pith. machine review for the scientific record. sign in

arxiv: 2605.02639 · v1 · submitted 2026-05-04 · 🌌 astro-ph.HE

Recognition: 2 theorem links

ENGRAVE follow-up of a type IIb supernova spatially coincident with the sub-threshold gravitational wave trigger S250818k

K. Ackley , M. T. Botticella , A. Boye , M. Branchesi , G. Bruni , E. Cappellaro , S. Chaty , T.-W. Chen
show 48 more authors
F. D'Ammando V. D'Elia F. F. De Pasquale Dimple R. A. J. Eyles-Ferris M. Fraser G. Gianfagna J. H. Gillanders G. Greco M. Gromadzki C. P. Guti\`errez A. Hajela L. Izzo P. G. Jonker S. Kobayashi R. Kotak G. P. Lamb G. Leloudas A. J. Levan J. D. Lyman K. Maguire A. Martin-Carrillo A. Melandri M. J. Micha{\l}owski S. R. Oates F. Onori B. Patricelli E. Pian G. Pignata S. Piranomonte L. Piro Q. Pognan M. L. Pumo A. Rossi R. Roy A. Saccardi O. S. Salafia R. Salvaterra N. Sarin S. Schulze S. J. Smartt R. L. C. Starling D. Steeghs N. R. Tanvir A. L. Thakur S. D. Vergani S. Yi D. R. Young
Authors on Pith no claims yet

Pith reviewed 2026-05-08 17:43 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords type IIb supernovagravitational wave triggerkilonova searchshock coolingelectromagnetic counterparttransientsupernova classification
0
0 comments X

The pith

Follow-up shows SN2025ulz is a type IIb supernova unrelated to the sub-threshold GW trigger S250818k

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents extensive multi-wavelength observations of the transient SN2025ulz, initially noted for its spatial and temporal overlap with a candidate gravitational wave event. Spectra and light-curve data establish the source as a type IIb supernova whose early evolution is dominated by a shock-cooling tail. This classification demonstrates that the apparent coincidence with the GW alert is accidental rather than causal. The work further identifies shock-cooling tails from type IIb supernovae as a frequent source of contamination in searches for kilonovae produced by neutron-star mergers. Readers care because accurate rejection of such contaminants is required to confirm true electromagnetic counterparts to gravitational-wave detections.

Core claim

The central claim is that the transient SN2025ulz is a type IIb supernova on the basis of its spectral features and photometric evolution, that it bears no relation to the sub-threshold gravitational-wave trigger S250818k, and that shock-cooling tails associated with type IIb supernovae constitute one of the most prominent contaminants in kilonova searches.

What carries the argument

The multi-wavelength observational campaign that combines spectroscopy and light-curve monitoring to classify the transient and separate its evolution from any potential kilonova signal.

If this is right

  • The transient is unrelated to the candidate gravitational-wave event.
  • Shock-cooling tails from type IIb supernovae must be treated as a major background in future kilonova searches.
  • Prompt spectroscopic classification can reliably distinguish such supernovae from true merger counterparts.
  • Large-area follow-up campaigns will continue to encounter these transients as false positives.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Search pipelines could incorporate early color and decay-rate cuts tuned to shock-cooling signatures to reduce the rate of spectroscopic follow-up on false candidates.
  • The same classification methods may be applied to other sub-threshold GW alerts to quantify the expected contamination fraction.
  • Rapid public release of spectra for similar fast-fading transients would help the community build a library of reference light curves.

Load-bearing premise

The observed light curve and spectra are produced entirely by a standard type IIb supernova shock-cooling tail and the spatial-temporal overlap with the gravitational-wave alert is purely accidental.

What would settle it

A confirmed gravitational-wave detection from S250818k with binary-neutron-star parameters, sky location, and timing that match those of SN2025ulz would falsify the claim of no physical connection.

Figures

Figures reproduced from arXiv: 2605.02639 by A. Boye, A. Hajela, A. J. Levan, A. L. Thakur, A. Martin-Carrillo, A. Melandri, A. Rossi, A. Saccardi, B. Patricelli, C. P. Guti\`errez, Dimple, D. R. Young, D. Steeghs, E. Cappellaro, E. Pian, F. D'Ammando, F. F. De Pasquale, F. Onori, G. Bruni, G. Gianfagna, G. Greco, G. Leloudas, G. Pignata, G. P. Lamb, J. D. Lyman, J. H. Gillanders, K. Ackley, K. Maguire, L. Izzo, L. Piro, M. Branchesi, M. Fraser, M. Gromadzki, M. J. Micha{\l}owski, M. L. Pumo, M. T. Botticella, N. R. Tanvir, N. Sarin, O. S. Salafia, P. G. Jonker, Q. Pognan, R. A. J. Eyles-Ferris, R. Kotak, R. L. C. Starling, R. Roy, R. Salvaterra, S. Chaty, S. D. Vergani, S. J. Smartt, S. Kobayashi, S. Piranomonte, S. R. Oates, S. Schulze, S. Yi, T.-W. Chen, V. D'Elia.

Figure 2
Figure 2. Figure 2: VLT/HAWK-I difference imaging. Similar to view at source ↗
Figure 3
Figure 3. Figure 3: HST/WFC3 F606W imaging. Both panels show images of the same sky position and with the same scale, with the SN 2025ulz position indicated with tick marks. The image in the left-hand panel was taken on 26 August, while that in the right￾hand panel is from 30 December. The disparity in quality be￾tween the two images is due to the different exposure times view at source ↗
Figure 4
Figure 4. Figure 4: The VLT/X-shooter spectrum of SN 2025ulz taken on the night of Aug 20, plotted in the rest frame. The upper panel shows the UVB and VIS arms, while the lower panel shows the NIR arm. In both cases, the reduced spectrum at the native pixel sampling is shown in light grey, the black line is after the spectrum is averaged and rebinned to 10 sampling. Red lines mark the position of Hα and Hβ, while the residua… view at source ↗
Figure 5
Figure 5. Figure 5: Left: The host of SN 2025ulz observed with MUSE on the night of Aug 24. The blue aperture marks the spaxels for ex￾tracting the transient spectrum at the location of SN 2025ulz. The other regions were used to estimate and remove the host galaxy background. Right: Spectra of SN 2025ulz for different extractions and host galaxy removal, including a circular annulus and the background apertures shown on the l… view at source ↗
Figure 6
Figure 6. Figure 6: Cleaned VLA S-band image using Briggs weighting of view at source ↗
Figure 7
Figure 7. Figure 7: Multi-band light curves and colour evolution of SN 2025ulz. view at source ↗
Figure 9
Figure 9. Figure 9: Gaussian jet afterglow model light curves at 3 GHz. view at source ↗
Figure 8
Figure 8. Figure 8: Comparisons of the MUSE spectra obtained on Aug 24 view at source ↗
Figure 10
Figure 10. Figure 10: 5 GHz luminosity density of the radio emission view at source ↗
Figure 11
Figure 11. Figure 11: Left-hand panel: fit to the first four days of photometry post GW trigger of SN 2025ulz with two-component KN models. Solid lines refer to the KN plus cocoon cooling model, while the dashed lines are for the KN-only model (see text). The shaded bands contain, at each fixed time, the 68% credible interval of the posterior samples in the g band (green), r band (orange, offset by +2.5 mag for presentation pu… view at source ↗
read the original abstract

The candidate gravitational wave (GW) event S250818k was one of only three non-retracted LIGO-Virgo-KAGRA public alerts issued during the fourth observing run of the network (O4) with a binary neutron star (BNS) merger classification probability exceeding one percent. This triggered a prompt search for a potential electromagnetic (EM) counterpart in the large localisation error region (949 deg$^2$ projected in the sky at 90% credible level). The transient SN2025ulz, discovered by the Zwicky Transient Facility (ZTF) during the search, attracted a great deal of attention due to a potential spatial and temporal coincidence, and due to its initial fast decay and featureless spectrum. Here, we report on the follow up of this transient by the Electromagnetic counterparts of gravitational wave sources at the Very Large Telescope (ENGRAVE) Collaboration. We conducted an extensive multi-wavelength observational campaign, which led to the spectral classification of the transient as a type IIb supernova (SN), indicating that it is unrelated to the candidate GW event. In this article, we describe our observing strategies, data reduction, and interpretation. All of our results confirm and strengthen our classification of the source, and also show that shock cooling tails associated with type IIb SNe are one of the most prominent contaminants in kilonova searches.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 2 minor

Summary. The manuscript reports the ENGRAVE collaboration's multi-wavelength follow-up of the optical transient SN2025ulz, discovered by ZTF within the 949 deg² localization of the sub-threshold GW candidate S250818k. Using VLT spectroscopy and photometry, the authors classify SN2025ulz as a type IIb supernova on the basis of emerging H and He spectral features together with light-curve evolution matching published shock-cooling templates. They conclude that the transient is unrelated to S250818k and that type IIb shock-cooling tails constitute one of the most prominent contaminants in kilonova searches.

Significance. If the classification holds, the result is significant because it supplies a well-documented, real-time example of a common false-positive contaminant in GW EM counterpart searches during O4. The direct spectroscopic and photometric match to standard type IIb templates, obtained without post-hoc cuts, provides concrete evidence that rapid spectroscopic classification is essential in large error regions and strengthens the broader literature on kilonova search strategies.

minor comments (2)
  1. [Abstract] Abstract: the informal phrase 'attracted a great deal of attention' could be replaced with a more neutral statement such as 'prompted extensive follow-up observations by multiple groups'.
  2. [Observing strategies and data reduction] Observing strategies and data reduction: explicitly list the specific VLT instrument modes, exposure times, and reduction pipelines (e.g., ESO Reflex or custom scripts) used for each epoch so that the classification can be independently reproduced.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive assessment of the manuscript, accurate summary of the key results, and recommendation to accept. We are pleased that the significance of documenting a type IIb supernova shock-cooling tail as a prominent contaminant in kilonova searches has been recognized.

Circularity Check

0 steps flagged

No significant circularity in observational classification

full rationale

The paper reports an observational classification of SN2025ulz as a type IIb supernova based on spectral features (H and He lines) and light-curve evolution, using standard reduction pipelines and external template libraries. No equations or derivations are present that reduce to self-defined inputs, fitted parameters renamed as predictions, or load-bearing self-citations. The conclusion of unrelatedness to the GW trigger follows directly from mismatch with expected kilonova signatures, and the contaminant statement is contextual inference rather than a closed-loop claim. The work is self-contained against external benchmarks for supernova classification.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The work rests on standard supernova classification criteria and the assumption that the observed coincidence is accidental; no new free parameters, ad-hoc axioms, or invented entities are introduced.

axioms (1)
  • domain assumption Type IIb supernovae are identified by the presence of hydrogen and helium lines together with a characteristic early light-curve decline due to shock cooling
    The classification directly invokes established spectral and photometric templates for type IIb events.

pith-pipeline@v0.9.0 · 5879 in / 1222 out tokens · 77434 ms · 2026-05-08T17:43:02.490721+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

170 extracted references · 104 canonical work pages · 1 internal anchor

  1. [1]

    arXiv e-prints , keywords =

    AT2025ulz and S250818k: Deep X-ray and radio limits on off-axis afterglow emission and prospects for future discovery. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.23728 , archivePrefix =. 2510.23728 , primaryClass =

    work page doi:10.48550/arxiv.2510.23728

  2. [2]

    J., Busmann, M., Koehn, H., et al

    AT2025ulz and S250818k: Investigating early time observations of a subsolar mass gravitational-wave binary neutron star merger candidate. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.24620 , archivePrefix =. 2510.24620 , primaryClass =

    work page doi:10.48550/arxiv.2510.24620

  3. [3]

    P., & Kobayashi, S

    Electromagnetic counterparts to structured jets from gravitational wave detected mergers. , keywords =. doi:10.1093/mnras/stx2345 , archivePrefix =. 1706.03000 , primaryClass =

    work page doi:10.1093/mnras/stx2345

  4. [4]

    J., Palmese, A., O’Connor, B., et al

    AT2025ulz and S250818k: Leveraging DESI spectroscopy in the hunt for a kilonova associated with a sub-solar mass gravitational wave candidate. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.23723 , archivePrefix =. 2510.23723 , primaryClass =

    work page doi:10.48550/arxiv.2510.23723

  5. [5]

    arXiv e-prints , keywords =

    AT2025ulz and S250818k: zooming in with the Hubble Space Telescope. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.18854 , archivePrefix =. 2510.18854 , primaryClass =

    work page doi:10.48550/arxiv.2510.18854

  6. [6]

    Nature , author =

    A lanthanide-rich kilonova in the aftermath of a long gamma-ray burst. , keywords =. doi:10.1038/s41586-023-06979-5 , archivePrefix =. 2308.00638 , primaryClass =

    work page doi:10.1038/s41586-023-06979-5

  7. [7]

    arXiv e-prints , keywords =

    Optimizing Kilonova Searches: A Case Study of the Type IIb SN 2025ulz in the Localization Volume of the Low-Significance Gravitational Wave Event S250818k. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.17104 , archivePrefix =. 2510.17104 , primaryClass =

    work page doi:10.48550/arxiv.2510.17104

  8. [8]

    M., Ahumada, T., Stein, R., et al

    ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate Superkilonova from a Sub-threshold Sub-Solar Gravitational Wave Trigger. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.23732 , archivePrefix =. 2510.23732 , primaryClass =

    work page doi:10.48550/arxiv.2510.23732

  9. [9]

    arXiv e-prints , keywords =

    Heavy element nucleosynthesis associated with a gamma-ray burst. arXiv e-prints , keywords =. doi:10.48550/arXiv.2308.00633 , archivePrefix =. 2308.00633 , primaryClass =

    work page doi:10.48550/arxiv.2308.00633

  10. [10]

    H., Huber, M

    Pan-STARRS Follow-up of the Gravitational-wave Event S250818k and the Light Curve of SN2025ulz. , keywords =. doi:10.3847/2041-8213/ae2125 , archivePrefix =. 2510.01142 , primaryClass =

    work page doi:10.3847/2041-8213/ae2125 2041

  11. [11]

    H., & Smartt, S

    Analysis of the JWST spectra of the kilonova AT 2023vfi accompanying GRB 230307A. , keywords =. doi:10.1093/mnras/staf287 , archivePrefix =. 2408.11093 , primaryClass =

    work page doi:10.1093/mnras/staf287

  12. [12]

    GRB Coordinates Network , year = 2025, month = sep, volume =

    LIGO/Virgo/KAGRA S250818k: HCT optical follow-up. GRB Coordinates Network , year = 2025, month = sep, volume =

    2025

  13. [13]

    GRB Coordinates Network , year = 2025, month = sep, volume =

    LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data. GRB Coordinates Network , year = 2025, month = sep, volume =

    2025

  14. [14]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  15. [15]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: uGMRT 1.3 GHz observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  16. [16]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: SAO RAS BTA z-band observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  17. [17]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: GTC/OSIRIS Confirmation of Rebrightening of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  18. [18]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: VLA upper limits on AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  19. [19]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: nature of the AT2025ulz/ZTF25abjmnnps OT. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  20. [20]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Pan-STARRS imaging confirms re-brightening of SN2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  21. [21]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Continued Keck I LRIS spectroscopy of ZTF25abjmnps (AT2025ulz). GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  22. [22]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: FTW Observations Show Continued Reddening of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  23. [23]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  24. [24]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: ENGRAVE observations of SN 2025ulz as a type II supernova. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  25. [25]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Swift Observations of AT 2025ulz - Second Epoch. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  26. [26]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: CFH/MegaCam follow-up observation for AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  27. [27]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: COLIBR \'I confirmation of rebrightening of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  28. [28]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Rebrightening detected with Gemini/GMOS. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  29. [29]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: HST nIR detection of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  30. [30]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: J-GEM follow-up observation for AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  31. [31]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: PRIME nIR observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  32. [32]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: JinShan optical observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  33. [33]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: GTC/OSIRIS Optical Detection of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  34. [34]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/Kagra S250818k: STEP/T80N upper limits on 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  35. [35]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: 3 GHz MeerKAT observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  36. [36]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Pan-STARRS coverage of the skymap and candidate counterparts. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  37. [37]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: NOT optical observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  38. [38]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: GRAWITA TNG NIR observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  39. [39]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Continued fading and reddening of AT2025ulz from Keck/LRIS imaging observations. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  40. [40]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: ENGRAVE observations of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  41. [41]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k : Tautenburg observations, upper limits. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  42. [42]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: GOTO counterpart search and upper limits. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  43. [43]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: 10 GHz VLA observations of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  44. [44]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: WFST pre-discovery limits and follow-up observations of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  45. [45]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: EP/FXT observation of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  46. [46]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: WINTER J-band observations of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  47. [47]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Pan-STARRS grizy-band imaging and photometry of AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  48. [48]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Swift observations of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  49. [49]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Multi-band Gemini GMOS Detections. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  50. [50]

    arXiv e-prints , keywords =

    SNID-SAGE: A Modern Framework for Interactive Supernova Classification and Spectral Analysis. arXiv e-prints , keywords =

  51. [51]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: ATLAS pre-discovery limits for AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  52. [52]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: AstroSat CZTI non-detection and upper limits. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  53. [53]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  54. [54]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Updated Sky localization and EM Bright Classification. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  55. [55]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Pan-STARRS pre-detection limits for AT2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  56. [56]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Properties of the low-significance GW compact binary merger candidate potentially associated with AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  57. [57]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Keck I LRIS spectroscopy of ZTF25abjmnps (AT2025ulz). GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  58. [58]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: FTW Fast reddening of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  59. [59]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: FTW optical and NIR observations of AT 2025ulz. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  60. [60]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Candidates from the Zwicky Transient Facility. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  61. [61]

    GRB Coordinates Network , year = 2025, month = aug, volume =

    LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations. GRB Coordinates Network , year = 2025, month = aug, volume =

    2025

  62. [62]

    , keywords =

    Radio Evolution of a Type IIb Supernova SN 2016gkg. , keywords =. doi:10.3847/1538-4357/ac7c1e , archivePrefix =. 2206.12103 , primaryClass =

    work page doi:10.3847/1538-4357/ac7c1e

  63. [63]

    W., Williams, C

    Long-Term Radio Monitoring of SN 1993J. , keywords =. doi:10.1086/523258 , archivePrefix =. 0709.1136 , primaryClass =

    work page doi:10.1086/523258

  64. [64]

    Soderberg, A. M. and Chevalier, R. A. and Kulkarni, S. R. and Frail, D. A. , title =. 2006 , month =. doi:10.1086/507571 , url =

    work page doi:10.1086/507571 2006

  65. [65]

    R., Nelemans, G., & Steeghs, D

    Ryder, Stuart D. and Sadler, Elaine M. and Subrahmanyan, Ravi and Weiler, Kurt W. and Panagia, Nino and Stockdale, Christopher , title =. Monthly Notices of the Royal Astronomical Society , volume =. 2004 , month =. doi:10.1111/j.1365-2966.2004.07589.x , url =

    work page doi:10.1111/j.1365-2966.2004.07589.x 2004

  66. [66]

    Bietenholz, M. F. and Bartel, N. and Argo, M. and Dua, R. and Ryder, S. and Soderberg, A. , title =. 2021 , month =. doi:10.3847/1538-4357/abccd9 , url =

    work page doi:10.3847/1538-4357/abccd9 2021

  67. [67]

    M., et al

    Kamble, Atish and Margutti, Raffaella and Soderberg, Alicia M. and Chakraborti, Sayan and Fransson, Claes and Chevalier, Roger and Powell, Diana and Milisavljevic, Dan and Parrent, Jerod and Bietenholz, Michael , title =. 2016 , month =. doi:10.3847/0004-637X/818/2/111 , url =

    work page doi:10.3847/0004-637x/818/2/111 2016

  68. [68]

    Krauss, M. I. and Soderberg, A. M. and Chomiuk, L. and Zauderer, B. A. and Brunthaler, A. and Bietenholz, M. F. and Chevalier, R. A. and Fransson, C. and Rupen, M. , title =. 2012 , month =. doi:10.1088/2041-8205/750/2/L40 , url =

    work page doi:10.1088/2041-8205/750/2/l40 2012

  69. [69]

    and Pignata, G

    Bufano, F. and Pignata, G. and Bersten, M. and Mazzali, P. A. and Ryder, S. D. and Margutti, R. and Milisavljevic, D. and Morelli, L. and Benetti, S. and Cappellaro, E. and Gonzalez-Gaitan, S. and Romero-Cañizales, C. and Stritzinger, M. and Walker, E. S. and Anderson, J. P. and Contreras, C. and de Jaeger, T. and Förster, F. and Gutierrez, C. and Hamuy, ...

    work page doi:10.1093/mnras/stu065 2014

  70. [70]

    and Williams, Christopher L

    Stockdale, Christopher J. and Williams, Christopher L. and Weiler, Kurt W. and Panagia, Nino and Sramek, Richard A. and Van Dyk, Schuyler D. and Kelley, Matthew T. , title =. 2007 , month =. doi:10.1086/522584 , url =

    work page doi:10.1086/522584 2007

  71. [71]

    and Herrero-Illana, R

    Romero-Cañizales, C. and Herrero-Illana, R. and Pérez-Torres, M. A. and Alberdi, A. and Kankare, E. and Bauer, F. E. and Ryder, S. D. and Mattila, S. and Conway, J. E. and Beswick, R. J. and Muxlow, T. W. B. , title =. Monthly Notices of the Royal Astronomical Society , volume =. 2014 , month =. doi:10.1093/mnras/stu430 , url =

    work page doi:10.1093/mnras/stu430 2014

  72. [72]

    oxkat: Semi-automated imaging of MeerKAT observations

  73. [73]

    , archivePrefix = "arXiv", eprint =

    WSCLEAN: an implementation of a fast, generic wide-field imager for radio astronomy. , keywords =. doi:10.1093/mnras/stu1368 , archivePrefix =. 1407.1943 , primaryClass =

    work page doi:10.1093/mnras/stu1368 1943

  74. [74]

    , keywords =

    An optimized algorithm for multiscale wideband deconvolution of radio astronomical images. , keywords =. doi:10.1093/mnras/stx1547 , archivePrefix =. 1706.06786 , primaryClass =

    work page doi:10.1093/mnras/stx1547

  75. [75]

    Astronomical Data Analysis Software and Systems XVI , year = 2007, editor =

    CASA Architecture and Applications. Astronomical Data Analysis Software and Systems XVI , year = 2007, editor =

    2007

  76. [76]

    PyBDSF: Python Blob Detection and Source Finder

  77. [77]

    2024, MNRAS, 528, 2600, doi: 10.1093/mnras/stae198

    Gianfagna, Giulia and Piro, Luigi and Pannarale, Francesco and Van Eerten, Hendrik and Ricci, Fulvio and Ryan, Geoffrey , title =. Monthly Notices of the Royal Astronomical Society , volume =. 2024 , month =. doi:10.1093/mnras/stae198 , url =

    work page doi:10.1093/mnras/stae198 2024

  78. [78]

    2024, ApJ, 975, 131, doi: 10.3847/1538-4357/ad6a14

    Modeling of Long-term Afterglow Counterparts to Gravitational Wave Events: The Full View of GRB 170817A. , keywords =. doi:10.3847/1538-4357/ad6a14 , archivePrefix =. 2310.02328 , primaryClass =

    work page doi:10.3847/1538-4357/ad6a14

  79. [79]

    2019, Monthly Notices of the Royal Astronomical Society, doi: 10.1093/mnras/stz2248

    Troja, E and van Eerten, H and Ryan, G and Ricci, R and Burgess, J M and Wieringa, M H and Piro, L and Cenko, S B and Sakamoto, T , title =. Monthly Notices of the Royal Astronomical Society , volume =. 2019 , month =. doi:10.1093/mnras/stz2248 , url =

    work page doi:10.1093/mnras/stz2248 2019

  80. [80]

    S., et al

    Hajela, A. and Margutti, R. and Bright, J. S. and Alexander, K. D. and Metzger, B. D. and Nedora, V. and Kathirgamaraju, A. and Margalit, B. and Radice, D. and Guidorzi, C. and Berger, E. and MacFadyen, A. and Giannios, D. and Chornock, R. and Heywood, I. and Sironi, L. and Gottlieb, O. and Coppejans, D. and Laskar, T. and Cendes, Y. and Duran, R. Barniol...

    work page doi:10.3847/2041-8213/ac504a 2022

Showing first 80 references.