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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"

32702 results found.

  1. Fermi GRB 251011A: Global MASTER-Net observations report
  2. GRB 251011B: SVOM/GRM observation
  3. GRB 251011B: Fermi GBM Observation
  4. GRB 251011B : MASTER optical observations
  5. GRB 251010A: AstroSat CZTI detection
  6. GRB 251011A: AstroSat CZTI detection
  7. GRB 251009B: SVOM/GRM observation of short GRB
  8. GRB 251007B: Swift/UVOT Upper Limits
  9. GRB251007A: Swift/UVOT Detection
  10. GRB 251009A: GECAM-B detection of a short burst
  11. GRB 251009A: Insight-HXMT detection of a short burst
  12. GRB 251009B (short): Glowbug gamma-ray detection
  13. GRB 251007A: Swift-BAT refined analysis
  14. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  15. GRB 251007A: SVOM/GRM observation
  16. GRB 251007A: Insight-HXMT detection
  17. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  18. GRB 251007B - SVOM/ECLAIRs refined analysis
  19. GRB 250916A: TERI Gamma-ray detection
  20. GRB 250919A: TERI gamma-ray detection
  21. EP251006a: Global MASTER-Net observations report
  22. GRB 251006A: Fermi GBM Observation
  23. GRB 251002A - SVOM/ECLAIRs refined analysis
  24. GRB 251003A: Fermi GBM Observation
  25. GRB 251006B: Fermi GBM Observation
  26. GRB 251007B: COLIBRÍ optical upper limit
  27. GRB 251007A: AstroSat CZTI detection
  28. GRB 251006B/EP251006a: EP-FXT afterglow detection
  29. GRB 250917B: iTelescope T-26 upper limit
  30. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  31. GRB 251007B: SVOM/VT optical candidate
  32. GRB 251007A: NOT optical observations
  33. GRB 251007A: AKO Optical Upper Limit
  34. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  35. GRB 251006B: Insight-HXMT detection
  36. GRB 251007A: SVOM/C-GFT optical observations
  37. GRB 251005C: PRIME J-band upper limit
  38. Swift GRB 251007B: Global MASTER-Net observations report
  39. GRB 251007A: Glowbug gamma-ray detection
  40. GRB 251007B: SVOM/C-GFT upper limit
  41. Swift GRB 251007A: Global MASTER-Net observations report
  42. GRB 251007B: SVOM detection of a faint burst
  43. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  44. GRB 251005B: Glowbug gamma-ray detection
  45. EP251003a: LCO and VST fading optical counterpart
  46. GRB 251006B/EP251006a: SVOM/VT optical candidate
  47. GRB 251006B/EP251006a: EP-FXT follow-up observation
  48. GRB 251006B: SVOM/GRM observation
  49. GRB 251006B: COLIBRÍ optical upper limit
  50. GRB 251006B/EP251006a: EP-WXT detection
  51. GRB 251005C: SVOM/VT optical fading
  52. GRB 251005C: SVOM/GRM observation of a likely short GRB
  53. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  54. Fermi GRB 251006B: Global MASTER-Net observations report
  55. GRB 251006A (short): Glowbug gamma-ray detection
  56. GRB 251005C: COLIBRÍ optical observations
  57. Fermi GRB 251006A: Global MASTER-Net observations report
  58. GRB 251005C: VLT/X-shooter Imaging
  59. GRB 251003A: LAST optical observations
  60. GRB 251002A: LAST optical observations
  61. GRB 251005C: SVOM/VT optical candidate
  62. GRB 251005C: AstroSat CZTI detection
  63. GRB 251005C: Swift/UVOT Upper Limits
  64. GRB 250902A: MSU cubesats detection
  65. GRB 251005C: Fermi GBM Observation
  66. Swift GRB 251005A: Global MASTER-Net observations report
  67. GRB 251005C: GOTO optical upper limits
  68. GRB 251002A: Mondy/AZT-33IK optical observations
  69. GRB 251002A: Insight-HXMT detection
  70. GRB 251002A: Insight-HXMT detection
  71. GRB 251003A: J-band detection with WINTER
  72. GRB 251002A: NIR observations with WINTER
  73. Fermi GBM Sub-Threshold Detection of GRB 250910A
  74. GRB 251003A: Swift-BAT refined analysis
  75. GRB 251001B: NIR observations with WINTER
  76. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  77. GRB 251003A: Swift/UVOT Upper Limits
  78. GRB 251002A: Swift/UVOT detection
  79. GRB 251001A: AstroSat CZTI detection
  80. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  81. GRB 251003A: COLIBRÍ photometric redshift
  82. GRB 251003A: GOTO detection of the optical counterpart
  83. GRB 251002A: Fermi GBM Observation
  84. GRB 251002A: GOTO detection of optical counterpart
  85. GRB 251001C: SVOM/GRM observation
  86. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  87. GRB 251002A: AKO Early Optical Afterglow Detection
  88. GRB 251003A: GTC/OSIRIS+ spectroscopic redshift z = 4.412
  89. GRB 251003A: Kilonova-Catcher optical afterglow detection
  90. GRB 251002A: Swift-XRT afterglow detection
  91. GRB 251001B: AbAO optical upper limit
  92. GRB 251002A: Kilonova-Catcher optical afterglow detection
  93. GRB 251002A: AbAO optical observations
  94. GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
  95. GRB 251001C: CALET Gamma-Ray Burst Monitor detection
  96. GRB 251002A: J band observations by SYSU 80cm infrared telescope
  97. GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
  98. GRB 251002A: VLT/X-shooter spectroscopic redshift z = 2.178
  99. GRB 251002A: EP-FXT counterpart detection
  100. GRB 251003A: LCOGT Optical Detection

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