اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدImaging Simulations of the Sunyaev-Zeldovich Effect for ALMA
86
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present imaging simulations of the Sunyaev-Zeldovich effect of galaxy clusters for the Atacama Large Millimeter/submillimeter Array (ALMA) including the Atacama Compact Array (ACA). In its most compact configuration at 90GHz, ALMA will resolve the intracluster medium with an effective angular resolution of 5 arcsec. It will provide a unique probe of shock fronts and relativistic electrons produced during cluster mergers at high redshifts, that are hard to spatially resolve by current and near-future X-ray detectors. Quality of image reconstruction is poor with the 12m array alone but improved significantly by adding ACA; expected sensitivity of the 12m array based on the thermal noise is not valid for the Sunyaev-Zeldovich effect mapping unless accompanied by an ACA observation of at least equal duration. The observations above 100 GHz will become excessively time-consuming owing to the narrower beam size and the higher system temperature. On the other hand, significant improvement of the observing efficiency is expected once Band 1 is implemented in the future.
قيم البحث
اقرأ أيضاً
We present the first image of the thermal Sunyaev-Zeldovich effect (SZE) obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combining 7-m and 12-m arrays in Band 3, we create an SZE map toward a galaxy cluster RXJ1347.5-1145 with 5
arc-second resolution (corresponding to the physical size of 20 kpc/h), the highest angular and physical spatial resolutions achieved to date for imaging the SZE, while retaining extended signals out to 40 arc-seconds. The 1-sigma statistical sensitivity of the image is 0.017 mJy/beam or 0.12 mK_CMB at the 5 arc-second full width at half maximum. The SZE image shows a good agreement with an electron pressure map reconstructed independently from the X-ray data and offers a new probe of the small-scale structure of the intracluster medium. Our results demonstrate that ALMA is a powerful instrument for imaging the SZE in compact galaxy clusters with unprecedented angular resolution and sensitivity. As the first report on the detection of the SZE by ALMA, we present detailed analysis procedures including corrections for the missing flux, to provide guiding methods for analyzing and interpreting future SZE images by ALMA.
The pairwise kinematic Sunyaev-Zeldovich (kSZ) signal from galaxy clusters is a probe of their line-of-sight momenta, and thus a potentially valuable source of cosmological information. In addition to the momenta, the amplitude of the measured signal
depends on the properties of the intra-cluster gas and observational limitations such as errors in determining cluster centers and redshifts. In this work we simulate the pairwise kSZ signal of clusters at z<1, using the output from a cosmological N-body simulation and including the properties of the intra-cluster gas via a model that can be varied in post-processing. We find that modifications to the gas profile due to star formation and feedback reduce the pairwise kSZ amplitude of clusters by ~50%, relative to the naive gas traces mass assumption. We demonstrate that mis-centering can reduce the overall amplitude of the pairwise kSZ signal by up to 10%, while redshift errors can lead to an almost complete suppression of the signal at small separations. We confirm that a high-significance detection is expected from the combination of data from current-generation, high-resolution CMB experiments, such as the South Pole Telescope, and cluster samples from optical photometric surveys, such as the Dark Energy Survey. Furthermore, we forecast that future experiments such as Advanced ACTPol in conjunction with data from the Dark Energy Spectroscopic Instrument will yield detection significances of at least 20{sigma}, and up to 57{sigma} in an optimistic scenario. Our simulated maps are publicly available at: http://www.hep.anl.gov/cosmology/ksz.html
Quasar feedback has most likely a substantial but only partially understood impact on the formation of structure in the universe. A potential direct probe of this feedback mechanism is the Sunyaev-Zeldovich effect: energy emitted from quasar heats th
e surrounding intergalactic medium and induce a distortion in the microwave background radiation passing through the region. Here we examine the formation of such hot quasar bubbles using a cosmological hydrodynamic simulation which includes a self-consistent treatment of black hole growth and associated feedback, along with radiative gas cooling and star formation. From this simulation, we construct microwave maps of the resulting Sunyaev-Zeldovich effect around black holes with a range of masses and redshifts. The size of the temperature distortion scales approximately with black hole mass and accretion rate, with a typical amplitude up to a few micro-Kelvin on angular scales around 10 arcseconds. We discuss prospects for the direct detection of this signal with current and future single-dish and interferometric observations, including ALMA and CCAT. These measurements will be challenging, but will allow us to characterize the evolution and growth of supermassive black holes and the role of their energy feedback on galaxy formation.
The masses of galaxy clusters are a key tool to constrain cosmology through the physics of large-scale structure formation and accretion. Mass estimates based on X-ray and Sunyaev--Zeldovich measurements have been found to be affected by the contribu
tion of non-thermal pressure components, due e.g. to kinetic gas energy. The characterization of possible ordered motions (e.g. rotation) of the intra-cluster medium could be important to recover cluster masses accurately. We update the study of gas rotation in clusters through the maps of the kinetic Sunyaev--Zeldovich effect, using a large sample of massive synthetic galaxy clusters ($ M_{vir} > 5times 10^{14} h^{-1}$M$_odot$ at $z~=~0 $) from MUSIC high-resolution simulations. We select few relaxed objects showing peculiar rotational features, as outlined in a companion work. To verify whether it is possible to reconstruct the expected radial profile of the rotational velocity, we fit the maps to a theoretical model accounting for a specific rotational law, referred as the vp2b model. We find that our procedure allows to recover the parameters describing the gas rotational velocity profile within two standard deviations, both with and without accounting for the bulk velocity of the cluster. The amplitude of the temperature distortion produced by the rotation is consistent with theoretical estimates found in the literature, and it is of the order of 23 per cent of the maximum signal produced by the cluster bulk motion. We also recover the bulk velocity projected on the line of sight consistently with the simulation true value.
We used the APEX-SZ and LABOCA bolometer cameras on the APEX telescope to map the decrement of the Sunyaev-Zeldovich effect at 150 GHz and the increment at 345 GHz toward the galaxy cluster Abell 2163. The SZE images were used to model the radial den
sity and temperature distribution of the ICM, and to derive the gas mass fraction in the cluster under the assumption of hydrostatic equilibrium. We used the isothermal beta model to fit the SZE decrement/increment radial profiles. We performed a simple, non-parametric de-projection of the radial density and temperature profiles, in conjunction with XMM-Newton X-ray data, under the simplifying assumption of spherical symmetry. We combined the peak SZE signals derived in this paper with published SZE measurements of this cluster to derive the cluster line-of-sight bulk velocity and the central Comptonization, using priors on the ICM temperature. We find that the best-fit isothermal model to the SZE data is consistent with the ICM properties implied by the X-ray data, particularly inside the central 1 Mpc radius. Although the assumptions of hydrostatic equilibrium and spherical symmetry may not be optimal for this complex system, the results obtained under these assumptions are consistent with X-ray and weak-lensing measurements. This shows the applicability of the simple joint SZE and X-ray de-projection technique described in this paper for clusters with a wide range of dynamical states. (Abridged)
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
