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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.

Advanced Search Examples (click to copy):

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

32603 results found.

  1. GRB 251214B: UAFO optical upper limit
  2. GRB 251214B: VLT/X-shooter observations
  3. GRB 251213A: GRID-10B observation
  4. GRB 251214B: Swift-BAT refined analysis
  5. GRB 251202A: radio detection with the VLA
  6. EP251214b: Global MASTER-Net observations report
  7. EP251214b : Einstein Probe detection of a fast X-ray transient
  8. EP251214b : Einstein Probe detection of a fast X-ray transient
  9. GRB 251214B: AbAO optical observations
  10. GRB 251214B: LCO detection of the optical counterpart
  11. GRB 251209A: GECAM-B observation of a long burst
  12. GRB 251214D: GECAM-B observation of a long burst
  13. GRB 251214B: Fermi GBM Observation
  14. GRB 251209A: Insight-HXMT/HE detection
  15. GRB 251215A: Swift ToO observations
  16. EP251214b (EP trigger 01709250023): LCO optical limits
  17. GRID detection of GRB 251213A
  18. GRB 251203B: AbAO optical observations
  19. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  20. GRB 251214B: GECAM-B observation of a long burst
  21. GRB 251213A: SVOM/GRM observation
  22. EP251214a: KAIT optical upper limit
  23. GRB 251213A: AstroSat CZTI detection
  24. GRB 251214A: AstroSat CZTI detection
  25. GRB 251214B: Swift/UVOT Detection
  26. GRB 251214B: COLIBRÍ observations of the afterglow
  27. EP251214a: EP-FXT non-detection and upper limit
  28. GRB 251214A: GECAM-B observation of a likely long burst
  29. GRB 251214B: 1.3m DFOT optical detection
  30. EP251214a: Global MASTER-Net observations report
  31. GRB 251214B: Xinglong-2.16m optical observation
  32. GRB 251214B : MASTER optical afterglow detection
  33. GRB 251214B: SVOM/C-GFT optical observations
  34. EP251214a: COLIBRÍ optical upper limit
  35. Swift GRB 251214B: Global MASTER-Net observations report
  36. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  37. Fermi GRB 251214A: Global MASTER-Net observations report
  38. EP251212a: Global MASTER-Net observations report
  39. EP251212a: KAIT optical upper limit
  40. EP251212a / GRB 251212A: AstroSat CZTI detection
  41. EP251212a: EP-FXT follow-up observation
  42. GRB 251211B: AstroSat CZTI detection
  43. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  44. GRB 251209A: NuSTAR detection of prompt emission
  45. EP251212a : COLIBRÍ optical upper limit
  46. EP251212a: Einstein Probe detection of an X-ray transient
  47. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  48. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  49. Fermi GRB 251211B: Global MASTER-Net observations report
  50. IceCube-251210A: DDOTI Optical Upper Limit
  51. GRB 251209A: Fermi GBM observation
  52. GRB 251205A: 1.3m DFOT optical upper limit
  53. GRB 251209A: AstroSat CZTI detection
  54. EP251124a: Mondy optical upper limit
  55. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  56. EP251130a: Mondy and AbAO optical observations
  57. GRB 251208A: AstroSat CZTI detection
  58. Fermi GBM Sub-Threshold Detection of GRB 251205A
  59. GRB 251208A: Glowbug gamma-ray detection
  60. GRB 251208B: COLIBRÍ optical upper limits
  61. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  62. GRB 251208C: GECAM-B observation of a short burst
  63. GRB 251208A: GECAM-B observation of a short burst
  64. Fermi GRB 251209A: Global MASTER-Net observations report
  65. Fermi GRB 251208C: Global MASTER-Net observations report
  66. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  67. GRB 251208B: Swift-XRT afterglow detection
  68. GRB 251208D: LAST optical upper limit
  69. GRB 251208D: LCO analysis of the XRT sources
  70. GRB 251208B: Fermi GBM Observation
  71. GRB 251208B: GROWTH-India Telescope optical upper limits
  72. GRB 251205A: J-band detection with WINTER
  73. GRB 251208D: Swift-XRT observations
  74. GRB 251208A: SVOM/GRM observation of a short burst
  75. GRB 251208C: SVOM/GRM observation of a short burst
  76. GRB 251129A: e-MERLIN C-band observations
  77. GRB 251205A: Liverpool Telescope further optical follow-up observations
  78. GRB 251208D: LCO optical upper limits
  79. GRB 251208B: Swift ToO observations
  80. GRB 251208B: Fermi-LAT detection
  81. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  82. GRB 251208D: SVOM possible detection of a faint burst
  83. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  84. GRB 251205A: FTW optical and NIR observations
  85. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  86. GRB 251205A: Liverpool Telescope further optical follow-up observations
  87. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  88. GRB 251205A: ZTF and ATLAS optical afterglow detections
  89. GRB 251205A: GROWTH-India Telescope optical observations
  90. GRB 251205A: Swift-BAT refined analysis
  91. GRB 251205A: Swift/UVOT Detection
  92. GRB 251205A: Liverpool Telescope optical follow-up observations
  93. GRB 251203C: Swift/UVOT Upper Limit
  94. Konus-Wind detection of GRB 251118A
  95. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  96. GRB 251205A: COLIBRÍ optical observations
  97. GRB 251205A: GOTO optical afterglow detection
  98. GRB 251205A: NOT optical observations
  99. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  100. Swift GRB 251205A : MASTER OT detection with host galaxy

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