scholarly journals Probing ultra-light axion dark matter from 21 cm tomography using Convolutional Neural Networks

2022 ◽  
Vol 2022 (01) ◽  
pp. 020
Author(s):  
Cristiano G. Sabiu ◽  
Kenji Kadota ◽  
Jacobo Asorey ◽  
Inkyu Park
Keyword(s):  
Dark Matter ◽  
Temperature Field ◽  
Brightness Temperature ◽  
Neutral Hydrogen ◽  
Mass Range ◽  
Training Data ◽  
Small Scale ◽  
Axion Mass ◽  
Density Perturbations ◽  
Square Kilometer Array

Abstract We present forecasts on the detectability of Ultra-light axion-like particles (ULAP) from future 21 cm radio observations around the epoch of reionization (EoR). We show that the axion as the dominant dark matter component has a significant impact on the reionization history due to the suppression of small scale density perturbations in the early universe. This behavior depends strongly on the mass of the axion particle. Using numerical simulations of the brightness temperature field of neutral hydrogen over a large redshift range, we construct a suite of training data. This data is used to train a convolutional neural network that can build a connection between the spatial structures of the brightness temperature field and the input axion mass directly. We construct mock observations of the future Square Kilometer Array survey, SKA1-Low, and find that even in the presence of realistic noise and resolution constraints, the network is still able to predict the input axion mass. We find that the axion mass can be recovered over a wide mass range with a precision of approximately 20%, and as the whole DM contribution, the axion can be detected using SKA1-Low at 68% if the axion mass is M X < 1.86 × 10-20 eV although this can decrease to M X < 5.25 × 10-21 eV if we relax our assumptions on the astrophysical modeling by treating those astrophysical parameters as nuisance parameters.

scholarly journals Bridging Galaxy Dynamics and Baryon Efficiency of 40 EDGE-CALIFA galaxies

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Veselina Kalinova ◽  
Dario Colombo ◽  
Erik Rosolowsky
Keyword(s):  
Dark Matter ◽  
Neutral Hydrogen ◽  
Expansion Method ◽  
Mass Range ◽  
Stellar Mass ◽  
Molecular Gas ◽  
Galaxy Dynamics ◽  
Circular Velocity ◽  
Hydrogen Mass ◽  
Stellar Kinematic

AbstractWe apply the Jeans Axisymmetric Multi-Gaussian Expansion method to the stellar kinematic maps of 40 Sa–Sd EDGE-CALIFA galaxies and derive their circular velocity curves (CVCs). The CVCs are classified using the Dynamical Classification method developed in Kalinova et al. (2015). We also calculate the observational baryon efficiency, OBE, where M*/Mb=M*/(M*+MHI+MH2) of the galaxies using their stellar mass, total neutral hydrogen mass and total molecular gas from CO luminosities. Slow-rising, Flat and Round-peaked CVC types correspond to specific OBEs, stellar and dark matter (DM) halo mass values, while the Sharp-peaked CVCs span in the whole DM halo mass range of 1011-1014M⊙.

scholarly journals Properties of Subhalos in the Interacting Dark Matter Scenario

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 80 ◽  
Author(s):  
Ángeles Moliné ◽  
Jascha A. Schewtschenko ◽  
Miguel A. Sánchez-Conde ◽  
Alejandra Aguirre-Santaella ◽  
Sofía A. Cora ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Massive Particle ◽  
Mass Range ◽  
Small Mass ◽  
Indirect Detection ◽  
Small Scale ◽  
Collisional Damping ◽  
Small Scale Structures

One possible and natural derivation from the collisionless cold dark matter (CDM) standard cosmological framework is the assumption of the existence of interactions between dark matter (DM) and photons or neutrinos. Such a possible interacting dark matter (IDM) model would imply a suppression of small-scale structures due to a large collisional damping effect, even though the weakly-interacting massive particle (WIMP) can still be the DM candidate. Because of this, IDM models can help alleviate alleged tensions between standard CDM predictions and observations at small mass scales. In this work, we investigate the properties of the DM halo substructure or subhalos formed in a high-resolution cosmological N-body simulation specifically run within these alternative models. We also run its CDM counterpart, which allowed us to compare subhalo properties in both cosmologies. We show that, in the lower mass range covered by our simulation runs, both subhalo concentrations and abundances are systematically lower in IDM compared to the CDM scenario. Yet, as in CDM, we find that median IDM subhalo concentration values increase towards the innermost regions of their hosts for the same mass subhalos. Similarly to CDM, we find IDM subhalos to be more concentrated than field halos of the same mass. Our work has a direct application to studies aimed at the indirect detection of DM where subhalos are expected to boost the DM signal of their host halos significantly. From our results, we conclude that the role of the halo substructure in DM searches will be less important in interacting scenarios than in CDM, but is nevertheless far from being negligible.

scholarly journals Probing small-scale power spectra with pulsar timing arrays

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Vincent S. H. Lee ◽  
Andrea Mitridate ◽  
Tanner Trickle ◽  
Kathryn M. Zurek
Keyword(s):  
Monte Carlo ◽  
Dark Matter ◽  
Time Delay ◽  
Milky Way ◽  
Power Spectra ◽  
Small Scale ◽  
Pulsar Timing ◽  
Relic Density ◽  
Small Scales ◽  
Density Perturbations

Abstract Models of Dark Matter (DM) can leave unique imprints on the Universe’s small scale structure by boosting density perturbations on small scales. We study the capability of Pulsar Timing Arrays to search for, and constrain, subhalos from such models. The models of DM we consider are ordinary adiabatic perturbations in ΛCDM, QCD axion miniclusters, models with early matter domination, and vector DM produced during inflation. We show that ΛCDM, largely due to tidal stripping effects in the Milky Way, is out of reach for PTAs. Axion miniclusters may be within reach, although this depends crucially on whether the axion relic density is dominated by the misalignment or string contribution. Models where there is matter domination with a reheat temperature below 1 GeV may be observed with future PTAs. Lastly, vector DM produced during inflation can be detected if it is lighter than 10−16 GeV. We also make publicly available a Python Monte Carlo tool for generating the PTA time delay signal from any model of DM substructure.

scholarly journals A Table-Top Pilot Experiment for Narrow Mass Range Light Cold Dark Matter Particle Searches

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 28
Author(s):  
Masroor H. S. Bukhari
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Resonant Cavity ◽  
Dark Matter Particle ◽  
Preliminary Test ◽  
Mass Range ◽  
Low Noise ◽  
Small Scale ◽  
Detection Scheme ◽  
Symmetric Scheme

This report presents the detection framework and a proposal for a pilot table-top experiment (supported by simulations and preliminary test results) for adoption into narrow mass range light Cold Dark Matter (CDM) searches, specifically for axions or Axion-Like Particles (ALPs) in a resonant cavity-based scheme. The novelty of this proposal lies in an attempt to concentrate searches corresponding to specific axion masses of interest (coinciding with recent proposals), using multiple cavities in a symmetric scheme, instead of using noisy and complicated tuning mechanisms, and in reduction of associated hardware by employing simpler underlying instrumentation instead of heterodyne mode of detection, by means of a low-noise ac amplification and dc phase-sensitive detection scheme, in order to make a viable and compact table-top experiment possible. These simplifications could possibly be valuable in substantially reducing detection hardware, experiment complexities (and associated noise) and long run-times, while maintaining low noise similar to conventional axion searches. The feasibility of proposed scheme and the experiment design are demonstrated with some calculations, simulations and preliminary tests with artificial axion signals injected into the cavities. The technique and ideas reported here have significant potential to be developed into a small-scale table-top, narrow-range, dark matter axion/ALP spectroscopy experiment, in addition to aiding in the on-going resonant cavity-based and broadband experiments.

scholarly journals Data Quality Measures and Efficient Evaluation Algorithms for Large-Scale High-Dimensional Data

2021 ◽  
Vol 11 (2) ◽  
pp. 472
Author(s):  
Hyeongmin Cho ◽  
Sangkyun Lee
Keyword(s):  
Machine Learning ◽  
Data Quality ◽  
Large Scale ◽  
High Dimensional Data ◽  
Quality Measures ◽  
Training Data ◽  
Measure Data ◽  
High Dimensional ◽  
Small Scale ◽  
Class Separability

Machine learning has been proven to be effective in various application areas, such as object and speech recognition on mobile systems. Since a critical key to machine learning success is the availability of large training data, many datasets are being disclosed and published online. From a data consumer or manager point of view, measuring data quality is an important first step in the learning process. We need to determine which datasets to use, update, and maintain. However, not many practical ways to measure data quality are available today, especially when it comes to large-scale high-dimensional data, such as images and videos. This paper proposes two data quality measures that can compute class separability and in-class variability, the two important aspects of data quality, for a given dataset. Classical data quality measures tend to focus only on class separability; however, we suggest that in-class variability is another important data quality factor. We provide efficient algorithms to compute our quality measures based on random projections and bootstrapping with statistical benefits on large-scale high-dimensional data. In experiments, we show that our measures are compatible with classical measures on small-scale data and can be computed much more efficiently on large-scale high-dimensional datasets.

scholarly journals Small-scale clumps of dark matter

2014 ◽  
Vol 57 (1) ◽  
pp. 1-36 ◽  
Author(s):  
V S Berezinsky ◽  
V I Dokuchaev ◽  
Yu N Eroshenko
Keyword(s):  
Dark Matter ◽  
Small Scale

scholarly journals An HI Mosaic of the Large Magellanic Cloud

1997 ◽  
Vol 14 (1) ◽  
pp. 119-121 ◽  
Author(s):  
Sungeun Kim ◽  
K. C. Freeman ◽  
L. Staveley-Smith ◽  
R. J. Sault ◽  
M. J. Kesteven ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Neutral Hydrogen ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Compact Array

AbstractThe parameters of a new Australia Telescope Compact Array (ATCA) mosaic of the Large Magellanic Cloud (LMC) in the 21-cm line of neutral hydrogen are described. A preliminary peak-brightness-temperature image of the whole of the LMC, and a detailed image of the region around the supergiant shells LMC 4 and 5 is shown.

Neutrino emission from the collapse of ∼104 M⊙ Population III supermassive stars

2021 ◽  
Vol 508 (1) ◽  
pp. 828-841
Author(s):  
Chris Nagele ◽  
Hideyuki Umeda ◽  
Koh Takahashi ◽  
Takashi Yoshida ◽  
Kohsuke Sumiyoshi
Keyword(s):  
Dark Matter ◽  
Massive Star ◽  
Direct Detection ◽  
Mass Range ◽  
Core Collapse ◽  
Low Density ◽  
Large Radius ◽  
Neutrino Luminosity ◽  
Neutrino Background ◽  
Population Iii

ABSTRACT We calculate the neutrino signal from Population III supermassive star (SMS) collapse using a neutrino transfer code originally developed for core-collapse supernovae and massive star collapse. Using this code, we are able to investigate the SMS mass range thought to undergo neutrino trapping (∼104 M⊙), a mass range which has been neglected by previous works because of the difficulty of neutrino transfer. For models in this mass range, we observe a neutrino sphere with a large radius and low density compared to typical massive star neutrino spheres. We calculate the neutrino light curve emitted from this neutrino sphere. The resulting neutrino luminosity is significantly lower than the results of a previous analytical model. We briefly discuss the possibility of detecting a neutrino burst from an SMS or the neutrino background from many SMSs and conclude that the former is unlikely with current technology, unless the SMS collapse is located as close as 1 Mpc, while the latter is also unlikely even under very generous assumptions. However, the SMS neutrino background is still of interest as it may serve as a source of noise in proposed dark matter direct detection experiments.

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