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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"

5849 results found.

  1. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  2. Fermi trigger No 740430582: Global MASTER-Net observations report
  3. X-ray transient EP240414a: Chandra late time observation
  4. Fermi GRB 240616A: Global MASTER-Net observations report
  5. Fermi trigger No 740166710: Global MASTER-Net observations report
  6. Fermi GRB 240610A: Global MASTER-Net observations report
  7. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  8. Fermi trigger No 739632045: Global MASTER-Net observations report
  9. Fermi GRB 240607A: Global MASTER-Net observations report
  10. Fermi GRB 240604A: Global MASTER-Net observations report
  11. Fermi GRB 240605A: Global MASTER-Net observations report
  12. Fermi GRB 240603C: Global MASTER-Net observations report
  13. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  14. GRB 240603C: Fermi GBM Final Real-time Localization
  15. GRB 240529A: continued SAO RAS optical observations
  16. Fermi GRB 240602A: Global MASTER-Net observations report
  17. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  18. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  19. Fermi GRB 240527A: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  22. Fermi trigger No 738348224: Global MASTER-Net observations report
  23. Fermi trigger No 738330463: Global MASTER-Net observations report
  24. Fermi trigger No 737996942: Global MASTER-Net observations report
  25. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  26. Fermi trigger No 737523389: Global MASTER-Net observations report
  27. GRB 240514B: GOTO candidate optical counterpart
  28. MAXI GRB240514.78: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  30. LAT GRB240513.31: Global MASTER-Net observations report
  31. Fermi GRB 240513B: Global MASTER-Net observations report
  32. Fermi trigger No 737277727: Global MASTER-Net observations report
  33. Fermi trigger No 737247400: Global MASTER-Net observations report
  34. Fermi trigger No 737196587: Global MASTER-Net observations report
  35. Fermi trigger No 737168073: Global MASTER-Net observations report
  36. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  37. GRB 240511A: Swift detection of a burst
  38. Fermi trigger No 737111207: Global MASTER-Net observations report
  39. Fermi trigger No 736967879: Global MASTER-Net observations report
  40. EP240506a: Archival radio searching
  41. EP240506a: TRT optical upper limit
  42. Fermi trigger No 736379109: Global MASTER-Net observations report
  43. GRB 240502C: GOTO possible optical counterpart candidates
  44. Fermi GRB 240502A: Global MASTER-Net observations report
  45. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  46. LIGO/Virgo/KAGRA S240430ca: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  48. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  50. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  51. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  52. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  53. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  54. GRB 240421B: GRBAlpha detection
  55. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  56. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  57. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  58. Fermi trigger No 735470374: Global MASTER-Net observations report
  59. GRB 240415B: Swift-XRT observations
  60. GRB 240421B: AstroSat CZTI detection
  61. GRB 240421B: Fermi GBM Observation
  62. GRB240421B: BOOTES-5/JGT optical upper limit
  63. GRB 240421B: Swift detection of a burst
  64. Fermi trigger No 735280430: Global MASTER-Net observations report
  65. EP240414A: Terskol Zeiss-2000 optical upper limit
  66. GRB 240419B: Swift detection of a burst
  67. Fermi GRB 240417A: Global MASTER-Net observations report
  68. GRB 240415A: Swift-BAT refined analysis
  69. EP240416A: MASTER optical observations
  70. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  71. EP240414a: EP-FXT follow-up observation
  72. Fermi GRB 240415A: Global MASTER-Net observations report
  73. EP 240414a: NOT optical counterpart confirmation
  74. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  75. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  76. Fermi trigger No 734754044: Global MASTER-Net observations report
  77. GRB 240414A : MITSuME Akeno optical upper limits
  78. GRB 240414A : OHP/T193 redshift determination
  79. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  80. EP240408A: MASTER optical observations
  81. EP240408a: GROND detection of a candidate counterpart
  82. Swift Trigger 1220736: detection of 4U 1543-62.
  83. Fermi GRB 240408A: Global MASTER-Net observations report
  84. Fermi GRB 240405B: Global MASTER-Net observations report
  85. Fermi GRB 240402A: Global MASTER-Net observations report
  86. GRB 240328B: Fermi GBM Final Real-time Localization
  87. Fermi trigger No 733092476: Global MASTER-Net observations report
  88. X-ray transient EP240315a: ATCA detection of radio counterpart
  89. GRB 240317A: AstroSat CZTI detection
  90. Fermi GRB 240317B: Global MASTER-Net observations report
  91. GRB 240317A: Fermi GBM Final Real-time Localization
  92. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  93. Fermi trigger No 732299243: Global MASTER-Net observations report
  94. Fermi GRB 240314A: Global MASTER-Net observations report
  95. Fermi trigger No 731839490: Global MASTER-Net observations report
  96. Swift GRB240309.61: Global MASTER-Net observations report
  97. GRB 240309A: MAXI/GSC detection
  98. GRB 240305A: Fermi GBM observation
  99. GRB 240305A: Fermi GBM Final Real-time Localization
  100. Fermi trigger No 731161136: Global MASTER-Net observations report

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