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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

649 results found.

  1. Konus-Wind detection of GRB 261007A/EP261007a
  2. Konus-Wind detection of GRB 260924A
  3. GRB 260922A: Swift-BAT refined analysis
  4. GRB 260921A: AstroSat CZTI detection
  5. GRB 260921A: Swift-BAT refined analysis
  6. EP260920a: COLIBRÍ optical upper limits
  7. EP Alert 260918.24: Global MASTER-Net observations report
  8. SVOM GRB260918.16: Global MASTER-Net observations report
  9. Fermi GRB 260805A: Global MASTER-Net observations report
  10. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  11. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  12. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  13. GRB 260616A: AstroSat CZTI detection
  14. GRB 260616A: SVOM/GRM observation
  15. Fermi GRB 260523A: Global MASTER-Net observations report
  16. EP260509a: Global MASTER-Net observations report
  17. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  18. GRB 260321A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  19. Fermi GRB 260310B: Global MASTER-Net observations report
  20. Fermi GRB 260221A: Global MASTER-Net observations report
  21. Fermi GRB 260219A: Global MASTER-Net observations report
  22. EP260209a: Global MASTER-Net observations report
  23. Fermi GRB 260208C: Global MASTER-Net observations report
  24. GRB 260208B: Fermi GBM Detection
  25. Konus-Wind detection of GRB 260128A / EP260128a
  26. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  27. EP260119a: SVOM/VT optical observation
  28. Swift trigger on the HMXB 1A 1118-61
  29. Swift triggered on the HMXB 1A 1118-61
  30. IceCube Alert 260111A: Global MASTER-Net observations report
  31. Swift GRB 251214B: Global MASTER-Net observations report
  32. SVOM GRB251211.12: Global MASTER-Net observations report
  33. GRB 251208A: SVOM/GRM observation of a short burst
  34. Fermi GRB 251127A: Global MASTER-Net observations report
  35. Fermi trigger No 784279167: Global MASTER-Net observations report
  36. GRB 251103A: NOT spectroscopic redshift z = 0.76
  37. Fermi GRB 251013A: Global MASTER-Net observations report
  38. GRB 250909A: AstroSat CZTI detection
  39. EP250901a: Mondy, Assy and SAO RAS optical limits
  40. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  41. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  42. GRB 250831A (SVOM trigger sb25083102) is likely an outburst from star G 272-61
  43. GRB 250831A: Swift-XRT counterpart detection
  44. GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  45. GRB 250831A: SVOM/VT upper limit with VHF data
  46. EP250711a: COLIBRÍ continuous optical observations
  47. IceCube-250708A: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 3-Initial Localization Volume
  49. EP250610a: Global MASTER-Net observations report
  50. GRB 250516A: Swift-BAT refined analysis
  51. MAXI GRB250515.65: Global MASTER-Net observations report
  52. GRB 250430A: Swift-BAT refined analysis
  53. Fermi GRB 250502B: Global MASTER-Net observations report
  54. Fermi-LAT gamma-ray observations of IceCube-250421A
  55. GRB 250327A: Swift-XRT refined Analysis
  56. GRB 250327A: SVOM/VT optical candidate
  57. GRB 250322A: AstroSat CZTI detection of a short burst
  58. Fermi trigger No 763509110: Global MASTER-Net observations report
  59. Fermi GRB 250309B: Global MASTER-Net observations report
  60. GRB 250226A: Fermi GBM Observation
  61. Fermi GRB 250223A: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  63. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  65. GRB 250207A: REM IR afterglow detection
  66. GRB 250207A: REM optical afterglow detection
  67. GRB 250114B: OHP/T193 optical upper limit
  68. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  69. GRB 241207C: MASTER optical observations
  70. Fermi trigger No 755225799: Global MASTER-Net observations report
  71. Swift GRB 241128A: Global MASTER-Net observations report
  72. Swift GRB241127.91: Global MASTER-Net observations report
  73. GRB 241113A: Swift/UVOT Detection
  74. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  75. Fermi GRB 240918A: Global MASTER-Net observations report
  76. EP EP240913a: Global MASTER-Net observations report
  77. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  78. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  79. GRB 240829A: Swift-BAT refined analysis
  80. LAT GRB240828.62: Global MASTER-Net observations report
  81. Fermi trigger No 745866488: Global MASTER-Net observations report
  82. Fermi trigger No 745057312: Global MASTER-Net observations report
  83. Swift GRB 240811A: Global MASTER-Net observations report
  84. GRB 240727C: AstroSat CZTI detection of a long burst
  85. Konus-Wind detection of GRB 240627A
  86. Fermi GRB 240702A: Global MASTER-Net observations report
  87. Fermi trigger No 741211696: Global MASTER-Net observations report
  88. Swift Trigger 1232465: consistent with noise
  89. Konus-Wind detection of GRB 240529A
  90. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  91. GRB 240419B: Swift-BAT refined analysis
  92. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  93. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  94. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  95. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  96. Swift GRB 240419B: Global MASTER-Net observations report
  97. GRB 240414A: Swift-BAT refined analysis
  98. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  99. Fermi GRB 240408A: Global MASTER-Net observations report
  100. Konus-Wind detection of LXT 240402A/GRB 240402B

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