University of Washington logoUniversity of WashingtonCNRS logoCNRSCalifornia Institute of Technology logoCalifornia Institute of TechnologyUniversity of Illinois at Urbana-Champaign logoUniversity of Illinois at Urbana-ChampaignSLAC National Accelerator LaboratoryNational Central UniversityUCLA logoUCLACarnegie Mellon University logoCarnegie Mellon UniversityImperial College London logoImperial College LondonDESYUniversity of Chicago logoUniversity of ChicagoUC Berkeley logoUC BerkeleyUniversity College London logoUniversity College LondonUniversity of Oxford logoUniversity of Oxfordthe University of Tokyo logothe University of TokyoStanford University logoStanford UniversityUniversity of EdinburghINFN logoINFNETH Zürich logoETH ZürichUniversity of California, San Diego logoUniversity of California, San DiegoUniversity of British Columbia logoUniversity of British ColumbiaNASA Goddard Space Flight Center logoNASA Goddard Space Flight CenterUniversity of Texas at Austin logoUniversity of Texas at AustinKavli Institute for the Physics and Mathematics of the UniverseCurtin UniversityCERN logoCERNSpace Telescope Science Institute logoSpace Telescope Science InstituteJohns Hopkins University logoJohns Hopkins UniversityArizona State University logoArizona State UniversityUniversity of Maryland logoUniversity of MarylandThe Alan Turing InstituteUniversity of North Carolina at Chapel HillPurdue University logoPurdue UniversityUniversity of HelsinkiPolitecnico di MilanoUniversity of California, Davis logoUniversity of California, DavisDuke University logoDuke UniversityMIT logoMITCEA logoCEAPrinceton University logoPrinceton UniversityUniv. LilleUniversity of Central Florida logoUniversity of Central FloridaUniversity of Colorado BoulderUniversité Côte d’AzurUniversidade Federal do Rio de JaneiroNorthern Arizona UniversityJet Propulsion LaboratoryUniversidad de ChileEuropean Space AgencyUniversity of MontenegroCNESAdam Mickiewicz UniversityPSL Research UniversitySouthwest Research InstituteSETI InstituteUniversity of North DakotaThe Johns Hopkins University Applied Physics LaboratoryObservatoire de la Côte d’AzurUniversity of Hawai’iCalifornia State Polytechnic University, PomonaThe University of ArizonaMIT Kavli Institute for Astrophysics and Space ResearchUniversidade Federal de SergipeKavli Institute for Cosmological PhysicsThe Open UniversityCarnegie Institution for ScienceUniversidad Nacional de ColombiaVera C. Rubin ObservatoryCEA SaclayCNRS/IN2P3Queen's University BelfastInstituto de Astrofísica de Canarias (IAC)Lowell ObservatoryIPACLAPPUniv Grenoble AlpesIJCLabU.S. Naval ObservatoryPlanetary Science InstituteNSF’s National Optical-Infrared Astronomy Research LaboratoryPontificia Universidad Catolica de ChileUniversidad MayorLPNHEUniversities Space Research AssociationAcademia Sinica Institute of Astronomy and Astrophysics (ASIAA)California Polytechnic State University - San Luis ObispoMullard Space Science LaboratoryELTE Gothard Astrophysical ObservatoryParis ObservatoryAstroparticule et Cosmologie (APC)Universit\`a degli Studi di Urbino ‘Carlo Bo’Universit´e Paris DiderotIMCCEELTE Eotvos Lorand UniversityAix-Marseille Universit\'eUK ATCLaboratoire d’Astrophysique de Marseille (LAM)Observatorio Astronomico NacionalInstituto Nacional de Astrofısica Optica y ElectronicaObservatorio do ValongoEarth and Planets LaboratoryUniversit´e Paris Cit´eLSST Discovery AllianceUTFPR— Universidade Tecnol´ogica Federal do Paran´aInstituto de Ciencias Planetarias y Exoplanetarias (ICPE)CONICET-IARLaborat´orio Nacional de Astrof´ısica (LNA)The ExploratoriumELKH-CSFK Konkoly ObservatoryObservat´orio Nacional, MCTILudwig-Maximilians-Universität MünchenNASA, Ames Research CenterUniversité Paris-SaclayCenter for Astrophysics  Harvard & SmithsonianINAF ` Osservatorio Astronomico di TriesteSorbonne Université
We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin Observatory. The third interstellar object, comet 3I/ATLAS, was first discovered on UT 2025 July 1. Serendipitously, the Rubin Observatory collected imaging in the area of the sky inhabited by the object during regular commissioning activities. We successfully recovered object detections from Rubin visits spanning UT 2025 June 21 (10 days before discovery) to UT 2025 July 7. Facilitated by Rubin's high resolution and large aperture, we report on the detection of cometary activity as early as June 21st, and observe it throughout. We measure the location and magnitude of the object on 37 Rubin images in r, i, and z bands, with typical precision of about 20 mas (100 mas, systematic) and about 10 mmag, respectively. We use these to derive improved orbit solutions, and to show there is no detectable photometric variability on hourly timescales. We derive a V-band absolute magnitude of H_V = (13.7 +/- 0.2) mag, and an equivalent effective nucleus radius of around (5.6 +/- 0.7) km. These data represent the earliest observations of this object by a large (8-meter class) telescope reported to date, and illustrate the type of measurements (and discoveries) Rubin's Legacy Survey of Space and Time (LSST) will begin to provide once operational later this year.
White dwarfs (WDs) showing transits from orbiting planetary debris provide significant insights into the structure and dynamics of debris disks. This is a rare class of objects with only eight published systems. In this work, we perform a systematic search for such systems within 500 pc in the Gaia-eDR3 catalog of WDs using the light curves from the Zwicky Transient Facility (ZTF) and present six new candidates. Our selection process targets the top 1% most photometrically variable sources identified using a combined variability metric from ZTF and Gaia eDR3 photometry, boosted by a metric space we define using von Neumann statistics and Pearson-Skew as a novel discovery tool to identify these systems. This is followed by optical spectroscopic observations of visually selected variables to confirm metal pollution. Four of the six systems show long-timescale photometric variability spanning several months to years, resulting either from long-term evolution of transit activity or dust and debris clouds at wide orbits. Among them, WD J1013-0427 shows an indication of reddening during the long-duration dip. Interpreting this as dust extinction makes it the first system to indicate an abundance of small dust grains (radius \lesssim0.3 μm0.3~{\rm \mu m}) in the occulting material. The same object also shows metal emission lines that map an optically thick eccentric gas disk orbiting within the star's Roche limit. For each candidate, we infer the abundances of the photospheric metals and estimate accretion rates. We show that transiting debris systems tend to have higher inferred accretion rates compared to the general population of metal-polluted WDs. Growing the number of these systems will further illuminate such comparative properties in the near future. Separately, we also serendipitously discovered an AM CVn showing a very long-duration outburst - only the fourth such system to be known.
We present a statistical study of spatially resolved chemical enrichment in 18 main-sequence galaxies at z=4z=4--6, observed with \jwst/NIRSpec IFU as part of the ALPINE-CRISTAL-\jwst\ survey. Performing an optimized reduction and calibration procedure, including local background subtraction, light-leakage masking, stripe removal, and astrometry refinement, we achieve robust emission-line mapping on kiloparsec scales. Although line-ratio distributions vary across galaxies in our sample, we generally find mild central enhancements in [O\,\textsc{iii}]/Hβ\beta, [O\,\textsc{ii}]/[O\,\textsc{iii}], [S\,\textsc{ii}]6732_{6732}/[S\,\textsc{ii}]6718_{6718}, Hα\alpha/Hβ\beta, and LHα/LUVL_{\rm H\alpha}/L_{\rm UV}, consistent with elevated electron density, dust obscuration, and bursty star formation accompanied by reduced metallicity and ionization parameter. These features point to inside-out growth fueled by recent inflows of pristine gas. Nevertheless, the median metallicity gradient is nearly flat over a few kpc scale, Δlog(O/H)=0.02±0.01\Delta \log({\rm O/H}) = 0.02 \pm 0.01 dex kpc1^{-1}, implying efficient chemical mixing through inflows, outflows, and mergers. From pixel-by-pixel stellar and emission-line characterizations, we further investigate the resolved Fundamental Metallicity Relation (rFMR). Metallicity is described by a fundamental plane with stellar mass and SFR surface densities, but with a stronger dependence on ΣSFR\Sigma_{\rm SFR} than seen in local galaxies. Our results indicate that the regulatory processes linking star formation, gas flows, and metal enrichment were already vigorous \sim1 Gyr after the Big Bang, producing the nearly flat metallicity gradient and a stronger coupling between star formation and metallicity than observed in evolved systems in the local universe.
We present morphological classifications of over 41,000 galaxies out to zphot2.5z_{\rm phot}\sim2.5 across six square degrees of the Euclid Deep Field North (EDFN) from the Hawaii Twenty Square Degree (H20) survey, a part of the wider Cosmic Dawn survey. Galaxy Zoo citizen scientists play a crucial role in the examination of large astronomical data sets through crowdsourced data mining of extragalactic imaging. This iteration, Galaxy Zoo: Cosmic Dawn (GZCD), saw tens of thousands of volunteers and the deep learning foundation model Zoobot collectively classify objects in ultra-deep multiband Hyper Suprime-Cam (HSC) imaging down to a depth of mHSCi=21.5m_{HSC-i} = 21.5. Here, we present the details and general analysis of this iteration, including the use of Zoobot in an active learning cycle to improve both model performance and volunteer experience, as well as the discovery of 51 new gravitational lenses in the EDFN. We also announce the public data release of the classifications for over 45,000 subjects, including more than 41,000 galaxies (median zphotz_{\rm phot} of 0.42±0.230.42\pm0.23), along with their associated image cutouts. This data set provides a valuable opportunity for follow-up imaging of objects in the EDFN as well as acting as a truth set for training deep learning models for application to ground-based surveys like that of the newly operational Vera C. Rubin Observatory.
The Near-Earth Object (NEO) Surveyor mission is a NASA observatory designed to discover and characterize near-Earth asteroids and comets. The mission's primary objective is to find the majority of objects large enough to cause severe regional impact damage (>>140 m in effective spherical diameter) within its five-year baseline survey. Operating at the Sun-Earth L1 Lagrange point, the mission will survey to within 45 degrees of the Sun in an effort to find the objects in the most Earth-like orbits. The survey cadence is optimized to provide observational arcs long enough to reliably distinguish near-Earth objects from more distant small bodies that cannot pose an impact hazard. Over the course of its survey, NEO Surveyor will discover \sim200,000 - 300,000 new NEOs down to sizes as small as \sim10 m and thousands of comets, significantly improving our understanding of the probability of an Earth impact over the next century.
We report the discovery of two broad-line X-ray AGNs cid_414 and cid_947 at z~3 that exhibit prominent He Iλ\lambda10830+ Paγ\gamma emission and absorption, identified from the JWST Cycle 3 large GO treasury program COSMOS-3D using NIRCam F444W grism spectroscopy. Additional UV/optical line measurements (e.g., Lyα\alpha, Si IV, C IV) come from complementary COSMOS-field spectroscopy. Both sources are robustly detected in the mid-infrared, with detections in MIRI F1000W for both AGNs and an additional detection in MIRI F2100W for cid_414, indicating the presence of hot dust emission. The source cid_947 shows a higher He Iλ\lambda10830 absorption column density and X-ray-inferred NHN_{\rm H}, and displays strong outflow signatures in He I, Si IV, and C IV with velocity offsets exceeding 5000 km/s. The source cid_414 shows a narrow Lyα\alpha emission line with luminosity logLLyα=42.49±0.01 erg s1\log L_{\rm Ly\alpha}=42.49\pm0.01~\mathrm{erg~s^{-1}} and a higher intrinsic 2-10 keV X-ray luminosity. Host-galaxy decomposition and multi-component SED fitting indicate that cid_947 hosts a more massive black hole but lower star formation rate than cid_414. From simplified photoionization modeling, we infer that the dense absorbing gas has a characteristic size comparable to the nuclear broad-line region and is likely kinematically coupled to the obscuration associated with the dust torus. He Iλ\lambda1083 absorption has also been identified in several compact little red dots at similar redshifts. Together with the two AGNs reported here, these findings suggest that dense circumnuclear gas are plausibly prevalent at high redshift and plays an important role in regulating AGN obscuration and black hole--host co-evolution.
We describe the Zwicky Transient Facility (ZTF) Forced Photometry Service (ZFPS) as developed and maintained by the ZTF Science Data System Team at IPAC/Caltech. The service is open for public use following a subscription. The ZFPS has been operational since early 2020 and has been used to generate publication quality lightcurves for a myriad of science programs. The ZFPS has been recently upgraded to allow users to request forced-photometry lightcurves for up to 1500 sky positions per request in a single web-application submission. The underlying software has been recoded to take advantage of a parallel processing architecture with the most compute-intensive component rewritten in C and optimized for the available hardware. The ZTF processing cluster consists of 66 compute nodes, each hosting at least 16 physical cores. The compute nodes are generally idle following nightly real-time processing of the ZTF survey data and when other ad hoc processing tasks have been completed. The ZFPS and associated infrastructure at IPAC/Caltech therefore enable thousands of forced-photometry lightcurves to be generated along with a wealth of quality metrics to facilitate analyses and filtering of bad quality data prior to scientific use.
Time-domain surveys such as the Zwicky Transient Facility (ZTF) have opened a new frontier in the discovery and characterization of transients. While photometric light curves provide broad temporal coverage, spectroscopic observations remain crucial for physical interpretation and source classification. However, existing spectral analysis methods -- often reliant on template fitting or parametric models -- are limited in their ability to capture the complex and evolving spectra characteristic of such sources, which are sometimes only available at low resolution. In this work, we introduce SpectraNet, a deep convolutional neural network designed to learn robust representations of optical spectra from transients. Our model combines multi-scale convolution kernels and multi-scale pooling to extract features from preprocessed spectra in a hierarchical and interpretable manner. We train and validate SpectraNet on low-resolution time-series spectra obtained from the Spectral Energy Distribution Machine (SEDM) and other instruments, demonstrating state-of-the-art performance in classification. Furthermore, in redshift prediction tasks, SpectraNet achieves a root mean squared relative redshift error of 0.02, highlighting its effectiveness in precise regression tasks as well.
We present a measurement of the free-streaming length of dark matter (DM) and subhalo abundance around 28 quadruple image strong lenses using observations from JWST MIRI presented in Paper III of this series. We improve on previous inferences on DM properties from lensed quasars by simultaneously reconstructing extended lensed arcs with image positions and relative magnifications (flux ratios). Our forward modeling framework generates full populations of subhalos, line-of-sight halos, and globular clusters, uses an accurate model for subhalo tidal evolution, and accounts for free-streaming effects on halo abundance and concentration. Modeling lensed arcs leads to more-precise model-predicted flux ratios, breaking covariance between subhalo abundance and the free-streaming scale parameterized by the half-mode mass mhmm_{\rm{hm}}. Assuming subhalo abundance predicted by the semi-analytic model {\tt{galacticus}} (N-body simulations), we infer (Bayes factor of 10:1) m_{\rm{hm}} < 10^{7.4} \mathrm{M}_{\odot} (m_{\rm{hm}} < 10^{7.2} \mathrm{M}_{\odot}), a 0.4 dex (0.3 dex) improvement relative to omitting lensed arcs. These bounds correspond to lower limits on thermal relic DM particle masses of 7.47.4 and 8.48.4 keV, respectively. Conversely, assuming DM is cold, we infer a projected mass in subhalos (10^6 < m/M_{\odot}<10^{10.7}) of 1.61.1+2.4×107 M kpc21.6_{-1.1}^{+2.4} \times 10^7 \ \mathrm{M}_{\odot} \ \rm{kpc^{-2}} at 95%95 \% confidence. This is consistent with {\tt{galacticus}} predictions (0.6×107M kpc20.6 \times 10^7 \mathrm{M}_{\odot} \ \rm{kpc^{-2}}), but in tension with recent N-body simulations (0.3×107M kpc20.3 \times 10^7 \mathrm{M}_{\odot} \ \rm{kpc^{-2}}). Our results are the strongest limits on WDM, and the most precise measurement of subhalo abundance around strong lenses. Further improvements will follow from the large sample of lenses to be discovered by Euclid, Rubin, and Roman.
We describe the SPHEREx Sky Simulator, a software tool designed to model science data for NASA's SPHEREx mission that will carry out a series of all-sky spectrophotometric surveys at \sim6'' spatial resolution in 102 spectral channels spanning 0.75 to 5 μ\mum. The Simulator software implements models for astrophysical emission, instrument characteristics, and survey strategy to generate realistic infrared sky scenes as they will be observed by SPHEREx. The simulated data includes a variety of realistic noise and systematic effects that are estimated using up-to-date astrophysical measurements and information from pre-launch instrument characterization campaigns. Through the pre-flight mission phases the Simulator has been critical in predicting the impact of various effects on SPHEREx science performance, and has played an important role guiding the development of the SPHEREx data analysis pipeline. In this paper, we describe the \skysim\ architecture, pre-flight instrument and sky models, and summarize high-level predictions from the Simulator, including a pre-launch prediction for the 5σ\sigma point source sensitivity of SPHEREx, which we estimate to be mABm_{\rm AB} 18.5--19 from 0.75 to 3.8~μ\mum and mABm_{\rm AB} 16.6--18 from 3.8 to 5 μ\mum, with the sensitivity limited by the zodiacal light background at all wavelengths. In the future, on-orbit data will be used to improve the Simulator, which will form the basis of a variety of forward-modeling tools that will be used to model myriad instrumental and astrophysical processes to characterize their systematic effects on our final data products and analyses.
We present James Webb Space Telescope (JWST) observations of four Luminous Red Novae (LRNe): dusty, extragalactic transients from stellar mergers following common-envelope evolution (CEE) in massive binary stars. Our targets - AT2021blu, AT2021biy, AT2018bwo, and M31-LRN-2015 - span a broad range in progenitor primary masses (\approx3-24M_{\odot}) and post-merger ages (\approx1100-3700 days). All four were observed with the Mid-Infrared Instrument (MIRI) from 5-25μ\mum; AT2021blu and AT2021biy additionally have 5-12μ\mum spectra from the Low-Resolution Spectrometer. These spectra show strong features of oxygen-rich molecules, including water vapor, supporting the recent association of water fountain sources with CEE. Radiative transfer modeling of the spectral energy distributions yields dust masses of \approx4.2×105\times10^{-5}, 3×104\times10^{-4}, 7.5×105\times10^{-5}, and 7.7×104\times10^{-4}M_{\odot} respectively - corresponding to 10\approx10%, 60%, 6% and 12% of median dust masses in core-collapse supernovae (CCSNe) at similar phases. Accounting for their occurrence rates, we estimate that LRNe can contribute \sim25% as much dust as CCSNe to the cosmic dust budget. Furthermore, the lower expansion velocities of LRNe may reduce dust destruction by reverse shocks compared to CCSNe, potentially increasing this contribution. In addition to dust masses, we use our \emph{JWST} observations to measure late-time properties such as the luminosities, temperatures, radii, and dust-to-gas ratios of the merger remnants. Our results highlight the need for broader infrared studies of LRNe to quantify their contribution to the cosmic dust budget, study the evolution of oxygen-rich molecules, and probe the final fates of CEE.
SPHEREx, a NASA explorer satellite launched on 11 March 2025, is carrying out the first all-sky near-infrared spectral survey. The satellite observes in 102 spectral bands from 0.75 to 5.0 um with a resolving power ranging from 35 to 130 in 6.2 arcsecond pixels. The observatory obtains a 5-sigma depth of 19.5 - 19.9 AB mag for 0.75 to 3.8 um and 17.8 - 18.8 AB mag for 3.8 to 5.0 um after mapping the full sky four times over two years. Scientifically, SPHEREx will produce a large galaxy redshift survey over the full sky, intended to constrain the amplitude of inflationary non-Gaussianity. The observations will produce two deep spectral maps near the ecliptic poles that will use intensity mapping to probe the evolution of galaxies over cosmic history. By mapping the depth of infrared absorption features over the Galactic plane, SPHEREx will comprehensively survey the abundance and composition of water and other biogenic ice species in the interstellar medium. The initial data are rapidly released in the form of spectral images to the public. The project will release specialized data products over the life of the mission as the surveys proceed. The science team will also produce specialized spectral catalogs on planet-bearing and low-mass stars, solar system objects, and galaxy clusters 3 years after launch. We describe the design of the instrument and spacecraft, which flow from the core science requirements. Finally, we present an initial evaluation of the in-flight performance and key characteristics.
We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) integral-field spectroscopy of the nearby luminous infrared galaxy, NGC 7469. We take advantage of the high spatial/spectral resolution and wavelength coverage of JWST /NIRSpec to study the 3.3 um neutral polycyclic aromatic hydrocarbon (PAH) grain emission on ~60 pc scales. We find a clear change in the average grain properties between the star-forming ring and the central AGN. Regions in the vicinity of the AGN, with [NeIII]/[NeII]>0.25, tend to have larger grain sizes and lower aliphatic-to-aromatic (3.4/3.3) ratios indicating that smaller grains are preferentially removed by photo-destruction in the vicinity of the AGN. We find an overall suppression of the total PAH emission relative to the ionized gas in the central 1 kpc region of the AGN in NGC 7469 compared to what has been observed with Spitzer on 3 kpc scales. However, the fractional 3.3 um to total PAH power is enhanced in the starburst ring, possibly due to a variety of physical effects on sub-kpc scales, including recurrent fluorescence of small grains or multiple photon absorption by large grains. Finally, the IFU data show that while the 3.3 um PAH-derived star formation rate (SFR) in the ring is 8% higher than that inferred from the [NeII] and [NeIII] emission lines, the integrated SFR derived from the 3.3 um feature would be underestimated by a factor of two due to the deficit of PAHs around the AGN, as might occur if a composite system like NGC 7469 were to be observed at high-redshift.
New mid-infrared HgCdTe (MCT) detector arrays developed in collaboration with Teledyne Imaging Sensors (TIS) have paved the way for improved 10-μ\mum sensors for space- and ground-based observatories. Building on the successful development of longwave HAWAII-2RGs for space missions such as NEO Surveyor, we characterize the first 13-μ\mum GeoSnap detector manufactured to overcome the challenges of high background rates inherent in ground-based mid-IR astronomy. This test device merges the longwave HgCdTe photosensitive material with Teledyne's 2048x2048 GeoSnap-18 (18-μ\mum pixel) focal plane module, which is equipped with a capacitive transimpedance amplifier (CTIA) readout circuit paired with an onboard 14-bit analog-to-digital converter (ADC). The final assembly yields a mid-IR detector with high QE, fast readout (>85 Hz), large well depth (>1.2 million electrons), and linear readout. Longwave GeoSnap arrays would ideally be deployed on existing ground-based telescopes as well as the next generation of extremely large telescopes. While employing advanced adaptive optics (AO) along with state-of-the-art diffraction suppression techniques, instruments utilizing these detectors could attain background- and diffraction-limited imaging at inner working angles <10 λ/D\lambda/D, providing improved contrast-limited performance compared to JWST MIRI while operating at comparable wavelengths. We describe the performance characteristics of the 13-μ\mum GeoSnap array operating between 38 and 45K, including quantum efficiency, well depth, linearity, gain, dark current, and frequency-dependent (1/f) noise profile.
ETH Zurich logoETH ZurichCNRS logoCNRSCalifornia Institute of Technology logoCalifornia Institute of TechnologyUniversity of OsloUniversity of Cambridge logoUniversity of CambridgeHeidelberg UniversityINFN Sezione di NapoliUniversity of Waterloo logoUniversity of WaterlooUniversity of Manchester logoUniversity of ManchesterUniversity of ZurichUniversity College London logoUniversity College LondonUniversity of California, Irvine logoUniversity of California, IrvineUniversity of Copenhagen logoUniversity of CopenhagenUniversity of EdinburghNASA Goddard Space Flight Center logoNASA Goddard Space Flight CenterUniversidade de LisboaLancaster UniversityUniversity of Florida logoUniversity of FloridaSpace Telescope Science Institute logoSpace Telescope Science InstituteUniversität HeidelbergUniversidad Autónoma de MadridUniversité Paris-Saclay logoUniversité Paris-SaclayHelsinki Institute of PhysicsUniversity of HelsinkiThe University of ManchesterSorbonne Université logoSorbonne UniversitéÉcole Normale SupérieureUniversity of TurkuLeiden University logoLeiden UniversityCEA logoCEAUniversity of GenevaÉcole Polytechnique Fédérale de Lausanne (EPFL)University of PortsmouthThe Ohio State University logoThe Ohio State UniversityEuropean Southern Observatory (ESO)Ludwig-Maximilians-Universität MünchenUniversidad Complutense de MadridUniversität BonnUniversità di GenovaKTH Royal Institute of Technology logoKTH Royal Institute of TechnologyUniversità di Milano-BicoccaUniversity of SussexUniversity of OuluObservatoire de ParisTechnical University of DenmarkINAF - Osservatorio Astrofisico di TorinoUniversité Côte d’AzurUniversità di TriesteDurham University logoDurham UniversityUniversity of Groningen logoUniversity of GroningenInstituto de Astrofísica e Ciências do EspaçoJet Propulsion Laboratory, California Institute of TechnologySejong UniversityJet Propulsion LaboratoryJagiellonian UniversityInstituto de Astrofísica de CanariasMax Planck Institute for Plasma PhysicsEuropean Space AgencyNational Tsing-Hua UniversityEuropean Southern Observatory logoEuropean Southern ObservatoryRuhr-Universität BochumSISSACNESINFN, Sezione di TorinoUniversidad de ValparaísoJodrell Bank Centre for AstrophysicsUniversidad de La LagunaConsejo Superior de Investigaciones Científicas (CSIC)INFN, Sezione di MilanoUniversidad Técnica Federico Santa MaríaThe Open UniversityMax Planck Institute for AstronomyInstituto de Astrofísica de Andalucía, IAA-CSICINAF – Osservatorio Astronomico di RomaInstitut d'Astrophysique de ParisUniversidad de SalamancaInstitut de Física d’Altes Energies (IFAE)IPACInstitut d’Estudis Espacials de Catalunya (IEEC)Università della CalabriaLaboratoire de Physique des 2 Infinis Irène Joliot-CurieINFN - Sezione di PadovaIJCLabINAF-IASF MilanoInstitute of Space ScienceInstitut d’Astrophysique SpatialeINFN-Sezione di GenovaINFN Sezione di LecceINFN-Sezione di BolognaUniversidad Politécnica de CartagenaUniversidad de La SerenaINFN - PadovaDTU Space, Technical University of DenmarkInstitut de Ciències de l’Espai (ICE, CSIC)TelespazioCenter for Theoretical Physics, Polish Academy of SciencesAIMASI - Agenzia Spaziale ItalianaMuseo Storico della Fisica e Centro Studi e Ricerche Enrico FermiInstituto de Física Teórica UAM/CSICUniversité LyonFinnish Centre for Astronomy with ESO (FINCA)Institut de Recherche en Astrophysique et Planétologie (IRAP)ESACInfrared Processing and Analysis Center, California Institute of TechnologyObservatoire de SauvernyIstituto Nazionale di Fisica Nucleare, Sezione di NapoliUniversity of AlexandriaInstitut de Physique des 2 Infinis de Lyon (IP2I)Centre de Recherche Astrophysique de Lyon (CRAL)Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências da Universidade de LisboaLaboratoire d’Astrophysique de Marseille (LAM)Port d'Informació Científica (PIC)Institut de Ciències de l’Espai (ICE)Centro de Astrobiología (CAB), CSIC–INTAINAF-IASF, BolognaAurora Technology for ESASerco for ESAUniversity of Rome Tre* National and Kapodistrian University of AthensCosmic Dawn Center(DAWN)Universit degli Studi di FerraraUniversit de ToulouseUniversit Claude Bernard Lyon 1Universit del SalentoINAF Osservatorio Astronomico di CapodimonteMax Planck Institut fr AstronomieAix-Marseille Universit",Universit degli Studi di PadovaExcellence Cluster ‘Origins’Universit de BordeauxUniversit Paris CitUniversit de StrasbourgMax Planck-Institute for Extraterrestrial PhysicsUniversit di TorinoUniversit di PadovaUniversit degli Studi di MilanoINAF Osservatorio Astronomico di PadovaUniversit degli Studi di TorinoUniversit degli Studi di Napoli Federico IIUniversit degli Studi della Campania Luigi VanvitelliINAF Osservatorio di Astrofisica e Scienza dello Spazio di BolognaUniversit Di BolognaIFPU Institute for fundamental physics of the UniverseINFN Sezione di TriesteAgenzia Spaziale Italiana (ASI) – Space Science Data CenterICSC – Centro Nazionale Supercalcolo, Big Data e Quantum ComputingIEEC – Institut d’Estudis Espacials de CatalunyaIFCA – Instituto de Física de CantabriaSerendipity in the Universe (SIU)INAF ` Osservatorio Astronomico di Trieste
Strong gravitational lensing (SL) by galaxy clusters is a powerful probe of their inner mass distribution and a key test bed for cosmological models. However, the detection of SL events in wide-field surveys such as Euclid requires robust, automated methods capable of handling the immense data volume generated. In this work, we present an advanced deep learning (DL) framework based on mask region-based convolutional neural networks (Mask R-CNNs), designed to autonomously detect and segment bright, strongly-lensed arcs in Euclid's multi-band imaging of galaxy clusters. The model is trained on a realistic simulated data set of cluster-scale SL events, constructed by injecting mock background sources into Euclidised Hubble Space Telescope images of 10 massive lensing clusters, exploiting their high-precision mass models constructed with extensive spectroscopic data. The network is trained and validated on over 4500 simulated images, and tested on an independent set of 500 simulations, as well as real Euclid Quick Data Release (Q1) observations. The trained network achieves high performance in identifying gravitational arcs in the test set, with a precision and recall of 76% and 58%, respectively, processing 2'x2' images in a fraction of a second. When applied to a sample of visually confirmed Euclid Q1 cluster-scale lenses, our model recovers 66% of gravitational arcs above the area threshold used during training. While the model shows promising results, limitations include the production of some false positives and challenges in detecting smaller, fainter arcs. Our results demonstrate the potential of advanced DL computer vision techniques for efficient and scalable arc detection, enabling the automated analysis of SL systems in current and future wide-field surveys. The code, ARTEMIDE, is open source and will be available at this http URL.
The Euclid, Rubin/LSST and Roman (WFIRST) projects will undertake flagship optical/near-infrared surveys in the next decade. By mapping thousands of square degrees of sky and covering the electromagnetic spectrum between 0.3 and 2 microns with sub-arcsec resolution, these projects will detect several tens of billions of sources, enable a wide range of astrophysical investigations by the astronomical community and provide unprecedented constraints on the nature of dark energy and dark matter. The ultimate cosmological, astrophysical and time-domain science yield from these missions will require joint survey processing (JSP) functionality at the pixel level that is outside the scope of the individual survey projects. The JSP effort scoped here serves two high-level objectives: 1) provide precise concordance multi-wavelength images and catalogs over the entire sky area where these surveys overlap, which accounts for source confusion and mismatched isophotes, and 2) provide a science platform to analyze concordance images and catalogs to enable a wide range of astrophysical science goals to be formulated and addressed by the research community. For the cost of about 200WY, JSP will allow the U.S. (and international) astronomical community to manipulate the flagship data sets and undertake innovative science investigations ranging from solar system object characterization, exoplanet detections, nearby galaxy rotation rates and dark matter properties, to epoch of reionization studies. It will also allow for the ultimate constraints on cosmological parameters and the nature of dark energy, with far smaller uncertainties and a better handle on systematics than by any one survey alone.
Astrometry, one of the oldest branches of astronomy, has been revolutionized by missions like Hipparcos and especially Gaia, which mapped billions of stars with extraordinary precision. However, challenges such as detecting Earth-like exoplanets in nearby habitable zones and probing the influence of dark matter in galactic environments require sub-microarcsecond accuracy. With a 6--8 meter large-aperture telescope operating across at visible wavelengths, the Habitable Worlds Observatory by NASA can combine astrometry and direct imaging to detect rocky exoplanets within 10 parsecs and study their atmospheres. We consider here the scientific requirements and present a concept for a dedicated astrometric instrument on HWO. It is capable to produce diffraction-limited images of large fields, achieving a point-spread function (PSF) precision of 20 milliarcseconds. Equipped with a detector calibration system, HWO can perform high precision astrometry, and, detect and measure the orbit of Earth-mass planets in the habitable zone of Nearby Solar-type stars. HWO can dramatically improve current constraints on the self- interaction cross-section of heavy dark matter particles (WIMPs) and on the masses of ultra-high dark matter particles, through the study of stellar motions in galactic environments. The visible channel of the instrument features a large CMOS-based focal plane with stitched pixel arrays, enabling a large field of view. The ``Detector Calibration Unit'' system uses interferometric laser fringes to calibrate pixel positions. Using differential astrometry and pointed observations with a stable telescope design enables extended integration times, enhancing sensitivity to sub-microarcsecond precision for detecting exoplanets and studying dark matter through stellar motion.
Kishalay De et al. present observational evidence for the direct formation of a stellar-mass black hole from the terminal collapse of a massive, hydrogen-depleted supergiant in the Andromeda galaxy (M31), identified through its mid-infrared brightening and subsequent dramatic fading without a bright optical outburst. The study provides strong support for the 'failed supernova' pathway, where a star's core collapses directly into a black hole with minimal light emission.
We measure galaxy sizes from 2 &lt; z &lt; 10 using COSMOS-Web, the largest-area JWST imaging survey to date, covering \sim0.54 deg2^2. We analyze the rest-frame optical (~5000A) size evolution and its scaling relation with stellar mass (ReMαR_e\propto M_*^\alpha) for star-forming and quiescent galaxies. For star-forming galaxies, the slope α\alpha remains approximately 0.20 at $2 < z < 8$, showing no significant evolution over this redshift range. At higher redshifts, the slopes are 0.13±0.15-0.13 \pm 0.15 and 0.37±0.360.37 \pm 0.36 for 8 &lt; z &lt; 9 and 9 &lt; z &lt; 10, respectively. At fixed galaxy mass, the size evolution for star-forming galaxies follows Re(1+z)βR_e \propto (1+z)^{-\beta}, with $\beta = 1.21 \pm 0.05.Forquiescentgalaxies,theslopeissteeper. For quiescent galaxies, the slope is steeper \alpha\sim 0.5-0.8$ at 2 &lt; z &lt; 5, and β=0.81±0.26\beta=0.81\pm0.26. We find that the size-mass relation is consistent between UV and optical at z &lt; 8 for star-forming galaxies. However, we observe a decrease in the slope from UV to optical at z &gt; 8, with a tentative negative slope in the optical at 8 &lt; z &lt; 9, suggesting a complex interplay between intrinsic galaxy properties and observational effects such as dust attenuation. We discuss the ratio between galaxies' half-light radius, and underlying halos' virial radius, RvirR_{vir}, and find the median value of Re/Rvir=2.7%R_e/R_{vir}=2.7\%. The star formation rate surface density evolves as logΣSFR=(0.20±0.08)z+(0.65±0.51)\log\Sigma_\text{SFR} = (0.20\pm0.08)\,z+(-0.65\pm0.51), and the ΣSFR\Sigma_\text{SFR}-MM_* relation remains flat at 232 3 provides new insights into galaxy size and related properties in the rest-frame optical.
There are no more papers matching your filters at the moment.