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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"

5157 results found.

  1. Fermi GRB 241207A: Global MASTER-Net observations report
  2. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  3. GRB 241130A: EIRSAT-1 GMOD Detection
  4. The EP-WXT trigger 01709126243 is not a real source
  5. Fermi trigger No 754701230: Global MASTER-Net observations report
  6. GRB 241128A: Swift-XRT refined Analysis
  7. Swift GRB241127.91: Global MASTER-Net OT detection
  8. Konus-Wind detection of GRB 241115D / EP 241115a
  9. GRB 241026A: radio detection with the VLA
  10. EP241125a: EP detection of an X-ray transient
  11. GRB 241113B: SVOM/VT optical afterglow observations
  12. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  13. GRB 241026A: VIRT Optical Upper Limit
  14. EP241119a: Global MASTER-Net observations report
  15. Fermi GRB 241118A: Global MASTER-Net observations report
  16. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  17. GRB 241115A: LCOGT Optical Upper Limits
  18. GRB 241115A: Fermi GBM Final Real-time Localization
  19. GRB 241113B: KAIT Optical Afterglow Candidate
  20. EP241113a: Global MASTER-Net observations report
  21. EP241113b: Global MASTER-Net observations report
  22. GRB 241113A: Swift-XRT refined Analysis
  23. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  24. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  25. Fermi trigger No 752990530: Global MASTER-Net observations report
  26. Fermi trigger No 752878030: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  28. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  30. EP241107A: MASTER optical observations of xray transient
  31. GRB 241105A: Swift/UVOT Detection
  32. GRB 241105A: Swift-XRT afterglow detection
  33. GRB 241105A: GOTO tentative optical counterpart candidate
  34. Fermi GRB 241105A: Global MASTER-Net observations report
  35. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  36. GRB 240821A: further radio observations with the VLA
  37. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  38. EP241103a: an X-ray transient detected by Einstein Probe
  39. Fermi trigger No 752083996: Global MASTER-Net observations report
  40. EP EP241030a: Global MASTER-Net observations report
  41. Fermi trigger No 752006065: Global MASTER-Net observations report
  42. GRB 241030A: Swift-XRT refined Analysis
  43. GRB 241030B: AKO Optical Afterglow Detection
  44. Fermi trigger No 751861204: Global MASTER-Net observations report
  45. Konus-Wind detection of GRB 241025A
  46. GRB 241026A: BTA and Zeiss-1000 optical observations
  47. GRB 241026A: Swift-XRT refined Analysis
  48. EP241021a: e-MERLIN radio observation
  49. Fermi trigger No 751616906: Global MASTER-Net observations report
  50. EP241021a: optical follow-up observations with the Liverpool Telescope
  51. EP241021a: Liverpool Telescope optical follow-up observations
  52. GRB 241025A: TRT optical afterglow observation
  53. Fermi GRB 241024B: Global MASTER-Net observations report
  54. GRB 241024B: Fermi GBM Final Localization
  55. GRB 241024A: Fermi GBM Final Localisation
  56. Fermi trigger No 751449953: Global MASTER-Net observations report
  57. EP241021a: Optical upper limits with Kinder observations
  58. Fermi trigger No 750788395: Global MASTER-Net observations report
  59. GRB 241006A: Swift-XRT refined Analysis
  60. IceCube Alert 241006.94: Global MASTER-Net observations report
  61. GRB 241002A: Swift-XRT refined Analysis
  62. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  63. Fermi GRB 241002B: Global MASTER-Net observations report
  64. EP EP240930a: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  66. Fermi GRB 240929A: Global MASTER-Net observations report
  67. IPN triangulation of GRB 240918B
  68. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  71. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  72. Fermi GRB 240918A: Global MASTER-Net observations report
  73. EP EP240918a: Global MASTER-Net observations report
  74. EP240918a: JinShan optical upper limits
  75. EP240918a: GMG Optical Upper Limit
  76. EP240918a: an X-ray transient detected by Einstein Probe
  77. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  78. GRB 240912A: Swift-XRT refined Analysis
  79. IPN triangulation of GRB 240905B (short)
  80. EP240908a: Mondy and AbAO follow-up observations
  81. EP240908a: Updates on the WXT detection result around the trigger time
  82. EP240908a: optical afterglow candidate
  83. GRB 240905E: Swift-XRT refined Analysis
  84. GRB 240828B: GRANDMA Optical Upper Limit
  85. GRB 240828A: Swift-XRT afterglow detection
  86. GRB 240828B: Swift-XRT afterglow detection
  87. Swift GRB240829.16: Global MASTER-Net observations report
  88. GRB 240825A: Upper limits from a neutrino search with IceCube
  89. Fermi trigger No 746438824: Global MASTER-Net observations report
  90. GRB 240824A: GIT optical upper limit
  91. GRB 240825A: Swift-XRT refined Analysis
  92. GRB 240824B: Fermi GBM Observation
  93. GRB 240824A: SVOM/C-GFT optical upper limit
  94. Fermi GRB 240824C: Global MASTER-Net observations report
  95. GRB 240824C: Fermi GBM Final Localization
  96. GRB 240824B: MAXI/GSC detection
  97. GRB 240824B: Fermi GBM Final Real-time Localization
  98. GRB 240824A: Retraction of GCN 37255
  99. GRB 240824A: Skynet Optical Afterglow Discovery
  100. Swift GRB240824.04: Global MASTER-Net observations report

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