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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"

22059 results found.

  1. Konus-Wind detection of GRB 240529A
  2. GRB 240529A: SAO RAS optical observations
  3. GRB 240529A: optical photometry from Konkoly
  4. GRB 240529A: T193/MISTRAL observations
  5. GRB 240529A: AKO Optical Afterglow Detection
  6. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  7. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  8. GRB 240529A: J-band detections with WINTER
  9. GRB 240529A: Skynet Optical Observations
  10. LXT 240528A: LEIA detection of a fast X-ray transient
  11. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  12. GRB 240529A: Swift/UVOT Detection
  13. GRB 240529A: NOT optical observations
  14. GRB 240529A: GOTO optical afterglow detection
  15. GRB 240527B: Swift-XRT afterglow detection
  16. Swift GRB240529.12: Global MASTER-Net observations report
  17. Fermi GRB 240527A: Global MASTER-Net observations report
  18. LAT GRB240527.59: Global MASTER-Net observations report
  19. Fermi GRB 240527B: Global MASTER-Net observations report
  20. Fermi trigger No 738348224: Global MASTER-Net observations report
  21. Fermi trigger No 738330463: Global MASTER-Net observations report
  22. GRB 240513A: Swift-XRT afterglow detection
  23. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  24. Fermi trigger No 737996942: Global MASTER-Net observations report
  25. EP240518a: GSP optical upper limit
  26. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  29. GRB 240516A: Swift/UVOT Upper Limits
  30. Fermi trigger No 737788024: Global MASTER-Net observations report
  31. EP240518a: EP-WXT detection of a new X-ray transient
  32. Fermi GRB 240517A: Global MASTER-Net observations report
  33. GRB 240516A ATCA radio observations
  34. GRB 240513A: Swift ToO observations
  35. GRB 240514E: A possible candidate BD-21 1074
  36. Fermi trigger No 737559855: Global MASTER-Net observations report
  37. GRB 240511A: Observations from GTC/OSIRIS+
  38. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  39. Fermi trigger No 737523389: Global MASTER-Net observations report
  40. Swift GRB240516.15: Global MASTER-Net observations report
  41. Fermi trigger No 737476171: Global MASTER-Net observations report
  42. GRB 240511A: radio detection of afterglow candidate
  43. GRB 240514B: GOTO candidate optical counterpart
  44. MAXI GRB240514.78: Global MASTER-Net observations report
  45. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S240422ed: Las Cumbres Observatory Follow-up Observations of the Localization Region
  47. GRB 240513A: Swift-XRT observations
  48. Fermi GRB 240514B: Global MASTER-Net observations report
  49. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  50. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  53. GRB 240513A: Tiled Swift observations
  54. LAT GRB240513.31: Global MASTER-Net observations report
  55. Fermi GRB 240513B: Global MASTER-Net observations report
  56. Fermi trigger No 737277727: Global MASTER-Net observations report
  57. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  58. Fermi trigger No 737258655: Global MASTER-Net observations report
  59. GRB 240511A: J-band observations with WINTER
  60. Fermi trigger No 737247400: Global MASTER-Net observations report
  61. Fermi trigger No 737244199: Global MASTER-Net observations report
  62. Fermi trigger No 737218721: Global MASTER-Net observations report
  63. Fermi trigger No 737196587: Global MASTER-Net observations report
  64. Fermi trigger No 737168073: Global MASTER-Net observations report
  65. GRB 240511A: optical afterglow detection from the NOT
  66. Fermi trigger No 737173236: Global MASTER-Net observations report
  67. Fermi GRB 240511A: Global MASTER-Net observations report
  68. Swift GRB 240511A: Global MASTER-Net observations report
  69. Fermi trigger No 737105243: Global MASTER-Net observations report
  70. Fermi trigger No 737152719: Global MASTER-Net observations report
  71. Fermi trigger No 737102480: Global MASTER-Net observations report
  72. Fermi trigger No 737111207: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  74. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  75. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  76. Fermi trigger No 736967879: Global MASTER-Net observations report
  77. EP240506a: CrAO ZTSH optical upper limit
  78. EP240506a: Archival radio searching
  79. EP240506a: TRT optical upper limit
  80. Fermi trigger No 736733320: Global MASTER-Net observations report
  81. EP240506a: Optical upper limit with Kinder observations
  82. EP240506a: EP-WXT detection of a new fast X-ray transient
  83. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  84. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  85. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  86. Fermi trigger No 736564880: Global MASTER-Net observations report
  87. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  88. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  89. Fermi trigger No 736461232: Global MASTER-Net observations report
  90. Fermi GRB 240504A: Global MASTER-Net observations report
  91. Fermi trigger No 736472503: Global MASTER-Net observations report
  92. GW170817: VLA observations at ~5.5 yrs since merger
  93. Fermi trigger No 736387941: Global MASTER-Net observations report
  94. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  95. GRB 240502A: GOTO optical upper limit
  96. Fermi trigger No 736379109: Global MASTER-Net observations report
  97. GRB 240502C: GOTO possible optical counterpart candidates
  98. Fermi GRB 240502B: Global MASTER-Net observations report
  99. Fermi GRB 240502A: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates

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