Explanipedia

Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes Open

Saeed Fakhry, Sara Gholamhoseinian, M. Farhang · 2024

In this study, we investigate the impact of modified gravity (MG) on the merger rate of compact binaries within dark matter spikes surrounding supermassive black holes (SMBHs). Specifically, we calculate the binary merger rates involving p…

Compact Binary Merger Rate with Modified Gravity in Dark-Matter Spikes Open

Saeed Fakhry, Sara Gholamhoseinian, M. Farhang · 2024

In this study, we investigate the impact of modified gravity on the merger rate of compact binaries within dark-matter spikes surrounding super-massive black holes (SMBHs). Specifically, we calculate binary merger rates involving primordia…

In-flight performance of SPIDER's 280 GHz receivers Open

Elle C. Shaw, P. A. R. Ade, Scott Akers, M. Amiri, Jason E. Austermann , et al. · 2024

SPIDER is a balloon-borne instrument designed to map the cosmic microwave background at degree-angular scales in the presence of Galactic foregrounds. Spider has mapped a large sky area in the Southern Hemisphere using more than 2000 trans…

Primordial Black Hole–Neutron Star Merger Rate in Modified Gravity Open

Saeed Fakhry, Maryam Shiravand, M. Farhang · 2024

In this work, we investigate the merger rate of primordial black hole–neutron star (PBH-NS) binaries in two widely studied modified gravity (MG) models: Hu–Sawicki f ( R ) gravity and the normal branch of Dvali–Gabadadze–Porrati gravity. I…

Sensitivity of Cosmological Parameter Estimation to Nonlinear Prescription from Cosmic Shear Open

Sarah Safi, M. Farhang · 2024

Several ongoing and upcoming large-scale structure surveys aim to explore the nonlinear regime of structure formation with high precision. Making reliable cosmological inferences from these observations necessitates precise theoretical mod…

A Semiblind Reconstruction of the History of Effective Number of Neutrinos Using CMB Data Open

Sarah Safi, M. Farhang, Olga Mena, Eleonora Di Valentino · 2024

We explore the possibility of redshift-dependent deviations in the contribution of relativistic degrees of freedom to the radiation budget of the cosmos, conventionally parameterized by the effective number of neutrinos $N_{\rm eff}$, from…

Sensitivity of Cosmological Parameter Estimation to Nonlinear Prescription from Cosmic Shear Open

Sarah Safi, M. Farhang · 2023

Several ongoing and upcoming large scale structure surveys aim to explore the nonlinear regime of structure formation with high precision. Making reliable cosmological inferences from these observations necessitates precise theoretical mod…

Toward More Realistic Mass Functions For Ultradense Dark Matter Halos Open

Saeed Fakhry, M. Farhang, Antonino Del Popolo · 2023

Ultradense dark matter halos (UDMHs) are high concentrations of dark matter, assumed to have formed deep in the radiation-dominated era from amplified primordial perturbations. In this work we improve the previous works for the calculation…

Reconstruction of a Scale-dependent Gravitational Phase Transition Open

M. Farhang, Nima Khosravi · 2023

In this work we extend our earlier phenomenological model for a gravitational phase transition and its generalization to early times by letting the modifications in the linearly perturbed Einstein equations be scale dependent. These modifi…

Reconstruction of A Scale-Dependent Gravitational Phase Transition Open

M. Farhang, Nima Khosravi · 2023

In this work we extend our earlier phenomenological model for a gravitational phase transition (GPT) and its generalization to early times by letting the modifications in the linearly-perturbed Einstein equations be scale-dependent. These …

Multi-scale search machine to detect cosmic strings Open

Alireza Vafaei Sadr, M. Sadegh Movahed, M. Farhang, Christophe Ringeval, F. R. Bouchet , et al. · 2022

In-Flight Gain Monitoring of SPIDER’s Transition-Edge Sensor Arrays Open

J. P. Filippini, A. E. Gambrel, A. Rahlin, E. Young, P. A. R. Ade , et al. · 2022

A Simulation-based Method for Correcting Mode Coupling in CMB Angular Power Spectra Open

Jason S.-Y. Leung, John W. Hartley, Johanna M. Nagy, C. B. Netterfield, J. A. Shariff , et al. · 2022

Modern cosmic microwave background (CMB) analysis pipelines regularly employ complex time-domain filters, beam models, masking, and other techniques during the production of sky maps and their corresponding angular power spectra. However, …

Phenomenological gravitational phase transition: Early and late modifications Open

Nima Khosravi, M. Farhang · 2022

In this work we generalize the idea of a gravitational phase transition or\nGPT at late times to allow for a modified gravity scenario in the early\nuniverse as well. The original GPT was shown to simultaneously relax the $H_0$\nand $\\sig…

Consistency of Planck Data With Power-law Primordial Scalar Power Spectrum Open

M. Farhang, Muhammad Sadegh Esmaeilian · 2022

In this work we explore the possibility of variations in the primordial scalar power spectrum around the power-law shape, as predicted by single-field slow-roll inflationary scenarios. We search for a trace of these fluctuations in a semib…

The XFaster Power Spectrum and Likelihood Estimator for the Analysis of Cosmic Microwave Background Maps Open

A. E. Gambrel, A. Rahlin, Xue Song, Carlo Contaldi, P. A. R. Ade , et al. · 2021

We present the XFaster analysis package, a fast, iterative angular power spectrum estimator based on a diagonal approximation to the quadratic Fisher matrix estimator. It uses Monte Carlo simulations to compute noise biases and filter tran…

<i>Planck</i> 2018 results Open

N. Aghanim, Y. Akrami, M. Ashdown, J. Aumont, C. Baccigalupi , et al. · 2021

In the original version, the bounds given in Eqs. (87a) and (87b) on the contribution to the early-time optical depth, (15,30), contained a numerical error in deriving the 95th percentile from the Monte Carlo samples. The corrected 95% upp…

Planck Limits on Cosmic String Tension Using Machine Learning Open

Mehri Torki, H. Hajizadeh, M. Farhang, Alireza Vafaei Sadr, M. Sadegh Movahed · 2021

We develop two parallel machine-learning pipelines to estimate the contribution of cosmic strings (CSs), conveniently encoded in their tension ($Gμ$), to the anisotropies of the cosmic microwave background radiation observed by {\it Planck…

Phenomenological gravitational phase transition: Reconciliation between the late and early Universe Open

M. Farhang, Nima Khosravi · 2021

In this work we investigate whether a certain phenomenological extension to\nthe general relativity (GR), in the form of a gravitational phase transition\n(GPT) in the Universe, can reduce the external $Planck$ tensions with the local\nHub…

CMB Cold Spot in the Planck Light Open

M. Farhang, M. Sadegh Movahed · 2021

The Cold Spot, with an unusually cold region surrounded by a hot ring, is a statistically significant anomaly in the cosmic microwave background (CMB) sky. In this work we assess whether different sets of multiple subvoids based on the 2dF…

Design and pre-flight performance of SPIDER 280 GHz receivers Open

E. C. Shaw, P. A. R. Ade, Scott Akers, M. Amiri, Jason E. Austermann , et al. · 2020

In this work we describe upgrades to the Spider balloon-borne telescope in preparation for its second flight, currently planned for December 2021. The Spider instrument is optimized to search for a primordial B-mode polarization signature …

<i>Planck</i> 2018 results Open

N. Aghanim, Y. Akrami, M. Ashdown, J. Aumont, C. Baccigalupi , et al. · 2020

We present cosmological parameter results from the final full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstructio…

CMB dipole asymmetry through annular variance Open

Mona Valipour, M. Farhang · 2020

Dipole asymmetry is among the most important anomalies in the cosmic microwave background (CMB). A dipole, if primordial, would challenge the isotropy of the Universe. In this work, we propose a novel method to find the direction of the di…

CMB dipole asymmetry through annular variance Open

Mona Valipour, M. Farhang · 2020

Dipole asymmetry is one of the most important anomalies in the cosmic microwave background (CMB).A dipole, if primordial, would challenge the isotropy of the Universe.In this work, we propose a novel method to find the direction of the dip…

Polarization of the CMB cold spot by the gravitational lensing of a cosmic void and texture Open

M. Farhang, M. Sadegh Movahed · 2019

The cold spot is one of the observed CMB anomalies proposed to be produced by various primary and secondary effects. In this work, we study the gravitational lensing of some of the candidates that could produce the cold spot, namely a huge…

Eigen Reconstruction of Perturbations to the Primordial Tensor Power Spectrum Open

M. Farhang, Alireza Vafaei Sadr · 2019

We explore the potential of the B-mode anisotropies of the cosmic microwave background radiation to constrain the shape of the primordial tensor power spectrum in a model-independent way. We expand possible perturbations to the power-law p…

SPIDER: CMB Polarimetry from the Edge of Space Open

R. Gualtieri, J. P. Filippini, P. A. R. Ade, M. Amiri, Steven J. Benton , et al. · 2018

Observational assessment of the viability of de Sitter-Gödel-de Sitter phase transition Open

Sh. Khodabakhshi, M. Farhang, Muhammad Sadegh Esmaeilian, Ali Shojai · 2018

de Sitter--Gödel--de Sitter phase transition(dGd) is a possible geometrical phase transition in the very early universe. It induces fluctuations with possibly observable traces on matter and radiation fields. Here we present a simulation b…

On the Detectability of CMB Anisotropies Induced by de Sitter-Gödel-de Sitter Phase Transition Open

Sh. Khodabakhshi, M. Farhang, Ali Shojai · 2018

A geometrical phase transition in the very early Universe, from de Sitter to Godel and back to de Sitter (dGd) spacetimes, can explain the universal phenomenon of rotation of many large scale structures. This phase transition is shown to i…

Planck 2018 results. VI. Cosmological parameters Open

N. Aghanim, Y. Akrami, M. Ashdown, J. Aumont, C. Baccigalupi , et al. · 2018

We present cosmological parameter results from the final full-mission Planck\nmeasurements of the CMB anisotropies. We find good consistency with the\nstandard spatially-flat 6-parameter $\\Lambda$CDM cosmology having a power-law\nspectrum…

M. Farhang YOU? Author Swipe