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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

15387 results found.

  1. GRB 250910A: SVOM/ECLAIRs refined analysis
  2. LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
  3. SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
  4. SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
  5. SVOM/sb25091517: SVOM detection of an X-ray transient
  6. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  7. GRB 250912A: Swift-XRT observations
  8. GRB250912A: VLT/HAWK-I follow-up observations
  9. GRB 250912A: Fermi GBM Observation
  10. GRB 250911A: Insight-HXMT detection
  11. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  12. GRB 250912A: SVOM detection of a burst
  13. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  14. EP250911a: Upper limit from Fermi-GBM Observations
  15. GRB 250911A: GECAM-B detection
  16. GRB 250910B: SVOM/GRM observation
  17. GRB 250911A: MASTER optical counterpart observations
  18. EP250911a: Swift-XRT observations
  19. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  20. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  21. GRB 250909B: Insight-HXMT detection
  22. GRB 250909B: SVOM/GRM observation
  23. EP250911a: COLIBRÍ optical observations
  24. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  25. GRB 250903A: SVOM/ECLAIRs refined analysis
  26. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  27. GRB 250909B: AstroSat CZTI detection of a long burst
  28. EP250908C: GROND observation of the fading optical counterpart
  29. GRB 250909A: AstroSat CZTI detection
  30. GRB 250910A: SVOM detection of a faint burst
  31. EP250908b/EP#01709240653: Swift/UVOT Detection
  32. EP250908c: VLT/FORS2 optical counterpart identification
  33. GRB 250907A: GECAM-B detection
  34. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  35. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  36. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  37. EP250905a: Liverpool Telescope i-band upper limits
  38. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  39. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  40. EP250905a: FTW one optical and multiple NIR counterpart candidates
  41. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  42. GRB 250901A - SVOM/ECLAIRs refined analysis
  43. GRB250904A: Liverpool Telescope upper limits
  44. GRB 250903A: Swift/UVOT detection
  45. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  46. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  47. EP250827b: Gemini Spectroscopic Confirmation of AT2025wkm as a Ic-BL Supernova
  48. GRB 250902A: VZLUSAT-2 detection
  49. EP#01709201209: Swift-XRT observations
  50. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  51. GRB 250830C: VZLUSAT-2 detection
  52. GRB 250903A: EP-FXT counterpart detection
  53. GRB 250902A: GECAM-B detection
  54. GRB 250903A: LCO optical afterglow detection
  55. GRB 250903A: SVOM/VT optical confirmation with VHF data
  56. EP250903a: SVOM/VT optical confirmation
  57. Subject GRB 250903A: SVOM/MXT afterglow detection
  58. GRB 250902B: AstroSat CZTI detection
  59. GRB 250903A: SVOM detection of a burst
  60. EP 250827B: Detection of supernova counterpart by LCO.
  61. GRB 250902B: SVOM/GRM observation
  62. LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
  63. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  64. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  65. GRB 250902A: Fermi GBM Detection
  66. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  67. GRB 250830B: Swift-XRT afterglow detection
  68. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  69. GRB 250902A: SVOM/GRM observation
  70. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  71. GRB 250901A: EP-FXT follow-up observation
  72. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  73. LIGO/Virgo/KAGRA S250830bp: DECam GW-MMADS candidates
  74. EP250827b: Swift observations of AT 2025wkm
  75. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
  76. EP250827b: Gemini Spectroscopy of AT 2025wkm
  77. EP250827b: FTW Observations of AT 2025wkm
  78. GRB 250901A: SVOM detection of a burst
  79. GRB 250831B: SVOM/GRM observation
  80. GRB 250830C: Insight-HXMT detection
  81. EP250901a: Mephisto optical upper limits
  82. GRB 250830C: GECAM-B detection
  83. GRB 250830C: AstroSat CZTI detection of a long burst
  84. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  85. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 250831A (SVOM trigger sb25083102) is likely an outburst from star G 272-61
  87. GRB 250831A: Swift-XRT counterpart detection
  88. GRB 250831A: SVOM detection of a soft burst
  89. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  90. LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  91. GRB 250830B: Swift ToO observations
  92. EP-WXT trigger 01709200994: confirmation of a stellar flare by BOOTES-6
  93. EP250821a: SOAR observations
  94. EP250827a: very early ATLAS detections, starting 43 sec after the EP trigger
  95. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  96. GRB 250808B: SVOM detection of a burst through offline search
  97. EP250828a: Liverpool Telescope upper limits
  98. EP250828a: KAIT optical upper limit
  99. EP250828a: NOT optical counterpart confirmation
  100. EP250827a: STEP/T80S Confirmation of fading optical counterpart

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