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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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.

Lucene Examples (click to copy):

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

3363 results found.

  1. GRB 240912A: Swift-BAT refined analysis
  2. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  4. Fermi GRB 240908A: Global MASTER-Net observations report
  5. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  6. GRB 240902B: AstroSat CZTI detection of a long burst
  7. GRB 240825A: Montarrenti Observatory optical follow-up observations
  8. Fermi trigger No 746923430: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  10. Fermi trigger No 746587425: Global MASTER-Net observations report
  11. Swift GRB240829.16: Global MASTER-Net observations report
  12. Fermi trigger No 746438824: Global MASTER-Net observations report
  13. GRB 240824A: GIT optical upper limit
  14. GRB 240824B: Ondrejov D50 optical limit
  15. GRB 240825A: AKO Optical Follow-Up Observations
  16. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  17. GRB 240824B: Fermi GBM Observation
  18. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  19. GRB 240824B: Swift-XRT afterglow detection
  20. GRB 240824B: Swift/BAT arcminute localization of a burst
  21. GRB 240824B: MAXI/GSC detection
  22. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  23. Fermi GRB 240821B: Global MASTER-Net observations report
  24. Fermi trigger No 745866488: Global MASTER-Net observations report
  25. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  26. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  27. Fermi GRB 240814B: Global MASTER-Net observations report
  28. GRB 240808A: AstroSat CZTI detection
  29. GRB 240809B: MAXI/GSC detection
  30. GRB 240808A: SVOM/GRM observation
  31. EP EP240807a: Global MASTER-Net observations report
  32. EP EP240806a: Global MASTER-Net observations report
  33. GRB 240805B: Swift-BAT refined analysis
  34. Fermi trigger No 744629911: Global MASTER-Net observations report
  35. Fermi GRB 240805A: Global MASTER-Net observations report
  36. Fermi GRB 240804A: Global MASTER-Net observations report
  37. Fermi trigger No 744459130: Global MASTER-Net observations report
  38. Fermi trigger No 744128417: Global MASTER-Net observations report
  39. GRB240730A: BOOTES-5/JGT early optical upper limit
  40. GRB 240720A: Swift-BAT refined analysis
  41. Fermi trigger No 743219692: Global MASTER-Net observations report
  42. GRB 240721A: Fermi GBM Final Real-time Localization
  43. Fermi GRB 240720A: Global MASTER-Net observations report
  44. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  45. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  46. Fermi trigger No 742405878: Global MASTER-Net observations report
  47. Fermi trigger No 742317942: Global MASTER-Net observations report
  48. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  49. Fermi trigger No 741448122: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  51. Fermi trigger No 741356809: Global MASTER-Net observations report
  52. GRB 240624A: Swift-BAT refined analysis
  53. Fermi trigger No 740949590: Global MASTER-Net observations report
  54. EP240617a: tentative Swift/XRT detection of the afterglow
  55. EP240618a: GRANDMA Optical Upper Limits
  56. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  57. Fermi trigger No 740430582: Global MASTER-Net observations report
  58. Fermi trigger No 740221779: Global MASTER-Net observations report
  59. Fermi GRB 240616A: Global MASTER-Net observations report
  60. Fermi trigger No 740166710: Global MASTER-Net observations report
  61. Fermi trigger No 739506569: Global MASTER-Net observations report
  62. Fermi GRB 240607A: Global MASTER-Net observations report
  63. GRB 240607A: AstroSat CZTI detection of bright long burst
  64. Fermi GRB 240604A: Global MASTER-Net observations report
  65. GRB 240603B: Swift detection of a possible burst
  66. Fermi GRB 240602A: Global MASTER-Net observations report
  67. GRB 240529A: AKO Optical Afterglow Detection
  68. Fermi trigger No 738348224: Global MASTER-Net observations report
  69. Fermi trigger No 738330463: Global MASTER-Net observations report
  70. Fermi trigger No 737996942: Global MASTER-Net observations report
  71. Fermi trigger No 737788024: Global MASTER-Net observations report
  72. GRB 240514E: A possible candidate BD-21 1074
  73. Fermi trigger No 737559855: Global MASTER-Net observations report
  74. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  75. Fermi trigger No 737523389: Global MASTER-Net observations report
  76. MAXI GRB240514.78: Global MASTER-Net observations report
  77. GRB 240514E: MAXI/GSC detection of a probable afterglow
  78. LAT GRB240513.31: Global MASTER-Net observations report
  79. Fermi trigger No 737277727: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  81. Fermi trigger No 737258655: Global MASTER-Net observations report
  82. Fermi trigger No 737247400: Global MASTER-Net observations report
  83. Fermi trigger No 737196587: Global MASTER-Net observations report
  84. Fermi trigger No 737152719: Global MASTER-Net observations report
  85. Fermi trigger No 736967879: Global MASTER-Net observations report
  86. Fermi trigger No 736564880: Global MASTER-Net observations report
  87. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  88. GRB 240502C: GOTO possible optical counterpart candidates
  89. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  90. Fermi GRB 240501A: Global MASTER-Net observations report
  91. Fermi trigger No 736197684: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  93. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  94. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  95. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  96. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  97. GRB 240421B: Swift-BAT refined analysis
  98. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  99. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  100. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a

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