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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"

44399 results found.

  1. GRB 240825A: iTelescope optical observations
  2. GRB 240828B: Swift-XRT afterglow detection
  3. GRB 240829A: Swift detection of a burst
  4. Swift GRB240829.16: Global MASTER-Net observations report
  5. GRB 240828A: Fermi-LAT detection
  6. GRB 240828A: Tiled Swift observations
  7. LAT GRB240828.62: Global MASTER-Net observations report
  8. GRB 240828A: AstroSat CZTI detection of a long burst
  9. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  10. GRB 240825A: Upper limits from a neutrino search with IceCube
  11. GRB 240819A as a likely X-Ray Flash
  12. GRB 240828B: Swift ToO observations
  13. GRB 240821A: PRIME near-infrared observations
  14. GRB 240825A: VLA detection
  15. Fermi GRB 240828A: Global MASTER-Net observations report
  16. Fermi trigger No 746438824: Global MASTER-Net observations report
  17. SVOM GRB 240821A: optical afterglow discovery
  18. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  19. GRB 240828A: Fermi GBM Final Real-time Localization
  20. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  21. GRB 240825A: GECAM detection
  22. GRB 240825A: ALMA detection
  23. GRB 240825A: SAO RAS optical observations
  24. GRB 240824A: GIT optical upper limit
  25. GRB 240819A: Swift afterglow confirmation
  26. GRB 240825A: TNG optical photometry and spectroscopy
  27. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  28. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  29. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  30. GRB 240825A: GMG Continued Optical Observation on the Second Night
  31. GRB 240824B: Ondrejov D50 optical limit
  32. GRB 240825A: KAIT optical observations
  33. GRB 240825A: PRIME near-infrared detection
  34. Konus-Wind detection of GRB 240825A (bright/long)
  35. GRB 240825A: Fermi GBM Observation
  36. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  37. GRB 240825A: AKO Optical Follow-Up Observations
  38. GRB 240825A: AstroSat CZTI detection of the long bright burst
  39. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  40. GRB 240825A: Swift/UVOT Detection
  41. GRB 240825A: REM detection of the optical/NIR afterglow
  42. GRB 240825A: Swift-XRT refined Analysis
  43. GRB 240825A: VLT/X-shooter redshift
  44. GRB 240825A: SVOM/C-GFT optical observations
  45. GRB 240825A: Montarrenti Observatory optical observations
  46. GRB 240825A: Enhanced Swift-XRT position
  47. GRB 240825A: MASTER optical counterpart observation
  48. GRB 240825A: Fermi-LAT detection
  49. GRB 240825A: LCO optical observations
  50. GRB 240824B: KAIT optical upper limit
  51. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  52. GRB 240824B: Fermi GBM Observation
  53. Fermi GRB 240825A: Global MASTER-Net observations report
  54. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  55. GRB 240824B: NOT optical upper limit
  56. GRB 240825A: GMG Optical Observation
  57. Swift GRB 240825A: Global MASTER-Net observations report
  58. GRB 240825A: 1.6m Mephisto multi-band detection
  59. GRB 240825A: AKO Optical Afterglow Detection
  60. GRB 240825A: Skynet Optical Afterglow observations
  61. GRB 240825A: Nanshan/HMT optical afterglow observations
  62. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  63. GRB 240825A: Fermi GBM Final Real-time Localization
  64. GRB 240824A: Swift-BAT refined analysis
  65. GRB 240824A: SVOM/C-GFT optical upper limit
  66. GRB 240824B: Swift-XRT afterglow detection
  67. GRB 240824A: Swift-XRT observations
  68. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  69. GRB 240824B: Swift/BAT arcminute localization of a burst
  70. GRB 240824B: Swift ToO observations
  71. Fermi GRB 240824C: Global MASTER-Net observations report
  72. GRB 240824C: Fermi GBM Final Localization
  73. GRB 240824A: Swift/UVOT Upper Limits
  74. GRB 240821A: Swift/UVOT observations of the XRT sources.
  75. GRB 240824B: MAXI/GSC detection
  76. GRB 240824B: Fermi GBM Final Real-time Localization
  77. GRB 240824A: Retraction of GCN 37255
  78. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  79. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  80. GRB 240824A: KAIT optical upper limit
  81. GRB 240824A: Skynet Optical Afterglow Discovery
  82. GRB 240824A: Swift detection of a burst
  83. Swift GRB240824.04: Global MASTER-Net observations report
  84. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  85. GRB 240821A: Colibri Optical Upper Limit
  86. EP240820a: PRIME J-band Observations
  87. GRB 240821A: Swift-XRT observations
  88. GRB 240822A: AstroSat CZTI detection of a short burst
  89. GRB 240821A: REM optical/NIR upper limits
  90. GRB 240821A: LCO optical observations
  91. GRB 240821A: JinShan optical upper limits
  92. GRB 240809A: Mondy and AbAO Optical Observations
  93. GRB 240821A: SVOM/VT follow-up and optical upper limit
  94. GRB 240821A: GMG Optical Upper Limit
  95. Fermi GRB 240821A: Global MASTER-Net observations report
  96. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  97. GRB 240821A: Fermi GBM Observation
  98. Fermi trigger No 745964969: Global MASTER-Net observations report
  99. Fermi trigger No 745925274: Global MASTER-Net observations report
  100. GRB 240821A: Swift ToO observations

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