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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.

Advanced Search Examples (click to copy):

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

3533 results found.

  1. Fermi trigger No 752878030: Global MASTER-Net observations report
  2. Integral GRB241109.89: Global MASTER-Net observations report
  3. GRB 241105A: EP-FXT follow-up observations
  4. GRB 241025A: LBT optical observations
  5. Fermi GRB 241105A: Global MASTER-Net observations report
  6. Fermi GRB 241104A: Global MASTER-Net observations report
  7. EP241103a: EP observation update
  8. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  9. S241102cy: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  11. GRB 241030A: further SAO RAS optical observations
  12. GRB 241030B: Montarrenti Observatory optical upper limit
  13. Fermi trigger No 752083996: Global MASTER-Net observations report
  14. Fermi trigger No 752006065: Global MASTER-Net observations report
  15. GRB 241030B: BTA observations
  16. GRB 241026A: LBT optical observations
  17. GRB 241030A : MITSuME Akeno optical afterglow detection
  18. GRB 241026A: SAO RAS optical observations
  19. EP241021a: SAO RAS observations of rebrightening
  20. GRB 241029A: AKO Optical Afterglow Detection
  21. EP241021a: Gemini-South detection of optical rebrightening
  22. GRB 241025A: SAO RAS optical observations
  23. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  24. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  25. Fermi GRB 241026A: Global MASTER-Net observations report
  26. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  27. Fermi trigger No 751554401: Global MASTER-Net observations report
  28. EP241021a: optical follow-up observations with the Liverpool Telescope
  29. GRB 241025A: DDOTI Afterglow detection
  30. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  31. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 241018A: SVOM/VT follow-up and optical candidate
  33. GRB 241017A: GROWTH-India Telescope optical upper limit
  34. Fermi trigger No 750788395: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  36. Fermi trigger No 750211959: Global MASTER-Net observations report
  37. Fermi trigger No 750291012: Global MASTER-Net observations report
  38. Fermi GRB 241010B: Global MASTER-Net observations report
  39. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  40. GRB 241006A: Swift/UVOT Upper Limits
  41. GRB 241001A: Swift-XRT afterglow detection
  42. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  43. GRB 241001A: correction to GCN 37667
  44. Fermi GRB 241002B: Global MASTER-Net observations report
  45. GRB 241001A: Swift-XRT observations
  46. GRB241001A: optical afterglow candidate
  47. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  48. Fermi GRB 240930B: Global MASTER-Net observations report
  49. Fermi trigger No 749339671: Global MASTER-Net observations report
  50. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  51. EP240918b and EP240918c: EP-FXT follow-up observations
  52. Konus-Wind detection of GRB 240918B
  53. EP240913a/GRB 240913C: 1.6m Mephisto observations
  54. EP240919a / GRB 240919A: REM optical and NIR upper limits
  55. EP EP240918a: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  57. EP240908a: Updates on the WXT detection result around the trigger time
  58. GRB 240905E: GIT optical upper limit
  59. GRB 240905B: Fermi-LAT detection
  60. Fermi trigger No 746923430: Global MASTER-Net observations report
  61. GRB 240828B: Mephisto optical upper limit
  62. GRB 240828B: SVOM/C-GFT optical upper limit
  63. Fermi trigger No 746587425: Global MASTER-Net observations report
  64. GRB 240828A: Fermi GBM Observation
  65. GRB 240629A: First GRB Detected by BurstCube
  66. GRB 240825A: further SAO RAS optical observations
  67. GRB 240829A: Swift detection of a burst
  68. GRB 240828A: Fermi-LAT detection
  69. LAT GRB240828.62: Global MASTER-Net observations report
  70. GRB 240828A: AstroSat CZTI detection of a long burst
  71. Fermi GRB 240828A: Global MASTER-Net observations report
  72. Fermi trigger No 746438824: Global MASTER-Net observations report
  73. SVOM GRB 240821A: optical afterglow discovery
  74. GRB 240828A: Fermi GBM Final Real-time Localization
  75. GRB 240825A: SAO RAS optical observations
  76. GRB 240825A: REM detection of the optical/NIR afterglow
  77. Fermi GRB 240824C: Global MASTER-Net observations report
  78. GRB 240824A: Retraction of GCN 37255
  79. GRB 240821A: Fermi GBM Observation
  80. Fermi trigger No 745866488: Global MASTER-Net observations report
  81. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  82. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  83. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  84. Fermi trigger No 745501396: Global MASTER-Net observations report
  85. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  86. GRB 240809A: ALMA detection
  87. GRB 240809B: MAXI/GSC detection
  88. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  89. GRB 240809A: SVOM/GRM observation
  90. EP EP240807a: Global MASTER-Net observations report
  91. EP EP240806a: Global MASTER-Net observations report
  92. Fermi trigger No 744761058: Global MASTER-Net observations report
  93. Fermi trigger No 744629911: Global MASTER-Net observations report
  94. Fermi trigger No 744544656: Global MASTER-Net observations report
  95. EP240801a: BTA BVRI photometry
  96. GRB 240805B: Swift detection of a burst
  97. Fermi GRB 240804A: Global MASTER-Net observations report
  98. EP240801a: optical observations at CrAO and AbAO
  99. Fermi trigger No 744083370: Global MASTER-Net observations report
  100. Fermi trigger No 743953682: Global MASTER-Net observations report

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