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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"

21114 results found.

  1. GRB 210802A: Further Swift/XRT observation and afterglow confirmation
  2. GRB 210807C: Swift/UVOT Upper Limits
  3. GRB 210807A: Swift/UVOT Detection
  4. GRB 210807A: correction to the GCN Circ. #30614 Assy optical observations
  5. GRB 210610B: Assy optical observations
  6. Swift GRB210807.74: Global MASTER-Net observations report
  7. Fermi GRB 210807C: Global MASTER-Net observations report
  8. Swift GRB210807.96: Global MASTER-Net observations report
  9. Fermi GRB 210807B: Global MASTER-Net observations report
  10. Swift GRB 210807A: Global MASTER-Net observations report
  11. Swift GRB210807.79: Global MASTER-Net observations report
  12. Swift GRB210807.78: Global MASTER-Net observations report
  13. Fermi trigger No 650046564: Global MASTER-Net observations report
  14. Fermi trigger No 649814537: Global MASTER-Net observations report
  15. Fermi trigger No 649684549: Global MASTER-Net observations report
  16. GRB 210802A: Swift-XRT afterglow detection
  17. GRB 210802A: Tiled Swift observations
  18. Fermi trigger No 649627691: Global MASTER-Net observations report
  19. GRB 210731A: continued GROND observations
  20. GRB 210731A: VLT/X-shooter redshift
  21. Fermi trigger No 649524889: Global MASTER-Net observations report
  22. Fermi trigger No 649519043: Global MASTER-Net observations report
  23. GRB 210731A: GROND observations
  24. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  25. Swift GRB210731.62: Global MASTER-Net observations report
  26. GRB 210731A: MeerLICHT optical afterglow detection
  27. Swift GRB210731.93: Global MASTER-Net observations report
  28. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  29. GRB 210730A: Campo Imperatore optical observations
  30. Swift GRB 210730A: Global MASTER-Net observations report
  31. Fermi trigger No 649390368: Global MASTER-Net observations report
  32. GRB 210730A: TNG optical observations
  33. GRB 210726A: Chandra detection of the X-ray afterglow
  34. Fermi trigger No 649313854: Global MASTER-Net observations report
  35. GRB 210730A: Swift/UVOT Upper Limits
  36. GRB 210726A: OSIRIS/GTC observations
  37. GRB 210726A: 6 GHz VLA radio upper limit
  38. GRB 210702A: MeerKAT radio detection
  39. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  40. Fermi trigger No 649072251: Global MASTER-Net observations report
  41. GRB 210725A: AbAO optical upper limit
  42. GRB 210724A: Swift/UVOT Upper Limits
  43. GRB 210723A: Swift/UVOT Upper Limits
  44. GRB 210725A: Swift/UVOT Upper Limits
  45. GRB 210725B: Swift/UVOT Upper Limits
  46. Swift GRB210726.80: Global MASTER-Net observations report
  47. Fermi trigger No 648959581: Global MASTER-Net observations report
  48. Swift GRB 210725B: Global MASTER-Net observations report
  49. GRB 210724A: Afterglow candidate from OSIRIS/GTC
  50. GRB 210722A: continued Assy optical observations
  51. GRB 210722A: Nanshan/NEXT further optical observations
  52. Fermi trigger No 648868114: Global MASTER-Net observations report
  53. Swift GRB210725.16: Global MASTER-Net observations report
  54. GRB210724A: MeerLICHT upper limits
  55. Swift GRB210724.84: Global MASTER-Net observations report
  56. GRB 210722A: continued Assy optical observations
  57. Swift GRB 210723A: Global MASTER-Net observations report
  58. GRB 210722A: Kitab optical observations, light curve
  59. GRB 210722A: Redshift from OSIRIS/GTC
  60. GRB 210722A: RATIR Optical Observations
  61. GRB 210722A: Swift/UVOT Detection
  62. GRB 210722A: GIT optical detection and preliminary analysis
  63. Swift GRB 210722A: Global MASTER-Net observations report
  64. GRB 210702A: ALMA detection of mm-band rebrightening
  65. GRB 210702A: ATCA detection of radio rebrightening
  66. GRB 210722A: Nanshan/NEXT optical afterglow observations
  67. Fermi trigger No 648602917: Global MASTER-Net observations report
  68. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  69. Fermi trigger No 648359752: Global MASTER-Net observations report
  70. Fermi trigger No 648278666: Global MASTER-Net observations report
  71. Fermi trigger No 647942198: MASTER optical afterglow detection
  72. GRB 210704A: Zeiss-1000/SAO-RAS optical observations
  73. Fermi trigger No 648033323: Global MASTER-Net observations report
  74. Fermi trigger No 648024201: Global MASTER-Net observations report
  75. Fermi trigger No 647942198: Global MASTER-Net observations report
  76. GRB 210712A: Swift/UVOT Upper Limits
  77. GRB 210712A: BOOTES-3/YA optical upper limit
  78. Fermi trigger No 647805873: Global MASTER-Net observations report
  79. GRB 210704A: Lowell Discovery Telescope Optical Observations
  80. Fermi trigger No 647775795: Global MASTER-Net observations report
  81. GRB 210704A: Continued Gemini-North NIR K-band Detections
  82. GRB 210704A: INTEGRAL observations
  83. GRB 210704A: NOT optical observations and color change
  84. GRB210704A: Gemini near-infrared upper limits
  85. Fermi trigger No 647653174: Global MASTER-Net observations report
  86. GRB 210704A: Assy optical afterglow upper limit
  87. Fermi trigger No 647641569: Global MASTER-Net observations report
  88. Fermi trigger No 647624281: Global MASTER-Net observations report
  89. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
  90. MAXI GRB210709.93: Global MASTER-Net observations report
  91. Fermi trigger No 647522278: Global MASTER-Net observations report
  92. GRB 210704A: Gemini-North Infrared Source Detection
  93. GRB 210704A: further TNG optical observations
  94. GRB 210706A: Swift/XRT afterglow confirmation
  95. Fermi GRB 210709A: Global MASTER-Net observations report
  96. Swift GRB 210708B: Global MASTER-Net observations report
  97. GRB 210708A: Swift/UVOT Upper Limits
  98. GRB 210702A: ATCA detection
  99. GRB 210702A: ALMA detection
  100. IceCube-210629A - Spectroscopic observation of AT2021osi

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