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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"

22063 results found.

  1. Swift GRB 240904A: Global MASTER-Net observations report
  2. Fermi trigger No 747163821: Global MASTER-Net observations report
  3. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  4. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  5. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  6. GRB 240825A: MeerLICHT afterglow detection
  7. Fermi trigger No 746923430: Global MASTER-Net observations report
  8. GRB 240828A: SAO RAS AS-500(2) optical observations
  9. GRB 240821A: VLT spectroscopic observations
  10. Fermi trigger No 746882332: Global MASTER-Net observations report
  11. GRB240828B: REM optical/NIR upper limits
  12. Fermi trigger No 746816563: Global MASTER-Net observations report
  13. GRB 240825A: SOAR observations
  14. GRB 240828B: Mephisto optical upper limit
  15. GRB 240828B: GRANDMA Optical Upper Limit
  16. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  17. GRB 240825A: MeerKAT detection
  18. GRB 240828B: J-band upper limit from WINTER
  19. Fermi trigger No 746684112: Global MASTER-Net observations report
  20. GRB 240828A: KAIT continued optical observations
  21. GRB 240828A: SAO RAS optical observations
  22. Fermi trigger No 746587425: Global MASTER-Net observations report
  23. GRB 240828A: KAIT Optical Afterglow Candidate
  24. GRB 240825A: SVOM/VT optical detection
  25. GRB 240828A: Swift-XRT afterglow detection
  26. GRB 240825A: further SAO RAS optical observations
  27. GRB 240825A: iTelescope optical observations
  28. GRB 240828B: Swift-XRT afterglow detection
  29. Swift GRB240829.16: Global MASTER-Net observations report
  30. GRB 240828A: Tiled Swift observations
  31. LAT GRB240828.62: Global MASTER-Net observations report
  32. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  33. GRB 240819A as a likely X-Ray Flash
  34. GRB 240828B: Swift ToO observations
  35. GRB 240821A: PRIME near-infrared observations
  36. GRB 240825A: VLA detection
  37. Fermi GRB 240828A: Global MASTER-Net observations report
  38. Fermi trigger No 746438824: Global MASTER-Net observations report
  39. SVOM GRB 240821A: optical afterglow discovery
  40. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  41. GRB 240825A: ALMA detection
  42. GRB 240825A: SAO RAS optical observations
  43. GRB 240824A: GIT optical upper limit
  44. GRB 240825A: TNG optical photometry and spectroscopy
  45. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  46. GRB 240824B: Ondrejov D50 optical limit
  47. GRB 240825A: KAIT optical observations
  48. GRB 240825A: PRIME near-infrared detection
  49. Konus-Wind detection of GRB 240825A (bright/long)
  50. GRB 240825A: AKO Optical Follow-Up Observations
  51. GRB 240825A: Swift/UVOT Detection
  52. GRB 240825A: REM detection of the optical/NIR afterglow
  53. GRB 240825A: SVOM/C-GFT optical observations
  54. GRB 240825A: Montarrenti Observatory optical observations
  55. GRB 240825A: MASTER optical counterpart observation
  56. GRB 240825A: LCO optical observations
  57. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  58. Fermi GRB 240825A: Global MASTER-Net observations report
  59. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  60. GRB 240824B: NOT optical upper limit
  61. Swift GRB 240825A: Global MASTER-Net observations report
  62. GRB 240825A: 1.6m Mephisto multi-band detection
  63. GRB 240825A: Skynet Optical Afterglow observations
  64. GRB 240825A: Nanshan/HMT optical afterglow observations
  65. GRB 240824B: Swift-XRT afterglow detection
  66. GRB 240824A: Swift-XRT observations
  67. GRB 240824B: Swift/BAT arcminute localization of a burst
  68. GRB 240824B: Swift ToO observations
  69. Fermi GRB 240824C: Global MASTER-Net observations report
  70. GRB 240824A: Swift/UVOT Upper Limits
  71. GRB 240821A: Swift/UVOT observations of the XRT sources.
  72. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  73. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  74. GRB 240824A: KAIT optical upper limit
  75. GRB 240824A: Skynet Optical Afterglow Discovery
  76. Swift GRB240824.04: Global MASTER-Net observations report
  77. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  78. GRB 240821A: Colibri Optical Upper Limit
  79. EP240820a: PRIME J-band Observations
  80. GRB 240821A: Swift-XRT observations
  81. GRB 240821A: REM optical/NIR upper limits
  82. GRB 240821A: LCO optical observations
  83. GRB 240821A: JinShan optical upper limits
  84. GRB 240809A: Mondy and AbAO Optical Observations
  85. GRB 240821A: SVOM/VT follow-up and optical upper limit
  86. Fermi GRB 240821A: Global MASTER-Net observations report
  87. Fermi trigger No 745964969: Global MASTER-Net observations report
  88. Fermi trigger No 745925274: Global MASTER-Net observations report
  89. GRB 240821A: Swift ToO observations
  90. Fermi trigger No 746019401: Global MASTER-Net observations report
  91. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  92. Fermi trigger No 745935375: Global MASTER-Net observations report
  93. Fermi GRB 240821B: Global MASTER-Net observations report
  94. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  95. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  96. Fermi trigger No 745866488: Global MASTER-Net observations report
  97. GRB 240819A: Swift-XRT observations
  98. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  99. EP240820a: TRT optical upper limit
  100. EP240820a: EP detection of a fast X-ray transient

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