scholarly journals Constraining VLBI−optical offsets in high redshift galaxies using strong gravitational lensing

2020 ◽  
Vol 494 (2) ◽  
pp. 2312-2326 ◽  
Author(s):  
Cristiana Spingola ◽  
Anna Barnacka
Keyword(s):  
Gravitational Lensing ◽  
Angular Resolution ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Monte Carlo Sampling ◽  
High Angular Resolution ◽  
Radio Emissions ◽  
High Redshift Galaxies ◽  
Long Baseline ◽  
Redshift Galaxies

ABSTRACT We present a multiwavelength analysis of two highly magnified strong gravitationally lensed galaxies, CLASS B0712+472 and CLASS B1608+656, at redshifts 1.34 and 1.394, respectively, using new VLBI (very long baseline interferometry) and archival Hubble Space Telescope observations. We reconstruct the positions of the radio and optical emissions with their uncertainties using Monte Carlo sampling. We find that in CLASS B0712+472 the optical and radio emissions are co-spatial within 2 ± 5 mas (17 ± 42 pc at redshift of 1.34). But, in CLASS B1608+656, we reconstruct an optical–radio offset of 25 ± 16 mas (214 ± 137 pc at redshift of 1.394), among the smallest offsets measured for an AGN (active galactic nucleus) at such high redshift. The spectral features indicate that CLASS B1608+656 is a post-merger galaxy, which, in combination with the optical–VLBI offset reported here, makes CLASS B1608+656 a promising candidate for a high- z offset–AGN. Furthermore, the milliarcsecond angular resolution of the VLBI observations combined with the precise lens models allow us to spatially locate the radio emission at 0.05 mas precision (0.4 pc) in CLASS B0712+472, and 0.009 mas precision (0.08 pc) in CLASS B1608+656. The search for optical–radio offsets in high redshift galaxies will be eased by the upcoming synoptic all-sky surveys, including Extremely Large Telescope and Square Kilometre Array, which are expected to find ∼105 strongly lensed galaxies, opening an era of large strong lensing samples observed at high angular resolution.

scholarly journals Hierarchical fragmentation in high redshift galaxies revealed by hydrodynamical simulations

2021 ◽  
Author(s):  
Baptiste Faure ◽  
Frédéric Bournaud ◽  
Jérémy Fensch ◽  
Emanuele Daddi ◽  
Manuel Behrendt ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
Gas Clusters ◽  
Very High ◽  
Redshift Galaxies

Abstract High-redshift star-forming galaxies have very different morphologies compared to nearby ones. Indeed, they are often dominated by bright star-forming structures of masses up to 108 − 9 M⊙ dubbed «giant clumps». However, recent observations questioned this result by showing only low-mass structures or no structure at all. We use Adaptative Mesh Refinement hydrodynamical simulations of galaxies with parsec-scale resolution to study the formation of structures inside clumpy high-redshift galaxies. We show that in very gas-rich galaxies star formation occurs in small gas clusters with masses below 107 − 8 M⊙ that are themselves located inside giant complexes with masses up to 108 and sometimes 109 M⊙ . Those massive structures are similar in mass and size to the giant clumps observed in imaging surveys, in particular with the Hubble Space Telescope. Using mock observations of simulated galaxies, we show that at very high resolution with instruments like the Atacama Large Millimeter Array or through gravitational lensing, only low-mass structures are likely to be detected, and their gathering into giant complexes might be missed. This leads to the non-detection of the giant clumps and therefore introduces a bias in the detection of these structures. We show that the simulated giant clumps can be gravitationally bound even when undetected in mocks representative for ALMA observations and HST observations of lensed galaxies. We then compare the top-down fragmentation of an initially warm disc and the bottom-up fragmentation of an initially cold disc to show that the process of formation of the clumps does not impact their physical properties.

scholarly journals The e-MERGE Survey (e-MERLIN Galaxy Evolution Survey): overview and survey description

2020 ◽  
Vol 495 (1) ◽  
pp. 1188-1208 ◽  
Author(s):  
T W B Muxlow ◽  
A P Thomson ◽  
J F Radcliffe ◽  
N H Wrigley ◽  
R J Beswick ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Angular Resolution ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Continuum Emission ◽  
High Angular Resolution ◽  
Very Large Array ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Large Program

ABSTRACT We present an overview and description of the e-MERGE Survey (e-MERLIN Galaxy Evolution Survey) Data Release 1 (DR1), a large program of high-resolution 1.5-GHz radio observations of the GOODS-N field comprising ∼140 h of observations with enhanced-Multi-Element Remotely Linked Interferometer Network (e-MERLIN) and ∼40 h with the Very Large Array (VLA). We combine the long baselines of e-MERLIN (providing high angular resolution) with the relatively closely packed antennas of the VLA (providing excellent surface brightness sensitivity) to produce a deep 1.5-GHz radio survey with the sensitivity (${\sim}1.5\, \mu$ Jy beam−1), angular resolution (0.2–0.7 arcsec) and field-of-view (∼15 × 15 arcmin2) to detect and spatially resolve star-forming galaxies and active galactic nucleus (AGN) at $z$ ≳ 1. The goal of e-MERGE is to provide new constraints on the deep, sub-arcsecond radio sky which will be surveyed by SKA1-mid. In this initial publication, we discuss our data analysis techniques, including steps taken to model in-beam source variability over an ∼20-yr baseline and the development of new point spread function/primary beam models to seamlessly merge e-MERLIN and VLA data in the uv plane. We present early science results, including measurements of the luminosities and/or linear sizes of ∼500 galaxies selected at 1.5 GHz. In combination with deep Hubble Space Telescope observations, we measure a mean radio-to-optical size ratio of re-MERGE/rHST ∼ 1.02 ± 0.03, suggesting that in most high-redshift galaxies, the ∼GHz continuum emission traces the stellar light seen in optical imaging. This is the first in a series of papers that will explore the ∼kpc-scale radio properties of star-forming galaxies and AGN in the GOODS-N field observed by e-MERGE DR1.

scholarly journals Searches for High Redshift Galaxies Using Gravitational Lensing

2004 ◽  
pp. 27-30 ◽  
Author(s):  
J. Richard ◽  
R. Pelló ◽  
J.-P. Kneib ◽  
D. Schaerer ◽  
M. R. Santos ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

Progress in search for high-redshift galaxies magnified by gravitational lensing

2013 ◽  
Vol 334 (4-5) ◽  
pp. 474-477 ◽  
Author(s):  
W. Zheng ◽  
L. Bradley ◽  
A. Zitrin ◽  
J. Moustakas ◽  
M. Postman ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

scholarly journals The image plane approach to cosmic telescopes

2015 ◽  
Vol 11 (A29B) ◽  
pp. 783-784
Author(s):  
Masamune Oguri
Keyword(s):  
Gravitational Lensing ◽  
Luminosity Function ◽  
High Redshift ◽  
Selection Effect ◽  
Image Plane ◽  
High Redshift Galaxies ◽  
The Public ◽  
Size Evolution ◽  
Redshift Galaxies

AbstractStudies of high-redshift galaxies behind the cores of mass clusters require the correction of gravitational lensing effects. We present our approach to estimate shapes, magnitudes, and the selection effect of high-redshift galaxies in the image plane, which allows us to include not only lensing magnifications but also lensing distortions and image multiplications. For this purpose we construct new mass models for the Frontier Fields clusters using the public software glafic. We present some results on faint-end slopes of the luminosity function and the size evolution of high-redshift galaxies from the analysis of Frontier Fields clusters.

scholarly journals High redshift galaxies through gravitational lensing

2011 ◽  
Vol 314 ◽  
pp. 012119
Author(s):  
José A de Diego ◽  
Jordi Cepa ◽  
Mario De Leo ◽  
Ángel Bongiovanni
Keyword(s):  
Gravitational Lensing ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

scholarly journals Dynamics and Interactions of High-Redshift Galaxies

1999 ◽  
Vol 186 ◽  
pp. 431-438
Author(s):  
M. Noguchi
Keyword(s):  
Galaxy Evolution ◽  
Galactic Center ◽  
Hubble Space Telescope ◽  
Gravitational Instability ◽  
High Redshift ◽  
Evolutionary Process ◽  
Dynamical Response ◽  
Massive Black Hole ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

A large number of high redshift galaxies observed with the Hubble Space Telescope (HST) show anomalous morphology and photometric properties, which may be an indication of evolutionary process in young galaxies. We show here by means of numerical simulations that the copious interstellar gas existing in the disks of rapidly collapsing protogalaxies can bring about these peculiarities. Gravitational instability in a gas-rich disk leads to the formation of massive gas clumps with a typical mass of 109M⊙. These subgalactic clumps make disk galaxy evolution a dynamically energetic and chaotic process, and give a natural explanation for peculiar morphology of high redshift galaxies. Moreover, the present model provides a new picture on the causal relationship between the emergence of quasar activities and the dynamical evolution of host galaxies. The clump-driven evolution model is also capable of explaining the correlations observed among present-day galaxies. Namely, the relative bulge dominance, existence of a thick disk, and a mass of the super-massive black hole situated at the galactic center should all be correlated positively. In contrast to their vigorous evolution in isolated state, primeval disk galaxies do not show any dramatic enhancement of activity or remarkable dynamical response in interaction with another galaxies.

scholarly journals Gravitational Lensing and Dynamics (GLaD): combined analysis to unveil properties of high-redshift galaxies

2020 ◽  
Vol 643 ◽  
pp. A135 ◽  
Author(s):  
G. Chirivì ◽  
A. Yıldırım ◽  
S. H. Suyu ◽  
A. Halkola
Keyword(s):  
Gravitational Lensing ◽  
Surface Brightness ◽  
Mass Density ◽  
High Redshift ◽  
Dynamical Structure ◽  
Local Universe ◽  
High Redshift Galaxies ◽  
Strong Gravitational Lensing ◽  
Dynamical Modelling ◽  
Redshift Galaxies

The dynamical modelling of integral field unit (IFU) stellar kinematics is a powerful tool to unveil the dynamical structure and mass build-up of galaxies in the local Universe, while gravitational lensing is nature’s cosmic telescope to explore the properties of galaxies beyond the local Universe. We present a new approach, which unifies dynamical modelling of galaxies with the magnification power of strong gravitational lensing, to reconstruct the structural and dynamical properties of high-redshift galaxies. By means of axisymmetric Jeans modelling, we create a dynamical model of the source galaxy, assuming a surface brightness and surface mass density profile. We then predict how the source’s surface brightness and kinematics would look when lensed by the foreground mass distribution and compare with the mock observed arcs of strong gravitational lensing systems. For demonstration purposes, we created and also analysed mock data of the strong lensing system RX J1131−1231. By modelling both the lens and source, we recover the dynamical mass within the effective radius of strongly lensed high-redshift sources within 5% uncertainty, and we improve the constraints on the lens mass parameters by up to 50%. This machinery is particularly well-suited for future observations from large segmented-mirror telescopes, such as the James Webb Space Telescope, which will yield high sensitivity and angular-resolution IFU data for studies on distant and faint galaxies.

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