More Like this

1. JWST NIRCam Observations of SN 1987A: Spitzer Comparison and Spectral Decomposition

   https://doi.org/10.3847/1538-4357/acfd95  

   Arendt, Richard G; Boyer, Martha L; Dwek, Eli; Matsuura, Mikako; Ravi, Aravind P; Rest, Armin; Chevalier, Roger; Cigan, Phil; De_Looze, Ilse; De_Marchi, Guido; et al (December 2023, The Astrophysical Journal)

   Abstract JWST Near Infrared Camera (NIRCam) observations at 1.5–4.5μm have provided broadband and narrowband imaging of the evolving remnant of SN 1987A with unparalleled sensitivity and spatial resolution. Comparing with previous marginally spatially resolved Spitzer Infrared Array Camera (IRAC) observations from 2004 to 2019 confirms that the emission arises from the circumstellar equatorial ring (ER), and the current brightness at 3.6 and 4.5μm was accurately predicted by extrapolation of the declining brightness tracked by IRAC. Despite the regular light curve, the NIRCam observations clearly reveal that much of this emission is from a newly developing outer portion of the ER. Spots in the outer ER tend to lie at position angles in between the well-known ER hotspots. We show that the bulk of the emission in the field can be represented by five standard spectral energy distributions, each with a distinct origin and spatial distribution. This spectral decomposition provides a powerful technique for distinguishing overlapping emission from the circumstellar medium and the supernova ejecta, excited by the forward and reverse shocks, respectively. 

   more » « less
2. JWST PEARLS. Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results

   https://doi.org/10.3847/1538-3881/aca163  

   Windhorst, Rogier A.; Cohen, Seth H.; Jansen, Rolf A.; Summers, Jake; Tompkins, Scott; Conselice, Christopher J.; Driver, Simon P.; Yan, Haojing; Coe, Dan; Frye, Brenda; et al (December 2022, The Astronomical Journal)

   Abstract We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (PEARLS) project. PEARLS uses up to eight NIRCam filters to survey several prime extragalactic survey areas: two fields at the North Ecliptic Pole (NEP); seven gravitationally lensing clusters; two high redshift protoclusters; and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. The main goal of PEARLS is to study the epoch of galaxy assembly, active galactic nucleus (AGN) growth, and First Light. Five fields—the JWST NEP Time-Domain Field (TDF), IRAC Dark Field, and three lensing clusters—will be observed in up to four epochs over a year. The cadence and sensitivity of the imaging data are ideally suited to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9–4.5 μ m galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9–4.5 μ m. PEARLS is designed to be of lasting benefit to the community. 

   more » « less
3. Long-term 4.6 μm Variability in Brown Dwarfs and a New Technique for Identifying Brown Dwarf Binary Candidates

   https://doi.org/10.3847/1538-3881/acccf7  

   Brooks, Hunter; Kirkpatrick, J. Davy; Meisner, Aaron M.; Gelino, Christopher R.; Bardalez Gagliuffi, Daniella C.; Marocco, Federico; Schneider, Adam C.; Faherty, Jacqueline K.; Casewell, S. L.; Raghu, Yadukrishna; et al (May 2023, The Astronomical Journal)

   Abstract Using a sample of 361 nearby brown dwarfs, we have searched for 4.6μm variability, indicative of large-scale rotational modulations or large-scale, long-term changes on timescales of over 10 yr. Our findings show no statistically significant variability in Spitzer’s Infrared Array Camera (IRAC) channel 2 (ch2) or Wide-field Infrared Survey Explorer W2 photometry. For Spitzer the ch2 1σlimits are ∼8 mmag for objects at 11.5 mag and ∼22 mmag for objects at 16 mag. This corresponds to no variability above 4.5% at 11.5 mag and 12.5% at 16 mag. We conclude that highly variable brown dwarfs, at least two previously published examples of which have been shown to have 4.6μm variability above 80 mmag, are very rare. While analyzing the data, we also developed a new technique for identifying brown dwarf binary candidates in Spitzer data. We find that known binaries have IRAC ch2 point response function (PRF) flux measurements that are consistently dimmer than aperture flux measurements. We have identified 59 objects that exhibit such PRF versus aperture flux differences and are thus excellent binary brown dwarf candidates. 

   more » « less
4. Euclid preparation: LXI. Cosmic Dawn Survey: ‘Pre-launch’ multiwavelength catalogues for EuclidDeep Field North and Euclid Deep Field Fornax

   https://doi.org/10.1051/0004-6361/202451857  

   Zalesky, L; McPartland, C_J R; Weaver, J R; Toft, S; Sanders, D B; Mobasher, B; Suzuki, N; Szapudi, I; Valdes, I; Murphree, G; et al (March 2025, Astronomy & Astrophysics)

   The Cosmic Dawn Survey (DAWN survey) provides multiwavelength (UV/optical to mid-IR) data across the combined 59 deg²of the Euclid Deep and Auxiliary fields (EDFs and EAFs). In this work, the first public data release from the DAWN survey is presented. The catalogues made available herein consist of a subset of the full DAWN survey that includes two EDFs: EDF North (EDF-N) and EDF Fornax (EDF-F). Each field has been covered by the ongoing Hawaii Twenty Square Degree Survey (H20), which includes imaging from the CFHT MegaCam in theufilter and from the Subaru Hyper Suprime-Cam (HSC) in thegrizfilters. Each field has been further covered bySpitzer/IRAC 3.6–4.5µm imaging spanning 10 deg²and reaching ~25 mag AB (5σ). All present H20 imaging and all publicly available imaging from the aforementioned facilities were combined with the deepSpitzer/IRAC data to create source catalogues spanning a total area of 16.87 deg²in EDF-N and 2.85 deg²in EDF-F for this first release. These catalogues are referred to as the ‘pre-launch’ (PL), asEucliddata is not yet public for these fields and therefore it is not included. Photometry was measured from these multiwavelength data usingThe Farmer, a novel and well validated model-based photometry code. Photometric redshifts and stellar masses were computed using two independent codes for modelling spectral energy distributions:EAZYandLePhare. Photometric redshifts show good agreement with spectroscopic redshifts (σ_NMAD~ 0.5,η <8% ati< 25). Number counts, photometric redshifts and stellar masses were further validated in comparison to the COSMOS2020 catalogue. The DAWN survey PL catalogues are designed to be of immediate use in these two EDFs and will be continuously updated and made available as both new ground-based data and spaced-based data fromEuclidare acquired and made public. Future data releases will provide catalogues of all EDFs and EAFs and includeEucliddata. 

   more » « less
5. Physical Constraints on the Extended Interstellar Medium of the z = 6.42 Quasar J1148+5251: [C ii] _{158 μm} , [N ii] _{205 μm} , and [O i] _{146 μm} Observations

   https://doi.org/10.3847/1538-4357/ac4e94  

   Meyer, Romain A.; Walter, Fabian; Cicone, Claudia; Cox, Pierre; Decarli, Roberto; Neri, Roberto; Novak, Mladen; Pensabene, Antonio; Riechers, Dominik; Weiss, Axel (March 2022, The Astrophysical Journal)

   Abstract We report new Northern Extended Millimeter Array observations of the [C ii ] 158 μ m , [N ii ] 205 μ m , and [O i ] 146 μ m atomic fine structure lines (FSLs) and dust continuum emission of J1148+5251, a z = 6.42 quasar, which probe the physical properties of its interstellar medium (ISM). The radially averaged [C ii ] 158 μ m and dust continuum emission have similar extensions (up to θ = 2.51 − 0.25 + 0.46 arcsec , corresponding to r = 9.8 − 2.1 + 3.3 kpc , accounting for beam convolution), confirming that J1148+5251 is the quasar with the largest [C ii ] 158 μ m -emitting reservoir known at these epochs. Moreover, if the [C ii ] 158 μ m emission is examined only along its NE–SW axis, a significant excess (>5.8 σ ) of [C ii ] 158 μ m emission (with respect to the dust) is detected. The new wide-bandwidth observations enable us to accurately constrain the continuum emission, and do not statistically require the presence of broad [C ii ] 158 μ m line wings that were reported in previous studies. We also report the first detection of the [O i ] 146 μ m and (tentatively) [N ii ] 205 μ m emission lines in J1148+5251. Using FSL ratios of the [C ii ] 158 μ m , [N ii ] 205 μ m , [O i ] 146 μ m , and previously measured [C i ] 369 μ m emission lines, we show that J1148+5251 has similar ISM conditions compared to lower-redshift (ultra)luminous infrared galaxies. CLOUDY modeling of the FSL ratios excludes X-ray-dominated regions and favors photodissociation regions as the origin of the FSL emission. We find that a high radiation field (10 3.5–4.5 G 0 ), a high gas density ( n ≃ 10 3.5–4.5 cm −3 ), and an H i column density of 10 23 cm −2 reproduce the observed FSL ratios well. 

   more » « less