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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"

28360 results found.

  1. EP Alert 261108.92: Global MASTER-Net observations report
  2. GRB 261108D: DECam optical detection of candidate afterglow
  3. GRB 261108D: PRIME near-infrared candidate
  4. EP261105A: Gemini-South/GMOS Optical Upper Limit
  5. GRB 261101A: SVOM/GRM observation
  6. EP Alert 261109.41: Global MASTER-Net observations report
  7. The EP-WXT trigger 01709322330 is likely a AGN
  8. EP261105a: Second EP-FXT follow-up observation
  9. GRB 261108C: SVOM/VT early optical upper limits
  10. GRB 261108C: LCO optical upper limits
  11. SVOM GRB261108.99: Global MASTER-Net observations report
  12. SVOM GRB261108.89: Global MASTER-Net observations report
  13. GRB 261108C: SVOM detection of a burst
  14. GRB 261108A: Fermi GBM Observation
  15. GRB 261108A: SVOM/C-GFT optical upper limit
  16. GRB 261108A: SVOM/VT optical upper limits
  17. Fermi trigger No 815809059: Global MASTER-Net observations report
  18. EP261105a: VLT/HAWK-I nIR detection
  19. GRB 261108A: LCO optical upper limits
  20. GRB 261108A: FRAM-Auger optical limits
  21. SVOM GRB261108.05: Global MASTER-Net observations report
  22. EP-WXT trigger 01709322272 : SVOM/C-GFT confirmation of a stellar flare
  23. EP Alert 261106.89: Global MASTER-Net observations report
  24. GRB 261029C: SVOM/GRM detection of a short burst
  25. EP-WXT trigger 01709322274: Ondrejov D50 detection of a likely stellar flare
  26. EP Alert 261106.58: Global MASTER-Net observations report
  27. EP261105a: PRIME near-infrared upper limit
  28. EP261105a: VLT/FORS2 optical detection
  29. EP Alert 261105.81: Global MASTER-Net observations report
  30. EP261105a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  31. EP261103a: refined WXT analysis and FXT follow-up observations
  32. GRB 261104A：EP-FXT follow-up observation
  33. EP261105a: Global MASTER-Net observations report
  34. GRB 261104A: DECam Detection of an Optical Counterpart Candidate
  35. GRB 261104A: SVOM/ECLAIRs refined analysis
  36. EP261105a: LCO optical upper limits
  37. EP261105a: SVOM/VT optical candidate
  38. IPN triangulation of GRB 261029C (short / bright)
  39. GRB 261103A: SVOM/C-GFT optical upper limit
  40. EP261105a: Einstein Probe detection of an X-ray transient
  41. GRB 261104A: LCO optical upper limits
  42. SVOM GRB261104.86: Global MASTER-Net observations report
  43. EP241208a: SVOM/ECLAIRs refined analysis
  44. GRB 261104A: SVOM detection of burst
  45. GRB 260924A: CrAO ZTSh optical observations
  46. EP261103a: NTT optical observation
  47. GRB 261029A : MITSuME Akeno optical afterglow detection
  48. EP261103a: SVOM/VT optical observation
  49. EP261103a: NOT optical counterpart candidate
  50. EP261103a: Einstein Probe detection of an X-ray transient
  51. GRB 261029A: VST/OmegaCAM detection of the optical afterglow at 3 days
  52. EP Alert 261103.85: Global MASTER-Net observations report
  53. GRB 261029A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  54. GRB 261103A: LCO optical upper limits
  55. EP Alert 261102.98: Global MASTER-Net observations report
  56. GRB 261029A: SAO RAS optical observations
  57. GRB 261102A: Fermi GBM Detection
  58. GRB 261101B: BALROG localization (Fermi Trigger 815240277 / GRB 261101651)
  59. GRB 261101B: Fermi GBM Final Real-time Localization
  60. EP261030a: EP-FXT follow-up observation
  61. EP261030a: GROWTH-India Telescope Upper Limit
  62. GRB 261101A: Fermi GBM Final Real-time Localization
  63. EP261030a: Global MASTER-Net observations report
  64. EP261030a: Einstein Probe detection of a fast X-ray transient
  65. GRB 261030A: Fermi GBM Detection
  66. Fermi GRB 261030B: Global MASTER-Net observations report
  67. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  68. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  69. GRB 261029A: Glowbug gamma-ray detection
  70. GRB 261024D: SVOM/GRM observation
  71. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  72. GRB 261029A : SVOM/GWAC-F60 observations
  73. EP Alert 261030.22: Global MASTER-Net observations report
  74. GRB 261029A: WFST optical observations
  75. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  76. GRB 261029A: Ondrejov D50 optical observations, possible rebrightening
  77. GRB 261029A: NuSTAR detection of bright prompt emission
  78. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  79. GRB 261029A: Fermi GBM Observation
  80. GRB 261029A: FRAM-ORM and FRAM-Auger optical afterglow light curve
  81. GRB261029A: Infrared fading detected with MDM/MIRAGE
  82. GRB 261029A: SVOM/VT optical observation
  83. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  84. GRB 261029A : AstroSat CZTI detection
  85. GRB 261029A: SVOM/C-GFT optical observations
  86. EP261010a: Xinglong optical follow-up
  87. GRB 261029A: EP-FXT follow-up observation
  88. GRB 261029A: LCO optical observations (correction to GCN 46082)
  89. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  90. GRB 261029A: LCO optical observations
  91. GRB261029A: Early infrared detection with MDM/MIRAGE
  92. GRB 261029A: KAIT optical observations
  93. GRB 261029A: TRT optical observations
  94. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  95. EP261025a: EP-FXT follow-up observations
  96. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  97. GRB 261021A: Glowbug gamma-ray detection
  98. GRB261026A: Infrared detection with MDM/MIRAGE
  99. GRB 261026A: SAO RAS optical observations
  100. EP Alert 261026.29: Global MASTER-Net observations report

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