations ◽  
The Impact

Abstract The pressure distribution on sluice gate walls was investigated in this paper, based on CFD simulations. The flow characteristics impacting the pressure distribution were analyzed. Based on this analyzation, a new parametrization approach for the gate pressure distribution is derived for both, standard sluice gates and inclined sluice gates. Based on these investigations the impact of 3D flow characteristics on the pressure profile at the sluice gate wall is presented and discussed in detail.

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