Cosmic rays in molecular clouds probed by H$_{2}$ rovibrational lines -- Perspectives for the James Webb Space Telescope
Marco Padovani, Shmuel Bialy, Daniele Galli, Alexei V. Ivlev, Tommaso Grassi, Liam H. Scarlett, Una S. Rehill, Mark C. Zammit, Dmitry V. Fursa, Igor Bray
Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitation of H$_{2}$. Their characterisation is important both for the interpretation of observations and for the development of theoretical models. The methods used so far for estimating the CR ionisation rate ($ζ$) in molecular clouds have several limitations due to uncertainties in the adopted chemical networks. We refine and extend the method proposed by Bialy (2020) to estimate $ζ$ by observing rovibrational transitions of H$_{2}$ at near-infrared wavelengths, which are mainly excited by secondary CR electrons. Combining models of interstellar CR propagation and attenuation with the calculation of the expected secondary electron spectrum and updated H$_{2}$ excitation cross sections by electron collisions, we derive the intensity of the four H$_{2}$ rovibrational transitions observable in dense, cold gas: (1-0)O(2), (1-0)Q(2), (1-0)S(0), and (1-0)O(4). The proposed method allows the estimation of $ζ$ for a given observed line intensity and H$_{2}$ column density. We are also able to deduce the shape of the low-energy CR proton spectrum impinging upon the molecular cloud. We present a look-up plot and a web-based application that can be used to constrain the low-energy spectral slope of the interstellar CR proton spectrum. We comment on the capability of the James Webb Space Telescope to detect these near-infrared H$_{2}$ lines, making it possible to derive for the first time spatial variation of $ζ$ in dense gas. Besides the implications for the interpretation of the chemical-dynamic evolution of a molecular cloud, it will be possible to test competing models of CR propagation and attenuation in the interstellar medium, as well as compare CR spectra in different Galactic regions.
The scheduled launch of James Webb Space Telescope (JWST) in late 2021 marks a new start for studies of galaxy formation at high redshift z>~6 during the era of Cosmic Reionization. JWST can capture sensitive, high-resolution images and multi-object spectroscopy in the infrared that will transform our view of galaxy formation during the first billion years of cosmic history. This review summarizes our current knowledge of the role of galaxies in reionizing intergalactic hydrogen ahead of JWST, achieved through observations with Hubble Space Telescope and ground-based facilities including Keck,…
The build-up of galaxies is regulated by a complex interplay between gravitational collapse, galaxy merging and feedback related to AGN and star formation. The energy released by these processes has to dissipate for gas to cool, condense, and form stars. How gas cools is thus a key to understand galaxy formation. \textit{Spitzer Space Telescope} infrared spectroscopy revealed a population of galaxies with weak star formation and unusually powerful H$_2$ line emission. This is a signature of turbulent dissipation, sustained by large-scale mechanical energy injection. The cooling of the multipha…
A dust-free hierarchically nested supermassive-star model for James Webb Space Telescope Little Red Dots
Universitat Politècnica de València（瓦伦西亚理工大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；Kavli Institute for Astronomy and Astrophysics at Peking University（北京大学科维理天文与天体物理研究所）
We present the $NuSTAR$ extragalactic survey of the $James$ $Webb$ $Space$ $Telescope$ ($JWST$) North Ecliptic Pole (NEP) Time-Domain Field. The survey covers a $\sim$0.16 deg$^2$ area with a total exposure of 681 ks acquired in a total of nine observations from three epochs. The survey sensitivities at 20% of the area are 2.39, 1.14, 2.76, 1.52, and 5.20 $\times$ 10$^{-14}$ erg cm$^{-2}$ s$^{-1}$ in the 3-24, 3-8, 8-24, 8-16, and 16-24 keV bands, respectively. The NEP survey is one of the most sensitive extragalactic surveys with $NuSTAR$ so far. A total of 33 sources were detected above 95% …
The upcoming launch of the James Webb Space Telescope (JWST) in less than three years is certain to bring a revolution in our understanding of many area of astrophysics, with one of the key goals being galaxy evolution. As the first proposals will be due in a little over two years, the time is ripe to take a holistic look at the science goals which the community would wish to accomplish with this observatory. Contrary to our experiences with the Hubble Space Telescope, which has now operated successfully for over two decades due to several timely servicing missions, the lifetime of JWST is fin…
The James Webb Space Telescope (JWST) will open a new window of the most distant universe and unveil the early growth of supermassive black holes (BHs) in the first galaxies. In preparation for deep JWST imaging surveys, it is crucial to understand the color selection of high-redshift accreting seed BHs. We model the spectral energy distribution of super-Eddington accreting BHs with millions of solar masses in metal-poor galaxies at $z\gtrsim 8$, applying post-process line transfer calculations to radiation hydrodynamical simulation results. Ten kilosecond exposures with the NIRCam and MIRI br…
We present mid-infrared galaxy number counts based on the Early Release Observations obtained by the James Webb Space Telescope (JWST) at 7.7-, 10- and 15-$μ$m (F770W, F1000W and F1500W, respectively) bands of the Mid-Infrared Instrument (MIRI). Due to the superior sensitivity of JWST, the 80 percent completeness limits reach 0.32, 0.79 and 2.0 $μ$Jy in F770W, F1000W and F1500W filters, respectively, i.e., $\sim$100 times deeper than previous space infrared telescopes such as Spitzer or AKARI. The number counts reach much deeper than the broad bump around $0.05\sim0.5$ mJy due to polycyclic ar…
We have calibrated the 6.5 m James Webb Space Telescope (JWST) mid-infrared filters as star formation rate indicators, using JWST photometry synthesized from $Spitzer$ spectra of 49 low redshift galaxies, which cover a wider luminosity range than most previous studies. We use Balmer decrement corrected $\rm{Hα}$ luminosity and synthesized mid-infrared photometry to empirically calibrate the $Spitzer$, WISE and JWST filters as star formation rate indicators. Our $Spitzer$ and WISE calibrations are in good agreement with recent calibrations from the literature. While mid-infrared luminosity may …
Dark matter halos that reach the HI-cooling mass without prior star formation or external metal pollution represent potential sites for the formation of small - extremely faint - Population III galaxies at high redshifts. Gravitational lensing may in rare cases boost their fluxes to detectable levels, but to find even a small number of such objects in randomly selected regions of the sky requires very large areas to be surveyed. Because of this, a small, wide-field telescope can in principle offer better detection prospects than a large telescope with a smaller field of view. Here, we derive t…
We present a new analysis of the potential power of deep, near-infrared, imaging surveys with the James Webb Space Telescope (JWST) to improve our knowledge of galaxy evolution. In this work we properly simulate what can be achieved with realistic survey strategies, and utilise rigorous signal:noise calculations to calculate the resulting posterior constraints on the physical properties of galaxies. We explore a broad range of assumed input galaxy types (>20,000 models, including extremely dusty objects) across a wide redshift range (out to z~12), while at the same time considering a realistic…
In this paper, we study the effects of a recent drop in star formation rate (SFR) on the spectra of epoch of reionization (EoR) galaxies, and the resulting degeneracy with the spectral features produced by extreme Lyman continuum leakage. In order to study these effects in the wavelength range relevant for the upcoming James Webb Space Telescope (JWST), we utilize synthetic spectra of simulated EoR galaxies from cosmological simulations together with synthetic spectra of partially quenched mock galaxies. We find that rapid declines in the SFR of EoR galaxies could seriously affect the applicab…
On July 13, 2022, NASA released to the whole world the data obtained by the James Webb Space Telescope (JWST) Early Release Observations (ERO). These are the first set of science-grade data from this long-awaited facility, marking the beginning of a new era in astronomy. In the study of the early universe, JWST will allow us to push far beyond z ~ 11, the redshift boundary previously imposed by the 1.7 um red cut-off of the Hubble Space Telescope (HST). In contrast, JWST's NIRCam reaches 5 um. Among the JWST ERO targets there is a nearby galaxy cluster SMACS 0723-73, which is a massive cluster…
Using four different suites of cosmological simulations, we generate synthetic spectra for galaxies with different Lyman continuum escape fractions (fesc) at redshifts z=7-9, in the rest-frame wavelength range relevant for the James Webb Space Telescope (JWST) NIRSpec instrument. By investigating the effects of realistic star formation histories and metallicity distributions on the EW(Hb)-beta diagram (previously proposed as a tool for identifying galaxies with very high fesc), we find that neither of these effects are likely to jeopardize the identification of galaxies with extreme Lyman cont…
A Mysteriously Tight H$α$-[O III] Correlation and Non-Case B Balmer Decrements Revealed by the Spectra from the James Webb Space Telescope NIRSpec Instrument
Population III stars were the first stars to form after the Big Bang, and are believed to have made the earliest contribution to the metal content of the universe beyond the products of the Big Bang Nucleosynthesis. These stars are theorized to have had extremely short lifespans, and therefore would only be observable at high redshifts ($z \geq 3-17$) and faint apparent magnitudes ($m_{AB} \gtrsim 40$). The direct detection of Population III stars therefore remains elusive. However, the recently launched James Webb Space Telescope (JWST) may be capable of detecting stars in the relevant magnit…
We use two independent, galaxy formation simulations, FLARES, a cosmological hydrodynamical simulation, and SHARK, a semi-analytic model, to explore how well the James Webb Space Telescope (JWST) will be able to uncover the existence and parameters of the star-forming main sequence (SFS) at $z=5\to10$, i.e. shape, scatter, normalisation. Using two independent simulations allows us to isolate predictions (e.g., stellar mass, star formation rate, SFR, luminosity functions) that are robust to or highly dependent on the implementation of the physics of galaxy formation. Both simulations predict th…
The James Webb Space Telescope (JWST) NIRSpec instrument will allow rest-frame ultraviolet/optical spectroscopy of galaxies in the epoch of reionization (EoR). Some galaxies may exhibit significant leakage of hydrogen-ionizing photons into the intergalactic medium, resulting in faint nebular emission lines. We present a machine learning framework for identifying cases of very high hydrogen-ionizing photon escape from galaxies based on the data quality expected from potential NIRSpec observations of EoR galaxies in lensed fields. We train our algorithm on mock samples of JWST/NIRSpec data for g…
The GLASS James Webb Space Telescope Early Release Science (hereafter GLASS-JWST-ERS) Program will obtain and make publicly available the deepest extragalactic data of the ERS campaign. It is primarily designed to address two key science questions, namely, "what sources ionized the universe and when?" and "how do baryons cycle through galaxies?", while also enabling a broad variety of first look scientific investigations. In primary mode, it will obtain NIRISS and NIRSpec spectroscopy of galaxies lensed by the foreground Hubble Frontier Field cluster, Abell 2744. In parallel, it will use NIRCa…
Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of superEarths (1-3 Earth radii). Recent results from the Doppler surveys suggest that discovery of a transiting superEarth in the habitable zone of a lower main sequence star may be possible. We evaluate the prospects for an all-sky transit survey targeted to the brightest stars, that would find the most favorable cases for photometric and spectroscopic characterization using the James Webb Space Telescope (JWST). We use the proposed Transiting Exoplanet Survey Satellite…
For the past 400 years, astronomers have sought to observe and interpret the Universe by building more powerful telescopes. These incredible instruments extend the capabilities of one of our most important senses, sight, towards new limits such as increased sensitivity and resolution, new dimensions such as exploration of wavelengths across the full electromagnetic spectrum, new information content such as analysis through spectroscopy, and new cadences such as rapid time-series views of the variable sky. The results from these investments, from small to large telescopes on the ground and in s…
We describe the selection of the James Webb Space Telescope (JWST) North Ecliptic Pole (NEP) Time-Domain Field (TDF), a ~14' diameter field located within JWST's northern Continuous Viewing Zone (CVZ) and centered at (RA, Dec)_J2000 = (17:22:47.896, +65:49:21.54). We demonstrate that this is the only region in the sky where JWST can observe a clean (i.e., free of bright foreground stars and with low Galactic foreground extinction) extragalactic deep survey field of this size at arbitrary cadence or at arbitrary orientation, and without a penalty in terms of a raised Zodiacal background. This w…
The James Webb Space Telescope Time-Domain Field (JWST-TDF) is an $\sim$14$'$ diameter field near the North Ecliptic Pole that will be targeted by one of the JWST Guaranteed Time Observations programs. Here, we describe our James Clerk Maxwell Telescope SCUBA-2 850 $μ$m imaging of the JWST-TDF and present the submillimeter source catalog and properties. We also present a catalog of radio sources from Karl J. Jansky Very Large Array 3 GHz observations of the field. These observations were obtained to aid JWST's study of the dust-obscured galaxies that contribute significantly to the cosmic star…
Extragalactic Multi-Band Exploration of Red Supergiants (EMBERS): Pipeline, Source Classification, and Bolometric Properties of 101,219 Red Supergiants from James Webb Space Telescope Imaging
Northwestern University（西北大学）；University of Toronto（多伦多大学）；University of Florida（佛罗里达大学）；INAF（意大利国家天体物理研究所）
The Large Magellanic Cloud through the lens of the James Webb Space Telescope: Binaries and the mass function in the galaxy's outskirts
Univ. di Padova（帕多瓦大学）；INAF - Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Australian National University（澳大利亚国立大学）；American University of Sharjah（沙迦美国大学）；Space Telescope Science Institute（太空望远镜科学研究所）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天体物理与空间科学观测站）；Yonsei University（延世大学）
New Measurements of Distances to Galaxies in the NGC 1052 Field with the Hubble and James Webb Space Telescopes: Testing the Bullet-Dwarf Origin of the Trail
University of California Santa Cruz（加州大学圣克鲁兹分校）；Space Telescope Science Institute（太空望远镜科学研究所）；San José State University（圣何塞州立大学）；Yale University（耶鲁大学）
Searching for the elusive CH2+ with the James Webb Space Telescope. Another carbocation to constrain astrochemical networks
Instituto de Física Fundamental (CSIC)（基础物理研究所（西班牙高等科学研究委员会））；Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS（巴黎萨克雷大学空间天体物理学研究所（法国国家科学研究中心））；Institut des Sciences Moléculaires d’Orsay, UMR8214, CNRS, Université Paris-Saclay（奥赛分子科学学院（法国国家科学研究中心，巴黎萨克雷大学））；Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca（萨拉曼卡大学化学学院物理化学系）；Department of Physics & Astronomy, The University of Western Ontario（韦仕敦大学物理与天文系）；Institute for Earth and Space Exploration, The University of Western Ontario（韦仕敦大学地球与太空探索研究所）
H2 emission in the Orion Bar, NGC7023 and the Horsehead Nebula observed with the James Webb Space Telescope
Instituto de Física Fundamental (CSIC)（基础物理研究所（西班牙科学理事会））；Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS（空间天体物理学研究所，巴黎萨克雷大学，法国国家科学研究中心）；Department of Physics and Astronomy, University of Western Ontario（韦仕敦大学物理与天文系）；Institute for Earth and Space Exploration, The University of Western Ontario（韦仕敦大学地球与太空探索研究所）；Department of Astronomy, University of Michigan（密歇根大学天文系）；Astronomy Department, University of Maryland（马里兰大学天文系）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）
The J-PAS survey will observe ~1/3 of the northern sky with a set of 56 narrow-band filters using the dedicated 2.55 m JST telescope at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera, in order to demonstrate the scientific potential of J-PAS, two small surveys were performed with the single-CCD Pathfinder camera: miniJPAS (~1 deg2 along the Extended Groth Strip), and J-NEP (~0.3 deg2 around the JWST North Ecliptic Pole Time Domain Field), including all 56 J-PAS filters as well as u, g, r, and i. J-NEP is ~0.5-1.0 magnitudes deeper than miniJPAS, providin…
PEARLS: 21 Transients Found in the Three-Epoch NIRCam Observations in the Continuous Viewing Zone of the James Webb Space Telescope
University of Missouri（密苏里大学）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；Texas A. & M. University（德克萨斯农工大学）；University of Arizona（亚利桑那大学）；Oklahoma State University（俄克拉荷马州立大学）；Space Telescope Science Institute（太空望远镜科学研究所）；The Ohio State University（俄亥俄州立大学）
Some few hundred million years after the big bang the Universe was illuminated by the first stars and galaxies thereby bringing an end to the cosmological dark ages. Since the installation of WFC3 on the Hubble Space Telescope our ability to probe this critical period of the Universe's history has dramatically changed with thousands of objects now identified within the first billion years of the Universe's history. Our understanding of this period of the Universe's history will further grow thanks to both the Atacama Large millimetre/sub-millimetre Array and the James Webb Space Telescope.
The dwarf galaxies of the Local Group are believed to be similar to the most abundant galaxies during the epoch of reionization (z>6). As a result of their proximity, there is a wealth of information that can be obtained about these galaxies; however, due to their low surface brightnesses, detecting their progenitors at high redshifts is challenging. We compare the physical properties of these dwarf galaxies to those of galaxies detected at high redshifts using Hubble Space Telescope and Spitzer observations and consider the promise of the upcoming James Webb Space Telescope on the prospects f…
Water nanoclusters ejected to space from abundant amorphous water-ice-coated cosmic dust have been proposed to constitute Rydberg baryonic dark matter. This phenomenological model is now qualitatively supported by several recent observations: the laboratory-generated ejection of water nanoclusters from amorphous water-ice; the absence of dark matter in Galaxy NGC 1052-DF2; a recent study of dark matter in distant galaxies reporting the direct interaction of dark matter with galactic baryonic matter; the bullet cluster; and the birefringence of the cosmic microwave background. A link between Ry…
