More Like this

1. The Search for Failed Supernovae with the Large Binocular Telescope: The Mid-infrared Counterpart to N6946-BH1

   https://doi.org/10.3847/1538-4357/ad18d7  

   Kochanek, Christopher_S; Neustadt, Jack_M_M; Stanek, Krzysztof_Z (February 2024, The Astrophysical Journal)

   Abstract We present JWST MIRI 5.6, 10, and 21μm observations of the candidate failed supernova N6946-BH1 along with Hubble Space Telescope (HST) WFPC/IR 1.1 and 1.6μm data and ongoing optical monitoring data with the Large Binocular Telescope. There is a very red, dusty source at the location of the candidate, which has only ∼10%–15% of the luminosity of the progenitor star. The source is very faint in the HST near-IR observations (∼10³L_⊙) and is not optically variable to a limit of ∼10³L_⊙at theRband. The dust is likely silicate and probably has to be dominated by very large grains, as predicted for dust formed in a failed supernova. The required visual optical depths are modest, so it should begin to significantly brighten in the near-IR over the next few years. 

   more » « less
2. High-resolution Observations of an X6.4 Solar Flare in the Mid-infrared

   https://doi.org/10.3847/2041-8213/adee95  

   Yang, Xu; Cao, Wenda; Wang, Meiqi; Jennings, Don; Qiu, Jiong; He, Wen; Perriyil, Solomon M; Yurchyshyn, Vasyl; Fletcher, Lyndsay; Simões, Paulo_J A; et al (July 2025, The Astrophysical Journal Letters)

   Abstract We present a unique observation of the X6.4-class flare SOL2024-02-22T22:34 using the Mid-InfraRed Imager (MIRI) at the Goode Solar Telescope. Three ribbon-like flare sources and one unidentified source were detected in MIRI’s two mid-infrared (mid-IR) bands at 5.2 and 8.2μm. The two stronger ribbons displayed maximum mid-IR enhancements of 21% and 18% above quiet-Sun levels and 10% in Helioseismic and Magnetic Imager (HMI) continuum intensity (I_c). The weak ribbon and the unidentified source had maximum mid-IR enhancements of 7% but showed HMI/I_cdimmings, instead of excess emissions. Our result suggests that mid-IR emission forms in a higher layer during the flare and is more sensitive to flare heating than HMI/I_cemission. The MIRI observations have high temporal resolution (2.6 s cadence in these observations) and show apparent source motions. One flare ribbon extends along weak vertical magnetic-field channels in the sunspot umbra, light bridge, and penumbra, with an approximately 30 s delay between HMI/I_cand 8.2μm emissions. Meanwhile, the unidentified source moved at an apparent speed of 130 km s⁻¹from a mixed-polarity area to one flare ribbon with a strong HMI/I_cenhancement. We studied available hard X-ray/microwave imaging spectroscopy and used nonlinear force-free field extrapolation modeling to identify flare structures. The observational evidence strongly favors the chromospheric origin of the unidentified mid-IR source. Comparison with the X1.0 flare SOL2022-10-02T20:25 indicates that the total amount of high-energy electron (>60 keV) flux density is a key factor in determining the total brightening area and the maximum intensity enhancement in HMI/I_cemissions. 

   more » « less
3. The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems I: High-contrast Imaging of the Exoplanet HIP 65426 b from 2 to 16 μm

   https://doi.org/10.3847/2041-8213/acd93e  

   Carter, Aarynn L.; Hinkley, Sasha; Kammerer, Jens; Skemer, Andrew; Biller, Beth A.; Leisenring, Jarron M.; Millar-Blanchaer, Maxwell A.; Petrus, Simon; Stone, Jordan M.; Ward-Duong, Kimberly; et al (July 2023, The Astrophysical Journal Letters)

   Abstract We present JWST Early Release Science coronagraphic observations of the super-Jupiter exoplanet, HIP 65426b, with the Near-Infrared Camera (NIRCam) from 2 to 5μm, and with the Mid-Infrared Instrument (MIRI) from 11 to 16μm. At a separation of ∼0.″82 (87 ${}_{-31}^{+108}$au), HIP 65426b is clearly detected in all seven of our observational filters, representing the first images of an exoplanet to be obtained by JWST, and the first-ever direct detection of an exoplanet beyond 5μm. These observations demonstrate that JWST is exceeding its nominal predicted performance by up to a factor of 10, depending on separation and subtraction method, with measured 5σcontrast limits of ∼1 × 10⁻⁵and ∼2 × 10⁻⁴at 1″ for NIRCam at 4.4μm and MIRI at 11.3μm, respectively. These contrast limits provide sensitivity to sub-Jupiter companions with masses as low as 0.3M_Jupbeyond separations of ∼100 au. Together with existing ground-based near-infrared data, the JWST photometry are fit well by aBT-SETTLatmospheric model from 1 to 16μm, and they span ∼97% of HIP 65426b's luminous range. Independent of the choice of model atmosphere, we measure an empirical bolometric luminosity that is tightly constrained between $\log \left(L_{\mathrm{bol}}/L_{\odot }\right)$= −4.31 and −4.14, which in turn provides a robust mass constraint of 7.1 ± 1.2M_Jup. In totality, these observations confirm that JWST presents a powerful and exciting opportunity to characterize the population of exoplanets amenable to high-contrast imaging in greater detail. 

   more » « less
4. High-contrast JWST-MIRI Spectroscopy of Planet-forming Disks for the JDISC Survey

   https://doi.org/10.3847/1538-4357/ad20f0  

   Pontoppidan, Klaus M; Salyk, Colette; Banzatti, Andrea; Zhang, Ke; Pascucci, Ilaria; Öberg, Karin I; Long, Feng; Romero-Mirza, Carlos E; Carr, John; Najita, Joan; et al (March 2024, The Astrophysical Journal)

   Abstract The JWST Disk Infrared Spectral Chemistry Survey (JDISCS) aims to understand the evolution of the chemistry of inner protoplanetary disks using the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST). With a growing sample of >30 disks, the survey implements a custom method to calibrate the MIRI Medium Resolution Spectrometer (MRS) to contrasts of better than 1:300 across its 4.9–28μm spectral range. This is achieved using observations of Themis family asteroids as precise empirical reference sources. The high spectral contrast enables precise retrievals of physical parameters, searches for rare molecular species and isotopologues, and constraints on the inventories of carbon- and nitrogen-bearing species. JDISCS also offers significant improvements to the MRS wavelength and resolving power calibration. We describe the JDISCS calibrated data and demonstrate their quality using observations of the disk around the solar-mass young star FZ Tau. The FZ Tau MIRI spectrum is dominated by strong emission from warm water vapor. We show that the water and CO line emission originates from the disk surface and traces a range of gas temperatures of ∼500–1500 K. We retrieve parameters for the observed CO and H₂O lines and show that they are consistent with a radial distribution represented by two temperature components. A high water abundance ofn(H₂O) ∼ 10⁻⁴fills the disk surface at least out to the 350 K isotherm at 1.5 au. We search the FZ Tau environs for extended emission, detecting a large (radius of ∼300 au) ring of emission from H₂gas surrounding FZ Tau, and discuss its origin. 

   more » « less
5. GOALS-JWST: NIRCam and MIRI Imaging of the Circumnuclear Starburst Ring in NGC 7469

   https://doi.org/10.3847/2041-8213/acab61  

   Bohn, Thomas; Inami, Hanae; Diaz-Santos, Tanio; Armus, Lee; Linden, S. T.; U, Vivian; Surace, Jason; Larson, Kirsten L.; Evans, Aaron S.; Hoshioka, Shunshi; et al (January 2023, The Astrophysical Journal Letters)

   Abstract We present James Webb Space Telescope (JWST) imaging of NGC 7469 with the Near-Infrared Camera and the Mid-InfraRed Instrument. NGC 7469 is a nearby, z = 0.01627, luminous infrared galaxy that hosts both a Seyfert Type-1.5 nucleus and a circumnuclear starburst ring with a radius of ∼0.5 kpc. The new near-infrared (NIR) JWST imaging reveals 66 star-forming regions, 37 of which were not detected by Hubble Space Telescope (HST) observations. Twenty-eight of the 37 sources have very red NIR colors that indicate obscurations up to A v ∼ 7 and a contribution of at least 25% from hot dust emission to the 4.4 μ m band. Their NIR colors are also consistent with young (<5 Myr) stellar populations and more than half of them are coincident with the mid-infrared (MIR) emission peaks. These younger, dusty star-forming regions account for ∼6% and ∼17% of the total 1.5 and 4.4 μ m luminosity of the starburst ring, respectively. Thanks to JWST, we find a significant number of young dusty sources that were previously unseen due to dust extinction. The newly identified 28 young sources are a significant increase compared to the number of HST-detected young sources (4–5). This makes the total percentage of the young population rise from ∼15% to 48%. These results illustrate the effectiveness of JWST in identifying and characterizing previously hidden star formation in the densest star-forming environments around active galactic nuclei (AGN). 

   more » « less