scholarly journals Candidate Population III stellar complex at z = 6.629 in the MUSE Deep Lensed Field

2020 ◽  
Vol 494 (1) ◽  
pp. L81-L85 ◽  
Author(s):  
E Vanzella ◽  
M Meneghetti ◽  
G B Caminha ◽  
M Castellano ◽  
F Calura ◽  
...  
Keyword(s):  
Rest Frame ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
Galaxy Cluster ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
H Ii Region ◽  
Large Telescopes ◽  
The Continuum ◽  
Population Iii

ABSTRACT We discovered a strongly lensed (μ ≳ 40) Ly α emission at z = 6.629 (S/N ≃ 18) in the MUSE Deep Lensed Field (MDLF) targeting the Hubble Frontier Field (HFF) galaxy cluster MACS J0416. Dedicated lensing simulations imply that the Ly α emitting region necessarily crosses the caustic. The arc-like shape of the Ly α extends 3 arcsec on the observed plane and is the result of two merged multiple images, each one with a de-lensed Ly α luminosity L ≲ 2.8 × 1040 erg s−1 arising from a confined region (≲150 pc effective radius). A spatially unresolved Hubble Space Telescope(HST) counterpart is barely detected at S/N ≃ 2 after stacking the near-infrared bands, corresponding to an observed (intrinsic) magnitude m1500 ≳ 30.8 (≳35.0). The inferred rest-frame Ly α equivalent width is EW0 > 1120 Å if the IGM transmission is TIGM < 0.5. The low luminosities and the extremely large Ly α EW0 match the case of a Population III (Pop III) star complex made of several dozens stars (∼104 M⊙) that irradiate an H ii region crossing the caustic. While the Ly α and stellar continuum are among the faintest ever observed at this redshift, the continuum and the Ly α emissions could be affected by differential magnification, possibly biasing the EW0 estimate. The aforementioned tentative HST detection tends to favour a large EW0, making such a faint Pop III candidate a key target for the James Webb Space Telescope and Extremely Large Telescopes.

scholarly journals Asymmetric surface brightness structure of caustic crossing arc in SDSS J1226+2152: a case for dark matter substructure

2020 ◽  
Vol 495 (3) ◽  
pp. 3192-3208
Author(s):  
Liang Dai ◽  
Alexander A Kaurov ◽  
Keren Sharon ◽  
Michael Florian ◽  
Jordi Miralda-Escudé ◽  
...  
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Cold Dark Matter ◽  
Hubble Space Telescope ◽  
Galaxy Cluster ◽  
Critical Curve ◽  
Space Telescope ◽  
Star Forming ◽  
James Webb Space Telescope ◽  
Image Pairs

ABSTRACT We study the highly magnified arc SGAS J122651.3+215220 caused by a star-forming galaxy at zs = 2.93 crossing the lensing caustic cast by the galaxy cluster SDSS J1226+2152 (zl = 0.43), using Hubble Space Telescope observations. We report in the arc several asymmetric surface brightness features whose angular separations are a fraction of an arcsecond from the lensing critical curve and appear to be highly but unequally magnified image pairs of underlying compact sources, with one brightest pair having clear asymmetry consistently across four filters. One explanation of unequal magnification is microlensing by intracluster stars, which induces independent flux variations in the images of individual or groups of source stars in the lensed galaxy. For a second possibility, intracluster dark matter subhaloes invisible to telescopes effectively perturb lensing magnifications near the critical curve and give rise to persistently unequal image pairs. Our modelling suggests, at least for the most prominent identified image pair, that the microlensing hypothesis is in tension with the absence of notable asymmetry variation over a six-year baseline, while subhaloes of ∼106–$10^8\, \mathrm{ M}_\odot$ anticipated from structure formation with cold dark matter typically produce stationary and sizable asymmetries. We judge that observations at additional times and more precise lens models are necessary to stringently constrain temporal variability and robustly distinguish between the two explanations. The arc under this study is a scheduled target of a Director’s Discretionary Early Release Science program of the James Webb Space Telescope, which will provide deep images and a high-resolution view with integral field spectroscopy.

scholarly journals The European optical contribution to the James Webb Space Telescope

2018 ◽  
Vol 7 (6) ◽  
pp. 353-364
Author(s):  
Maurice te Plate ◽  
Brian O’Sullivan ◽  
Pierre Ferruit ◽  
David Lee ◽  
Martyn Wells ◽  
...  
Keyword(s):  
Near Infrared ◽  
Hubble Space Telescope ◽  
European Space Agency ◽  
Status Report ◽  
Mid Infrared ◽  
Space Telescope ◽  
International Partnership ◽  
Optical Science ◽  
Space Agency ◽  
James Webb Space Telescope

Abstract The James Webb Space Telescope (JWST) is frequently referred to as the follow-on mission to the Hubble Space Telescope (HST). The ‘Webb’ will be the biggest space telescope ever built and is expected to enable astounding new science. The observatory comprises a 6.5-m-diameter telescope with a segmented primary mirror and four high-performance optical science instruments. The JWST has mostly been optimized to work in the near- (0.6–5.0 μm) and mid-infrared (5.0–29 μm) wavelength regions. The project is a strong international partnership led by the National Aeronautics and Space Administration (NASA) with contributions from the European Space Agency (ESA) and the Canadian Space Agency (CSA). The observatory is currently scheduled for launch in early 2021 from Kourou, French Guyana, by an ESA-provided Ariane 5 rocket. This paper will focus on the European optical contribution to the mission, which mainly consists of two highly advanced optical science instruments: The multi-object near-infrared spectrograph (NIRSpec) and the mid-infrared instrument (MIRI). The opto-mechanical design considerations and the realization of both instruments will be described, and we will conclude with a short JWST project status report and future outlook.

scholarly journals What we learn from the Frontier Fields cluster MACS J0416.1-2403

2015 ◽  
Vol 11 (A29B) ◽  
pp. 787-790
Author(s):  
S. H. Suyu ◽  
C. Grillo ◽  
P. Rosati
Keyword(s):  
Mass Distribution ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Galaxy Cluster ◽  
Essential Elements ◽  
Central Mass ◽  
Great Opportunity ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
High Redshift Universe

AbstractThe Frontier Fields cluster MACS J0416.1-2403 with its extensive imaging and spectroscopic data sets provides a great opportunity to study the mass distribution of the galaxy cluster and members, the high-redshift Universe and cosmology. By taking advantage of the observations in the 16 Hubble Space Telescope imaging bands of the Cluster Lensing And Supernova survey with Hubble (CLASH) survey and our large spectroscopic follow-up program with the VIsible Multi-Object Spectrograph (VIMOS) on the Very Large Telescope (VLT), we have been able to identify and obtain the spectroscopic redshifts of 10 important strong lensing systems in this cluster. Furthermore, we have selected and modeled the mass distribution of ~200 candidate cluster members residing in the inner regions of the cluster. We present the results on the model-predicted central mass profile and subhalo population, which are detailed in Grillo et al. (2015). Work is underway to quantify the effects of line-of-sight structures. These are essential elements to make progress in our understanding of the dark matter distribution in massive galaxy clusters and of the distant Universe within the current Frontier Fields initiative and before the advent of the James Webb Space Telescope.

scholarly journals All NIRspec Needs is HST/WFC3 Pre-Imaging? The Use of Milky Way Stars in WFC3 Imaging to Register NIRspec MSA Observations

2016 ◽  
Vol 05 (03) ◽  
pp. 1650008
Author(s):  
B. W. Holwerda ◽  
R. J. Bouwens ◽  
M. Trenti ◽  
M. A. Kenworthy
Keyword(s):  
Near Infrared ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Wide Field ◽  
Galactic Latitude ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
Specific Formula ◽  
The Right ◽  
Guide Star

The James Webb Space Telescope (JWST) will be an exquisite new near-infrared observatory with imaging and multi-object spectroscopy through ESA’s NIRspec instrument with its unique Micro-Shutter Array (MSA), allowing for slits to be positioned on astronomical targets by opening specific [Formula: see text]-wide micro shutter doors. To ensure proper Target Acquisition (TA), the on-sky position of the MSA needs to be verified before spectroscopic observations start. An onboard centroiding program registers the position of pre-identified guide stars in a TA image, a short pre-spectroscopy exposure without dispersion (image mode) through the MSA with all shutters open. The outstanding issue is the availability of Galactic stars in the right luminosity range for TA relative to typical high redshift targets. We explore this here using the stars and [Formula: see text] candidate galaxies identified in the source extractor catalogs of Brightest of Reionizing Galaxies survey (BoRG[z8]), a pure-parallel program with Hubble Space Telescope Wide-Field Camera 3. We find that (a) a single WFC3 field contains enough Galactic stars to satisfy the NIRspec astrometry requirement (20 milli-arcseconds), provided its and the NIRspec TA’s are [Formula: see text] AB in WFC3 [Formula: see text], (b) a single WFC3 image can therefore serve as the pre-image if need be, (c) a WFC3 mosaic and accompanying TA image satisfy the astrometry requirement at [Formula: see text] AB mag in WFC3 [Formula: see text], (d) no specific Galactic latitude requires deeper TA imaging due to a lack of Galactic stars, and (e) a depth of [Formula: see text] AB mag in WFC3 [Formula: see text] is needed if a guide star in the same MSA quadrant as a target is required. We take the example of a BoRG identified [Formula: see text] candidate galaxy and require a Galactic star within 20[Formula: see text] of it. In this case, a depth of 25.5 AB in [Formula: see text] is required (with [Formula: see text]97% confidence).

scholarly journals Search for giant planets around seven white dwarfs in the Hyades cluster with the Hubble Space Telescope

2020 ◽  
Vol 500 (3) ◽  
pp. 3920-3925
Author(s):  
Wolfgang Brandner ◽  
Hans Zinnecker ◽  
Taisiya Kopytova
Keyword(s):  
White Dwarfs ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
Infrared Camera ◽  
Detection Limits ◽  
Giant Planets ◽  
High Angular Resolution ◽  
Mass Detection ◽  
Space Telescope ◽  
Hyades Cluster

ABSTRACT Only a small number of exoplanets have been identified in stellar cluster environments. We initiated a high angular resolution direct imaging search using the Hubble Space Telescope (HST) and its Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument for self-luminous giant planets in orbit around seven white dwarfs in the 625 Myr old nearby (≈45 pc) Hyades cluster. The observations were obtained with Near-Infrared Camera 1 (NIC1) in the F110W and F160W filters, and encompass two HST roll angles to facilitate angular differential imaging. The difference images were searched for companion candidates, and radially averaged contrast curves were computed. Though we achieve the lowest mass detection limits yet for angular separations ≥0.5 arcsec, no planetary mass companion to any of the seven white dwarfs, whose initial main-sequence masses were >2.8 M⊙, was found. Comparison with evolutionary models yields detection limits of ≈5–7 Jupiter masses (MJup) according to one model, and between 9 and ≈12 MJup according to another model, at physical separations corresponding to initial semimajor axis of ≥5–8 au (i.e. before the mass-loss events associated with the red and asymptotic giant branch phase of the host star). The study provides further evidence that initially dense cluster environments, which included O- and B-type stars, might not be highly conducive to the formation of massive circumstellar discs, and their transformation into giant planets (with m ≥ 6 MJup and a ≥6 au). This is in agreement with radial velocity surveys for exoplanets around G- and K-type giants, which did not find any planets around stars more massive than ≈3 M⊙.

scholarly journals The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot-Jupiter WASP-74b

2021 ◽  
Vol 162 (6) ◽  
pp. 271
Author(s):  
Guangwei Fu ◽  
Drake Deming ◽  
Erin May ◽  
Kevin Stevenson ◽  
David K. Sing ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Hubble Space Telescope ◽  
Absorption Feature ◽  
Spectral Library ◽  
Data Set ◽  
Space Telescope ◽  
Methane Absorption ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot-Jupiter WASP-74b into the ever growing data set of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope and Spitzer Space Telescope (Spitzer), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 μm band. Future James Webb Space Telescope follow-up observations are needed to confirm these results.

scholarly journals Fracture of Be and Its Alloys - Webb Space Telescope Revisited

2021 ◽  
Author(s):  
Muhammad Musaddique Ali Rafique
Keyword(s):  
Near Infrared ◽  
Joint Venture ◽  
Coefficient Of Thermal Expansion ◽  
Infrared Range ◽  
Linear Coefficient ◽  
Space Telescope ◽  
Hexagonal Close Packed ◽  
James Webb Space Telescope ◽  
Layer Deposition ◽  
Slip Planes

NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (α) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.

Detectors for the James Webb Space Telescope near infrared spectrograph (NIRSpec)

2006 ◽  
Author(s):  
Bernard J. Rauscher ◽  
Torsten Böker ◽  
Craig Cabelli ◽  
Guido De Marchi ◽  
Pierre Ferruit ◽  
...  
Keyword(s):  
Near Infrared ◽  
Space Telescope ◽  
James Webb Space Telescope

9. The next telescopes

2016 ◽  
pp. 122-138
Author(s):  
Geoff Cottrell
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Adaptive Optics ◽  
Hubble Space Telescope ◽  
Scientific Instrument ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
First Galaxies ◽  
New Generation ◽  
Optical Telescopes

Each question that telescopes have helped answer has led to new questions: what is dark matter and dark energy? How did the first galaxies form? Are there habitable, Earth-like exoplanets? To address these questions, a new generation of telescopes are being built. ‘The next telescopes’ describes some of these, including the three extremely large infrared/optical telescopes, equipped with adaptive optics systems, due to start operating in the next decade. Other new telescopes discussed are the Square Kilometre Array, a radio telescope that will soon be the world’s largest scientific instrument, and the James Webb Space Telescope due to be launched in 2018, which is the 100 times more powerful successor to the Hubble Space Telescope.

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