Article
Astronomy & Astrophysics
B. Novosyadlyj, Yu. Kulinich, B. Melekh, V. Shulga
Summary: This study examines the formation and destruction of the first molecules during the Dark Ages and Cosmic Dawn, evaluating the luminosity of protogalaxy clumps (halos) in molecular lines. The impact of photodissociation processes on molecules like H-2 and HD is significant before full reionization, while the number density of helium hydride ions HeH+ shows complicated dependences on halo kinetic temperature and models of the first light. The brightness temperature evolution of individual halos in rotational lines of certain molecules does not exceed microkelvin, but detection could provide important insights into physical processes during the formation of the first stars and galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Multidisciplinary Sciences
Guido Roberts-Borsani, Tommaso Treu, Wenlei Chen, Takahiro Morishita, Eros Vanzella, Adi Zitrin, Pietro Bergamini, Marco Castellano, Adriano Fontana, Karl Glazebrook, Claudio Grillo, Patrick L. Kelly, Emiliano Merlin, Themiya Nanayakkara, Diego Paris, Piero Rosati, Lilan Yang, Ana Acebron, Andrea Bonchi, Kit Boyett, Marusa Bradac, Gabriel Brammer, Tom Broadhurst, Antonello Calabro, Jose M. Diego, Alan Dressler, Lukas J. Furtak, Alexei V. Filippenko, Alaina Henry, Anton M. Koekemoer, Nicha Leethochawalit, Matthew A. Malkan, Charlotte Mason, Amata Mercurio, Benjamin Metha, Laura Pentericci, Justin Pierel, Steven Rieck, Namrata Roy, Paola Santini, Victoria Strait, Robert Strausbaugh, Michele Trenti, Benedetta Vulcani, Lifan Wang, Xin Wang, Rogier A. Windhorst
Summary: In the early universe, sources of ultraviolet photons played a crucial role in ionizing intergalactic hydrogen, making the universe transparent to UV radiation. Fainter galaxies that are surrounded by neutral gas were believed to dominate the photon budget. By using the James Webb Space Telescope and gravitational lensing, the ultra-faint galaxy JD1 was spectroscopically confirmed at a redshift of z = 9.79, showing a compact and complex morphology with low stellar mass and subsolar metallicity.
Article
Astronomy & Astrophysics
Tanja Rindler-Daller, Katherine Freese, Richard H. D. Townsend, Luca Visinelli
Summary: This study investigates the properties and pulsation modes of dark stars, showing that acoustic modes in smaller dark stars are excited by mechanisms in layers with partially ionized hydrogen or helium. It also reveals that mass-loss rates potentially induced by pulsations are negligible compared to accretion rates.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Philippa S. Cole, Joseph Silk
Summary: The production and existence of primordial black holes can impact the primordial power spectrum and matter power spectrum, potentially leading to observable effects on the 21 cm power spectrum. It is crucial to include the contribution from primordial fluctuations in predicting the 21 cm signal in order to avoid underestimation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Alexandres Lazar, Volker Bromm
Summary: The first generation of stars, known as Population III stars, played a crucial role in shaping the early universe, and their formation and evolution depend on the initial mass function (IMF). However, the detailed IMF remains elusive due to a lack of direct observational constraints. This paper presents a framework to probe the Pop III IMF using high-redshift pair-instability supernovae (PISNe) and gamma-ray bursts (GRBs). The combination of these observations can provide more accurate constraints on the IMF. Future observations have the potential to further enhance our understanding of the IMF.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
T. Roy Choudhury, Aseem Paranjape, Sarah E. Bosman
Summary: A computationally efficient method is proposed in this study to simulate Lyman alpha absorption optical depth in the presence of neutral hydrogen "islands" leftover from reionization at redshifts between 5 and 6. By analyzing large-scale fluctuations in optical depth, it is confirmed at greater than or similar to 2 sigma confidence that reionization is not complete before around 5.6, with a possibility of completion as late as around 5.2.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Irene Vanni, Stefania Salvadori, Asa Skuladottir, Martina Rossi, Ioanna Koutsouridou
Summary: This study aims to investigate whether all metal-poor stars are formed in environments polluted by the first generation of supernovae and at what level. The chemical abundances of an environment imprinted by a single first-generation supernova are studied, including the dependence on the initial mass and mixing of these stars, as well as the explosion energy of the supernova. The study also examines how subsequent generations of normal supernovae affect the chemical signatures of the first generation stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Antara Dey, Arnab Paul, Supratik Pal
Summary: In this article, we have thoroughly investigated the effects of dark matter and neutrino interaction on reionization history. We have constrained the interaction strength using 21-cm cosmology and found deviations from the standard non-interacting scenario. Comparison with existing observational constraints reveals that 21-cm observations are more effective in constraining the interaction strength by several orders of magnitude. We have also assessed the prospects of detecting such interaction in the upcoming 21-cm mission SKA1-Low through forecast analysis and error estimation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Luke Conaboy, Ilian T. Iliev, Anastasia Fialkov, Keri L. Dixon, David Sullivan
Summary: Supersonic relative motion affects the growth of small-scale structures. The inclusion of relative velocities in zoom simulations reduces the halo baryon fraction and delays the formation of star particles. It also suppresses the final stellar mass.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yuxiang Qin, J. Stuart B. Wyithe, Pascal A. Oesch, Garth D. Illingworth, Ecaterina Leonova, Simon J. Mutch, Rohan P. Naidu
Summary: This study investigates the Ly alpha IGM transmission and environment of bright galaxies during the epoch of reionization. It reveals that brighter galaxies are less affected by damping-wing absorption, while the transmission of fainter galaxies depends on UV luminosity. The brightest sources are located in the largest ionized regions, leading to a lower incidence of Ly alpha detection in fainter galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Anna T. P. Schauer, Simon C. O. Glover, Ralf S. Klessen, Paul Clark
Summary: Population III star formation occurs in small dark matter minihaloes with specific conditions for H-2 cooling. The minimum mass scale for this formation is influenced by baryon streaming relative to dark matter and photodissociation of H-2 by a high redshift LW background. Results from high resolution cosmological simulations show that these effects are additive and impact M-min and M-ave.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Lewis R. Prole, Anna T. P. Schauer, Paul C. Clark, Simon C. O. Glover, Felix D. Priestley, Ralf S. Klessen
Summary: Molecular hydrogen allows the primordial gas to cool and collapse into Population III stars. The Lyman-Werner radiation from these stars can destroy H-2 in other halos and delay further star formation. The study of selected halos shows that the IMF for masses above the brown dwarf limit is not significantly affected by the background Lyman-Werner field strength, indicating that the IMF for Pop III.2 stars is similar to the initial population of Pop III.1 stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yisheng Qiu, Simon J. Mutch, Pascal J. Elahi, Rhys J. J. Poulton, Chris Power, J. Stuart B. Wyithe
Summary: This article discusses the importance of resolving faint galaxies in large volumes for accurate cosmic reionization simulations. It introduces the extension of mass resolution in N-body simulations using a Monte Carlo algorithm and proposes a method to evolve positions of Monte Carlo haloes. The results show improvements in predictions on stellar mass functions, star formation rate densities, and volume-weighted neutral fractions in the semi-analytic reionization model with extended halo catalogues.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Tomer D. Yavetz, Xinyu Li, Lam Hui
Summary: We present a wave-based method for constructing self-consistent halos, which uses wave superposition instead of particle orbits to achieve the desired density profile. The stability of the constructed halos is verified through numerical evolution, and an efficient and accurate way to simulate the time-dependent substructures of dark matter halos is provided.
Article
Astronomy & Astrophysics
Paulo Montero-Camacho, Yi Mao
Summary: The impact of cosmic reionization on the Ly alpha forest power spectrum is significant, and upcoming observational efforts like DESI will likely provide accurate measurements of reionization parameters through the Ly alpha forest 3D power spectrum. This measurement has the potential to be an independent probe of reionization, potentially even earlier than measurements with HERA.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Paula S. Soares, Catherine A. Watkinson, Steven Cunnington, Alkistis Pourtsidou
Summary: This study applies Gaussian Process Regression (GPR) for foreground removal in single-dish, low redshift H i intensity mapping for the first time, and provides an open-source Python toolkit for this purpose. The results show that GPR can be used effectively as a foreground removal technique, outperforming PCA in recovering the H i power spectrum, particularly on small scales. GPR performs better in recovering the radial power spectrum and is an excellent option for foreground removal in single-dish, low-redshift H i intensity mapping.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. Mevius, F. Mertens, L. V. E. Koopmans, A. R. Offringa, S. Yatawatta, M. A. Brentjens, E. Chapman, B. Ciardi, H. Gan, B. K. Gehlot, R. Ghara, A. Ghosh, S. K. Giri, I. T. Iliev, G. Mellema, V. N. Pandey, S. Zaroubi
Summary: This article investigates the systematic effects in direction-dependent gain calibration in the LOFAR 21-cm EoR experiment. It shows that calibrating short baselines using longer baselines can avoid signal suppression but leads to excess variance. The study demonstrates that regularization algorithms can mitigate this excess variance.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Catherine A. Watkinson, Bradley Greig, Andrei Mesinger
Summary: This paper presents the first application of the isosceles bispectrum to MCMC parameter inference from the cosmic 21-cm signal. The study extends the MCMC sampler and uses the fast bispectrum code to compute the likelihood. The results show that using the isosceles bispectrum can substantially reduce the bias on the inferred parameter means and credible intervals in the reionization models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mohd Kamran, Raghunath Ghara, Suman Majumdar, Garrelt Mellema, Somnath Bharadwaj, Jonathan R. Pritchard, Rajesh Mondal, Ilian T. Iliev
Summary: This study investigates the impact of variation in two major source parameters, i.e., the minimum halo mass and X-ray photon production efficiency, on the non-Gaussianity of the 21-cm signal at Cosmic Dawn. The results show that the shape, sign, and magnitude of the bispectrum jointly provide a better measure of the signal fluctuations and its non-Gaussianity than the power spectrum alone.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Srijita Pal, Kh Md Asif Elahi, Somnath Bharadwaj, Sk Saiyad Ali, Samir Choudhuri, Abhik Ghosh, Arnab Chakraborty, Abhirup Datta, Nirupam Roy, Madhurima Choudhury, Prasun Dutta
Summary: The researchers applied the Tapered Gridded Estimator (TGE) to analyze the post-reionization neutral hydrogen (HI) 21-cm intensity mapping signal. The results showed that they obtained upper limits on the 21-cm brightness temperature fluctuation, which were orders of magnitude larger than the expected signal.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Kh Md Asif Elahi, Somnath Bharadwaj, Abhik Ghosh, Srijita Pal, Sk Saiyad Ali, Samir Choudhuri, Arnab Chakraborty, Abhirup Datta, Nirupam Roy, Madhurima Choudhury, Prasun Dutta
Summary: Neutral hydrogen (H I) 21-cm intensity mapping is an efficient technique for mapping large-scale structures in the Universe. The Cross' Tapered Gridded Estimator (Cross TGE) is introduced to estimate the multifrequency angular power spectrum and mitigate various effects. The application of Cross TGE on uGMRT Band 3 data yields improved upper limits and best-fitting values for foregrounds and parameters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Arindam Mazumdar, Debanjan Sarkar, Somnath Bharadwaj
Summary: The redshift space anisotropy of the bispectrum can be quantified using multipole moments. The ability to measure these multipoles in a survey depends on the level of statistical fluctuations. We compute the statistical fluctuations in the measurement of bispectrum multipoles for a Euclid like galaxy survey and present the signal-to-noise ratio (SNR) and rank correlation as quantities to quantify the detectability and correlation in measurement errors, respectively. Based on SNR values, Euclid can potentially measure bispectrum multipoles up to l = 4 across various triangle shapes in Fourier space.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Suman Chatterjee, Somnath Bharadwaj, Samir Choudhuri, Shiv Sethi, Akash Kumar Patwa
Summary: Intensity mapping with the redshifted 21-cm line is a promising tool in cosmology, and the Tracking Tapered Grided Estimator (TTGE) has been developed to quantify the power spectrum of the sky signal in drift scan radio interferometric observations. The TTGE utilizes data from different pointing centers to estimate the power spectrum of the signal from a small angular region around a fixed tracking center, providing accurate results in recovering the input model angular power spectrum.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Saswata Dasgupta, Samit Kumar Pal, Satadru Bag, Sohini Dutta, Suman Majumdar, Abhirup Datta, Aadarsh Pathak, Mohd Kamran, Rajesh Mondal, Prakash Sarkar
Summary: We analyze the evolution of the largest ionized region during reionization by studying the topological and morphological evolution of the redshifted 21-cm signal from neutral hydrogen. Using the Largest Cluster Statistics (LCS), we investigate the impact of the array synthesized beam on the LCS analysis of the 21-cm signal. We find that biased LCS estimates due to the effect of lower resolution and the telescope synthesized beam can lead to a biased interpretation of the reionization history.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Qing-Bo Ma, Raghunath Ghara, Benedetta Ciardi, Ilian T. Iliev, Leon V. E. Koopmans, Garrelt Mellema, Rajesh Mondal, Saleem Zaroubi
Summary: To self-consistently model galactic properties, reionization of the intergalactic medium, and the associated 21-cm signal, an algorithm named polar has been developed by integrating the one-dimensional radiative transfer code grizzly with the semi-analytical galaxy formation code L-Galaxies 2020. The proof-of-concept results show good agreement with observations of the star formation rate history, UV luminosity function, and the CMB Thomson scattering optical depth. Additionally, the study investigates the impact of different galaxy formation models on UV luminosity functions and 21-cm power spectra, finding that halo merger parameters have the strongest influence on the former, while supernovae feedback parameters have a stronger dependence on the latter, and both are affected by the escape fraction model.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Abinash Kumar Shaw, Raghunath Ghara, Saleem Zaroubi, Rajesh Mondal, Garrelt Mellema, Florent Mertens, Leon V. E. Koopmans, Benoit Semelin
Summary: The LC anisotropy of the cosmic dawn 21-cm signal along the LoS axis leads to non-ergodicity, which can be resolved using the MAPS. Unlike the 3D power spectrum, MAPS separates the cosmic evolution information of the signal along the LoS k modes. Simulation studies show that HERA and SKA-Low can measure the 21-cm MAPS at high significance levels, while NenuFAR requires a longer observation time and narrower channel width for significant measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Siddhartha Bhattacharyya, Somnath Bharadwaj, Himanshu Tiwari, Suman Majumdar
Summary: We characterized the intrinsic properties of any FRB using redshift z, spectral index a, and energy E33. The energy tracks for a sample of 254 non-repeating low dispersion measure FRBs were considered, and two distinct energy ranges were identified, indicating potentially two distinct FRB populations. High energies followed a modified Schechter function, while low energies exceeded the predictions, suggesting a different population of low-energy FRBs. The main findings were shown to be reasonably robust to assumptions about the Galactic Halo and Host galaxy contributions to the dispersion measure.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
P. Hartley, A. Bonaldi, R. Braun, J. N. H. S. Aditya, S. Aicardi, L. Alegre, A. Chakraborty, X. Chen, S. Choudhuri, A. O. Clarke, J. Coles, J. S. Collinson, D. Cornu, L. Darriba, M. Delli Veneri, J. Forbrich, B. Fraga, A. Galan, J. Garrido, F. Gubanov, H. Hakansson, M. J. Hardcastle, C. Heneka, D. Herranz, K. M. Hess, M. Jagannath, S. Jaiswal, R. J. Jurek, D. Korber, S. Kitaeff, D. Kleiner, B. Lao, X. Lu, A. Mazumder, J. Moldon, R. Mondal, S. Ni, M. Onnheim, M. Parra, N. Patra, A. Peel, P. Salome, S. Sanchez-Exposito, M. Sargent, B. Semelin, P. Serra, A. K. Shaw, A. X. Shen, A. Sjoberg, L. Smith, A. Soroka, V Stolyarov, E. Tolley, M. C. Toribio, J. M. van der Hulst, A. Vafaei Sadr, L. Verdes-Montenegro, T. Westmeier, K. Yu, L. Yu, L. Zhang, X. Zhang, Y. Zhang, A. Alberdi, M. Ashdown, C. R. Bom, M. Brueggen, J. Cannon, R. Chen, F. Combes, J. Conway, F. Courbin, J. Ding, G. Fourestey, J. Freundlich, L. Gao, C. Gheller, Q. Guo, E. Gustavsson, M. Jirstrand, M. G. Jones, G. Jozsa, P. Kamphuis, J-P Kneib, M. Lindqvist, B. Liu, Y. Liu, Y. Mao, A. Marchal, I Marquez, A. Meshcheryakov, M. Olberg, N. Oozeer, M. Pandey-Pommier, W. Pei, B. Peng, J. Sabater, A. Sorgho, J. L. Starck, C. Tasse, A. Wang, Y. Wang, H. Xi, X. Yang, H. Zhang, J. Zhang, M. Zhao, S. Zuo
Summary: The Square Kilometre Array Observatory (SKAO) will explore the radio sky to conduct transformational science, with large and complex data products that require advanced analysis techniques. SKAO is conducting Science Data Challenges to familiarize the scientific community with the data and drive the development of new analysis techniques. Challenge 2 saw over 100 participants develop new techniques, with the winning strategy combining predictions from two machine learning techniques to achieve a 20% improvement in overall performance.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Review
Astronomy & Astrophysics
Chandra Shekhar Murmu, Raghunath Ghara, Suman Majumdar, Kanan K. K. Datta
Summary: This paper reviews the latest developments in techniques, especially line-intensity mapping, to study the epoch of reionization (EoR) and emphasizes the contribution of the Indian community in this field. The role of line emissions such as [Hi](21cm), Lyman-alpha, and [Cii](158μm) as tracers in probing the EoR is discussed, along with methods to model these signals using simulations and machine learning approaches. The paper also addresses the challenges of foregrounds and interlopers and explores synergy opportunities among different tracers. Updates on relevant experiments and future improvements within the community are presented.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Abinash Kumar Shaw, Manoj Jagannath, Aishrila Mazumder, Arnab Chakraborty, Narendra Nath Patra, Rajesh Mondal, Samir Choudhuri
Summary: We have developed a MPI-based PYTHON pipeline to efficiently handle the massive amount of data that will be generated for HI science. By dividing the data and using a HI source finder, we can process and filter the detections effectively. Comparison with the true source catalog reveals that detection efficiency is influenced by various factors, such as parameters.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
