Conveners
WG1-Astroparticle Physics and Cosmology: D1-S1 - Parallel - 1
- Kinjalk Lochan
WG1-Astroparticle Physics and Cosmology: D1-S2 - Parallel - 1
- Pankaj Kushwaha
WG1-Astroparticle Physics and Cosmology: D2-S3 - Parallel - 1
- Kinjalk Lochan
- Pankaj Kushwaha
WG1-Astroparticle Physics and Cosmology: D2-S4 - Parallel - 1
- Pankaj Kushwaha
- H K Jassal (Faculty, IISER Mohali, Punjab)
WG1-Astroparticle Physics and Cosmology: D3-S5 - Parallel - 1
- Kinjalk Lochan
- Pankaj Kushwaha
WG1-Astroparticle Physics and Cosmology: D3-S6 - Parallel - 1
- Pankaj Kushwaha
- Satyajit Jena (IISER Mohali)
- Kinjalk Lochan
WG1-Astroparticle Physics and Cosmology: D4-S7 - Parallel - 1
- Kinjalk Lochan
- Ranjan Laha (Indian Institute of science (IN))
- Pankaj Kushwaha
WG1-Astroparticle Physics and Cosmology: D4-S8 - Parallel - 1
- Pankaj Kushwaha
- Kinjalk Lochan
- Ranjan Laha (Indian Institute of science (IN))
I will present a brief overview of astrophysical and cosmological constraints on dark matter and dark energy.
It is the most common assumption is that the pressure inside the neutron star (NS) is isotropic in nature. In this study, we calculate the anisotropic pressure inside the NS and calculate its effects on some properties such as mass, radius, compactness, and surface curvature. To obtain the NS properties, we use the relativistic mean-field equation of states. We observed that anisotropy has...
Recent image of the M87* and Sgr A* black hole by EHT collaboration has opened a new portal to unlock various mysteries of the universe. Due to extreme gravity around a black hole, there will be an enhanced distribution of dark matter, which will have a significant effect on the image of the black hole. One certain feature of a black hole image is the black hole shadow, which can be used...
We reconstruct late-time cosmology in a model-independent manner using the technique of Principal Component Analysis (PCA). We propose a variant of PCA which can be used to find out the functional form of late-time cosmological quantities. In the methodology we only need the tabulated dataset of the quantity we want to reconstruct and as an output we get the functional form of it in terms of...
In this talk, I will show applications of the state-of-the-art supervised, un-supervised and weakly-supervised machine learning (ML) algorithms to solve problems in cosmology and astronomy. I will show ML-based galaxy clusters' mass modeling to capture the Sunyaev Zel'dovich (SZE) and Cosmic Microwave Background (CMB) lensing effects, using convolutional neural networks (CNNs). I will show an...
Probing solar modulation of galactic cosmic rays in the interplanetary medium and terrestrial atmosphere with muon has recently gained appreciable importance. The muons have superior penetrating power, generated at an altitude higher than the thunderclouds. Thunderstorms drastically change the atmospheric electric field, which causes variation in muon count rate. At GRAPES-3, we are observing...
The deflection of cosmic rays (CRs) in the interstellar magnetic field results in an almost isotropic flux as observed on Earth. However, anisotropies of different angular scales have been predicted at the level of ~$10^{โ4}โ10^{โ3}$. Small-scale anisotropic structures on angular scales of โค 60โฆ have been predicted due to relative diffusion of CRs in the local turbulent magnetic fields, the...
As a part of its R&D, the ICAL collaboration has built a small prototype module called mini-ICAL to study the detector performance, and engineering challenges in the construction of large-scale magnet,
and magnetic field measurement systems as well as to test the ICAL electronics in the presence of the magnetic field. This detector was also used to measure the charge-dependent muon flux and...
Multiwavelength observations of Supernovae (SNe) have revealed the presence of dense Circumstellar Material (CSM) around their progenitor stars. This CSM is formed due to heavy mass loss that the progenitor stars suffer a few years prior to their death as SNe. High energy protons accelerated in SN explosion interacting with this CSM can produce secondary particles like high energy neutrinos...
Present work investigates the properties of a proto-quark star (PQS) using Polyakov Chiral $\text{SU(3)}$ Quark Mean Field (PCQMF) model in the presence of a strong magnetic field. Considering various snapshots of PQS along the star evolution, the analysis of longitudinal and transverse equation of state (EoS) is carried out. Also, the effect of vector interaction on magnetized PQS with the...
Instrumenting a gigaton of ice at the South Pole, the IceCube Neutrino Observatory can probe neutrino interactions and properties at high energies with large statistics. This is possible due to the existence of a flux of high-energy astrophysical neutrinos, discovered by IceCube in 2013-14, and the prevalence of neutrinos produced in cosmic ray interactions in the upper atmosphere. Recently,...
We study the possibility of generating light Dirac neutrino mass from a radiative seesaw mechanism with dark sector particles going inside the loop, known as the scotogenic framework. The loop suppression and additional free parameters allow large ($\sim\mathcal{O}(1))$ coupling of light Dirac neutrinos with the dark sector particles. Such large Yukawa coupling not only dictates the relic...
A good angular is essential for detecting gamma ray sources at multi-TeV energies. The GRAPES-3 experiment, located in Ooty, Tamil Nadu (11.4$^\circ$ N, 76.7$^\circ$ E, 2200 m a.s.l.), is designed with a dense array of 400 scintillator detectors spread over 25000 m$^2$ to study gamma rays sources in the TeV-PeV energy range. By exploiting the shower front curvature, almost a factor of two...
There are compelling theoretical arguments in favour of the existence of various baryon-rich exotic QCD phases in the core of a pulsar. However, proving such a hypothesis remains challenging due to the lack of a probe of the core. We suggested a technique of probing the phases by studying the effects of phase transition induced density inhomogeneities on pulse profile modulation. We initiated...
As the densities in the interior of neutron stars exceed those of terrestrial nuclear experiments, they provide scope for studying the nature of dense matter under extreme conditions. The composition of the inner core of neutron stars is highly uncertain, and it is speculated that exotic forms of matter such as hyperons may appear there. Gravitational waves emitted by unstable oscillation...
We consider an extension of Littlest Seesaw model with an additional scalar and a fermionic particle under the freeze-in scenario. Primordial black hole of a certain mass range can act as an alternate production mechanism for the dark matter particles as it evaporates via Hawking radiation. Furthermore, the presence of a primordial black hole with substantial energy density gives rise to...
We present an extension of the SM involving three triplet fermions, one triplet scalar and one singlet fermion, which can explain both neutrino masses and dark matter. One triplet of fermions and the singlet are odd under a $Z_2$ symmetry, thus the model features two possible dark matter candidates. The two remaining $Z_2$-even triplet fermions can reproduce the neutrino masses and...
Topological defects are a natural consequence of several symmetry breaking phase transitions. In this talk I will concentrate on cosmic strings and give an overview of the search for signatures of cosmic strings using various methods. I will then describe how magnetic fields can be generated in the wakes of Abelian Higgs strings. The magnetic field generated in these wakes can open up a whole...
Study of particle showers produced in the atmosphere due to the interactions of primary cosmic particles have provided a natural laboratory of physics of standard model and beyond standard model. While the showers encompass the physics of strong, weak and and electromagnetic interactions, the very first interactions are strong interactions producing hadronic showers which introduce the...
We consider the propagation of gravitational waves in the late time Universe with the presence of structure. Before detection, gravitational waves emitted from distant sources have to traverse through regions of spacetime which are far from smooth and homogeneous. We investigate the effect of inhomogeneities on the observables associated with the gravitational
wave sources. In particular, we...
We study a possible particle-antiparticle asymmetry in the dark matter (DM) sector via DM scatterings. We have studied two example scenarios in which we show a novel interplay between DM elastic and inelastic scatterings set the relic density and the composition of the DM sector in the present universe. The scenario can be realized in a $\mathcal{Z}_3$ symmetric effective theory with a...
Axions-like-particles (ALP) naturally appear in many extensions of the Standard Model of particle physics, and are viable candidates to Cosmological Dark Matter. The Sun can also be an astrophysical source of ALP, produced through the Primakoff process. It can leave their signatures at detector through the inverse Primakoff (IP) scattering.ย We identify inelastic channels to the IP-processes...
Standard model of cosmology (ฮ-CDM model) mainly suffers from two drawbacks, first one is the fine tunning problem and second one is a cosmic-coincidence problem. In this standard model of cosmology, ฮ represents the cosmological constant and CDM denotes the cold-dark matter. Another important downside of the ฮ-CDM model from the observational perspective is the discrepancy between the present...
We investigate a high momentum regime of inflation where the cosmological perturbation breaks down due to large inflationary quantum fluctuations to form the primordial black holes(PBHs). In our study, we have found that, in this region, the values of the Bardeen potential is large negative causing a gravitational instability conducive to the formation of the PBHs. We have used three...
Particulate dark matter captured by a population of neutron stars distributed around the galactic center while annihilating through long-lived mediators can give rise to an observable neutrino flux. We examine the prospect of an idealised gigaton detector like IceCube/KM3NeT in probing such scenarios. Within this framework, we report an improved reach in spin-dependent and spin-independent...
The recoil threshold of Direct Detection experiments limits the mass range of Dark Matter (DM) particles that can be detected, with most DD experiments being blind to sub-MeV DM particles. However, these light DM particles can be boosted to very high energies via collisions with energetic Cosmic Ray electrons. This allows Dark Matter particles to induce detectable recoil in the target of...
We discuss the imprint of high scale non-thermal leptogenesis on cosmic microwave background experiments from the measurement of spectral index ($n_s$) and tensor to scalar ratio ($r$) which is otherwise inaccessible to the conventional laboratory experiments. We argue that non-thermal production of baryon (lepton) asymmetry from tree level inflaton decay is sensitive to the reheating dynamics...
In the Standard Model a Dark Matter candidate is missing, but it is relatively
simple to enlarge the model including one or more suitable particles.
We consider in this paper one such extension, inspired by simplicity and
by the goal to solve more than just the Dark Matter issue.
Indeed we consider a local $U(1) $ extension of the SM providing an
axion particle to solve the strong CP...
The Galactic cosmic ray particles in the inner heliosphere are convected outward by the solar wind while they diffuse into the inner heliosphere along the interplanetary magnetic field direction. A balance between the two processes produces an anisotropic flow of the GCR particles. The ground-based neutron or muon detectors can observe it as a 24-hour periodic variation in their counting rates...
Observation of the rotational velocity of stars in our galaxy and other gravitational effects point to the existence of huge non-luminous matter which is known as Dark Matter. The most promising candidate of dark matter is the weakly interacting massive particles (WIMPs). They naturally give the appropriate relic abundance and also appear in the theories of weak scale physics beyond the...
Instrumenting a gigaton of ice at the South Pole, the IceCube Neutrino Observatory can probe neutrino interactions and properties at high energies with large statistics. This is possible due to the existence of a flux of high-energy astrophysical neutrinos, discovered by IceCube in 2013-14, and the prevalence of neutrinos produced in cosmic ray interactions in the upper atmosphere. Recently,...
Measurement of the number of effective relativistic degrees of freedom (Neff) by Planck experiment at Cosmic Microwave Background (CMB) strongly restricts the presence of additional light particles in the early Universe. We first discuss the cosmological constraints on MeV scale thermal dark matter from the current Planck data. Next we consider an MeV scale thermally decoupled non-minimal...
Primordial black holes are one of the most well-motivated dark matter candidates and it is important to devise new search strategies for them. Low-mass PBHs (masses between $\sim 10^{15}$ g to $10^{18}$ g) can be detected via their Hawking radiation. Evaporating PBHs inject energy into the intergalactic medium (IGM), which can significantly alter the thermal and ionization history of the...
The large area GRAPES-3 muon telescope (G3MT) is designed to record the muon component of the extensive air shower (EAS), playing an important role in the determination of the composition of primary cosmic rays (PCRs) and separation between ฮณ-rays and cosmic rays primaries for ฮณ-ray astronomy. These studies require a detailed understanding of the response of EAS components in the G3MT which...
The energy deposition due to the pair annihilation of neutrinos into electrons can energize events such as gamma ray bursts (GRBs). This energy deposition can also be enhanced in different spacetime backgrounds. In this talk I will discuss whether an inclusion of $Z^\prime$ mediated neutrino annihilation process can alter the energy deposition. Comparing with the GRB observation data, we...
Diffuse gamma-ray emission by interactions of ultra-high-energy cosmic rays (UHECRs) with the 2.7K cosmic microwave background (CMB) is expected to have an isotropic distribution around 10โ100 TeV. This radiation carries the information on the distribution of energetic sources and hence the cosmological evolution of the universe. The GRAPES-3 array comprises โผ 400 densely packed scintillator...
Primordial Black Holes (PBHs) in the mass range $\sim 10^{17}- 10^{22}$g are currently unconstrained, and can constitute the full Dark Matter (DM) density of the universe. Motivated by this, in the current work, we aim to relate the existence of PBHs in the said mass range to the production of observable Gravitational Waves (GWs). We follow a model-independent approach assuming that the PBHs...
Prospects of direct and indirect detection of DM are distinctively correlated to the phase space distribution of DM within the galactic haloes. A promising avenue to detect and constrain the properties of particulate DM is to explore the capture and subsequent heating signatures of DM annihilation from astronomical objects. The aim of this article is to systematically study the impact of...
In the standard cosmological model the universe is assumed to
be statistically isotropic & homogeneous when averaged on large scales. The dipole anisotropy of the CMB is ascribed to our peculiar motion due to local inhomogeneity. There should then be a corresponding dipole in the sky map of high redshift sources. Using catalogues of radio galaxies and quasars we find that this expectation is...
Motivated by the various theoretical studies regarding the efficient capturing of dark matter by neutron stars, we explore the possible indirect effects of captured dark matter on the cooling mechanism of a neutron star. The equation of states for different configurations of dark matter admixed star at finite temperature is obtained using the relativistic mean-field formalism with the IOPB-I...
