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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"

2907 results found.

  1. GRB 241228B: GOTO24jmz optical follow-up observations
  2. GRB 241228B: GOTO possible optical counterpart candidate
  3. Fermi GRB 241226A: Global MASTER-Net observations report
  4. Fermi trigger No 756678579: Global MASTER-Net observations report
  5. GRB 241219A: SVOM/GRM observation
  6. GRB241113A: 7DT Optical upper limits
  7. Fermi trigger No 756447119: Global MASTER-Net observations report
  8. EP241217a: Global MASTER-Net observations report
  9. EP241217A: Non-detection from Fermi-GBM Observations
  10. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  11. GRB 241215A: Montarrenti Observatory optical upper limit
  12. GRB 241212A: AstroSat CZTI detection
  13. GRB 241207A: TSHAO Zeiss-1000 optical observations
  14. GRB 241209A: Swift-XRT refined Analysis
  15. GRB 241209D: AstroSat CZTI detection
  16. Fermi GRB 241209C: Global MASTER-Net observations report
  17. GRB 241209C: AstroSat CZTI detection
  18. GRB 241209D: Swift detection of a burst
  19. Fermi GRB 241209A: Global MASTER-Net observations report
  20. GRB 241209A: GOTO optical upper limits
  21. Fermi GRB 241207B: Global MASTER-Net observations report
  22. GRB 241201A: AstroSat CZTI detection
  23. GRB 241207C: MASTER optical observations
  24. Fermi trigger No 755225799: Global MASTER-Net observations report
  25. IPN triangulation of GRB 241130A
  26. EP241201a: Global MASTER-Net observations report
  27. EP241126a: WFST Observations
  28. EP241126a: TRT optical counterpart detection
  29. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  30. GRB 241113A: Possible ATCA Radio detection
  31. GRB 241120A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 241118A: Global MASTER-Net observations report
  33. Fermi GRB 241117A: Global MASTER-Net observations report
  34. The EP-WXT trigger 01709120856 is likely a flaring star
  35. GRB 241115A: Fermi GBM Final Real-time Localization
  36. Fermi GRB 241114A: Global MASTER-Net observations report
  37. EP241113b: Global MASTER-Net observations report
  38. GRB 241112B: GMG Optical Upper Limit
  39. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  40. Fermi trigger No 752878030: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  42. GRB 241105A: SVOM/GRM observation
  43. GRB 241105A: GOTO tentative optical counterpart candidate
  44. Fermi GRB 241105A: Global MASTER-Net observations report
  45. GRB 241105A: Fermi GBM Final Real-time Localization
  46. Fermi GRB 241104A: Global MASTER-Net observations report
  47. Fermi trigger No 752365806: Global MASTER-Net observations report
  48. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  49. GRB 241101A: FRAM-ORM optical limit
  50. GRB 241026A: SAO RAS optical observations
  51. GRB 241030B : GIT optical upper limits
  52. EP EP241030a: Global MASTER-Net observations report
  53. Fermi trigger No 752006065: Global MASTER-Net observations report
  54. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  55. GRB 241030A: AKO Optical Afterglow Detection
  56. GRB 241026A: SAO RAS optical observations
  57. EP241021a: SAO RAS observations of rebrightening
  58. GRB 241026A: the 100th GRB detected by GRBAlpha
  59. GRB 241026A: GECAM detection
  60. GRB 241025A: further SAO RAS optical observations
  61. GRB 241026A: SVOM/GRM observation
  62. GRB 241026A Fermi GBM Analysis
  63. GRB 241026A: BTA redshift identification of z = 2.79
  64. GRB 241026A: Swift detection of a burst
  65. GRB 241026A: Fermi GBM Final Real-time Localization
  66. Fermi trigger No 751554401: Global MASTER-Net observations report
  67. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  68. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  69. Fermi trigger No 750788395: Global MASTER-Net observations report
  70. Fermi GRB 241013B: Global MASTER-Net observations report
  71. GRB 241013B: Fermi GBM Final Real-time Localization
  72. Fermi trigger No 750211959: Global MASTER-Net observations report
  73. Swift GRB 241010A: Global MASTER-Net observations report
  74. Fermi GRB 241008A: Global MASTER-Net observations report
  75. GRB 241006A: GRANDMA optical upper limits
  76. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  77. Fermi trigger No 749735279: Global MASTER-Net observations report
  78. Konus-Wind detection of GRB 240926A
  79. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  80. IPN triangulation of GRB 240926A
  81. Fermi trigger No 749339671: Global MASTER-Net observations report
  82. Fermi GRB 240929A: Global MASTER-Net observations report
  83. GRB 240926A: SVOM/GRM observation
  84. GRB 240918B: AstroSat CZTI detection
  85. EP240919a / GRB 240919A: Mondy optical upper limit
  86. EP240918b and EP240918c: Optical upper limits with Kinder observations
  87. GRB 240910A: radio detection with the VLA
  88. IPN triangulation of GRB 240913C / EP 240913a
  89. GRB 240913C: Fermi GBM detection
  90. GRB 240913C: Joint location by ETJASMIN
  91. GRB 240914B: AstroSat CZTI detection
  92. EP240913A / GRB 240913C: AstroSat CZTI detection
  93. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  94. GRB 240912A: Swift detection of a burst with an optical counterpart
  95. GRB 240825A: 7DT Optical Upper Limit
  96. GRB 240910B: Fermi GBM Final Real-time Localization
  97. Fermi GRB 240908A: Global MASTER-Net observations report
  98. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  99. GRB 240902B: AstroSat CZTI detection of a long burst
  100. GRB 240902A: AstroSat CZTI detection of a long burst

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