The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for ...detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5\(\mu\)m, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximise the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55-hour Early Release Science Program that will utilize all four JWST instruments to extend the characterisation of planetary mass companions to \(\sim\)15\(\mu\)m as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative datasets that will enable a broad user base to effectively plan for general observing programs in future cycles.
(Abridged) The luminous z=0.286 quasar HE0450-2958 is interacting with a companion galaxy at 6.5 kpc distance and the whole system is a ULIRG. A so far undetected host galaxy triggered the hypothesis ...of a mostly "naked" black hole (BH) ejected from the companion by three-body interaction. We present new HST/NICMOS 1.6micron imaging data at 0.1" resolution and VLT/VISIR 11.3micron images at 0.35" resolution that for the first time resolve the system in the near- and mid-infrared. We combine these with existing optical HST and CO maps. (i) At 1.6micron we find an extension N-E of the quasar nucleus that is likely a part of the host galaxy, though not its main body. If true, this places HE0450-2958 directly onto the M_BH-M_bulge-relation for nearby galaxies. (ii) HE0450-2958 is consistent with lying at the high-luminosity end of Narrow-Line Seyfert 1 Galaxies, and more exotic explanations like a "naked quasar" are unlikely. (iii) All 11.3micron radiation in the system is emitted by the quasar nucleus, which is radiating at super-Eddington rate, L/L_Edd=6.2+3.8-1.8, or 12 M_sun/yr. (iv) The companion galaxy is covered in optically thick dust and is not a collisional ring galaxy. It emits in the far infrared at ULIRG strength, powered by Arp220-like star formation (strong starburst-like). An M82-like SED is ruled out. (v) With its black hole accretion rate HE0450-2958 produces not enough new stars to maintain its position on the M_BH-M_bulge-relation, and star formation and black hole accretion are spatially disjoint; the bulge has to grow by redistribution of preexisting stars. (vi) Systems similar to HE0450-2958 with spatially disjoint ULIRG-strength star formation and quasar activity are rare. At z<0.43 we only find <4% (3/77) candidates for a similar configuration.
We report here on mid-infrared (MIR) observations of the companion stars of twelve Supergiant X-ray Binaries (SGXBs) recently discovered by INTEGRAL. We aimed at assessing the contribution of the ...star and the material enshrouding the system compared to the total emission, as well as comparing the intrinsic absorptions of the compact object and the companion star.By performing and fitting the optical to MIR broad-band Spectral Energy Distributions (SEDs) of the companion stars, we show that only three sources out of nine exhibit a warm MIR excess which can be explained by their peculiar nature. The lack of warm MIR excess in the other sources is expected as the winds of supergiant stars are not suitable for dust production and the presence of the compact object does not change this property.At last, our results suggest the presence in the system of two components of absorption, the first one around the companion star, composed of cold material and the second one, very dense around the compact object, as the extinction in the X-ray domain is generally several order of magnitudes higher than the extinction in the visible.
SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period ...extrasolar planets and circumstellar disks in the visible (450 - 900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/22, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5-10 AU) from nearby stars (\(<\)25 pc) with masses ranging from a few Jupiter masses to Super Earths (\(\sim\)2 Earth radii, \(\sim\)10 M\(_{\oplus}\)) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System.
WASP-107b is a warm (\(\sim\)740 K) transiting planet with a Neptune-like mass of \(\sim\)30.5 \(M_{\oplus}\) and Jupiter-like radius of \(\sim\)0.94 \(R_{\rm J}\), whose extended atmosphere is ...eroding. Previous observations showed evidence for water vapour and a thick high-altitude condensate layer in WASP-107b's atmosphere. Recently, photochemically produced sulphur dioxide (SO\(_2\)) was detected in the atmosphere of a hot (\(\sim\)1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 \(\mu\)m, but for temperatures below \(\sim\)1,000 K sulphur is predicted to preferably form sulphur allotropes instead of SO\(_2\). Here we report the 9\(\sigma\)-detection of two fundamental vibration bands of SO\(_2\), at 7.35 \(\mu\)m and 8.69 \(\mu\)m, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of the JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from \(\sim\)1,200 K down to \(\sim\)740 K. Additionally, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (\(\sim\)7\(\sigma\)) over simpler cloud setups. Furthermore, water is detected (\(\sim\)12\(\sigma\)), but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.
(abridged) A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood with uniform sensitivity down to Earth-mass planets within ...their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT - the Nearby Earth Astrometric Telescope. NEAT is designed to carry out space-borne extremely-high-precision astrometric measurements sufficient to detect dynamical effects due to orbiting planets of mass even lower than Earth's around the nearest stars. Such a survey mission would provide the actual planetary masses and the full orbital geometry for all the components of the detected planetary systems down to the Earth-mass limit. The NEAT performance limits can be achieved by carrying out differential astrometry between the targets and a set of suitable reference stars in the field. The NEAT instrument design consists of an off-axis parabola single-mirror telescope, a detector with a large field of view made of small movable CCDs located around a fixed central CCD, and an interferometric calibration system originating from metrology fibers located at the primary mirror. The proposed mission architecture relies on the use of two satellites operating at L2 for 5 years, flying in formation and offering a capability of more than 20,000 reconfigurations (alternative option uses deployable boom). The NEAT primary science program will encompass an astrometric survey of our 200 closest F-, G- and K-type stellar neighbors, with an average of 50 visits. The remaining time might be allocated to improve the characterization of the architecture of selected planetary systems around nearby targets of specific interest (low-mass stars, young stars, etc.) discovered by Gaia, ground-based high-precision radial-velocity surveys.
Half of the Seyfert-2 galaxies escaped detection of broad lines in their polarised spectra observed so far. Some authors have suspected that these non-HBLRs contain real Sy2 nuclei without intrinsic ...broad line region hidden behind a dust torus. If this were true, then their nuclear structure would fundamentally differ from that of Sy2s with polarised broad lines: in particular, they would not be explained by orientation-based AGN unification. Further arguments for two physically different Sy2 populations have been derived from the warm and cool IRAS F25/F60 ratios. These ratios, however, refer to the entire host galaxies and are unsuitable to conclusively establish the absence of a nuclear dust torus. Instead, a study of the Seyfert-2 dichotomy should be performed on the basis of nuclear properties only. Here we present the first comparison between OIII 5007A and mid-infrared imaging at matching spatial resolution. Exploring the Seyfert-2 dichotomy we find that the distributions of nuclear mid-infrared/OIII luminosity ratios are indistinguishable for Sy1s and Sy2s with and without detected polarised broad lines and irrespective of having warm or cool IRAS F25/F60 ratios. We find no evidence for the existence of a population of real Sy2s with a deficit of nuclear dust emission. Our results suggest 1) that all Seyfert nuclei possess the same physical structure including the putative dust torus and 2) that the cool IRAS colours are caused by a low contrast of AGN to host galaxy. Then the Seyfert-2 dichotomy is explained in part by unification of non-HBLRs with narrow-line Sy1s and to a larger rate by observational biases caused by a low AGN/host contrast and/or an unfavourable scattering geometry.
We study the stellar population properties of 182 spectroscopically-confirmed (MUSE/VLT) Lyman-\(\alpha\) emitters (LAEs) and 450 photometrically-selected Lyman-Break galaxies (LBGs) at z = 2.8 - 6.7 ...in the Hubble eXtreme Deep Field (XDF). Leveraging the combined power of HST and JWST NIRCam and MIRI observations, we analyse their rest-frame UV-through-near-IR spectral energy distributions (SEDs) with MIRI playing a crucial role in robustly assessing the LAE's stellar mass and ages. Our LAEs are low-mass objects (log\(_{10}\)(M\(_\star\)M\(_\odot\)) ~ 7.5), with little or no dust extinction (E(B - V) ~ 0.1) and a blue UV continuum slope (\(\beta\) ~ -2.2). While 75% of our LAEs are young (< 100 Myr), the remaining 25% have significantly older stellar populations (> 100 Myr). These old LAEs are statistically more massive, less extinct and have lower specific star formation rate (sSFR) compared to young LAEs. Besides, they populate the M\(_\star\) - SFR plane along the main-sequence (MS) of star-forming galaxies, while young LAEs populate the starburst region. The comparison between the LAEs properties to those of a stellar-mass matched sample of LBGs shows no statistical difference between these objects, except for the LBGs redder UV continuum slope and marginally larger E(B - V) values. Interestingly, 48% of the LBGs have ages < 10 Myr and are classified as starbursts, but lack detectable Ly\(\alpha\) emission. This is likely due to HI resonant scattering and/or selective dust extinction. Overall, we find that JWST observations are crucial in determining the properties of LAEs and shedding light on the properties and similarities between LAEs and LBGs.
We have observed a bright flare of Sgr A* in the near infrared with the adaptive optics assisted integral field spectrometer SINFONI. Within the uncertainties, the observed spectrum is featureless ...and can be described by a power law. The associated power law index is subject to systematic effects, namely the determination of the background level. We explore these effects and can show that while the absolute value of the spectral power law index is relatively uncertain, our data nevertheless suggest that the spectral index is correlated with the instantaneous flix. Both quantities experience signifbant changes within less than one hour. We argue that the near infrared flares from Sgr A* are due to synchrotron emission of transiently heated electrons, the emission being affected by orbital dynamics and synchrotron cooling, both acting on timescales of ≈20 minutes.
WASP-107b is a warm ($\sim$740 K) transiting planet with a Neptune-like mass
of $\sim$30.5 $M_{\oplus}$ and Jupiter-like radius of $\sim$0.94 $R_{\rm J}$,
whose extended atmosphere is eroding. ...Previous observations showed evidence for
water vapour and a thick high-altitude condensate layer in WASP-107b's
atmosphere. Recently, photochemically produced sulphur dioxide (SO$_2$) was
detected in the atmosphere of a hot ($\sim$1,200 K) Saturn-mass planet from
transmission spectroscopy near 4.05 $\mu$m, but for temperatures below
$\sim$1,000 K sulphur is predicted to preferably form sulphur allotropes
instead of SO$_2$. Here we report the 9$\sigma$-detection of two fundamental
vibration bands of SO$_2$, at 7.35 $\mu$m and 8.69 $\mu$m, in the transmission
spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of the JWST.
This discovery establishes WASP-107b as the second irradiated exoplanet with
confirmed photochemistry, extending the temperature range of exoplanets
exhibiting detected photochemistry from $\sim$1,200 K down to $\sim$740 K.
Additionally, our spectral analysis reveals the presence of silicate clouds,
which are strongly favoured ($\sim$7$\sigma$) over simpler cloud setups.
Furthermore, water is detected ($\sim$12$\sigma$), but methane is not. These
findings provide evidence of disequilibrium chemistry and indicate a
dynamically active atmosphere with a super-solar metallicity.
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