Status of the James Webb Space Telescope (JWST) Observatory
Presentation providing a high-level overview of the James Webb Space Telescope (JWST) and mission status
JWST Observatory↗
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Thermal Emission from the Earth-sized Exoplanet TRAPPIST-1 b using JWST
The TRAPPIST-1 system is remarkable for its seven planets that are similar in size, mass, density, and stellar heating to the rocky planets Venus, Earth, and Mars in our own Solar System [1]. All TRAPPIST-1 planets have been observed with the transmission spectroscopy technique using the Hubble or Spitzer Space Telescopes, but no atmospheric features have been detected or strongly constrained [2–5]. TRAPPIST-1 b is the closest planet to the system’s M dwarf star, and it receives 4 times as much irradiation as Earth receives from the Sun. This relatively large amount of stellar heating suggests that its thermal emission may be measurable. Here we present photometric secondary eclipse observations of the Earth-sized TRAPPIST1 b exoplanet using the F1500W filter of the MIRI instrument on JWST. We detect the secondary eclipse in each of five separate observations with 8.7-sigma confidence when all data are combined. These measurements are most consistent with re-radiation of the TRAPPIST-1 star’s incident flux from only the dayside hemisphere of the planet. The most straightforward interpretation is that there is little or no planetary atmosphere redistributing radiation from the host star and also no detectable atmospheric absorption from carbon dioxide (CO 2 ) or other species.
Thermal Emission↗
Enhanced early galaxy formation in JWST from axion dark matter?
We demonstrate that enhanced early galaxy formation can generically arise in axion-like particle (ALP) dark matter (DM) models with a delayed onset of axion field oscillation. In these models, the formation of localized massive objects enhances structure formation, potentially addressing the excess recently observed by the James Webb Space Telescope (JWST), while remaining consistent with existing constraints. We identify viable parameter space with the ALP mass in the range of 10 −22 eV m a < 10 –19 eV. In addition, we show that the ALP parameter regions of interest can lead to intriguing complementary signatures in the small scale structure of DM halos and existing experimental searches for ALPs.
Bird, Simeon↗
JWST’s PEARLS: A z ≃ 6 quasar in a train-wreck galaxy merger system
We present JWST NIRSpec integral field spectroscopy observations of the z = 5.89 quasar NDWFS J1425+3254 from 0.6–5.3 μm, covering the rest-frame ultraviolet and optical at a spectral resolution of R ∼ 100. The quasar has a black hole mass of M BH = (1.4 +3.1 −1.0 ) × 10 9 M ⊙ and an Eddington ratio of L Bol /L Edd = 0.3 +0.6 −0.2 , as implied from the broad Balmer Hα and Hβ lines. The quasar host has significant ongoing obscured star formation, as well as a quasar-driven outflow with velocity 6050 +460 −630 km s −1 and ionised outflow rate of 1650 +130 −1230 M ⊙ yr −1 . This is possibly one of the most extreme outflows in the early Universe. The data also reveal that two companion galaxies are merging with the quasar host. The north-eastern companion galaxy is relatively old and very massive, with a luminosity-weighted stellar age of 65 +9 −4 Myr, stellar mass of (3.6 +0.6 −0.3 #x00D7; 10 11 M ⊙ , and star-formation rate (SFR) of ∼15–30 M ⊙ yr −1 . A bridge of gas connects this companion galaxy and the host, confirming their ongoing interaction. A second merger is occurring between the quasar host and a much younger companion galaxy to the south, with a stellar age of 6.7 ± 1.8 Myr, stellar mass of (1.9 ± 0.4)×10 10 M ⊙ , and SFR of ∼40–65 M ⊙ yr −1 . There is also another galaxy in the field, likely in the foreground at z = 1.135, which could be gravitationally lensing the quasar with a magnification of 1 < μ < 2 and, thus, < 0.75 mag. Overall, the system is a ‘train-wreck’ merger of three galaxies, with star formation and extreme quasar activity that were likely triggered by these ongoing interactions.
79 ASTRONOMY AND ASTROPHYSICS↗
JWST lensed quasar dark matter survey – II. Strongest gravitational lensing limit on the dark matter free streaming length to date
This is the second in a series of papers in which we use JWST Mid Infrared Instrument multiband imaging to measure the warm dust emission in a sample of 31 multiply imaged quasars, to be used as a probe of the particle nature of dark matter. We present measurements of the relative magnifications of the strongly lensed warm dust emission in a sample of nine systems. The warm dust region is compact and sensitive to perturbations by populations of haloes down to masses $\sim 10^6$ M$_{\odot }$. Using these warm dust flux-ratio measurements in combination with five previous narrow-line flux-ratio measurements, we constrain the halo mass function. In our model, we allow for complex deflector macromodels with flexible third- and fourth-order multipole deviations from ellipticity, and we introduce an improved model of the tidal evolution of subhaloes. We constrain a WDM model and find an upper limit on the half-mode mass of $10^{7.6}\, {\rm M}_\odot$ at posterior odds of 10:1. This corresponds to a lower limit on a thermally produced dark matter particle mass of 6.1 keV. This is the strongest gravitational lensing constraint to date, and comparable to those from independent probes such as the Ly $\alpha$ forest and Milky Way satellite galaxies.
dark matter↗
Cold Gas and Star Formation in the Phoenix Cluster with JWST
We present integral field unit observations of the Phoenix Cluster with the JWST Mid-infrared Instrument’s Medium Resolution Spectrometer. We focus this study on the molecular gas, dust, and star formation in the brightest cluster galaxy (BCG). We use precise spectral modeling to produce maps of the silicate dust, molecular gas, and polycyclic aromatic hydrocarbons (PAHs) in the inner ∼50 kpc of the cluster. We measure the optical depth from silicates by comparing the observed H 2 line ratios to those predicted by excitation models. We provide updated measurements of the total molecular gas mass of $1.9^{+0.5}_{-0.04}$ x 10 10 M ⊙ , which agrees with CO-based estimates, providing an estimate of the CO-to-H 2 conversion factor of α CO = 0.8 ± 0.2 M ⊙ pc -2 (K km s -1 ) -1 ; an updated stellar mass of M * = 2.6 ± 0.5 × 10 10 M ⊙ ; and star formation rates (SFRs) averaged over 10 and 100 Myr of $\langle$SFR$\rangle$ 10 = 1340 ± 100 M ⊙ yr −1 and $\langle$SFR$\rangle$ 100 = 740 ± 80 M ⊙ yr −1 , respectively. The H 2 emission seems to be powered predominantly by shocks and star formation within the central ∼20 kpc, induced by stellar feedback and radio jets from the active galactic nucleus. Additionally, we find nearly an order-of-magnitude drop in the SFRs estimated by PAH fluxes in cool core BCGs compared to field galaxies, suggesting that hot particles from the intracluster medium are destroying PAH grains even in the central-most tens of kiloparsecs.
Active galaxies↗
JWST Observations of Starbursts: Dust Processing in the M82 Superwind
We present JWST MIRI and NIRCam imaging of the inner ∼5 kpc of the M82 superwind at ~ $0''_{.}05 - 0''_{.}375$(∼0.9–6.5 pc) resolution. Targeted filters probe emission from polycyclic aromatic hydrocarbons (PAHs; F335M, F360M, F770W, F1130W) and continuum (F250M, F360M) The images reveal a network of cool wind filaments traced by PAHs. PAH surface brightness declines with the inverse square of distance to the midplane, suggesting that the incident radiation field from the starburst drives the observed PAH intensity out to ±2.5 kpc. The 3.3/11.3 and 3.3/7.7 μm band ratios show uniformity with distance from the starburst, though comparisons with mid-IR dust emission models indicate a modest shift toward larger PAHs. Outside the disk, 11.3/7.7 μm increases moderately, reflecting that PAHs become more neutral with distance from the starburst as they are exposed to a declining radiation field and ionization parameter. Overall, PAHs in the wind are consistent with standard-to-large sizes and standard-to-high ionization states. Including Spitzer and Herschel data, PAH abundance (q PAH ) is set at ∼1% in the starburst and remains unchanging out to ±5 kpc off the disk. This flat q PAH profile suggests that PAHs are shielded from the hot wind, perhaps residing in the surface layers of cool clouds, with possible replenishment from cloud interiors and enrichment of the halo from previous bursts. In this picture, clouds are not dense enough to promote PAH growth, and they likely undergo radiative cooling and mixing with the hot phase to survive the gauntlet for at least ∼20 Myr.
Cronin, Serena A. [University of Maryland, College↗
Statistical imprints of wave-like dark matter on multiply-imaged galaxies in strong cluster lenses from JWST
Wave-like dark matter ($ψ$DM) is an elusive dark matter (DM) candidate. The model, often also called fuzzy or ultralight DM, proposes that DM is an extremely light ($m\sim10^{-22}$ eV) boson and thereby has a kpc-scale de Broglie wavelength. Hence, interference of DM gives rise to sub-galactic density fluctuations that can be studied with strong gravitational lensing. In this paper, we use the residual power spectrum, $\mathrm{P}_δ(k)$, as a probe of $ψ$DM, which quantifies deviations from smooth lensing predictions, measured from multiply-imaged galaxies in strong cluster lenses. The key idea is that imprinted in these deviations are lensing distortions from DM substructure, which can be harnessed statistically to distinguish among DM theories. We simulate JWST-quality mock observations of strong gravitational lensing in galaxy clusters, modeling line-of-sight DM substructure within $ψ$DM and the standard cold dark matter (CDM) paradigms. Using mock deep observations ($\sim$ 20 hours), we find that $\mathrm{P}_δ(k)$ is sensitive to both $ψ$DM particle mass and fluctuation amplitude, and can distinguish $ψ$DM fluctuations from CDM subhalos. We demonstrate that $\mathrm{P}_δ(k)$ can be measured directly from data by modeling the smooth lensing with a local Curved Arc Basis formalism. With realistic modeling systematics, we find a statistically significant separation between $ψ$DM and CDM across $1 \lesssim k \lesssim 11\,\mathrm{kpc}^{-1}$ -- offering an independent probe of the wave-like nature of DM complementary to existing constraints.
Cosmology and Nongalactic Astrophysics (astro-ph.C↗
James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Architecture and Technology
The James Webb Space Telescope (JWST) Optical Telescope Element (OTE) is the first NASA segmented space telescope and is planned for launch in 201 1. The telescope architecture was recently finalized with the selection of the primary mirror material. This presentation reviews the telescope architecture and discusses the remaining key technological challenges of this element.
Feinberg, Lee D.↗
James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Architecture and Technology
The James Webb Space Telescope (JWST) Optical Telescope Element (OTE) is the first NASA segmented space telescope and is planned for launch in 2011. The telescope architecture was recently finalized with the selection of the primary mirror material. This presentation reviews the telescope architecture and discusses the remaining key technological challenges of this element.
Feinberg, Lee D.↗
Detectors for the JWST Near-Infrared Spectrometer
The Near-Infrared Spectrometer (NIRSpec) places the most stringent demands upon its detectors of all James Webb Space Telescope (JWST) instruments. We present the scientific rationale for challenging requirements including noise <or=6 e- rms per exposure. In concert, we discuss laboratory test results that are informing the design of NIRSpec's detector system and operational concept.
Rauscher, B. J.↗
Broadband Wavefront Sensing for JWST Fine Phasing
An application of broadband image-based wavefront sensing is considered for JWST fine phasing. The wavefront sensing error is derived as a function of filter bandpass and then applied to determine the appropriate filter specifications for observatory fine-phasing. These specifications are defined by considering an optimization in the trade space consisting of detector integration time vs. filter bandpass subject to wavefront sensing error budget constraints.
Dean, Bruce↗
JWST ISIM Distortion Analysis Challenge
Very tight distortion requirements are imposed on the JWST's ISM structure due to the sensitivity of the telescope's mirror segment and science instrument positioning. The ISIM structure is a three dimensional truss with asymmetric gusseting and metal fittings. One of the primary challenges for ISIM's analysis team is predicting the thermal distortion of the structure both from the bulk cooldown from ambient to cryo, and the smaller temperature changes within the cryogenic operating environment. As a first cut to estimate thermal distortions, a finite element model of bar elements was created. Elements representing joint areas and metal fittings use effective properties that match the behavior of the stack-up of the composite tube, gusset and adhesive under mechanical and thermal loads. These properties were derived by matching tip deflections of a solid model simplified T-joint. Because of the structure s asymmetric gusseting, this effective property model is a first attempt at predicting rotations that cannot be captured with a smeared CTE approach. In addition to the finite element analysis, several first order calculations have been performed to gauge the feasibility of the material design. Because of the stringent thermal distortion requirements at cryogenic temperatures, a composite tube material with near zero or negative CTE is required. A preliminary hand analysis of the contribution of the various components along the distortion path between FGS and the other instruments, neglecting second order effects were examined. A plot of bounding tube longitudinal and transverse CTEs for thermal stability requirements was generated to help determine the feasibility of meeting these requirements. This analysis is a work in progress en route to a large degree of freedom hi-fidelity FEA model for distortion analysis. Methods of model reduction, such as superelements, are currently being investigated.
Cifie, Emmanuel↗
Microshutters Arrays for the JWST Near Infrared Spectrometer
The Near Infrared Spectrograph (NIRSpec) for the James Webb Space Telescope (JWST) is an essential instrument for measuring the number and density evolution of galaxies following the epoch of initial formation. The NIRSpec is a multi-object spectrograph, allowing simultaneous observation of more than 100 candidate high redshift galaxies. A critical element of the instrument is the programmable field selector, the Microshutter Array. The system consists of four 175 x 384 arrays of individually openable shutters, close packed on a 100 x 200 micron pitch, which allow selection of over 200 candidate objects over the 3 min x 3 min field of the NIRSpec. We will describe the development, production, and test of this critical element of the NIRSpec.
Moseley, Harvey↗
JWST: A New Kind of Space Telescope
Contents include the following: Why are the mirrors segmented? Why lightweight segmented mirrors? Why cold (cryogenic) mirrors? Why a space telescope? How did NASA go about developing the mirror technology to enable this? Why was beryllium selected for JWST s mirrors? How are the Beryllium mirrors made? What happens to the mirrors once they are complete?
Keski-Kuha, Ritva↗
James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Development Status
The James Webb Space Telescope (JWST) Optical Telescope Element (OTE) is a segmented, cryogenic telescope scheduled for launch in 2011. In September of 2002, NASA selected prime contractor Northrop Grumman Space Technology (NGST) to build the observatory including management of the OTE. NGST is teamed with subcontractors Ball Aerospace, Alliant Techsystems (ATK). and Kodak. The team has completed several significant design, technology, architecture definition, and manufacturing milestones in the past year that are summarized in this paper.
Feinberg, Lee D.↗
High Accuracy, Absolute, Cryogenic Refractive Index Measurements of Infrared Lens Materials for JWST NIRCam using CHARMS
The current refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF2, and ZnSe. In order to provide the instrument s optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA GSFC, densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Measurement methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented along with estimates of uncertainty. Coefficients for second order polynomial fits of measured index to temperature are provided for many wavelengths to allow accurate interpolation of index to other wavelengths and temperatures.
Leviton, Douglas↗
James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Cryogenic Component Test Facility
This viewgraph presentation provides information on the design, construction, and operation of a cryogenic chamber, and its use in testing the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST).
Packard, Edward A.↗