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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"

5051 results found.

  1. Swift GRB241127.91: Global MASTER-Net OT detection
  2. Konus-Wind detection of GRB 241115D / EP 241115a
  3. GRB 241026A: radio detection with the VLA
  4. EP241125a: EP detection of an X-ray transient
  5. GRB 241113B: SVOM/VT optical afterglow observations
  6. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  7. GRB 241026A: VIRT Optical Upper Limit
  8. EP241119a: Global MASTER-Net observations report
  9. Fermi GRB 241118A: Global MASTER-Net observations report
  10. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  11. GRB 241115A: LCOGT Optical Upper Limits
  12. GRB 241115A: Fermi GBM Final Real-time Localization
  13. GRB 241113B: KAIT Optical Afterglow Candidate
  14. EP241113a: Global MASTER-Net observations report
  15. EP241113b: Global MASTER-Net observations report
  16. GRB 241113A: Swift-XRT refined Analysis
  17. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  18. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  19. Fermi trigger No 752990530: Global MASTER-Net observations report
  20. Fermi trigger No 752878030: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  24. EP241107A: MASTER optical observations of xray transient
  25. GRB 241105A: Swift/UVOT Detection
  26. GRB 241105A: Swift-XRT afterglow detection
  27. GRB 241105A: GOTO tentative optical counterpart candidate
  28. Fermi GRB 241105A: Global MASTER-Net observations report
  29. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  30. GRB 240821A: further radio observations with the VLA
  31. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  32. EP241103a: an X-ray transient detected by Einstein Probe
  33. Fermi trigger No 752083996: Global MASTER-Net observations report
  34. EP EP241030a: Global MASTER-Net observations report
  35. Fermi trigger No 752006065: Global MASTER-Net observations report
  36. GRB 241030A: Swift-XRT refined Analysis
  37. GRB 241030B: AKO Optical Afterglow Detection
  38. Fermi trigger No 751861204: Global MASTER-Net observations report
  39. Konus-Wind detection of GRB 241025A
  40. GRB 241026A: BTA and Zeiss-1000 optical observations
  41. GRB 241026A: Swift-XRT refined Analysis
  42. EP241021a: e-MERLIN radio observation
  43. Fermi trigger No 751616906: Global MASTER-Net observations report
  44. EP241021a: optical follow-up observations with the Liverpool Telescope
  45. EP241021a: Liverpool Telescope optical follow-up observations
  46. GRB 241025A: TRT optical afterglow observation
  47. Fermi GRB 241024B: Global MASTER-Net observations report
  48. GRB 241024B: Fermi GBM Final Localization
  49. GRB 241024A: Fermi GBM Final Localisation
  50. Fermi trigger No 751449953: Global MASTER-Net observations report
  51. EP241021a: Optical upper limits with Kinder observations
  52. Fermi trigger No 750788395: Global MASTER-Net observations report
  53. GRB 241006A: Swift-XRT refined Analysis
  54. IceCube Alert 241006.94: Global MASTER-Net observations report
  55. GRB 241002A: Swift-XRT refined Analysis
  56. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  57. Fermi GRB 241002B: Global MASTER-Net observations report
  58. EP EP240930a: Global MASTER-Net observations report
  59. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  60. Fermi GRB 240929A: Global MASTER-Net observations report
  61. IPN triangulation of GRB 240918B
  62. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  64. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  65. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  66. Fermi GRB 240918A: Global MASTER-Net observations report
  67. EP EP240918a: Global MASTER-Net observations report
  68. EP240918a: JinShan optical upper limits
  69. EP240918a: GMG Optical Upper Limit
  70. EP240918a: an X-ray transient detected by Einstein Probe
  71. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  72. GRB 240912A: Swift-XRT refined Analysis
  73. IPN triangulation of GRB 240905B (short)
  74. EP240908a: Mondy and AbAO follow-up observations
  75. EP240908a: Updates on the WXT detection result around the trigger time
  76. EP240908a: optical afterglow candidate
  77. GRB 240905E: Swift-XRT refined Analysis
  78. GRB 240828B: GRANDMA Optical Upper Limit
  79. GRB 240828A: Swift-XRT afterglow detection
  80. GRB 240828B: Swift-XRT afterglow detection
  81. Swift GRB240829.16: Global MASTER-Net observations report
  82. GRB 240825A: Upper limits from a neutrino search with IceCube
  83. Fermi trigger No 746438824: Global MASTER-Net observations report
  84. GRB 240824A: GIT optical upper limit
  85. GRB 240825A: Swift-XRT refined Analysis
  86. GRB 240824B: Fermi GBM Observation
  87. GRB 240824A: SVOM/C-GFT optical upper limit
  88. Fermi GRB 240824C: Global MASTER-Net observations report
  89. GRB 240824C: Fermi GBM Final Localization
  90. GRB 240824B: MAXI/GSC detection
  91. GRB 240824B: Fermi GBM Final Real-time Localization
  92. GRB 240824A: Retraction of GCN 37255
  93. GRB 240824A: Skynet Optical Afterglow Discovery
  94. Swift GRB240824.04: Global MASTER-Net observations report
  95. Fermi GRB 240821A: Global MASTER-Net observations report
  96. GRB240821A: EIRSAT-1 GMOD Detection
  97. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  98. Fermi GRB 240821B: Global MASTER-Net observations report
  99. GRB 240821B: Fermi GBM Final Localization
  100. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73

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