THE PRIMEVAL STRUCTURE TELESCOPE

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1001-1008 ◽  
Author(s):  
JEFFERY B. PETERSON ◽  
UE-LI PEN ◽  
XIANG-PING WU
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Neutral Hydrogen ◽  
Large Scale Structure ◽  
Density Structure ◽  
First Stars ◽  
Early Epoch ◽  
The Past ◽  
Cosmic Background ◽  
Luminous Objects

The PrimevAl Structure Telescope (PAST), will be used to locate and study the era the of the first luminous objects, the epoch of reionization. The first stars ionized the gas around them producing a pattern of ionization that reflects the large scale density structure present at the time. The PAST array will be used to sense and study this ionization, by mapping the brightness of 21 cm neutral Hydrogen Cosmic Background (HCB) at redshift from 6 to 25. The HCB disappears on ionization, allowing the study of large scale structure and of star formation at this very early epoch.

scholarly journals Reconstructing large-scale structure with neutral hydrogen surveys

2019 ◽  
Vol 2019 (11) ◽  
pp. 023-023 ◽  
Author(s):  
Chirag Modi ◽  
Martin White ◽  
Anže Slosar ◽  
Emanuele Castorina
Keyword(s):  
Large Scale ◽  
Neutral Hydrogen ◽  
Large Scale Structure ◽  
Scale Structure

scholarly journals The implications of clustered star formation for (proto)planetary systems and habitability

2018 ◽  
Vol 14 (S345) ◽  
pp. 61-65
Author(s):  
J. M. Diederik Kruijssen ◽  
Steven N. Longmore
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Milky Way ◽  
Planetary Systems ◽  
Habitable Zone ◽  
Stellar Clusters ◽  
Galaxy Mergers ◽  
Multi Scale ◽  
The Past ◽  
Scale Properties

AbstractStar formation is spatially clustered across a range of environments, from dense stellar clusters to unbound associations. As a result, radiative or dynamical interactions with neighbouring stars disrupt (proto)planetary systems and limit their radii, leaving a lasting impact on their potential habitability. In the solar neighbourhood, we find that the vast majority of stars form in unbound associations, such that the interaction of (proto)planetary systems with neighbouring stars is limited to the densest sub-regions. However, the fraction of star formation occurring in compact clusters was considerably higher in the past, peaking at ∼50% in the young Milky Way at redshift z ∼ 2. These results demonstrate that the large-scale star formation environment affects the demographics of planetary systems and the occupation of the habitable zone. We show that planet formation is governed by multi-scale physics, in which Mpc-scale events such as galaxy mergers affect the AU-scale properties of (proto)planetary systems.

scholarly journals DIVISION VIII: GALAXIES AND THE UNIVERSE

2007 ◽  
Vol 3 (T26B) ◽  
pp. 179-180
Author(s):  
Francesco Bertola ◽  
Sadanori Okamura ◽  
Virginia L. Trimble ◽  
Mark Birkinshaw ◽  
Françoise Combes ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Local Group ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Cosmic Background ◽  
Distant Galaxies ◽  
The Universe

Division VIII gathers astronomers engaged in the study of the visible and invisible matter in the Universe at large, from Local Group galaxies via distant galaxies and galaxy clusters to the large-scale structure of the Universe and the cosmic background radiation.

scholarly journals Magnetic fields in our Milky Way Galaxy and nearby galaxies

2012 ◽  
Vol 8 (S294) ◽  
pp. 213-224 ◽  
Author(s):  
JinLin Han
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Large Scale ◽  
Milky Way ◽  
Spiral Galaxies ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Measure Data ◽  
Submillimeter Wavelength ◽  
Nearby Galaxies

AbstractMagnetic fields in our Galaxy and nearby galaxies have been revealed by starlight polarization, polarized emission from dust grains and clouds at millimeter and submillimeter wavelength, the Zeeman effect of spectral lines or maser lines from clouds or clumps, diffuse radio synchrotron emission from relativistic electrons in interstellar magnetic fields, and the Faraday rotation of background radio sources as well as pulsars for our Milky Way. It is easy to get a global structure for magnetic fields in nearby galaxies, while we have observed many details of magnetic fields in our Milky Way, especially by using pulsar rotation measure data. In general, magnetic fields in spiral galaxies probably have a large-scale structure. The fields follow the spiral arms with or without the field direction reversals. In the halo of spiral galaxies magnetic fields exist and probably also have a large-scale structure as toroidal and poloidal fields, but seem to be slightly weaker than those in the disk. In the central region of some galaxies, poloidal fields have been detected as vertical components. Magnetic field directions in galaxies seem to have been preserved during cloud formation and star formation, from large-scale diffuse interstellar medium to molecular clouds and then to the cloud cores in star formation regions or clumps for the maser spots. Magnetic fields in galaxies are passive to dynamics.

scholarly journals The whole picture of the large-scale structure of the CL1604 supercluster at z ∼ 0.9

2019 ◽  
Vol 71 (6) ◽  
Author(s):  
Masao Hayashi ◽  
Yusei Koyama ◽  
Tadayuki Kodama ◽  
Yutaka Komiyama ◽  
Yen-Ting Lin ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Stellar Population ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Star Formation History ◽  
Wide Field ◽  
The North ◽  
Formation History ◽  
Red Sequence

Abstract We present the large-scale structure over a more than 50 comoving Mpc scale at $z \sim 0.9$ where the CL1604 supercluster, which is one of the largest structures ever known at high redshifts, is embedded. The wide-field deep imaging survey by the Subaru Strategic Program with the Hyper Suprime-Cam reveals that the already-known CL1604 supercluster is a mere part of larger-scale structure extending to both the north and the south. We confirm that there are galaxy clusters at three slightly different redshifts in the northern and southern sides of the supercluster by determining the redshifts of 55 red-sequence galaxies and 82 star-forming galaxies in total via follow-up spectroscopy with Subaru/FOCAS and Gemini-N/GMOS. This suggests that the structure known as the CL1604 supercluster is the tip of the iceberg. We investigate the stellar population of the red-sequence galaxies using 4000 Å break and Balmer H$\delta$ absorption lines. Almost all of the red-sequence galaxies brighter than $21.5\:$mag in the z band show an old stellar population of $\gtrsim\! 2\:$Gyr. The comparison of composite spectra of the red-sequence galaxies in the individual clusters show that the galaxies at a similar redshift have a similar stellar population age, even if they are located $\sim\! 50\:$Mpc apart from each other. However, there could be a large variation in the star formation history. Therefore, it is likely that galaxies associated with the large-scale structure on a 50 Mpc scale formed at almost the same time, have assembled into the denser regions, and then have evolved with different star formation history along the hierarchical growth of the cosmic web.

scholarly journals Luminosity Bias. II. The Cosmic Web of the First Stars

2013 ◽  
Vol 30 ◽  
Author(s):  
R. Barkana
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Relative Velocity ◽  
Large Scale ◽  
Neutral Hydrogen ◽  
Unique Form ◽  
Velocity Difference ◽  
First Stars ◽  
Formation And Evolution ◽  
The Universe

AbstractUnderstanding the formation and evolution of the first stars and galaxies represents one of the most exciting frontiers in astronomy. Since the universe was filled with neutral hydrogen at early times, the most promising method for observing the epoch of the first stars is using the prominent 21-cm spectral line of the hydrogen atom. Current observational efforts are focused on the reionisation era (cosmic age t ~ 500 Myr), with earlier times considered much more challenging. However, the next frontier of even earlier galaxy formation (t ~ 200 Myr) is emerging as a promising observational target. This is made possible by a recently noticed effect of a significant relative velocity between the baryons and dark matter at early times. The velocity difference suppresses star formation, causing a unique form of early luminosity bias. The spatial variation of this suppression enhances large-scale clustering and produces a prominent cosmic web on 100 comoving Mpc scales in the 21-cm intensity distribution. This structure makes it much more feasible for radio astronomers to detect these early stars, and should drive a new focus on this era, which is rich with little-explored astrophysics.

scholarly journals H I Imaging Surveys: Gas and Galaxy Evolution in Different Environments

2010 ◽  
Vol 6 (S277) ◽  
pp. 41-46
Author(s):  
Jacqueline van Gorkom
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Galaxy Evolution ◽  
Large Scale ◽  
Large Scale Structure ◽  
Local Universe ◽  
Formation And Evolution ◽  
Gas Accretion ◽  
Optical Surveys ◽  
Matter Component

AbstractOur understanding of the formation and evolution of galaxies and the large scale structure has advanced enormously over the last decade, thanks to an impressive synergy between theoretical and observational efforts. While the growth of the dark matter component seems well understood, the physics of the gas, during its accretion, removal and/or depletion is less well understood. Increasingly large scale optical surveys are tracing out the cosmic web of filaments and voids and mathematical tools have been developed to describe these structures and identify galaxies in specific environments. H I imaging surveys begin to answer the question: how do galaxies get and lose their gas. The best evidence for ongoing gas accretion is found in the lowest density environments, while removal of gas in the highest density environments stops star formation and reddens the galaxies. Although current H I emission surveys are limited to redshifts less than 0.2, this is where the LSS is best defined and much can be learned in the local universe.

scholarly journals A new golden age: testing general relativity with cosmology

2011 ◽  
Vol 369 (1957) ◽  
pp. 4941-4946
Author(s):  
Rachel Bean ◽  
Pedro G. Ferreira ◽  
Andy Taylor
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Einstein Gravity ◽  
Field Equations ◽  
The Past ◽  
Cosmological Observations ◽  
Wide Range ◽  
Theories Of Gravity ◽  
The Universe

Gravity drives the evolution of the Universe and is at the heart of its complexity. Einstein's field equations can be used to work out the detailed dynamics of space and time and to calculate the emergence of large-scale structure in the distribution of galaxies and radiation. Over the past few years, it has become clear that cosmological observations can be used not only to constrain different world models within the context of Einstein gravity but also to constrain the theory of gravity itself. In this article, we look at different aspects of this new field in which cosmology is used to test theories of gravity with a wide range of observations.

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