UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)

Permanent URI for this collectionhttp://hdl.handle.net/11603/7798

The Center for Space Sciences and Technology (CSST) is the administrative unit for UMBC’s participation in the CRESST consortium. The NASA Goddard Space Flight Center (NASA/GSFC), The University of Maryland College Park (UMCP), Catholic University, Howard University and Southeastern Universities Research Association (SURA) are our partners in the consortium.

The Center for Research and Exploration in Space Science & Technology (CRESST), is a cooperative agreement between the partner institutions. The CRESST consortium currently has over 120 PhD astronomers and astrophysicists working within the Astrophysics Science Division at GSFC.

CSST was formed in 2006 and currently has over 20 UMBC research faculty, several of which are affiliated to the physics department. The research conducted by the members of CSST focuses on (i) Astrophysical Data Reduction, Interpretation & Archiving, (ii) Space Science Technology: Development & Calibration, and (iii) Theoretical Astrophysics: Simulations & Software.

CSST maintains close relations with (and is housed within) the Physics Department at UMBC. Combined, UMBC astrophysics faculty and CSST scientists contribute to the Undergraduate & Graduate activities (including the Undergrad & Grad internships) by teaching & mentoring students.

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Now showing 1 - 20 of 1523

Search for Extended GeV Sources in the Inner Galactic Plane
(2024-11-11) Abdollahi, S.; Acero, F.; Acharyya, A.; Adelfio, A.; Ajello, M.; Baldini, L.; Ballet, J.; Bartolini, C.; Gonzalez, J. Becerra; Bellazzini, R.; Bissaldi, E.; Bonino, R.; Bruel, P.; Cameron, R. A.; Caraveo, P. A.; Castro, D.; Cavazzuti, E.; Cheung, C. C.; Cibrario, N.; Ciprini, S.; Cozzolongo, G.; Orestano, P. Cristarella; Cuoco, A.; Cutini, S.; D'Ammando, F.; Lalla, N. Di; Dinesh, A.; Venere, L. Di; Domínguez, A.; Fiori, A.; Funk, S.; Fusco, P.; Gargano, F.; Gasbarra, C.; Gasparrini, D.; Germani, S.; Giacchino, F.; Giglietto, N.; Giliberti, M.; Giordano, F.; Giroletti, M.; Green, D.; Grenier, I. A.; Guillemot, L.; Guiriec, S.; Gupta, R.; Hashizume, M.; Hays, E.; Hewitt, J. W.; Horan, D.; Hou, X.; Kayanoki, T.; Kuss, M.; Laviron, A.; Lemoine-Goumard, M.; Liguori, A.; Li, J.; Liodakis, I.; Loizzo, P.; Longo, F.; Loparco, F.; Lorusso, L.; Lovellette, M. N.; Lubrano, P.; Maldera, S.; Malyshev, D.; Martí-Devesa, G.; Martin, P.; Mazziotta, M. N.; Mereu, I.; Michelson, P. F.; Mirabal, Nestor; Mitthumsiri, W.; Mizuno, T.; Monti-Guarnieri, P.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Omodei, N.; Orienti, M.; Orlando, E.; Paneque, D.; Panzarini, G.; Persic, M.; Pesce-Rollins, M.; Pillera, R.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Bernal, M. Rocamora; Sánchez-Conde, M.; Parkinson, P. M. Saz; Serini, D.; Sgrò, C.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Tajima, H.; Thayer, J. B.; Torres, D. F.; Valverde, Janeth; Wadiasingh, Z.; Wood, K.; Zaharijas, G.
The recent detection of extended γ-ray emission around middle-aged pulsars is interpreted as inverse-Compton scattering of ambient photons by electron-positron pairs escaping the pulsar wind nebula, which are confined near the system by unclear mechanisms. This emerging population of γ-ray sources was first discovered at TeV energies and remains underexplored in the GeV range. To address this, we conducted a systematic search for extended sources along the Galactic plane using 14 years of Fermi-LAT data above 10 GeV, aiming to identify a number of pulsar halo candidates and extend our view to lower energies. The search covered the inner Galactic plane (|l|≤ 100∘, |b|≤ 1∘) and the positions of known TeV sources and bright pulsars, yielding broader astrophysical interest. We found 40 such sources, forming the Second Fermi Galactic Extended Sources Catalog (2FGES), most with 68% containment radii smaller than 1.0∘ and relatively hard spectra with photon indices below 2.5. We assessed detection robustness using field-specific alternative interstellar emission models and by inspecting significance maps. Noting 13 sources previously known as extended in the 4FGL-DR3 catalog and five dubious sources from complex regions, we report 22 newly detected extended sources above 10 GeV. Of these, 13 coincide with H.E.S.S., HAWC, or LHAASO sources; six coincide with bright pulsars (including four also coincident with TeV sources); six are associated with 4FGL point sources only; and one has no association in the scanned catalogs. Notably, six to eight sources may be related to pulsars as classical pulsar wind nebulae or pulsar halos.
Panning for gold with the Neil Gehrels Swift Observatory: an optimal strategy for finding the counterparts to gravitational wave events
(2024-11-07) Eyles-Ferris, R. A. J.; Evans, P. A.; Breeveld, A. A.; Cenko, S. B.; Dichiara, S.; Kennea, J. A.; Klingler, Noel; Kuin, N. P. M.; Marshall, F. E.; Oates, S. R.; Page, M. J.; Ronchini, S.; Siegel, M. H.; Tohuvavohu, A.; Campana, S.; D'Elia, V.; Osborne, J. P.; Page, K. L.; Pasquale, M. De; Troja, E.
The LIGO, Virgo and KAGRA gravitational wave observatories are currently undertaking their O4 observing run offering the opportunity to discover new electromagnetic counterparts to gravitational wave events. We examine the capability of the Neil Gehrels Swift Observatory (Swift) to respond to these triggers, primarily binary neutron star mergers, with both the UV/Optical Telescope (UVOT) and the X-ray Telescope (XRT). We simulate Swift's response to a trigger under different strategies using model skymaps, convolving these with the 2MPZ catalogue to produce an ordered list of observing fields, deriving the time taken for Swift to reach the correct field and simulating the instrumental responses to modelled kilonovae and short gamma-ray burst afterglows. We find that UVOT using the u filter with an exposure time of order 120 s is optimal for most follow-up observations and that we are likely to detect counterparts in ∼6% of all binary neutron star triggers. We find that the gravitational wave 90% error area and measured distance to the trigger allow us to select optimal triggers to follow-up. Focussing on sources less than 300 Mpc away or 500 Mpc if the error area is less than a few hundred square degrees, distances greater than previously assumed, offer the best opportunity for discovery by Swift with ∼5−30% of triggers having detection probabilities ≥0.5. At even greater distances, we can further optimise our follow-up by adopting a longer 250 s or 500 s exposure time.
Characterization of a peculiar Einstein Probe transient EP240408a: an exotic gamma-ray burst or an abnormal jetted tidal disruption event?
(2024-10-29) O'Connor, B.; Pasham, D.; Andreoni, I.; Hare, J.; Beniamini, P.; Troja, E.; Ricci, R.; Dobie, D.; Chakraborty, J.; Ng, M.; Klingler, N.; Karambelkar, V.; Rose, S.; Schulze, S.; Ryan, G.; Dichiara, S.; Monageng, I.; Buckley, D.; Hu, L.; Srinivasaragavan, G.; Bruni, G.; Cabrera, T.; Cenko, S. B.; Eerten, H. van; Freeburn, J.; Hammerstein, E.; Kasliwal, M.; Kouveliotou, C.; Kunnumkai, K.; Leung, J. K.; Lien, Amy; Palmese, A.; Sakamoto, T.
We present the results of our multi-wavelength (X-ray to radio) follow-up campaign of the Einstein Probe transient EP240408a. The initial 10 s trigger displayed bright soft X-ray (0.5-4 keV) radiation with peak luminosity Lₓ≳10⁴⁹ (10⁵⁰) erg s⁻¹ for an assumed redshift z>0.5 (2.0). The Neil Gehrels Swift Observatory and Neutron star Interior Composition ExploreR discovered a fading X-ray counterpart lasting for ∼5 d (observer frame), which showed a long-lived (~4 d) plateau-like emission (t⁻⁰.⁵) before a sharp powerlaw decline (t⁻⁷). The plateau emission was in excess of Lₓ≳10⁴⁶ (10⁴⁷) erg s⁻¹ at z>0.5 (2.0). Deep optical and radio observations resulted in non-detections of the transient. Our observations with Gemini South revealed a faint potential host galaxy (r≈24 AB mag) near the edge of the X-ray localization. The faint candidate host, and lack of other potential hosts (r≳26 AB mag; J≳23 AB mag), implies a higher redshift origin (z>0.5), which produces extreme X-ray properties that are inconsistent with many known extragalactic transient classes. In particular, the lack of a bright gamma-ray counterpart, with the isotropic-equivalent energy (10−10,000 keV) constrained by GECam and Konus-Wind to Eγ,iso≲4×10⁵¹ (6×10⁵²) erg at z>0.5 (2.0), conflicts with known gamma-ray bursts (GRBs) of similar X-ray luminosities. We therefore favor a jetted tidal disruption event (TDE) as the progenitor of EP240408a at z>1.0, possibly caused by the disruption of a white dwarf by an intermediate mass black hole. The alternative is that EP240408a may represent a new, previously unknown class of transient.
An Empirical Framework Characterizing the Metallicity and Star-Formation History Dependence of X-ray Binary Population Formation and Emission in Galaxies
(2024-10-25) Lehmer, Bret D.; Monson, Erik B.; Eufrasio, Rafael T.; Amiri, Amirnezam; Doore, Keith; Basu-Zych, Antara; Garofali, Kristen; Oskinova, Lidia; Andrews, Jeff J.; Antoniou, Vallia; Geda, Robel; Greene, Jenny E.; Kovlakas, Konstantinos; Lazzarini, Margaret; Richardson, Chris T.
We present a new empirical framework modeling the metallicity and star-formation history (SFH) dependence of X-ray luminous (L>10³⁶ ergs s⁻¹) point-source population luminosity functions (XLFs) in normal galaxies. We expect the X-ray point-source populations are dominated by X-ray binaries (XRBs), with contributions from supernova remnants near the low luminosity end of our observations. Our framework is calibrated using the collective statistical power of 3,731 X-ray detected point-sources within 88 Chandra-observed galaxies at D< 40 Mpc that span broad ranges of metallicity (Z≈ 0.03-2 Z⊙), SFH, and morphology (dwarf irregulars, late-types, and early-types). Our best-fitting models indicate that the XLF normalization per unit stellar mass declines by ≈2-3 dex from 10 Myr to 10 Gyr, with a slower age decline for low-metallicity populations. The shape of the XLF for luminous X-ray sources (L<10³⁸ ergs s⁻¹) significantly steepens with increasing age and metallicity, while the lower-luminosity XLF appears to flatten with increasing age. Integration of our models provide predictions for X-ray scaling relations that agree very well with past results presented in the literature, including, e.g., the Lₓ-SFR-Z relation for high-mass XRBs (HMXBs) in young stellar populations as well as the Lₓ/M⋆ ratio observed in early-type galaxies that harbor old populations of low-mass XRBs (LMXBs). The model framework and data sets presented in this paper further provide unique benchmarks that can be used for calibrating binary population synthesis models.
Hard X-Ray Spectrum of the Vela Pulsar and Its Wind Nebula Constrained by NuSTAR
(IOP, 2024-11-04) Kargaltsev, Oleg; Hare, Jeremy; Lange, Alexander
We present the analysis of 200 ks NuSTAR observation of the Vela pulsar and the pulsar wind nebula (PWN). The phase-resolved spectra corresponding to two main peaks in the folded pulse profile differ significantly. The spectrum of Peak 1 is significantly harder than that of Peak 2 in qualitative agreement with the earlier Rossi X-ray Timing Explorer results. However, for both spectra, the values of power-law (PL) fit photon indices, Γ, are noticeably larger than the previously reported values. The harder (Peak 1) spectrum has Γ = 1.10 ± 0.15, which is close to those measured for the bright inner jets of the PWN. We used the off-pulse interval to remove the emission from the pulsar and measure the compact PWN spectrum in hard X-rays. We also measured the spectrum from the southwestern region of the PWN, which is resolved by NuSTAR from the compact PWN. For both regions, we fit the NuSTAR spectra by themselves and together with the Chandra X-ray Observatory spectra. We found that the PWN spectrum (for both regions) requires a more complex model than a simple PL. The fits to compact PWN spectrum favor an exponentially cutoff PL model, with Ec ≈ 50 keV over the broken PL model. The observed synchrotron photon energies imply electrons accelerated to ≈150 TeV.
Multiwavelength study of 1eRASS J085039.9-421151 with eROSITA NuSTAR and X-shooter
(2024-11-04) Zainab, Aafia; Avakyan, Artur; Doroshenko, Victor; Thalhammer, Philipp; Sokolova-Lapa, Ekaterina; Ballhausen, Ralf; Zalot, Nicolas; Stierhof, Jakob; Haemmerich, Steven; Diez, Camille M.; Weber, Philipp; Dauser, Thomas; Berger, Katrin; Kretschmar, Peter; Pottschmidt, Katja; Pradhan, Pragati; Islam, Nazma; Maitra, Chandreyee; Coley, Joel B.; Blay, Pere; Corbet, Robin; Rothschild, Richard E.; Wood, Kent; Santangelo, Andrea; Heber, Ulrich; Wilms, Joern
The eROSITA instrument on board Spectrum-Roentgen-Gamma has completed four scans of the X-ray sky, leading to the detection of almost one million X-ray sources in eRASS1 only, including multiple new X-ray binary candidates. We report on analysis of the X-ray binary 1eRASS J085039.9-421151, using a ~55\,ks long NuSTAR observation, following its detection in each eROSITA scan. Analysis of the eROSITA and NuSTAR X-ray spectra in combination with X-shooter data of the optical counterpart provide evidence of an X-ray binary with a red supergiant (RSG) companion, confirming previous results, although we determine a cooler spectral type of M2-3, owing to the presence of TiO bands in the optical and near infrared spectra. The X-ray spectrum is well-described by an absorbed power law with a high energy cutoff typically applied for accreting high mass X-ray binaries. In addition, we detect a strong fluorescent neutral iron line with an equivalent width of ~700\,eV and an absorption edge, the latter indicating strong absorption by a partial covering component. It is unclear if the partial absorber is ionised. There is no significant evidence of a cyclotron resonant scattering feature. We do not detect any pulsations in the NuSTAR lightcurves, possibly on account of a large spin period that goes undetected due to insufficient statistics at low frequencies or potentially large absorption that causes pulsations to be smeared out. Even so, the low persistent luminosity, the spectral parameters observed (photon index, photon index, Γ<1.0), and the minuscule likelihood of detection of RSG-black hole systems, suggest that the compact object is a neutron star.
The XRISM/Resolve view of the Fe K region of Cyg X-3
(2024-11-08) XRISM Collaboration; Boissay-Malaquin, Rozenn; Hamaguchi, Kenji; Hayashi, Takayuki; Mukai, Koji; Pottschmidt, Katja; Tamura, Keisuke; Yaqoob, Tahir
The X-ray binary system Cygnus X-3 (4U 2030+40, V1521 Cyg) is luminous but enigmatic owing to the high intervening absorption. High-resolution X-ray spectroscopy uniquely probes the dynamics of the photoionized gas in the system. In this paper we report on an observation of Cyg X-3 with the XRISM/Resolve spectrometer which provides unprecedented spectral resolution and sensitivity in the 2-10 keV band. We detect multiple kinematic and ionization components in absorption and emission, whose superposition leads to complex line profiles, including strong P-Cygni profiles on resonance lines. The prominent Fe XXV Heα and Fe XXVI Lyα emission complexes are clearly resolved into their characteristic fine structure transitions. Self-consistent photoionization modeling allows us to disentangle the absorption and emission components and measure the Doppler velocity of these components as a function of binary orbital phase. We find a significantly higher velocity amplitude for the emission lines than for the absorption lines. The absorption lines generally appear blueshifted by ∼−500-600km s⁻¹. We show that the wind decomposes naturally into a relatively smooth and large scale component, perhaps originating with the background wind itself, plus a turbulent more dense structure located close to the compact object in its orbit.
NARVis: Neural Accelerated Rendering for Real-Time Scientific Point Cloud Visualization
(2024-07-26) Hegde, Srinidhi; Kullman, Kaur; Grubb, Thomas; Lait, Leslie; Guimond, Stephen; Zwicker, Matthias
Exploring scientific datasets with billions of samples in real-time visualization presents a challenge - balancing high-fidelity rendering with speed. This work introduces a novel renderer - Neural Accelerated Renderer (NAR), that uses the neural deferred rendering framework to visualize large-scale scientific point cloud data. NAR augments a real-time point cloud rendering pipeline with high-quality neural post-processing, making the approach ideal for interactive visualization at scale. Specifically, we train a neural network to learn the point cloud geometry from a high-performance multi-stream rasterizer and capture the desired postprocessing effects from a conventional high-quality renderer. We demonstrate the effectiveness of NAR by visualizing complex multidimensional Lagrangian flow fields and photometric scans of a large terrain and compare the renderings against the state-of-the-art high-quality renderers. Through extensive evaluation, we demonstrate that NAR prioritizes speed and scalability while retaining high visual fidelity. We achieve competitive frame rates of > 126 fps for interactive rendering of > 350M points (i.e., an effective throughput of > 44 billion points per second) using ∼12 GB of memory on RTX 2080 Ti GPU. Furthermore, we show that NAR is generalizable across different point clouds with similar visualization needs and the desired post-processing effects could be obtained with substantial high quality even at lower resolutions of the original point cloud, further reducing the memory requirements.
MAUVE: An Ultraviolet Astrophysics Probe Mission Concept
(IOP, 2024-10-25) Balakrishnan, Mayura; Bowens, Rory; Aguirre, Fernando Cruz; Hughes, Kaeli; Jayaraman, Rahul; Kuhn, Emily; Louden, Emma; Louie, Dana R.; McBride, Keith; McGrath, Casey; Payne, Jacob; Presser, Tyler; Reding, Joshua S.; Rickman, Emily; Scrandis, Rachel; Symons, Teresa; Wiser, Lindsey; Jahoda, Keith; Kataria, Tiffany; Nash, Alfred; X, Team
We present the mission concept "Mission to Analyze the UltraViolet universE" (MAUVE), a wide-field spectrometer and imager conceived during the inaugural NASA Astrophysics Mission Design School. MAUVE responds to the 2023 Announcement of Opportunity for Probe-class missions, with a budget cap of $1 billion, and would hypothetically launch in 2031. However, the formulation of MAUVE was an educational exercise and the mission is not being developed further. The Principle Investigator-led science of MAUVE aligns with the priorities outlined in the 2020 Astrophysics Decadal Survey, enabling new characterizations of exoplanet atmospheres, the early-time light curves of some of the universe's most explosive transients, and the poorly-understood extragalactic background light. Because the Principle Investigator science occupies 30% of the observing time available during the mission's 5 yr lifespan, we provide an observing plan that would allow for 70% of the observing time to be used for General Observer programs, with community-solicited proposals. The onboard detector (THISTLE) claims significant heritage from the Space Telescope Imaging Spectrograph on Hubble, but extends its wavelength range down to the extreme UV. We note that MAUVE would be the first satellite in decades with the ability to access this regime of the electromagnetic spectrum. MAUVE has a field of view of 900'' × 900'', a photometric sensitivity extending to mᵤᵥ ≤ 24, and a resolving power of R ∼ 1000. This paper provides full science and mission traceability matrices for this concept, and also outlines cost and scheduling timelines aimed at enabling a within-budget mission and an on-time launch.
Spatio-spectral-temporal modelling of two young pulsar wind nebulae
(Oxford University Press, 2024-10-25) Kundu, Anu; Joshi, Jagdish C.; Venter, C.; Engelbrecht, N. E.; Zhang, W.; Torres, Diego F.; Sushch, I.; Tanaka, Shuta J.
Recent observations of a few young pulsar wind nebulae (PWNe) have revealed their morphologies in some detail. Given the availability of spatio-spectral-temporal data, we use our multi-zone (1D) leptonic emission code to model the PWNe associated with G29.7−0.3 (Kes 75) and G21.5−0.9 (G21.5), and obtain (by-eye) constraints on additional model parameters compared to spectral-only modelling. Kes 75 is a Galactic composite supernova remnant (SNR) with an embedded pulsar, PSR J1846−0258. X-ray studies reveal rapid expansion of Kes 75 over the past two decades. PWN G21.5 is also a composite SNR, powered by PSR J1833−1034. For Kes 75, we study a sudden plasma bulk speed increase that may be due to the magnetar-like outbursts of the central pulsar. An increase of a few per cent in this speed does not result in any significant change in the model outputs. For G21.5, we investigate different diffusion coefficients and pulsar spin-down braking indices. We can reproduce the broad-band spectra and X-ray surface brightness profiles for both PWNe, and the expansion rate, flux over different epochs, and X-ray photon index versus epoch and central radius for Kes 75 quite well. The latter three features are also investigated for G21.5. Despite obtaining reasonable fits overall, some discrepancies remain, pointing to further model revision. We find similar values to overlapping parameters between our 1D code and those of an independent 0D dynamical code (TIDE). Future work will incorporate spatial data from various energy wavebands to improve model constraints.
Tutorial on LuNaMaps Developed Tools andProcesses for Mapping the Lunar Surface
(2024-10) Liounis, Andrew; Gnam, Chris; Mazarico, Erwan Matias; Barker, Michael Kenneth; Petro, Noah Edward; Richardson, Jacob Armstrong; Scheidt, Stephen; Bertone, Stefano; Beyer, Ross A.
The main contribution of this project is the combined knowledge of terrain relative navigation experts and lunar scientists who are familiar with both the lunar orbital imagery and the instruments that collected the data as well as how a TRN system utilizes map data. This knowledge comes in the form of published technical papers, benchmark map data sets, and software tools that can help others automate the process of creating the necessary maps for their own landing sites in the future. This presentation provides a brief overview of the tools and processes developed by the project.
Broadband multi-wavelength properties of M87 during the 2018 EHT campaign including a very high energy flaring episode
(EDP Sciences, 2024-09-20) Algaba, J. C.; C, C.; Chandra, S.; Cheong, W.-Y.; Cui, Y.-Z.; Akiyama, K.; Alberdi, A.; Alef, W.; Anantua, R.; Asada, K.; Azulay, R.; Bach, U.; Baczko, A.-K.; Bandyopadhyay, B.; Barrett, J.; Bauböck, M.; Benson, B. A.; Bintley, D.; Blackburn, L.; Blundell, R.; Bouman, K. L.; Bower, G. C.; Boyce, H.; Bremer, M.; Brissenden, R.; Britzen, S.; Broderick, A. E.; Broguiere, D.; Bronzwaer, T.; Bustamante, S.; Carlstrom, J. E.; Chael, A.; Chan, C.-k; Chang, D. O.; Chatterjee, K.; Chatterjee, S.; Chen, M.-T.; Chen, Y.; Bellazzini, R.; Berenji, B.; Bissaldi, E.; Blandford, R. D.; Bonino, R.; Bruel, P.; Cameron, R. A.; Caraveo, P. A.; Cavazzuti, E.; Cheung, C.; Ciprini, S.; Orestano, P. Cristarella; Cutini, S.; Lalla, N. Di; Dinesh, A.; Venere, L. Di; Dom'inguez, A.; Fegan, S. J.; Franckowiak, A.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasbarra, C.; Germani, S.; Giliberti, M.; Grenier, I. A.; Hays, E.; Horan, D.; Kuss, M.; Larsson, S.; Liodakis, I.; Longo, F.; Loparco, F.; Lovellette, M. N.; Maldera, S.; Mazziotta, M. N.; Mereu, I.; Michelson, P. F.; Mirabal, Nestor; Mizuno, T.; Monzani, M. E.; Morselli, A.; Negro, M.; Omodei, N.; Orlando, E.; Persic, M.; Raino, S.; Rani, Bindu; Reimer, A.; Reimer, O.; S'anchez-Conde, M.; Parkinson, P. M. Saz; Sgro, C.; Siskind, E. J.; Spinelli, P.; Suson, D. J.; Tajima, H.; Torres, D. F.; Zaharijas, G.; Aharonian, F.; Benkhali, F. Ait; Aschersleben, J.; Ashkar, H.; Backes, M.; Martins, V. Barbosa; Batzofin, R.; Becherini, Y.; Berge, D.; Böttcher, M.; Boisson, C.; Bolmont, J.; Lavergne, M. de Bony de; Borowska, J.; Bouyahiaoui, M.; Bradascio, F.; Brose, R.; Brown, A.; Bruno, B.; Bulik, T.; Burger-Scheidlin, C.; Casanova, S.; Cecil, R.; Celic, J.; Cerruti, M.; Chand, T.; Chen, A.; Chibueze, J.; Chibueze, O.; Cotter, G.; Mbarubucyeye, J. Damascene; Devin, J.; Djuvsland, J.; Dmytriiev, A.; Einecke, S.; Ernenwein, J.-P.; Feijen, K.; Fontaine, G.; Funk, S.; Gabici, S.; Glawion, D.; Glicenstein, J. F.; Goswami, P.; Grolleron, G.; Haerer, L.; He, B.; Holch, T. L.; Holler, M.; Horns, D.; Huang, Zhiqiu; Jamrozy, M.; Jankowsky, F.; Jung-Richardt, I.; Kasai, E.; Katarzy, K.; 'n 'n; Ski, Ski; Khatoon, R.; Kh'elifi, B.; Z, Z.; Niak, Niak; Komin, Nu; Kosack, K.; Kundu, A.; Lang, R. G.; Stum, S. Le; Leitl, F.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leuschner, F.; Luashvili, A.; Mackey, J.; Malyshev, D.; Mart'i-Devesa, G.; Marx, R.; Meyer, M.; Mitchell, A.; Moderski, R.; Moghadam, M. O.; Mohrmann, L.; Montanari, A.; Moulin, E.; Naurois, M. de; Niemiec, J.; O'Brien, P.; Ohm, S.; Wilhelmi, E. de Ona; Ostrowski, M.; Panny, S.; Panter, M.; Pensec, U.; Pita, S.; Ddagger, Ddagger; Quirrenbach, A.; Ravikularaman, S.; Reimer, A.; Reimer, O.; Reville, B.; Reis, I.; Ren, H.; Rieger, F.; Roellinghoff, G.; Rudak, B.; Ruiz-Velasco, E.; Sabri, K.; Sahakian, V.; Salzmann, H.; Santangelo, A.; Sasaki, M.; Schäfer, J.; Schüssler, F.; Schutte, H. M.; Shapopi, J. N. S.; Sharma, A.; Sol, H.; Spencer, S.; Stawarz, Stawarz; Steppa, C.; Streil, K.; Suzuki, H.; Takahashi, T.; Tanaka, T.; Taylor, A. M.; Terrier, R.; Tluczykont, M.; Tsirou, M.; Eldik, C. van; Vecchi, M.; Wach, T.; Wagner, S. J.; Wierzcholska, A.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zywucka, N.; Abe, S.; Abhir, J.; Abhishek, A.; Acciari, V. A.; Aguasca-Cabot, A.; Agudo, I.; Aniello, T.; Ansoldi, S.; Antonelli, L. A.; Engels, A. Arbet; Arcaro, C.; Artero, M.; Asano, K.; Babi'c, A.; Almeida, U. Barres de; Barrio, J. A.; Batkovi'c, I.; Bautista, A.; Baxter, J.; Gonz'alez, J. Becerra; Bednarek, W.; Bernardini, E.; Bernete, J.; Berti, A.; Besenrieder, J.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Z, Z.; Bo; S, S.; Njak, Njak; Bronzini, E.; Burelli, I.; Busetto, G.; Campoy-Ordaz, A.; Carosi, A.; Carosi, R.; Carretero-Castrillo, M.; Castro-Tirado, A. J.; Cerasole, D.; Ceribella, G.; Chai, Y.; Cifuentes, A.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; Vela, P. Da; Dazzi, F.; Angelis, A. De; Lotto, B. De; Menezes, R. de; Delfino, M.; Delgado, J.; Mendez, C. Delgado; Pierro, F. Di; Tria, R. Di; Venere, L. Di; Prester, D. Dominis; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Escudero, J.; Farina, L.; Fattorini, A.; Foffano, L.; Font, L.; Fröse, S.; Fukami, S.; Fukazawa, Y.; L'opez, R. J. Garc'ia; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Paiva, J. G. Giesbrecht; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinovi'c, N.; Gradetzke, T.; Grau, R.; Green, D.; Green, J. G.; Günther, P.; Hadasch, D.; Hahn, A.; Hassan, T.; Heckmann, L.; Llorente, J. Herrera; Hrupec, D.; Imazawa, R.; Ishio, K.; Mart'inez, I. Jim'enez; Jormanainen, J.; Kayanoki, T.; Kerszberg, D.; Kluge, G. W.; Kobayashi, Y.; Kouch, P. M.; Kubo, H.; Kushida, J.; L'ainez, M.; Lamastra, A.; Leone, F.; Lindfors, E.; Lombardi, S.; L'opez-Coto, R.; L'opez-Moya, M.; L'opez-Oramas, A.; Loporchio, S.; Lorini, A.; Lyard, E.; Fraga, B. Machado de Oliveira; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mangano, S.; Mannheim, K.; Mariotti, M.; Mart'inez, M.; Mart'inez-Chicharro, M.; Mas-Aguilar, A.; S, S.; Menchiari, S.; Mender, S.; Miceli, D.; Miener, T.; Miranda, J. M.; Mirzoyan, R.; Gonz'alez, M. Molero; Molina, E.; Mondal, H. A.; Moralejo, A.; Morcuende, D.; Nakamori, T.; Nanci, C.; Neustroev, V.; Nickel, L.; Rosillo, M. Nievas; Nigro, C.; Nikoli'c, L.; Nilsson, K.; Nishijima, K.; Ekoume, T. Njoh; Noda, K.; Nozaki, S.; Ohtani, Y.; Okumura, A.; Otero-Santos, J.; Paiano, S.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Peresano, M.; Persic, M.; Pihet, M.; Pirola, G.; Podobnik, F.; Moroni, P. G. Prada; Prandini, E.; Priyadarshi, C.; Rib'o, M.; Rico, J.; Righi, C.; Sahakyan, N.; Saito, T.; Saturni, F. G.; Schmidt, K.; Schmuckermaier, F.; Schubert, J. L.; Schweizer, T.; Sciaccaluga, A.; Silvestri, G.; Sitarek, J.; Sliusar, V.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Stri, J.; S, S.; Kovi'c, Kovi'c; Strom, D.; Strzys, M.; Suda, Y.; Suutarinen, S.; Tajima, H.; Takahashi, M.; Takeishi, R.; Tavecchio, F.; Temnikov, P.; Terauchi, K.; Terzi'c, T.; Teshima, M.; Truzzi, S.; Tutone, A.; Ubach, S.; Scherpenberg, J. van; Acosta, M. Vazquez; Ventura, S.; Verna, G.; Viale, I.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Walter, R.; Will, M.; Wunderlich, C.; Yamamoto, T.; Acharyya, A.; Adams, C. B.; Bangale, P.; Bartkoske, J. T.; Benbow, W.; Christiansen, J. L.; Duerr, A.; Errando, M.; Feng, Q.; Foote, G. M.; Fortson, L.; Furniss, A.; Hanlon, W.; Hervet, O.; Hinrichs, C. E.; Holder, J.; Humensky, T. B.; Jin, W.; Johnson, M. N.; Kaaret, P.; Kertzman, M.; Kieda, D.; Kleiner, T. K.; Korzoun, N.; Krennrich, F.; Kumar, S.; Lang, M. J.; Lundy, M.; Maier, G.; McGrath, C. E.; Millard, M. J.; Mooney, C. L.; Moriarty, P.; Mukherjee, R.; Ning, W.; O'Brien, S.; Ong, R. A.; Pohl, M.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Ribeiro, D.; Roache, E.; Ryan, J. L.; Sadeh, I.; Saha, L.; Santander, M.; Textparagraph, Textparagraph; Sembroski, G. H.; Shang, R.; Splettstoesser, M.; Talluri, A. K.; Tucci, J. V.; Valverde, Janeth; Vassiliev, V.; Williams, D. A.; Wong, S. L.; Chen, Z.; Cui, L.; Hirota, T.; Li, B.; Li, G.; Liu, Q.; Liu, X.; Liu, Z.; Ma, J.; Niinuma, K.; Ro, H.; Sakai, N.; Sawada-Satoh, S.; Wajima, K.; Wang, J.; Wang, N.; Xia, B.; Yan, H.; Yonekura, Y.; Zhang, H.; Zhao, R.; Zhong, W.
The nearby elliptical galaxy M87 contains one of only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to gamma -ray energies) took part in the second M87 EHT campaign. The goal of this extensive MWL campaign was to better understand the physics of the accreting black hole M87*, the relationship between the inflow and inner jets, and the high-energy particle acceleration. Understanding the complex astrophysics is also a necessary first step towards performing further tests of general relativity. The MWL campaign took place in April 2018, overlapping with the EHT M87* observations. We present a new, contemporaneous spectral energy distribution (SED) ranging from radio to very high-energy (VHE) gamma -rays as well as details of the individual observations and light curves. We also conducted phenomenological modelling to investigate the basic source properties. We present the first VHE gamma -ray flare from M87 detected since 2010. The flux above 350 GeV more than doubled within a period of approx 36 hours. We find that the X-ray flux is enhanced by about a factor of two compared to 2017, while the radio and millimetre core fluxes are consistent between 2017 and 2018. We detect evidence for a monotonically increasing jet position angle that corresponds to variations in the bright spot of the EHT image. Our results show the value of continued MWL monitoring together with precision imaging for addressing the origins of high-energy particle acceleration. While we cannot currently pinpoint the precise location where such acceleration takes place, the new VHE gamma -ray flare already presents a challenge to simple one-zone leptonic emission model approaches, and it emphasises the need for combined image and spectral modelling.
Extragalactic Magnetar Giant Flare GRB 231115A: Insights from Fermi/GBM Observations
(2024-09-16) Trigg, Aaron C.; Stewart, Rachel; van Kooten, Alex; Burns, Eric; Roberts, Oliver J.; Frederiks, Dmitry D.; Baring, Matthew G.; Younes, George; Svinkin, Dmitry S.; Wadiasingh, Zorawar; Veres, Peter; Bhat, Narayana; Briggs, Michael S.; Scotton, Lorenzo; Goldstein, Adam; Busmann, Malte; O'Connor, Brendan; Hu, Lei; Gruen, Daniel; Riffeser, Arno; Zoeller, Raphael; Palmese, Antonella; Huppenkothen, Daniela; Kouveliotou, Chryssa
We present the detection and analysis of GRB 231115A, a candidate extragalactic magnetar giant flare (MGF) observed by Fermi/GBM and localized by INTEGRAL to the starburst galaxy M82. This burst exhibits distinctive temporal and spectral characteristics that align with known MGFs, including a short duration and a high peak energy. Gamma-ray analyses reveal significant insights into this burst, supporting conclusions already established in the literature: our time-resolved spectral studies provide further evidence that GRB 231115A is indeed a MGF. Significance calculations also suggest a robust association with M82, further supported by a high Bayes factor that minimizes the probability of chance alignment with a neutron star merger. Despite extensive follow-up efforts, no contemporaneous gravitational wave or radio emissions were detected. The lack of radio emission sets stringent upper limits on possible radio luminosity. Constraints from our analysis show no fast radio bursts (FRBs) associated with two MGFs. X-ray observations conducted post-burst by Swift/XRT and XMM/Newton provided additional data, though no persistent counterparts were identified. Our study underscores the importance of coordinated multi-wavelength follow-up and highlights the potential of MGFs to enhance our understanding of short GRBs and magnetar activities in the cosmos. Current MGF identification and follow-up implementation are insufficient for detecting expected counterparts; however, improvements in these areas may allow for the recovery of follow-up signals with existing instruments. Future advancements in observational technologies and methodologies will be crucial in furthering these studies.
GRB 221009A: the B.O.A.T Burst that Shines in Gamma Rays
(2024-09-06) Axelsson, M.; Ajello, M.; Arimoto, M.; Baldini, L.; Ballet, J.; Baring, M. G.; Bartolini, C.; Bastieri, D.; Gonzalez, J. Becerra; Bellazzini, R.; Berenji, B.; Bissaldi, E.; Blandford, R. D.; Bonino, R.; Bruel, P.; Buson, S.; Cameron, R. A.; Caputo, R.; Caraveo, P. A.; Cavazzuti, E.; Cheung, C. C.; Chiaro, G.; Cibrario, N.; Ciprini, S.; Cozzolongo, G.; Orestano, P. Cristarella; Crnogorcevic, M.; Cuoco, A.; Cutini, S.; D'Ammando, F.; De Gaetano, S.; Di Lalla, N.; Dinesh, A.; Di Tria, R.; Di Venere, L.; Domínguez, A.; Fegan, S. J.; Ferrara, E. C.; Fiori, A.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Galanti, G.; Gargano, F.; Gasbarra, C.; Germani, S.; Giacchino, F.; Giglietto, N.; Giliberti, M.; Gill, R.; Giordano, F.; Giroletti, M.; Granot, J.; Green, D.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hashizume, M.; Hays, E.; Hewitt, J. W.; Horan, D.; Kayanoki, T.; Kuss, M.; Laviron, A.; Li, J.; Liodakis, I.; Longo, F.; Loparco, F.; Lorusso, L.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Maldera, S.; Malyshev, D.; Manfreda, A.; Martí-Devesa, G.; Martinelli, R.; Castellanos, I. Martinez; Mazziotta, M. N.; McEnery, J. E.; Mereu, I.; Meyer, M.; Michelson, P. F.; Mirabal, Nestor; Mitthumsiri, W.; Mizuno, T.; Monti-Guarnieri, P.; Monzani, M. E.; Morishita, T.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Niwa, R.; Omodei, N.; Orienti, M.; Orlando, E.; Paneque, D.; Panzarini, G.; Persic, M.; Pesce-Rollins, M.; Petrosian, V.; Pillera, R.; Piron, F.; Porter, T. A.; Principe, G.; Racusin, J. L.; Rainò, S.; Rando, R.; Rani, Bindu; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Ryde, F.; Sánchez-Conde, M.; Parkinson, P. M. Saz; Serini, D.; Sgrò, C.; Sharma, Vidushi; Siskind, E. J.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Tak, D.; Thayer, J. B.; Torres, D. F.; Janeth; Zaharijas, G.; Lesage, S.; Briggs, M. S.; Burns, E.; Bala, S.; Bhat, P. N.; Cleveland, W. H.; Dalessi, S.; de Barra, C.; Gibby, M.; Giles, M. M.; Hamburg, R.; Hristov, B. A.; Hui, C. M.; Kocevski, D.; Mailyan, B.; Malacaria, C.; McBreen, S.; Poolakkil, S.; Roberts, O. J.; Scotton, L.; Veres, P.; von Kienlin, A.; Wilson-Hodge, C. A.; Wood, J.
We present a complete analysis of Fermi Large Area Telescope (LAT) data of GRB 221009A, the brightest Gamma-Ray Burst (GRB) ever detected. The burst emission above 30 MeV detected by the LAT preceded by 1 s the low-energy (< 10 MeV) pulse that triggered the Fermi Gamma-Ray Burst Monitor (GBM), as has been observed in other GRBs. The prompt phase of GRB 221009A lasted a few hundred seconds. It was so bright that we identify a Bad Time Interval (BTI) of 64 seconds caused by the extremely high flux of hard X-rays and soft gamma rays, during which the event reconstruction efficiency was poor and the dead time fraction quite high. The late-time emission decayed as a power law, but the extrapolation of the late-time emission during the first 450 seconds suggests that the afterglow started during the prompt emission. We also found that high-energy events observed by the LAT are incompatible with synchrotron origin, and, during the prompt emission, are more likely related to an extra component identified as synchrotron self-Compton (SSC). A remarkable 400 GeV photon, detected by the LAT 33 ks after the GBM trigger and directionally consistent with the location of GRB 221009A, is hard to explain as a product of SSC or TeV electromagnetic cascades, and the process responsible for its origin is uncertain. Because of its proximity and energetic nature, GRB 221009A is an extremely rare event.
The External Heating of Dust in a Homogeneous Spherical Shell
(2024-09-10) Dwek, Eli; Arendt, Richard
We present a procedure for calculating the heating of, and the infrared emission from, dust in a homogeneous spherical shell surrounded by a spherically symmetric source of radiation. The results are applicable to newly formed dust either in supernova ejecta or in the circumstellar medium that has been swept up by the expanding shock wave. They can also be applied to the heating and IR emission from dust in clumps or clouds embedded in a homogeneous radiation field.
TOI-5005 b: A super-Neptune in the savanna near the ridge
(2024-09-26) Castro-González, A.; Lillo-Box, J.; Armstrong, D. J.; Acuña, L.; Aguichine, A.; Bourrier, V.; Gandhi, S.; Sousa, S. G.; Delgado-Mena, E.; Moya, A.; Adibekyan, V.; Correia, A. C. M.; Barrado, D.; Damasso, M.; Winn, J. N.; Santos, N. C.; Barkaoui, K.; Barros, S. C. C.; Benkhaldoun, Z.; Bouchy, F.; Briceño, C.; Caldwell, D. A.; Collins, K. A.; Essack, Z.; Ghachoui, M.; Gillon, M.; Hounsell, Rebekah; Jehin, E.; Jenkins, J. M.; Keniger, M. a F.; Law, N.; Mann, A. W.; Nielsen, L. D.; Pozuelos, F. J.; Schanche, N.; Seager, S.; Tan, T.-G.; Timmermans, M.; Villaseñor, J.; Watkins, C. N.; Ziegler, C.
The Neptunian desert and savanna have been recently found to be separated by a ridge, an overdensity of planets in the ≃3-5 days period range. These features are thought to be shaped by dynamical and atmospheric processes. However, their relative roles are not yet well understood. We intend to confirm and characterise the super-Neptune TESS candidate TOI-5005.01, which orbits a moderately bright (V = 11.8) solar-type star (G2 V) with an orbital period of 6.3 days. We confirm TOI-5005 b to be a transiting super-Neptune with a radius of Rₚ = 6.25 ± 0.24 R⊕ (Rₚ = 0.558 ± 0.021 Rⱼ) and a mass of Mₚ = 32.7 ± 5.9 M⊕ (Mₚ = 0.103 ± 0.018 Mⱼ), which corresponds to a mean density of ρₚ = $0.74 ± 0.16 g cm⁻³. Our internal structure modelling indicates that the overall metal mass fraction is well constrained to a value slightly lower than that of Neptune and Uranus (Zₚₗₐₙₑₜ = 0.76⁺⁰.⁰⁴₋₀.₁₁). We also estimated the present-day atmospheric mass-loss rate of TOI-5005 b but found contrasting predictions depending on the choice of photoevaporation model. At a population level, we find statistical evidence (p-value = 0.0092⁺⁰.⁰¹⁸⁴₋₀.₀₀₆₆) that planets in the savanna such as TOI-5005 b tend to show lower densities than planets in the ridge, with a dividing line around 1 g cm⁻³, which supports the hypothesis of different evolutionary pathways populating both regimes. TOI-5005 b is located in a key region of the period-radius space to study the transition between the Neptunian ridge and the savanna. It orbits the brightest star of all such planets, which makes it a target of interest for atmospheric and orbital architecture observations that will bring a clearer picture of its overall evolution.
Time-Domain And MultiMessenger Astrophysics Communications Science Analysis Group Report
(2024-07) Kennea, Jamie A.; Racusin, Judith L.; Burns, Eric; Grefenstettte, Brian W.; Hounsell, Rebekah; Hui, C. Michelle; Kocevski, Daniel; Lazio, T. Joseph W.; Lesage, Stephen
A Low-Viscosity Lower Lunar Mantle Implied by Measured Monthly and Yearly Tides
(Wiley, 2024-09-14) Goossens, Sander; Matsuyama, Isamu; Cascioli, Gael; Mazarico, Erwan
The Moon's frequency-dependent tidal response, expressed as temporal variations in its gravity field through the Love number k₂ and as dissipation through the quality factor Q, provides information about its interior structure. Lunar laser ranging has provided measurements for Q, but so far no frequency-dependent values for k₂ have been determined. We provide the first spacecraft measurements of k₂ and Q at two frequencies, monthly and yearly, from an analysis of Gravity Recovery and Interior Laboratory and Lunar Reconnaissance Orbiter radio tracking data. Interior modeling indicates that these values can be matched only with a low-viscosity zone at the base of the lunar mantle, even when using complex rheological laws to model the mantle's response. The existence of this zone has profound implications for the Moon's thermal state and evolution.
The symbiotic recurrent nova V745 Sco at radio wavelengths
(Oxford University Press, 2024-09-06) Molina, Isabella; Chomiuk, Laura; Linford, Justin D.; Aydi, Elias; Mioduszewski, Amy J.; Mukai, Koji; Sokolovsky, Kirill V.; Strader, Jay; Craig, Peter; Dong, Dillon; Harris, Chelsea E.; Nyamai, Miriam M.; Rupen, Michael P.; Sokoloski, Jennifer L.; Walter, Frederick M.; Weston, Jennifer H. S.; Williams, Montana N.
V745 Sco is a Galactic symbiotic recurrent nova with nova eruptions in 1937, 1989, and 2014. We study the behaviour of V745 Sco at radio wavelengths (0.6–37 GHz), covering both its 1989 and 2014 eruptions and informed by optical, X-ray, and γ -ray data. The radio light curves are synchrotron-dominated. Surprisingly, compared to expectations for synchrotron emission from explosive transients such as radio supernovae, the light curves spanning 0.6–37 GHz all peak around the same time (∼18–26 d after eruption) and with similar flux densities (5–9 mJy). We model the synchrotron light curves as interaction of the nova ejecta with the red giant wind, but find that simple spherically symmetric models with wind-like circumstellar material (CSM) cannot explain the radio light curve. Instead, we conclude that the shock suddenly breaks out of a dense CSM absorbing screen around 20 d after eruption, and then expands into a relatively low-density wind (Mout ≈ 10⁻⁹–10⁻⁸ M yr⁻¹ for vw = 10 km s⁻¹) out to ∼1 yr post-eruption. The dense, close-in CSM may be an equatorial density enhancement or a more spherical red giant wind with M˙ᵢₙ ≈ [5–10] × 10⁻⁷ M yr⁻¹, truncated beyond several ×10¹⁴ cm. The outer lower-density CSM would not be visible in typical radio observations of Type Ia supernovae: V745 Sco cannot be ruled out as a Type Ia progenitor based on CSM constraints alone. Complementary constraints from the free–free radio optical depth and the synchrotron luminosity imply the shock is efficient at accelerating relativistic electrons and amplifying magnetic fields, with e and B ≈ 0.01–0.1.
Toward 2D Dynamo Models Calibrated by Global 3D Relativistic Accretion Disk Simulations
(2024-09-04) Duez, Matthew D.; Cadenhead, Courtney L.; Etienne, Zachariah B.; Kelly, Bernard; Werneck, Leonardo R.
Two-dimensional models assuming axisymmetry are an economical way to explore the long-term evolution of black hole accretion disks, but they are only realistic if the feedback of the nonaxisymmetric turbulence on the mean momentum and magnetic fields is incorporated. Dynamo terms added to the 2D induction equation should be calibrated to 3D MHD simulations. For generality, the dynamo tensors should be calibrated as functions of local variables rather than explicit functions of spatial coordinates in a particular basis. In this paper, we study the feedback of non-axisymmetric features on the 2D mean fields using a global 3D, relativistic, Cartesian simulation from the IllinoisGRMHD code. We introduce new methods for estimating overall dynamo alpha and turbulent diffusivity effects as well as measures of the dominance of non-axisymmetric components of energies and fluxes within the disk interior. We attempt closure models of the dynamo EMF using least squares fitting, considering both models where coefficient tensors are functions of space and more global, covariant models. None of these models are judged satisfactory, but we are able to draw conclusions on what sorts of generalizations are and are not promising.

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